Conservation Reserve Program (CRP) Contributions to 

Wildlife Habitat, Management Issues, Challenges and 

Policy Choices—An Annotated Bibliography

Scientific Investigations Report 2012–5066

U.S. Department of the Interior

U.S. Geological Survey
Cover photos: Harvested Conservation Reserve Program field, Mark Vandever, U.S. Geological Survey; Northern bobwhite quail, Steve 

Maslowski, U.S. Fish and Wildlife Service; Blanketflower, Mark Vandever, U.S. Geological Survey; Monarch butterfly, 

Dr. Thomas G. Barnes, U.S. Fish and Wildlife Service.

Report body photos: All photos were taken by the authors unless otherwise indicated.
i

Conservation Reserve Program (CRP) 

Contributions to Wildlife Habitat, 

Management Issues, Challenges and Policy 

Choices—An Annotated Bibliography

By Arthur W. Allen and Mark W. Vandever

Scientific Investigations Report 2012–5066

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2012

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Suggested citation:

Allen, A.W., and Vandever, M.W., 2012, Conservation Reserve Program (CRP) contributions to wildlife habitat, 

management issues, challenges and policy choices—An annotated bibliography: U.S. Geological Survey Scientific 

Investigations Report 2012–5066, 185 p.
iii

Contents

Abstract...........................................................................................................................................................1

Foreword .........................................................................................................................................................1

Acknowledgments.........................................................................................................................................2

Agricultural Conservation Policy ...............................................................................................................2

Agricultural Ecosystems.............................................................................................................................23

Biomass, Energy...........................................................................................................................................37

Economics.....................................................................................................................................................44

Grassland Management ...........................................................................................................................52

Grazing, Haying, Mowing...................................................................................................................62

Pollinators, Invertebrates, and Miscellaneous Wildlife........................................................................66

Mammals.......................................................................................................................................................75

Non-Game Birds...........................................................................................................................................80

Reptiles and Amphibians..........................................................................................................................113

Soils..............................................................................................................................................................116

Surveys, Landowner Opinions, and Public Attitudes ..........................................................................120

Upland Game Birds....................................................................................................................................135

Northern Bobwhite Quail.................................................................................................................135

Prairie Grouse, Sage Grouse ..........................................................................................................141

Ring-Necked Pheasant....................................................................................................................145

Waterfowl and Shorebirds .......................................................................................................................153

Wetlands, Aquatic Ecosystems...............................................................................................................159

Buffers and Filter Strips...................................................................................................................171

Woodland Management...........................................................................................................................177

Relevant Books and Publications ...........................................................................................................183

Agricultural and Conservation Policy............................................................................................183

Wildlife Habitat .................................................................................................................................185
iv
Conservation Reserve Program (CRP) Contributions to 

Wildlife Habitat, Management Issues, Challenges and 

Policy Choices—An Annotated Bibliography

By Arthur W. Allen and Mark W. Vandever

Foreword

While reviewing newer studies and editing the original 

draft of this document some conclusions became obvious. 

Since the CRP was initiated in 1985, we have learned a 

great deal, but there is still a need to intertwine conservation 

and agriculture for the long term. The implications cited in 

this bibliography reach far beyond farms and watersheds, as 

all lands are working lands. Whether under the plow or CRP 

grass, they all are providing services and products. The millions of acres enrolled in the CRP, and smaller programs, have 

benefited wildlife of all kinds. If you have sustainable populations of targeted wildlife species, it’s likely other species of 

wildlife are there with them. You cannot furnish ideal habitat 

for all species on any particular unit of land at any given 

time. Vegetative characteristics change. Objectives must be 

clearly defined. Desired results are most often not immediate. 

Grasslands support more beneficial insects than pest species. 

Properly managed, permissive use of CRP grasslands generally benefits habitat quality over the long-term. The ecological 

costs of putting existing conservation lands into corn production for ethanol exceed the environmental benefits realized. 

Little attention has been directed toward identifying conservation benefits to aquatic habitats. Renters of agricultural lands 

tend to have less concern about the future of the land they are 

farming than those who own it. Collaboration between agencies and programs brings greater benefits. The public, including the farm community, values environmental health and food 

quality; they want to protect it. 

Generally, those enrolled in the CRP will be first to 

acknowledge improvement in the landscape, greater numbers and kinds of wildlife, cleaner water and air, less erosion, 

and satisfaction to see farmland serving better purposes. 

The question is: can landowners keep their sensitive lands in 

conservation programs? Can conservation be made desirable 

and affordable to those who need it? The majority of papers 

included here document benefits of long-term evaluation of 

farm-conservation policy. It is information those who create 

farm policy can see, understand, believe in, and act upon. 

Abstract

The following bibliography presents brief summaries of 

documents relevant to Conservation Reserve Program (CRP) 

relations to wildlife habitat, habitat management in agriculturally dominated landscapes, and conservation policies potentially affecting wildlife habitats in agricultural ecosystems. 

Because the literature summaries furnished provide only 

sweeping overviews, users are urged to obtain and evaluate those papers appearing useful to obtain a more complete 

understanding of study findings and their implications to 

conservation in agricultural ecosystems. 

The bibliography contains references to reports that reach 

beyond topics that directly relate to the CRP. Sections addressing grassland management and landowner surveys/opinions, 

for example, furnish information useful for enhancing development and administration of conservation policies affecting 

lands beyond those enrolled in conservation programs. Some 

sections of the bibliography (for example, agricultural conservation policy, economics, soils) are far from inclusive of all 

relevant material written on the subject. Hopefully, these sections will serve as fundamental introductions to related issues. 

In a few instances, references may be presented in more 

than one section of the bibliography. For example, individual 

papers specifically addressing both non-game and game birds 

are included in respective sections of the bibliography. Duplication of citations and associated notes has, however, been 

kept to a minimum. 

This bibliography is available online at http://pubs.usgs.

gov/sir/2012/5066/.
2 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

The CRP and other conservation programs are not about 

recreating what was, but what “can be”; they strive to ensure 

working lands provide products and profits with negligible 

long-term environmental impacts across the U.S. from field to 

sea. It can be done. It needs to be done.

Arthur W. Allen 

Wildlife Biologist, (Ret.)

Policy Analysis and Science Assistance Group

Fort Collins Science Center

Acknowledgments

This work was funded jointly by the USDA, Farm 

Service Agency Economic and Policy Analysis Staff and Fort 

Collins Science Center under the U.S. Geological Survey. The 

authors would like to thank Clay Ogg and David Hoge for 

reviewing earlier drafts of this document.

Agricultural Conservation Policy 

largely on information provided by state and federal biologists 

familiar with the program and local or regional issues.

Allen, A.W., 1994a, Regional and state perspectives on Conservation Reserve Program (CRP) Contributions to Wildlife 

Habitat: Fort Collins, Colo., U.S. Fish and Wildlife Service 

Federal Aid Report, National Biological Survey, National 

Ecology Research Center, 28 p.

A review of literature and information furnished largely 

by state and federal biologists on relations between the CRP 

and wildlife habitats within agricultural ecosystems. The 

report provides regional reviews of benefits and weaknesses 

of early CRP implementation. Discussions and comparison of 

needs by endemic grassland species and those more traditionally affiliated with agricultural land use are provided. Recommendations are presented addressing the need for elevated 

involvement of state wildlife agencies in technical assistance 

to U.S. Department of Agriculture (USDA) agencies and 

contractees, increased flexibility in conservation practices, 

and greater recognition of regional and local priorities in 

program implementation.

Allen, A.W., 1994b, Wildlife benefits of the Conservation 

Reserve Program—A national perspective, in When Conservation Reserve Program Contract Expire—The policy 

options, Washington, D.C., 1994, Proceedings of the Soil 

and Water Conservation Society Conference: Ankeny, Iowa, 

Soil and Water Conservation Society, p.18–20.

This paper is a brief summary of CRP benefits to game 

and non-game species. A discussion of limitations of the 

program and recommendations for increasing effectiveness 

of USDA conservation programs in enhancing habitat quality 

associated with agricultural ecosystems is presented.

Allen, A.W., and Vandever, M.W., eds., 2005, The Conservation Reserve Program— Planting for the future—Proceedings of a National Conference, Fort Collins, Colo., June 

6–9, 2004: U.S. Geological Survey Scientific Investigations 

Report 2005–5145, 248 p.

Twenty-nine papers supplemented with moderator 

comments and appendices furnish differing perspectives on 

social, economic, and ecological effects of the CRP. Opinions 

expressed range from stating that the CRP has caused the 

downfall of U.S. agriculture to stating that the program represents the best in integration of agricultural and environmental 

policies. The focus of the conference, however, was on refinement and future direction of the CRP, particularly in relation to 

16 million acres of contracts expiring in 2007 and 2008.

A wide range of stakeholders that includes USDA, Soil 

and Water Conservation Society, Ducks Unlimited, Pheasants 

Forever, Wildlife Management Institute, International Association of Fish and Wildlife Agencies, National Cattlemen’s Beef 

Allen, A.W., 1993, Wildlife habitat criteria in relation to 

future use of CRP lands, in Proceedings of the Great Plains 

Agricultural Council Annual Meeting, Rapid City, S. 

Dak., 2–5 June 1993, Proceedings: Washington D.C., U.S. 

Environmental Protection Agency, Great Plains Agricultural 

Council, p. 41–88

The report focuses on identification of strengths and 

weaknesses of the CRP as it developed and potential consequences on wildlife habitat if the CRP were terminated or 

reduced in scope. The report presents information on relations between the CRP, specific conservation practices, spatial 

considerations, planning, and management. The report centers 

on a discussion of the need to explicitly define CRP/wildlife 

objectives on regional and local scales. The report is based 
Agricultural Conservation Policy 3

Association, Farm Bureau, American Seed Trade Association, 

and the National Grain and Feed Association offer perspectives 

and recommendations for the future of the program. Reports 

on monitoring of USDA conservation programs and aspects of 

CRP effects and management options are presented by representatives from the U.S. Fish and Wildlife Service (USFWS), 

U.S. Geological Survey (USGS), USDA Natural Resources 

Conservation Service (NRCS), USDA Economic Research Service, Oklahoma State University, Mississippi State University, 

University of Illinois, Kansas Department of Wildlife and Parks, 

Colorado Division of Wildlife, and Environmental Defense. 

Allen, K., 1990, Reflections on the past, challenges for the 

future—An examination of U.S. agricultural policy goals, 

in Allen, K., ed., Agricultural policies in a new decade: 

Washington, D.C., Resources for the Future, p. 3–23

The development of agricultural policy has become a 

process of mutual accommodation with large numbers of narrow provisions being fitted together to become broad-based 

legislation which often contains inconsistencies and few clues 

to real goals of policy. Agricultural policy is forced to address 

many more issues than farm prices and incomes. Food, fiber, 

trade, environmental health, rural macroeconomic, and foreign 

policies have all become important constituents in formulation 

of agricultural policies. The primary objective of farm groups 

remains price/income support and market stability. Overall 

goals of agricultural policies have broadened in response 

to a political environment in which non-farm interests are 

becoming increasingly aware and recognize that agricultural 

programs are at least partially responsible for detrimental environmental effects.

Environmental interests will become increasingly important to the largely urban Congress. Demographic changes in 

population will continue to result in changes in consumers’ 

tastes and preferences. Concerns about chemical residues in 

foods and their injection into the environment are a major 

issue and will continue to be so. The public wants to support 

farmers but is increasingly disenchanted with subsidies that 

go mainly to the largest, wealthiest operators. Farming and 

agricultural service industries together contributed only about 

8 percent of the personal income in non-metropolitan areas in 

1986. Raising farm prices for select agricultural commodities 

is an inefficient way to promote rural economic activity. Economically diversified rural communities offer greater employment opportunities to farmers who wish to continue farming 

but have difficulties meeting financial commitments. Small, 

marginal changes can yield significant results in the long run. 

Long-term goals of agricultural policies should be promotion 

of a healthy, competitive agricultural sector and viable, diverse 

rural communities.

Berner, A.H., 1989, The 1985 Farm Act and its implications 

for wildlife, in 1988/1989 Audubon wildlife report: New 

York, N.Y., National Audubon Society, p. 437–465.

Over the last 50 years changes in land use and agricultural production have significantly affected wildlife inhabiting 

agricultural landscapes. Specialization and intensification of 

agricultural production are responsible for severe declines in 

distribution and quality of wildlife populations and their habitats. Federal commodity programs have contributed to much 

of the decline. Regulations have encouraged development of 

unsafe habitat by allowing late-seeding and early destruction 

of vegetative cover on retired acres during the nesting season.

The 1934 Cropland Adjustment Act was the first retirement program with the purpose of stabilizing the market 

and farm economy. Planting cover on retired acres was not 

required. The 1936 Agriculture Conservation Program created 

the Soil Conservation Service (SCS) and the Agricultural 

Stabilization Conservation Service (ASCS) and required farmers to plant grass or grass-legume cover on set-aside lands. 

The Soil Bank (1956–72) provided annual and multi-year 

set-aside (Conservation Reserve) programs with 3, 5, and 

10-year options. 

Due to the annual nature of these programs and wide 

variety of agricultural management practices, little guidance 

on appropriate management of retired lands was furnished 

or required. The option of more restrictive, beneficial management guidelines are left to state and county committees 

comprised of local farmers which has, too often, resulted in 

environmentally questionable management practices. Many 

committees allow late seeding of cover crops or require no 

cover, and permit or require destruction of established cover in 

the fall. 

Acreage reduction programs (ARP) pay farmers to 

annually idle land to reduce production of commodity crops. 

Regulations that once required reducing soil loss now require 

highly erodible croplands be farmed under an approved Soil 

Conservation plan that “substantially” reduces soil loss. The 

USDA predicts that crop surpluses will exist at least through 

2000. More than 20 million acres per year are expected to be 

retired in ARP annually. Because ARP agreements are annual, 

farmers are not willing to pay to seed perennial grass-legume 

cover crops. Agricultural Stabilization Conservation Service 

committees generally opt to maintain maximum flexibility in 

establishing cover requirement, crop seeding dates, and rates 

and dates of cover destruction; consequently, there are minimal natural-resource benefits. 

Pheasant populations have substantially increased when 

ARP acres are planted early to annual cover crops (typically 

small grains) and maintained to multi-year covers. Presently, 

however, ARP encourages practices proven to be detrimental 

to wildlife. Pheasant production in Minnesota averages 30 

percent lower in years with an ARP when compared to years 

without the program. Minor modifications in administration 

could increase the value of these lands to wildlife. Recommendations to reduce negative impacts include seeding to annual 

cover crop (small grains) and not disturbing these plantings for 

at least 90 days. In areas where winter cover may be critical, a 

portion of acres in ARP should be seeded to cover crop such as 

forage sorghum and left undisturbed throughout winter. Cover 
4 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

for three or more years would provide maximum benefits 

to wildlife.

Berner, A.H., 1984, Federal land retirement program—A land 

management albatross, in Transactions of North American 

Wildlife and Natural Resources Conference, 49, Boston, 

Mass., March 23–28, 1984, Proceedings: Washington, D.C., 

Wildlife Management Institute, p. 118–130.

The acreage-reduction portion of Soil Bank and Feed 

Grain Program did not require the seeding of grass-legumes on 

retired acres. This lack of seeding resulted in loss of wildlife 

habitats associated with agricultural ecosystems. Annual programs have emphasized administrative flexibility in commodity control to the detriment of soil and wildlife conservation. 

Most acres in these programs are fallow or disked by the end 

of July to the detriment of both game and non-game species. 

Agricultural Stabilization and Conservation Service regulations require most fields be planted late (after June 15) and 

covers destroyed by mowing, disking, or plowing before grain 

matures (usually mid July). Present land-retirement programs 

are narrow in scope and deal exclusively with controlling 

production of domestic commodities. Policies tend to encourage conversion of non-cropland to cropland even if those lands 

are highly erodible. Uncertainties of program structure across 

years make planning difficult; therefore, farmers tend to prepare all acres for planting— this exposes even retired acres to 

erosion. Recent annual land-retirement programs (1961–1983) 

have aggravated soil erosion and wildlife habitat problems 

and encouraged unwise use of land. Long-term retirement 

options, resulting in grass-legume stands, virtually eliminate 

soil erosion and provide secure wildlife covers associated with 

farmland landscapes.

Block, D.R., 1993, Absentee enrollment and land quality 

in Conservation Reserve Program, in Nellis, M.D., ed., 

Geographic Perspectives on the Social and Economic 

Restructuring of Rural Areas, Proceedings of the Commission on Changing Rural Systems, Manhattan, Kans., 4–6 

August, 1992: Manhattan, Kans., Kansas State University, 

p. 100–109.

The CRP has transferred several billion dollars to about 

one percent of the nation’s farmers. Much of the social benefit 

of the CRP is based on characteristics of lands enrolled in the 

program. The paper reports on comparison between enrollment patterns among absentee and local landowners in Rock 

and Brown Counties, Nebr. The author concludes among lands 

eligible for CRP enrollment (that is, center pivot irrigated 

land) that absentee land ownership was not a significant variable in predicting enrollment in the program. Mean erosion 

susceptibility of absentee-owned pivots is almost identical to 

that of locally owned pivots. This leads to the conclusion that 

absentee owners are not farming in a manner more detrimental 

than local landowners. Mean erosion susceptibility rankings 

enrolled by local and absentee owners were nearly identical. 

Brown, D.J., Spontak, D.M., Tibbets, M.N., Connolly, A.R., 

and Baccus, J.T., 2008, Enhancing the Farm Bill’s conservation potential through land prioritization: Journal of Wildlife 

Management, v. 73, no. 4, p. 620–625.

The report describes a Geographic Information System 

(GIS) method to prioritize land for inclusion in agricultural 

conservation programs. The procedure is based on identification of lands of high conservation value (HCV) using habitats 

of greatest conservation need. Priority zones are delineated 

around HCV lands to identify high and low priority working 

lands (land in agricultural production) for potential inclusion 

in conservation programs. The authors believe the method 

developed encompasses broad conservation goals, has high 

adaptive potential, is economically and socially feasible, and 

is potentially applicable throughout the United States. Alternatives for identification of HCV lands and development of GIS 

data layers are described. Methods for definition of working 

land priority zones are described—these may include home 

range size for wildlife species of concern, percentage of 

landscape in HCV lands, or creation of a 1-mile (mi) buffer (1.6 kilometers [km]) priority zone surrounding existing 

HCV lands. A strong argument for using the third option is the 

method could be used nationwide as the Public Land Survey system (36 mi2 townships and 1 mi2 sections) covers 75 

percent of the U.S. landscape and all of the farm belt states. 

Various options for information layers are described. 

Burger Jr., L.W., 2006, Creating wildlife habitat through 

federal farm programs—An objective-driven approach: 

Wildlife Society Bulletin, v. 34, no. 4, p. 994–999.

The author states USDA conservation programs have 

tremendous potential to affect wildlife habitats on private land 

and have contributed to sustaining some regional populations 

of wildlife. However, he argues that for Farm Bill programs to 

realize consistent long-term improvement in quality of habitat, 

planners must have a better understanding of species-specific 

habitat requirements and ecological processes. Wildlife biologists must also have a better understanding of the conservation programs, practices, and knowledge of landowner needs 

and eligibility requirements. Comprehensive planning at the 

farm scale is needed to optimize potential benefits to wildlife 

from conservation programs. Too often landowner selection 

of conservation practices is program driven; this results in less 

than optimum benefits to wildlife. Identification of landowner 

conservation objectives and their application at the farm scale 

is more likely to produce longer term benefits resulting in 

sustainable populations of wildlife. 

While many benefits of USDA conservation programs 

have been realized, the failure to optimize benefits is a function of how programs have been designed and delivered across 
Agricultural Conservation Policy 5

levels of organization from the Washington to county levels. 

Benefits to wildlife cannot be realized if goals are not programmatic or are not statutory objectives of conservation policies. Conservation programs may also fail to produce wildlife 

profits at regional and local levels due to state and local interpretation of programs rules and objectives. The quality and 

kind of technical assistance provided by county level USDA 

offices will have a strong influence on the future of wildlife 

populations in agriculturally dominated landscapes. 

Planners and policy makers must understand that the 

well-being of local populations of wildlife is influenced 

not only by local conditions and land use but also by the 

structure and composition of the landscape at larger spatial 

scales. Therefore, long-term conservation planning should be 

undertaken at watershed, region, and even continental scales. 

However, implementation of current farm bill programs and 

selection of conservation practices is program driven; landowners enroll in specific programs and in subsequent management practices often driven by requirements unique to that 

program. These management practices may or may not meet 

participant objectives as the practices are simply required by 

the program. The reasons for this include a lack of clearly 

defined conservation objectives, poor understanding of programmatic options available, poor understanding and excessive work burdens on local USDA staff providing guidance 

to operators, and brief, limited sign-up periods which tend to 

result in USDA staff recommending simplistic prescriptions 

using “canned” alternatives. Field office personnel may also 

lack technical knowledge necessary to formulate effective 

conservation plans. Creative solutions to delivery of conservation planning may require partnerships between USDA and 

non-governmental organizations such as Ducks Unlimited, 

Pheasants Forever, and others. State wildlife agencies need 

to pursue cooperative arrangements for assistance in resource 

planning to local USDA offices. 

Burger Jr., L.W., McKenzie, D., Thackston, R., and Demaso, 

S.J., 2006, The role of farm policy in achieving large-scale 

conservation—Bobwhite and buffers: Wildlife Society Bulletin, v. 34, no. 4, p. 986–993.

Payments to farm operators under USDA conservation 

programs far outweigh the collective investment of the North 

American Wetlands Conservation Act, Endangered Species 

Act, Pittman Robertson Act, and Conservation Investment act 

with potential to alter land use on large spatial scales. However, the past effectiveness of these programs has varied by 

program, practice, region, and wildlife species affected and 

effects have ranged from positive to negative. These programs 

can be more effective if explicit goals are identified as part of 

large-scale conservation initiatives such as the North American Waterfowl Plan and the Northern Bobwhite Conservation 

Initiative. While USDA conservation programs have been 

designed to achieve broad conservation objectives, available 

policy options often have not been designed to address specific 

wildlife goals identified in comprehensive, multi-agency 

regional and national initiatives. In the 1996 Farm Bill, 

wildlife was elevated to co-equal status with soil erosion and 

water quality, but wildlife still does not carry the weight of 

other objectives in relation to conservation compliance. An 

overview of how the CRP, specifically Conservation Practice 

33 (Habitat Buffers for Upland Birds), is being used to address 

specific goals and objectives to enhance habitat for these species is presented. 

The authors describe the Northern Bobwhite Conservation Initiative as a case study for refinement of USDA 

conservation programs to achieve specific wildlife goals. 

The goal is to restore range-wide populations to an average 

density equivalent to that which existed in 1980; this would 

require management on 32.8 million hectares (81 million 

acres) of farm, forest, and rangeland. Recommended management practices would change primary use on only 6 to7 

percent of this land. The underlying assumption upon which 

this initiative is based is that insufficient native herbaceous 

grasses and forbs, primary covers for nesting and brood 

habitat, limit bobwhite populations across the range of these 

grasses and forbs. Conservation buffers and field borders in 

uplands were identified as key practices that could achieve 

this goal in agricultural ecosystems. Conservation Practice 33 

was the first continuous CRP practice specifically designed 

to meet habitat and population goals under a national species 

recovery plan. It was also the first CRP practice to specifically require monitoring to determine population response. 

Habitat buffers are typically 30–120 feet (ft) wide and seeded 

with native warm-season grasses, legumes, and shrubs, or 

vegetated through natural succession. Contracts are 10 years 

in length and require periodic disturbance through disking, 

prescribed fire, or application of selective herbicides. In the 

first year 29,588 hectares (73,113 acres) were enrolled in 35 

states. CP33 will likely succeed because it addresses producer 

economic needs, provides multiple wildlife and environmental 

benefits, and is based on scientific goals identified in largescale conservation initiatives. 

Christensen, J., 2003, Auditing conservation in an age of 

accountability: Conservation in Practice, v. 4, no. 3, 

p. 12–19.

A discussion of need for monitoring and documentation of conservation program performance using the Nature 

Conservancy as an example of an agency using monitoring 

to enhance success in reaching program objectives. In addition to being fundamental for accountability, measuring and 

auditing can be essential in learning and improving program 

performance. The author suggests that investors in conservation organizations and the public in general will demand more 

accountability in program success, not only from NGOs but 

from government agencies as well. Interactive measures of 

program performance are suggested, but purposes of measures 

are to focus attention on the most important aspects of the program. Monitoring should be limited to a set of key measures 

to assist managers and investors in making better decisions. 
6 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Monitoring should be ongoing with a plan that communicates 

what is learned so data can be used for adapting strategies to 

improve program performance. 

Claassen, R., Hansen, L., Peters, M., Breneman, V., Weinberg, 

M., Cattaneo, A., Feather, P., Gadsby, D., Hellerstein, D., 

Hopkins, J., Johnson, P., Morehart, M., and Smith, M., 

2001, Agri-environmental policy at the crossroads—Guideposts on a changing landscape: Washington, D.C., USDA 

Economic Research Service, Agricultural Economic Report 

No. 794, 66 p.

Agricultural policies implemented over the last 20 years 

have played an important role in reduction of soil erosion, protection/restoration of wetlands, and creation of wildlife habitat. Emerging agri-environmental issues, evolution of farmincome policies, and limits imposed by trade agreements may 

point toward reformulation of agri-environmental policies. 

This report identifies types of policy tools available and design 

features that enhance effectiveness of current programs. Agrienvironmental payments are analyzed in depth as a potentially important tool for future policies. Agri-environmental 

payments to producers who achieve desirable environmental 

performance or use environmentally sound practices have 

been proposed but have been subject to only limited formal 

analysis. Such payments may be useful in addressing environmental issues and elevating farm income. In a multi-objective 

policy, there is considerable risk of conflict among objectives. 

Consistency between income support and environmental 

objectives has been enhanced through compliance mechanisms 

but continued coordination among all farm programs is needed 

to minimize contradictory or duplicative efforts.

Performance-based payments may be advantageous 

because only environmentally relevant actions are subsidized 

and producers have flexibility to select low-cost alternatives. 

One-size-fits-all solutions are unlikely to be successful as 

solutions to agro-environmental problems. Performance-based 

payments will focus activity on practices most effective in a 

given resource setting and reduce costs by allowing selection 

of least cost alternatives. These methods may involve high 

costs for planning and enforcement because farm or field specific plans must be devised. Incentives to expand crop production can undermine agro-environmental program performance. 

Payments for good performance, or practices, can encourage 

expansion of crop production onto previously uncropped 

areas, while the absence of a sodbuster-type provision can 

result in greater losses of uncropped land. 

Claassen, R., Breneman, V., Bucholtz, S., Cattaneo, A., 

Johansson, R., and Morehart, M., 2004, Environmental 

compliance in U.S. agricultural policy—Past performance 

and future potential: Washington, D.C., USDA Economic 

Research Service, Agricultural Economic Report No. 832, 

50 p.

This article is a discussion of compliance incentive characteristics and potential for expanding compliance approach 

to address nutrient runoff from crop production. Farm commodity programs in the 1970s and early 1980s probably 

encouraged crop production on sensitive lands increasing 

environmental damage associated with agricultural production. 

Since 1985, U.S. agricultural producers have been required to 

practice soil erosion conservation practices on highly erodible 

cropland and to preserve wetlands as a condition of farm program eligibility. Compliance provisions link farm payments 

with environmental objectives by requiring farmers in selected 

Federal agricultural programs (for example, price support 

loans, income support payments) to implement soil conservation systems to remain eligible for participation. Soil erosion 

rates have been reduced on lands subject to compliance as 

well as on land not subject to compliance. About 25 percent of 

erosion reduction was attributed to Conservation Compliance. 

Compliance incentives have probably deterred conversion of 

highly erodible noncropped land and wetlands to production. 

Annual rate of soil erosion on U.S. cropland estimated to have 

declined by nearly 40 percent between 1982 and 1997. About 

one quarter of the decline can be attributed to compliance provisions. Nearly 90 percent of erosion reduction between 1982 

and 1987 occurred on farms receiving government program 

payments. Other factors that include technology, information, 

and markets also had an important influence on triggering 

reduction in rates of erosion. Compliance may have been a 

factor in wider adoption of farming practices (for example, 

conservation tillage) that may reduce erosion. 

Authors suggest compliance may be a better alternative 

to using conservation payments to protect lands because compliance sanctions are activated only when a violation occurs. 

Authors believe that, under favorable market conditions, from 

7 to 14 million acres of highly erodible land or wetlands could 

be converted to production. Compliance incentives may discourage producers from expanding crop production onto these 

lands. Compliance mechanisms are believed less likely than 

subsidies to produce unintended outcomes and may be particularly effective when subsidy programs are difficult or expensive to use. The majority of cropland with high potential for 

wind erosion and nutrient runoff problems is located on farms 

in government payment programs. Existing government payment programs have potential to affect a broader set of agricultural conservation issues but will be effective only where 

payments exceed the cost of required conservation actions. 

Council for Agricultural Science and Technology, 1990, 

Ecological impacts of federal Conservation and Cropland 

Reduction Programs: Ames, Iowa, Task Force Report No. 

117, 28 p.

Overproduction in agriculture first became a major problem following WWI. Food and fiber were produced for the 

war effort, but markets diminished following the end of war. 

This pattern was repeated following WWII. World demand 

is a major factor influencing domestic production and prices. 
Agricultural Conservation Policy 7

Overproduction of commodities also is due to increases in 

technology and productivity per acre. Between 1930 and 1980, 

farm production rose by almost 150 percent. If CRP reaches 

its goal of 45 million acres, the reduction in soil erosion is 

estimated to be 850 million tons per year. Other CRP benefits 

are cited as reduction in soil erosion, improved ground and 

surface-water quality, reduction in nitrate and pesticide use, 

and decrease in commodity surpluses. Ideas are presented to 

lessen negative effects of ARP, to extend the period a field 

may be idled from 1 to 3–5 years, to not permit the fallowing 

of fields that do not furnish vegetative cover, require ASCS to 

consider wildlife when setting rules for seeding and destruction of cover, and include natural resource professionals on 

ASCS committees.

Dahlberg, K.A., 1992, The conservation of biological diversity and U.S. agriculture—Goals, institutions, and policies: Agriculture, Ecosystems and Environment, v. 42, 

p. 177–193.

The modernization and transformation of agriculture over 

the past several decades has led to increasing genetic depletion of farm habitats and rural landscapes. Ways to modify 

policies to enhance diversity in agricultural landscapes include 

making changes in current set-aside policies, credit programs, 

and rangeland management practices. Water and energy should 

receive priority, but aesthetic values and diversity of rural 

landscapes should also be considered in design of agricultural 

policies. The overarching goal should be to achieve a more 

diversified lower-input agricultural system. 

Agricultural practices and efforts in conservation biology affect each other. American agriculture has gone from 

small-scale, diversified production based on local marketing 

systems dependent largely upon human and animal labor to 

large scale monoculture systems dependent on cheap energy 

and large markets. The size of rural populations and number of 

farm and farmers in the U.S. population continues to decline. 

Pressures to expand production have led to more monocultural 

production and the elimination of habitat for wildlife and pest 

predators through simplification of the agricultural landscape. 

These changes have generally also resulted in an increase in 

soil erosion and groundwater pollution. An important part 

of seeking new policy direction will be to educate the public 

regarding the value and importance of rebuilding a strong, 

diverse rural America. 

Davidson, J.H., 2003, The Federal Farm Bill and the environment: Natural Resources & Environment, v. 18, no. 1, 

p. 3–5, 36–39.

The article furnishes a review of the evolution of farm 

policy with an emphasis on development of environmental 

programs. The article’s critical review of USDA environmental programs administered under the Farm Bill(s) concludes 

that most programs are ineffective in realizing sustainable 

natural resource management and agricultural production 

because they contribute to pollution and resource degradation. 

Although well intended, farm policy and environmental programs (CRP and Environmental Quality Incentives Program 

(EQIP) in particular) suffer from their temporary nature, continued focus of benefits to the largest operations, and apparent 

signals to farmers to intensify production on existing fields or 

bring new fields into production. The failure to protect family 

farms is identified as perhaps the biggest failure of current 

farm policy. The economic effect of USDA farm policy continues to enhance the capacity of larger farms to absorb smaller 

operations. The conclusion is also drawn that farm programs 

fail to encourage production methods most consistent with a 

healthy environment. The Farm Bills have failed to reverse 

long-term declines in farm jobs, off-farm jobs, and the general 

quality of rural life. The temporary nature of most environmental programs is seen as a major risk and limitation to these 

programs’ long-term effectiveness in addressing environmental quality and the impacts of agricultural production. 

Although critical, the article concludes that environmental programs administered under the farm bills have been 

a good start in addressing environmental issues born from 

agriculture. Farm price and income supports must be decoupled from the amount of grain or other commodity produced. 

Financial support for agriculturalists should be based not just 

on commodities but to all crops produced with an emphasis 

on crops that generate conservation benefits such as a return to 

more diverse and healthy rotation of crops and greater use of 

grasslands. The author also recommends all farm operations 

should be required to demonstrate compliance with a wholefarm conservation plan to be eligible for income support. The 

Conservation Security Program (CSP) is identified as having 

the greatest potential for environmental benefits and being the 

sharpest deviation from the precedent set by other farm bill 

environmental programs and may become the foundation for 

future farm support legislation. 

Dimitri, C., Effland, A., and Conklin, N., 2005, The 20th 

century transformation of U.S. agriculture and farm policy: 

Washington D.C., U.S. Department of Agriculture, Economic Research Service, Economic Information Bulletin 

No. 3, 28 p.

The article provides an analysis of historical data on farm 

structure and developments in farm policy on farmers and 

the U.S. economy. American agriculture and rural life have 

undergone substantial transformation in the 20th century. The 

agricultural sector of the 21st century is concentrated on a 

small number of large, specialized farms in rural areas where 

less than 25 percent of the U.S. population now lives. Production agriculture has become a smaller player in the national 

and rural economies. While farming-dependent counties once 

comprised most of the rural economy, only 20 percent of nonmetro counties were considered farming-dependent in 2000. 

Since 1900, the number of farms has declined by 63 percent, 

while farm size has increased by 67 percent. Farm families 
8 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

have had both incentive and opportunity to seek off-farm 

work, which has made rural areas increasingly attractive to 

non-farm industries. Growing public interest in food safety 

and environmental quality has expanded markets for specialized products and influenced agricultural environmental 

policy. American agriculture has increasingly become part of 

a global market, with at times, volatile effects on the farming 

economy. Farm price and income-support programs have been 

the core of U.S. agricultural policy since 1933. These programs have been adjusted in response to economic, political, 

and social pressures. Authors conclude that the extent to which 

farm policy meets contemporary objectives for maintaining 

the well-being of farm households and improving the agricultural economy remains a matter for debate.

Doering, O., 1992, Federal policies and incentives or disincentives to ecologically sustainable agricultural systems, in

Olson, R.K., ed., Integrating sustainable agriculture, ecology and environmental policy: Binghamton, N.Y., Haworth 

Press Inc., p. 21–36.

Sustainable agriculture involves less use of off-farm 

inputs while introducing new management and cropping systems that make better use of on-farm resources. Until recently, 

federal farm policies have not been concerned with environmental issues but reflected goals of increased farm income 

and low cost food for the nation. Federal policies had other 

goals, such as improving rural conditions, increasing rural 

income, improving farming operations, and conserving natural 

resources as part of the base of agricultural productivity. At 

times these policies have been in conflict. Future policies must 

be concerned with the environmental impact of agriculture. 

Five-year average data on amount of increase in input 

prices (1950–1985): land 710 percent, pesticides 45 percent, 

fertilizer 88 percent, labor 387 percent, fuel 372 percent, and 

machinery 921 percent. Increase in quantities of farm inputs 

1950–1987: fertilizers and pesticides 426 percent, pounds 

per acre (lb/ac) nitrogen (N) 950 percent, and phosphate 136 

percent. Labor decreased 71 percent.

Government commodity programs in the past have 

rewarded farmers for producing the primary commercial food 

and feed grain crops and have encouraged farmers towards 

monocultures. Since World War II, fertilizers and pesticides 

have become comparatively cheaper compared to labor, fuel, 

and machinery encouraging greater use. The CRP has reduced 

environmental problems, but the program does not address 

sustainability or environmental concerns relative to acres 

remaining in production and the long-term use of CRP acres. 

What is required is a much more strongly held view by the 

general public that they have interest in long-term decisions 

about land use and resources.

Dunn, C.P., Stearns, F., Guntenspergen, G.R., and Sharpe, 

D.M., 1993, Ecological benefits of the Conservation 

Reserve Program: Conservation Biology, v. 7, no. 1, 

p. 132–139.

An overview of unintentional, yet significant, ecological 

benefits of CRP that include: reversal of landscape fragmentation, maintenance of regional biodiversity, increased habitat 

for wildlife, and regional changes in carbon (C) flux. The 

authors believe overall program costs would be more than 

offset by benefits from: increased net farm income, soil productivity improvements, enhanced water quality, and revenue 

from recreational activities if these benefits could be accurately documented. Dollar benefits derived from program are 

difficult precisely quantify. Other ecologically desirable benefits include: reduced sedimentation in lakes, rivers, streams; 

reduced non-point source agricultural runoff, improved water 

quality, and retention and development of wildlife habitat. 

Documenting the economic and social benefits should be completed in order to maintain and improve the program studies.

General Accounting Office, 2002, Agricultural Conservation—

State advisory committees’ views on how USDA programs 

could better address environmental concerns: Washington, 

D.C., U.S. General Accounting Office, 76 p.

Based on input from state conservation committee 

members, sixty-two percent of respondents indicated loss 

of wildlife habitat on farms and ranches was a moderate or 

major concern. Over half believed that loss of native species 

was of moderate or major concern. Almost 50 percent felt 

that CRP was from very to extremely effective in addressing 

state environmental and resource concerns. Nearly 53 percent 

felt CRP was from very to extremely effective in protecting 

or improving wildlife habitat. Over 35 percent felt there was 

enough NRCS technical assistance to meet program needs 

while 58 percent felt there was less than enough assistance 

provided than needed. Fifty-eight percent of respondents felt 

CRP had somewhat or very positive effects on economy of 

rural communities. Nearly 20 percent of respondents believed 

CRP had negative effects on local economies. Fifty percent 

felt that CRP needs more emphasis in protecting or improving 

wildlife habitat. 

General Accounting Office, 2003, Agricultural Conservation—

USDA needs to better ensure protection of highly erodible 

cropland and wetlands: Washington, D.C., Committee on 

Agriculture, Nutrition, and Forestry, U.S. Senate, U.S. General Accounting Office, GAO–03–418, 106 p. 

Investigation reveals that NRCS has not consistently 

implemented conservation provisions of the 1985 Food Security Act. The result is an increase in the possibility that some 

farmers continue to receive federal payments while their soil 

continues to erode at rates higher than permissible or that they 

convert wetlands to cropland. A nationwide survey reveals that 

almost 50 percent of NRCS field offices do not implement/

enforce conservation provisions as required because they lack 
Agricultural Conservation Policy 9

sufficient staff, recommended management does not emphasize conservation provisions, or staff are uncomfortable with 

enforcement role. Field offices consistently did not check on 

enforcement, see if recommended problems were corrected, 

or enforce wetland violations. Weak oversight of field offices 

impairs implementation of conservation provisions. Also, 

NRCS disproportionately emphasized tracts with little erosion 

potential (for example, rangeland, pasture) and noncompliance 

leading to inflated compliance rates. The General Accounting 

Office (GAO) concluded that NRCS field offices could not 

conduct timely reviews during critical erosion periods or furnish higher administrative levels with up-to-date information. 

The Farm Service Agency (FSA) was found to often waive 

noncompliance determinations without adequate justification. 

The resulting GAO recommendations were to: increase level 

of oversight of field offices on compliance reviews to improve 

accuracy and completeness, conduct compliance reviews on 

more representative tracts of land, develop and implement 

automated data system for reviews, and insure that FSA supports noncompliance issues and withholds benefits to operators in violation of conservation guidelines and provisions.

Government Accountability Office, 2006, Conservation 

Security Program—Despite cost controls, improved USDA 

management is needed to ensure proper payments and 

reduce duplication with other programs: Washington D.C., 

Committee on Appropriations, U.S. Senate, U.S. Government Accountability Office, GAO–06–312, 96 p.

The report investigates rising costs associated with 

implementation of the CSP. The primary factor leading to rising costs was identified as the availability of little information 

on how the program would be implemented at time of inception in 2002; this resulted in conservative estimates of costs. 

Estimates of participation level, number of acres enrolled, and 

amount and types of payments made were underestimated. As 

details became clear costs rose. Government Accountability 

Office concludes that costs could be brought under control by 

addressing weaknesses in internal controls and inconsistencies 

in the wildlife habitat criteria used by state offices to determine eligibility for the highest CSP payment level. 

NRCS cost-control efforts may be undermined by inconsistencies in the wildlife-habitat-assessment criteria used by 

state offices for determination of the highest tier of payments. 

Evaluation criteria were variable—this contributed to differences in Tier III participation and payments among watersheds. Some state offices developed and applied criteria for 

fiscal year 2005 that were inconsistent with national guidance. 

These discrepancies diminished NRCS’ ability to ensure that 

CSP is achieving intended wildlife habitat objectives. As of 

February 2006, NRCS had not reviewed their wildlife habitat 

assessment criteria and did not have plans to do so. 

To improve implementation of the CSP, GAO recommends the NRCS should review and field check 

wildlife-habitat-assessment criteria used in each state office 

to ensure consistency. In addition, it was recommended that 

NRCS develop an automated system to minimize or prevent 

duplication of payments and a process to review existing CSP 

contracts to ensure duplicate payments are not made. 

Government Accountability Office, 2006, Agricultural 

conservation—USDA should improve its management of 

key conservation programs to ensure payments promote 

environmental goals: Washington, D.C., Testimony before 

the Committee on Agriculture, Nutrition, and Forestry, U.S. 

Senate, GAO–07–370T, 11 p.

Farmers and ranchers own about 940 million acres 

(about half the area of the United States); therefore, they 

are among the most important stewards of the nation’s soil, 

water, and wildlife resources. This GAO report describes 

weaknesses in NRCS management of the EQIP and CSP. 

The GAO determined the NRCS process for providing EQIP 

funds to states was not clearly aligned to the program purpose 

of optimizing environmental benefits and may not be directing funds to states with the most significant environmental 

issues. NRCS does not have a viable plan to link long-term, 

outcome-oriented performance measures to the funding 

allocation process. NRCS did not have a process to prevent, 

or identify, when duplicate payments were made to operators 

under different programs. The GAO recommends that NRCS 

ensures factors and weights used in EQIP financial formulas 

are documented and linked to program priorities, continue 

monitoring of performance measures to refine financial 

assistance formulas, and develop a comprehensive process 

to identify and prevent duplicate payments between CSP and 

other conservation programs. 

Gersmehl, P.J. and Brown, D.A., 2004, The Conservation 

Reserve Program—A solution to the problem of agricultural production?, in Janelle, D.G., Warf, B., and Hansen, 

K., eds., Worldminds— Geographical Perspectives on 100 

Problems: Boston, Mass., Kluwer Academic Publishers, 

p. 381–386.

The report furnishes a critical look at the 1985 Farm 

Bill, the CRP, and the issue of slippage. Authors are critical 

of environmental study results attributing benefits to the CRP 

because only few spatially isolated studies have been used 

to derive benefits on larger scales. Authors believe scaled-up 

fallacies have given an artificial assessment of environmental 

benefits derived from the CRP. The authors state the CRP 

on the Great Plains is a “well-regarded failure” because the 

favorable effects of the program are offset by the widespread 

creation of new cropland during the same time periods of high 

enrollment. The authors estimate a slippage increase of nearly 

4 million hectares of new cropland in between 1992 and 1997
10 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

when CRP acreage in 15 Great Plains states increased to 9.5 

million acres. In absence of data to the contrary, the authors 

believe new lands would be at least as erosion prone and 

would potentially offer poor habitat for wildlife. The abundance of geographically suspect field-scale studies has overwhelmed other opinions resulting in the Federal government 

to expand the CRP to control “food surpluses.” A multi-scale 

approach is required to correctly expand field level studies 

to larger scales. Authors believe policy makers will have to 

recognize that a change in farm-scale incentives and policies 

is essential to finding solutions on a national scale. 

Goodwin, B.K. and Smith, V.H., 2003, An ex post evaluation 

of the Conservation Reserve, Federal Crop Insurance, and 

other government programs—Program participation and 

soil erosion: Journal of Agricultural and Resource Economics, v. 28, no. 2, p. 201–216.

For the most part, policy makers and evaluations of 

federal farm programs have given little attention to interactions between various programs potentially affecting erosion 

of soils. Effective design of federal agricultural policies must 

take into consideration interdependence of farm programs 

and the overall attainment of soil erosion goals. This study 

concludes that the CRP significantly reduced erosion in 

areas where farmers participated. However, the analysis also 

reveals that federal crop insurance and disaster relief programs have had little impact on rates of soil erosion. Incomesupport programs have encouraged production on other lands 

more susceptible to soil erosion. Estimates are CRP has 

significantly reduced annual soil loss by an average of about 

1.02 tons per acre (tons/ac). At the same time, increases in 

proportion of farm revenues resulting from federal payments 

between 1982 and 1992 were estimated to have increased 

erosion by about 0.55 tons/ac. 

Gray, R.L., and Teels, B.M., 2006, Wildlife and fish conservation through the Farm Bill: Wildlife Society Bulletin, 

v. 34, no. 4, p. 906–912.

Authors provide a synopsis of the history of Farm Bill 

contributions to wildlife habitats and conservation since the 

1985 Bill and creation of the CRP and other conservation 

programs. Descriptions and benefits of key programs: CRP, 

Wetlands Reserve Program (WRP), Wildlife Habitat Incentives Program (WHIP), EQIP, Grassland Reserve Program, 

and CSP are provided, as well as descriptions of Swampbuster and the Conservation Effects Assessment Project 

(CEAP). Authors describe the importance of these programs 

in meeting environmental and fish and wildlife conservation 

goals associated with the 70 percent of the U.S. land base 

held in private ownership. 

Gregory, S., Allen, A.W., Baker, M., Boyer, K., Dillaha, 

T., and Elliott, J., 2007, Realistic expectations of timing 

between conservation and restoration actions and ecological 

responses, in Schnepf, M., and Cox, C., eds., Managing agricultural landscapes for environmental quality—Strengthening the science base: Ankeny, Iowa, Soil and Water Conservation Society, p. 115–146.

How many months, years, decades, or lifetimes must 

we wait to see consequential evidence of conservation success? The needs and costs of conservation and restoration are 

constantly debated, sometimes with information. Frequently 

missing from deliberations are realistic estimates of the time 

required before desired environmental outcomes are realized. 

Often expectations about timing and effectiveness are unrealistically short. The objectives of this paper are to present 

information relative to timeframes over which conservation 

and restoration outcomes in agriculturally dominated landscapes are likely to be realized, definitions of success, and 

how conservation policies can be designed and evaluated to 

yield reasonable measures of effectiveness. The report presents 

examples of restoration and conservation issues in agricultural 

systems related to water temperature, water chemistry, pollutants and waste, aquatic communities, and terrestrial wildlife. 

Conservation and restoration are closely related but 

discrete processes. Dissimilarity between these concepts has 

enormous consequences in how the success of an ecological 

response is defined. Conservation attempts to maintain functional and ecological ecosystem components to sustain existing 

resources. Ideally, conservation maintains performance of the 

existing system. Restoration is an attempt to repair ecosystem 

processes to reestablish functions that have been diminished 

or eliminated. Exact restoration may take decades, or longer, to see meaningful response. Desired outcomes generally 

arrive more quickly under conservation objectives. Monitoring 

designs are intricate and expensive because they must measure 

ecologically complex processes, often over an extended period 

of time. 

The purpose of USDA conservation programs is not to 

restore ecosystems but to lessen undesirable environmental 

effects of agricultural production. Wildlife response to the CRP, 

and other conservation programs, has been geographically 

and ecologically far-reaching. Terrestrial wildlife response to 

conservation practices closely follows establishment and physical characteristics of vegetation planted. Wildlife response in 

terms of number and types of species will vary as vegetation 

characteristics change through time. Consequently, measurement objectives must be clearly defined. Evidence shows 

wildlife species have prospered where conservation practices 

have been designed to address regionally prevalent erosion 

issues. For example, whole field CRP enrollments planted to 

grasses in western states have decreased wind erosion and 

benefited grassland wildlife that are dependent on an extensive 

area of suitable habitat. In wetter regions, grass filter strips, 

riparian buffers, and field borders have diminished rates of soil 
Agricultural Conservation Policy 11

erosion while benefiting wildlife adapted to higher levels of 

habitat interspersion. 

Restoration of aquatic habitats is difficult to evaluate 

because effects can be influenced by physical, biological, and 

chemical factors on multiple spatial scales, from small site to 

inputs from the entire watershed. Conservation practices in a 

watershed will differentially influence the depth and timing 

of responses of physical habitats and aquatic species. Consequently, correlations between a specific practice and ecological 

responses are difficult to obtain. The maintenance connectivity 

of wetlands in a watershed, restoration of riparian vegetation, 

removal of obstacles, and placement of instream structure have 

been shown beneficial to aquatic species. Species affected and 

times of response to these practices can be variable through 

time and the watershed requiring judicial definition of success 

for conservation practices and policies. Farm policy, political 

administrations, landowner dynamics, and agency personnel 

could change many times before a watershed demonstrates 

true recovery. 

Measurable responses to long-term restoration and 

conservation programs are challenging to evaluate and report. 

A lack of evaluations, particularly for aquatic responses, is a 

consequence of the continually limited funding amount that 

is dedicated to assessment and represents a failure by those 

who formulate farm conservation policies to recognize the 

importance of monitoring to improve program performance. 

Unfortunately, often this lack of data on measurable, economic 

response has been incentive to further limit funding. Successful 

conservation policies can be supported only when their effectiveness in known. To gain such knowledge requires a commitment to gather immediate as well as long-term data. Time 

frames of conservation and restoration must be clearly defined 

for policy makers to understand that results may not be immediate. Practical timeframes for conservation policy to become 

effective must be taken into account in policy design.

Hansen, L., 2007, Conservation Reserve Program—Environmental benefits update: Agricultural and Resource Economics Review, v. 36, no. 2, p. 1–14.

Long-term retirement of cropland under the CRP has 

furnished scores of environmental benefits. Over time, environmental goals have become leading objectives of the program. 

This article presents an attempt to quantify some of the benefits 

of the program on a regional and national basis. Supporting 

methodology and assumptions of the analysis are presented. 

Based only on wildlife viewing and hunting for ring-necked 

pheasants (Phasianus colchicus), the authors estimate wildliferelated benefits of the CRP are approximately $737 million per 

year (million/yr). The value of improved hunting of pheasants 

is about $87 million/yr, 12 percent of the total benefits. The 

sum of the CRP’s total benefits is estimated at $1.32 billion 

per year (billion/yr). Conservation Reserve Program benefits 

in the Corn Belt are nearly twice those of the Southern Plains. 

The Corn Belt, Lake, and Southern plains regions hold about 

35 percent of all CRP acreage and account for over 60 percent 

of environmental benefits. In contrast, Mountain and Northern 

Plains regions have 45 percent of the CRP area but account for 

only 12 percent of estimated benefits. Authors conclude that 

the estimated environmental benefits compensate for 75–85 

percent of CRP costs. This is a conservative estimate because 

not all environmental benefits borne from the CRP have been 

included in this analysis. Many benefits remain unquantifiable 

and unknown. The authors conclude there is strong evidence 

the environmental benefits of the CRP exceed the costs of the 

program. In addition, they state that any assessment of the 

CRP should recognize the program brings additional economic 

benefits through favorable effects on other farm programs.

Hays, R.L., and Farmer, A.H., 1990, Effects of the CRP on 

wildlife habitat—Emergency haying in the Midwest and 

pine plantings in the southeast, in Transactions of North 

American Wildlife and Natural Resources Conference, 55, 

Denver, Colo., March 16–21, 1990, Proceedings: Washington, D.C., Wildlife Management Institute, p. 30–39. 

A multi-state evaluation of emergency haying of CRP in 

1988 documents impacts on the quality of habitat furnished by 

the program. Although a relatively small percentage of CRP 

fields (less than 20 percent) were hayed in 1986/1987, haying 

in many cases exceeded legal limits of percentage of field 

eligible for haying. Mowing for weed control was generally 

extensive in CRP fields with 82 percent of sampled fields having more than 75 percent of field area mowed. Fifty-five percent of these fields had been mowed entirely. It was estimated 

that about one-third of hay was cut during the period when 

about half of avian nests were still being incubated. Authors 

conclude emergency use probably had significant negative 

impacts on availability and quality of habitat in CRP. 

Hays, R.L. Webb, R. P., and Farmer, A.H., 1989, Effects of the 

Conservation Reserve Program on wildlife habitat—Results 

of 1988 monitoring, in Transactions of North American 

Wildlife and Natural Resources Conference, 54, Washington, D.C., March 17–22, 1989, Proceedings: Washington, 

D.C., Wildlife Management Institute, p. 365–376. 

Results of a multi-state evaluation of CRP contributions to wildlife habitat are discussed. The highest amount 

of persistent vegetation cover was recorded in CP2 (warm 

season grasses) fields. The highest pre-greenup average visual 

obstruction reading (VOR) was in CP2. Percentage of herbaceous cover made up of grasses was not different between 

CP1 (introduced grasses) or CP2 conservation practices. 

Ring-necked pheasants (Phasianus colchicus) may be more 

limited by winter food and cover than by nesting cover near 

some CRP fields. The planting of woody vegetation and food 

plots should be encouraged. CRP appears to be providing 

good nesting habitat for pheasants and fair nesting habitat for 

meadowlarks (Sturnella spp.). Improvement in habitat quality 

for cottontail rabbits (Sylvilagus floridanus) was not detected. 
12 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Winter cover values appear to be greater on CP2 than within 

CP1. Unless high-quality winter cover is developed on more 

CRP fields themselves, it seems likely that winter food will 

only contribute to usable pheasant habitat in years that have 

mild winters. It appears that CRP could provide a greater 

contribution to the quality of pheasant habitat if planted in 

association with other covers in short supply such as winter 

cover and winter food.

Heard, L.P., Allen, A.W., Best, L.B., Brady, S.J., Burger, W., 

Esser, A.J., Hackett, E., Johnson, D.H., Pederson, R.L., 

Reynolds, R.E., Rewa, C., Ryan, M.R., Molleur, R.T., and 

Buck , P., 2000, A comprehensive review of Farm Bill 

contributions to wildlife conservation, 1985–2000: Madison, Miss., USDA Natural Resources Conservation Service, 

Wildlife Habitat Management Institute, Technical Report 

USDA/NRCS/WHMI-2000, 208 p.

The report provides a comprehensive review of literature 

describing wildlife responses to USDA programs established 

under the Conservation Titles of the 1985 and 1990 and 1996 

Farm Bill amendments. Annotated literature and summaries 

are provided for the CRP, WRP, WHIP, and EQIP. In general, 

wildlife has showed a positive response to these programs. 

Precise quantifiable relations between Farm Bill conservation programs are, however, difficult to achieve and generally 

lacking. Programs are making significant contributions toward 

conservation on fish and wildlife resources. Most literature 

discussed pertains to CRP studies. Less documentation for 

other programs exists due to lack of scientific investigations 

focused on these programs.

Heard, L.P., Allen, A.W., Best, L.B., Brady, S.J., Berger, W., 

Esser, A.J., Hackett, E., Helinski, R.R., Hohman, W.L., 

Johnson, D.H., Reynolds, R.E., Rewa, C., and Ryan, M.R., 

2001, The history, status and future needs of fish and 

wildlife management on private lands as related to USDA 

agricultural programs, in Transactions of North American 

Wildlife and Natural Resources Conference, 66,Washington, 

D.C., March 16–20, 2001, Proceedings: Washington, D.C., 

Wildlife Management Institute, p. 54–67.

The report provides an overview of past USDA conservation programs and effects on wildlife in agricultural ecosystems. It also presents a synopsis of present USDA conservation program (CRP, WRP, Conservation Reserve Enhancement 

Program (CREP), WHIP effects on wildlife populations. 

Recommendations are made for future refinement of conservation programs to benefit environmental quality and wildlife 

associated with agricultural lands. 

Hovorka, D., 2007, Hidden treasures—The Conservation 

Security Program and wildlife: Washington, D.C., National 

Wildlife Federation, 40 p.

The report describes an overview of the structure of 

the CSP as well as some of the benefits to wildlife and their 

habitats brought by the program. Case studies of wildlife 

benefits provided by the CSP in the Chesapeake Bay, California, Georgia, Minnesota, Missouri, Nebraska, and Texas are 

presented. The author concludes that approximately 50 percent 

of CSP payments in 2006 will furnish direct or indirect benefits to wildlife and their habitats. However, benefits appear to 

be much lower in some states. For example, only 26 percent 

of payments in Nebraska support practices that benefit wildlife 

habitats. A major finding is that the CSP provides substantial 

benefits to wildlife, but these vary between states and could be 

substantially improved. 

Key findings of the report include a recommendation 

that Congress should enhance funding for the CSP to provide nationwide opportunities for enrollment in the program. 

USDA should fund new practices at the same rate furnished 

in other USDA conservation programs. All CSP Tier II and III 

contracts should address wildlife habitat and the emphasis on 

wildlife issues should be elevated in Tier I contracts. USDA 

should ensure CSP standards provide consistently high levels 

of benefits to wildlife. Monitoring of the effectiveness of 

conservations practices should be a fundamental part of the 

program to ensure funds are being spent appropriately and 

conservation practices are achieving desired results. 

Ikerd, J., 2002, New Farm Bill and U.S. Trade Policy—Implications for family farms and rural communities: Paper 

presented at “Grain Place” Farm Tour and Seminar, Aurora, 

Nebr., accessed July 27, 2002, at http://web.missouri.

edu/~ikerdj/papers/FarmBill.html.

The author advises government programs to focus 

on using “public funds” to create “public benefits,” not to 

subsidize wealthy landowners and corporate investors. The 

author furnishes a lucid argument detailing why current U.S. 

farm policy fails to meet the needs of individual farmers and 

is continually drifting toward providing benefits only to large 

corporate farms with consequential further disassociation from 

environmental quality and the public good.

There are few places left in the U.S. where prices of 

farmland are not affected by potential residential values. 

Land prices will continue to rise regardless of what happens 

to agriculture. Multinational agribusiness now controls much 

of the new technology and increasingly investments and 

technologies earn their greatest returns somewhere other than 

in America. American farmers are no longer competitive in 

world markets; they are heavily subsidized, but government 

payments have done nothing to address the real problems in 

American agriculture. Ten percent of agricultural producers, 

including many large corporate operations, have been receiving more than two-thirds of all commodity payments. The 

2002 Farm Bill is not designed to meet the needs of farmers 

but the needs of the Agricultural Establishment comprised 

of corporate agribusiness, commodity organizations, USDA, 

and Land Grant Universities. The main objective of these 
Agricultural Conservation Policy 13

members of the Agricultural Establishment is maintaining high 

levels of production. Profits come from margin and volume, 

not farm-level price. Limited demand domestically translates 

into high levels of exports, which are possible only if commodity prices are “competitive,” which means low. Multinational agribusiness corporations increasingly dominate the 

Agricultural Establishment.

Much of the current public support for agricultural programs is based on the belief that the programs help smaller, 

independent farmers; unfortunately, there is little truth in this 

assumption. Congress must find ways to focus agricultural 

programs to provide public benefits with these public funds. 

This goal must become the focus of public farm programs. 

American farm policy should be targeted toward long-run 

sustainability capable of meeting the needs of the present 

while leaving better opportunities for the future. Agricultural 

policy must be based on concepts that are ecologically sound, 

economically viable, and socially responsible. American agricultural policy must be based on benefits to the public beyond 

economic benefits to farmers. Benefits should be limited to 

individually owned and operated farms and family farms 

with the realization that no one has the right to degrade the 

natural environment. 

Johnson, J., and Maxwell, B., 2001, The role of the Conservation Reserve Program in controlling rural residential development: Journal of Rural Studies, v. 17, p. 323–332.

The report describes a model for the prediction of land 

use; the model is used to determine what influence the CRP 

may have on urban sprawl and sustainability of rural communities. Model results showed that the projected mean rural 

residential growth rate was about 50 percent the growth rate 

with CRP as compared to without the program. The preservation of ecosystem integrity increased with the presence of 

CRP. In some cases, CRP may have significantly impacted 

the economic and social character of the community. Authors 

propose modifications of the program to support the establishment of within-production field-scale ecological refuges that 

would meet conservation objectives yet permit a viable level 

of agricultural production.

 R.E., and Antle, J.M., 1990, Interaction between environmental and agricultural policies— Opportunities for coordination and limitations for evaluation: American Economic 

Review, v. 80, p. 197–202.

Agricultural policy has well-documented impacts on 

farmers’ production decisions policy thus affects the environment. There is growing public perception that existing agricultural policies are linked to agricultural pollution. Existing agricultural and environmental policies can have either positive 

or negative effects on non-point source pollution. Agricultural 

policy can be used to mitigate pollution if properly designed 

and implemented. Agricultural production and environmental 

impacts depend on highly location-specific environmental conditions. Generalizations about the environmental impacts of 

agricultural policies are easy to make but should be avoided. 

Keeney, D. and Kemp, L., 2003, A new agricultural policy 

for the United States: Minneapolis, Minn., North Atlantic 

Treaty Organization Advanced Research Workshop on Biodiversity and Rural Sustainability, November 2002, Institute 

for Agriculture and Trade Policy, 23 p. 

The report is an admirable presentation of agriculture and 

policy evolution resulting from industrialization of the U.S. 

commodity based agricultural industry. The report contains 

overviews of economic, social, and environmental implications from changes in agricultural structure. The report’s conclusions are based largely on evidence that while current production philosophies harm their own resource base and appear 

environmentally unsustainable, modern U.S. agriculture continues to be supported by policies furnishing major returns to 

suppliers and the largest of producers. Authors conclude that 

governmental initiatives and programs focused on one specific 

environmental problem (for example, erosion, wildlife), will 

be unsuccessful in finding solutions to problems. Although 

supported by the public, current approaches to control water 

pollution and other environmental impacts of agriculture are 

modest, poorly enforced, poorly funded, and lack long-term 

commitment. The report documents the public’s support for 

farming, potential social and environmental benefits, and the 

public’s willingness to pay for environmentally sustainable 

agricultural sector. The report describes, and strongly supports, 

potential benefits of implementation of the CSP created in the 

2002 Farm Bill. Authors believe that if successful, the CSP 

has potential to reduce agriculture’s environmental impacts, 

diversify agriculturally-dominated landscapes, improve farm 

income, and become the model that could form the foundation 

for a national green payment program displacing a significant 

portion of the failing commodity policies the USDA. (Also 

published in Light, S.S. ed., 2004, The role of biodiversity 

conservation in the transition to rural sustainability: Washington, D.C., IOS Press, 342 p.)

Kelly, C.R., and Loden, J.A., 1995, Federal farm program 

conservation initiatives—Past, present, and future: Natural 

Resources & Environment, v. 9, no. 3, p. 17–19.

From its New Deal beginnings, farm policy has been primarily designed to stabilize commodity prices and to support 

farm income. Natural-resources capital, on which agriculture 

is dependent, has not been the primary concern of those who 

have guided federal farm policy for the past 60 years. Conservation initiatives have largely served to gain political support 

or otherwise assist in achieving economic objectives. Although 

economic well-being will continue to be a predominant 

concern of federal policy, conservation is likely to assume a 

greater importance because agricultural impacts are receiving 
14 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

greater attention. Budgetary constraints and international competition will accelerate market-orientated policies diminishing 

the program’s tradition role in supply management. Paying 

farmers for adopting conservation practices is likely to expand 

and to replace other mechanisms for supporting farm income. 

A political problem that may result from green-payments 

is that recipients of green payments are not likely to be the 

same farmers favored by current income transfers. Current 

programs favor larger and midwestern farmers. Green payments are likely to be greatest where environmental problems 

are greatest and nearest to population centers; this may result 

in shifts to coasts and major watersheds. Furthermore, green 

payments may not provide benefits to small farmers because 

it can be argued that attention should be greatest to those who 

farm the most land. There is no guarantee that green payments 

would provide sufficient income to satisfy farmers. 

Kleiman, D.G., Reading, R.P., Miller, B.J., Clark, T.W., Scott, 

M., Robinson, J., Wallace, R.L., Cabin, R.J., and Felleman, 

F., 2000, Improving the evaluation of conservation programs: Conservation Biology, v. 14, no. 2, p. 356–365.

Evaluation of conservation program effectiveness is 

essential for improving the performance of these programs. 

However, evaluations have been rare because of resistance 

by participants, difficulty, and lack of funding. The author 

recommends an external peer review of long-term complex conservation programs every five years and an annual 

internal review. Measures of success must include biological and social measures and application of new knowledge. 

The authors furnish an example of program evaluations and 

advice on organization of effective assessment of programs. 

It is essential that goals and objectives are well defined with 

precise identification of what is to be evaluated. Criteria for 

success must be adequately identified for an evaluation/monitoring program to evolve to, so that conservation programs can 

ultimately provide the greatest benefits. 

Conservation program evaluations should assess success 

and failure in terms of goal achievement and accountability 

for outcomes. Quality of performance and dissemination of 

findings to appropriate staff/agencies involved and public 

should be fundamental goals of conservation program evaluation. Program evaluations should include assessment of 

program substance (what was accomplished) and process (how 

effectively the program has, or is, functioning). Because they 

involve living systems and change, most conservation programs should be viewed as a continuous feedback loop rather 

than linear program with a clear start and finish. Socioeconomic and political interests are often the foundation for most 

conservation programs; therefore, these factors must be considered in program assessments. Interdisciplinary approaches 

to conservation that address both biological and social science 

have best chance for success. Too many programs fail to educate the public or confront sociopolitical issues. 

A major challenge facing conservation is conflict 

among conservation scientists, government agencies, and 

non-government organizations competing to “own” a conservation problem or solution. The key measure of program’s 

success is its ability to develop a strategy to mobilize financial, 

political, and technical support. 

Lambert, D., Sullivan, P., Claassen, R., and Foreman, L., 2006, 

Conservation-Compatible Practices and Programs—Who 

Participates?: Washington, D.C., U.S. Department of Agriculture Economic Research Service Report No. 14, 43 p.

Farming and conservation practices adopted by the 2 million farmers in the U.S. can have major impacts on the health 

of ecosystems directly and indirectly affected by agricultural 

production. The effectiveness of farm conservation programs 

depend on the willingness of farm operators to participate. 

Factors other than profits and environmental considerations 

(for example, farm ownerships status, off-farm employment) 

can influence participation in conservation programs. Conservation programs based on the assumption that long-term profit 

is the sole driving force behind farm practices will not appeal 

to all farmers. In many cases, offsite environmental issues may 

not be adequately addressed by on-farm conservation practices 

capable of improving long-term profits. 

The report offers examination of business, operator, and 

household characteristics of farms adopting conservationcompatible practices. Operators of small farm operations 

and operators not primarily focused on farming are found to 

be less likely to adopt management-intensive conservation 

practices and are less likely to participate in working land-conservation programs than operators of large enterprises whose 

primary occupation is farming. Results suggest that farm size, 

commodities produced, and operator motivation are associated 

with use of various conservation practices, but these relationships vary. The authors conclude that both types of programs 

have differing appeal to operators and each may be needed 

to address total conservation needs of the diverse agricultural 

industry. Flexible incentive structures are needed to accommodate farm-operator goals such as ease of application and 

appropriateness to individual operations. Conservation compliance, improved levels of technical assistance, availability of 

information (for example, benefits of crop rotation) can all be 

used more effectively to provide conservation benefits. The 

farm commodity program (price supports), often criticized 

for encouraging more intensive use of agricultural lands, may 

have a beneficial effect on conservation because participants 

in these programs are more likely to have adopted conservation-compatible farming practices than are farm operations 

involved in production of nonprogram crops. 

Operators of small enterprises focused on non-farm occupations are less likely to adopt practices requiring additional 

time or expense. Conservation practices like grass waterways, 

riparian buffers, and planting erosive lands to grass-dominated 

covers result in a cost for installation and lost future production opportunities. Younger operators, whose primary occupation is farming, are more likely to install working land 
Agricultural Conservation Policy 15

structures compatible with agricultural production. Operators 

of larger farms are more likely to participate in working land 

programs such as the EQIP but only a small percentage of the 

operation is typically enrolled in conservation programs.

Land-retirement programs (for example, CRP) are more 

commonly used among smaller, retired, and “lifestyle” farm 

operations. Whole farm enrollments (where farm income is 

replaced by conservation program payments) are generally 

older and more dependent on non-farm sources of income. 

Approximately 50 percent of CRP participants fall into this 

classification. Partial farm enrollment in CRP (individual 

fields or portions of fields) tends to be on larger farms with 

farming the primary occupation. 

Authors believe that the availability of expert advice 

and technical assistance may assist in adoption of specialized 

conservation practices. For conservation practices that do not 

pay for themselves, incentives will be necessary to encourage 

adoption. For farm households dependent on farming as the 

primary source of income, working-land programs can make 

beneficial conservation practices affordable. A sliding scale 

of financial assistance could increase adoption by smaller 

farm operations. Working land-conservation programs may 

not furnish equal amounts of wildlife benefits as do retirement programs (for example, CRP). Authors conclude that the 

retirement of contiguous fields from production can provide 

broader environmental benefits than may be accomplished 

through working land approaches. Land-retirement programs 

can be an integral part of a working land approach to conservation. Authors conclude that future conservation programs 

have the greatest potential when viewed as a combination of 

working and retirement program options. 

Leathers, N., and Harrington, L.M.B., 2000, Effectiveness 

of Conservation Reserve Programs and land “slippage” in 

southwestern Kansas: Professional Geographer, v. 52, no. 1, 

p. 83–93.

Authors define slippage as occurring when the number of 

acres enrolled in a reserve program is not met by an equivalent 

reduction of acreage production. Slippage occurs when the 

amount of land enrolled in a reserve program is offset by additional land outside the program being brought into cultivation. 

The paper addresses slippage effect on CRP in southwestern 

Kansas from 1988 to 1994. At one extreme, conservation programs were 100 percent successful in removing land from production, but slippage resulted in reserve programs being nearly 

useless. Land in southwest Kansas is relatively flat with newly 

cultivated land often having equivalent or higher susceptibility 

to erosion than land being enrolled in the CRP. Authors conclude that there is a great deal of spatial and temporal variability and that analysis of potential effects should be done at the 

county level to evaluate effectiveness of CRP performance. 

Slippage occurs in part because not all farmers take part 

in farm programs. As participants reduce number of acres 

planted to meet eligibility requirements, nonparticipants often 

increase acreage in production in anticipation of higher prices 

for crops produced. CRP participants may also contribute by 

putting idle land in production. In the Great Plains this is often 

land left fallow or land with a high incidence of crop failure. 

A summary of earlier studies (cited in the paper) led authors 

to conclude: programs directed at reduction of a single commodity are especially vulnerable to slippage, low participation 

rates contribute to a program’s ineffectiveness, use of land 

reserves is subject to failure regardless of whether one crop or 

cropland in general is targeted, variability in slippage is influenced by availability of land easily brought into production; 

program enforcement affects slippage rates, long-term programs are slightly less effective than short-term programs, and 

production incentives for nonparticipants also affect slippage.

In southwest Kansas, slippage rates varied between counties and years. Rates were near 0 in some counties and 99 percent in other counties. In 1993, when the CRP accounted for 

most land in conservation programs, slippage rates decreased. 

Average annual slippage for 14 counties in the study was 

53 percent. Although 100 percent effectiveness may be too 

much to expect from conservation programs, slippage rates 

of 50 to 100 percent are unacceptable. During the years when 

CRP alone accounted for most land in reserve, the program 

was effective in reducing the number of acres in production proportionate to acres enrolled in the program in three 

counties but varied between 1 and 75 percent in remaining 11 

counties. Authors conclude that CRP was more effective than 

were other conservation programs, but the CRP was unable to 

completely overcome failures of previous programs. Authors 

cite limitations of USDA record keeping as a constraint in 

evaluation. County and regional evaluations are needed to 

refine program performance and evaluation. 

Miranowski, J.A., and Bender, R.L., 1982, Impact of erosion 

control policies on wildlife habitat on private lands: Journal 

of Soil and Water Conservation, v. 37, no. 2, p. 288–291.

Policies designed to maintain soil productivity and 

improve water quality tend to enhance upland habitat for wildlife with varying degrees of effectiveness. Generally, wildlife 

needs have been subordinate to other resource and conservation priorities addressed in agricultural policy. The dichotomy 

between private and public interest has been the major 

problem underlying all policies relating to wildlife and their 

habitats. The benefits of erosion-control policies and programs 

should incorporate social and economic benefits to wildlife/

habitats in analysis of impacts. A discussion of potential benefits of inclusion of wildlife is included in an evaluation of a 

linear program model using analysis of the Iowa River Basin.

Nassauer, J.I., Corry, R.C., and Cruse, R.M., 2002, Alternative 

future landscape scenarios—A means to consider agricultural policy: Journal of Soil and Water Conservation, v. 57, 

no. 2, p. 44–53.
16 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Each time a Farm Bill is a passed, new policy implies 

new future alternative scenarios for agriculturally dominated 

landscapes. The report’s authors state that it is difficult to perceive future landscapes and it is only in retrospect that people 

can see how much things change. This paper addresses policy 

implications to agricultural dominated landscapes through 

potential changes in two watersheds in Iowa. Three alternative 

futures are compared using 1994 conditions as the baseline. 

Scenarios include: (1) increasing agricultural production is 

primary goal, (2) water-quality improvement is key goal, and 

(3) biodiversity enhancement is primary objective. Implications of alternative federal agricultural policies for ecological 

functions, hydrological functions, economic return, and public 

acceptance are discussed. Consequences of alternative futures 

are discussed and show that effects of policy decisions can 

have dramatic effects. Authors conclude it is possible to have 

a healthy, agriculturally dominated landscape that furnishes 

beneficial environments and services.

Pimentel, D., Berger, B., Filiberto, D., Newton, M., Wolfe, 

B., Karabinakis, E., Clark, S., Poon, E., Abbett, E., and 

Nandagopal, S., 2004, Water resources—Agricultural and 

environmental issues: Bioscience, v. 54, no. 10, p. 909–918.

Growing demands on global supply of water threaten biodiversity (in both terrestrial and aquatic ecosystems), food production, and other vital human needs. Agriculture consumes 

about 70 percent of freshwater used worldwide. It takes 264 

gallons (gal) (1,000 liters [L]) of water to produce 2.2 pounds 

(lbs) (1 kilogram [kg]) of cereal grain and 11,360 gal (43,000 

L) of water to produce 2.2 lbs of beef. In the United States, 2.5 

acres (1 hectares) of corn with a yield of 1,636 lb/ac requires 

about 1.6 million gallons (6,000,000 L) of water during the 

growing season. Only about 17 percent of the world’s cropland is irrigated, but it accounts for 40 percent of the world’s 

food production. Irrigated agricultural production accounts for 

about 40 percent of the freshwater withdrawn in the United 

States and more than 80 percent of the water consumed. 

 New supplies of water are more likely to develop from 

conservation, recycling, and improved efficiency in use rather 

than from development of new, large projects. Population 

growth and associated increased use of water will severely 

reduce water availability and create additional stresses on biodiversity in the entire global ecosystem. Conflicts surrounding 

water issues are escalating among new industrial, agricultural, 

and urban sectors. 

Population growth, agriculture, and other water uses 

are mining groundwater resources faster than they can be 

recharged. The capacity of the Ogallala aquifer has decreased 

by 33 percent since about 1950, with a water withdrawal three 

times faster than the recharge rate. Similar problems exist 

throughout the world. The rapid depletion of groundwater 

poses a serious threat in world agricultural regions. An estimated 1 percent of the storage capacity of world’s reservoirs is 

lost each year to siltation of the basins. 

Approximately 40 percent of freshwater in the United 

States is deemed unfit for drinking or recreation due to 

contamination by microorganisms, pesticides, and fertilizers. 

Agricultural production in the United States is projected to 

expand to meet increased needs of the population, which is 

expected to double in the next 70 years. Increased crop and 

livestock production during the next 5 to 7 decades will significantly increase the demand on all water resources, especially 

in western, southern, and central states.

Authors suggest that because farmers are primary users, 

they should be the chief target for incentives to conserve 

water. Options include implementation of water- and soilconservation practices such as cover crops and crop rotations. 

Water subsidies that encourage wasteful use by farmers, 

industry, and the public should be eliminated. Furthermore, 

governmental policies should be directed toward protection of 

forests, wetlands, and natural ecosystems to enhance conservation of water. 

Plantinga, A.J., Alig, R., and Cheng, H., 2001, The supply of 

land for conservation uses—Evidence from the Conservation Reserve Program: Resources, Conservation and Recycling, v. 31, p. 199–215.

Using 1987–1990 data on CRP enrollment, the authors 

estimate grassland-supply functions for conservation lands in 

nine USDA farm production regions (excluding the Pacific 

region due to low enrollment at time of analysis). Subsequent 

to 1986 and prior to 1991, the CRP operated similarly to a 

competitive market for conservation lands. Competitive markets are characterized by many buyers and sellers who accept 

the price of goods as offered. With the CRP, the rental rate (set 

by USDA) is analogous to a price for land conservation. Study 

results suggest that low rental rates (less than $40 per acre per 

year [/ac/yr]) contribute to very little land enrolled except in 

the Northern Plains region. Significant acreage enrollment can 

be expected in the Mountain region (approaching $60/ac/yr). 

Annual rental payments of greater than $80/ac/yr will result in 

enrollments in the Lake States, Corn Belt, and Southern Plains 

regions. Even at relatively high payments, little land can be 

expected to be enrolled in the Appalachian, Delta, Northeast, 

and Southeast regions. The authors discuss implications for 

meeting other types of conservation objectives by enrolling 

agricultural lands in conservation programs.

Pretty, J., 2002, People, livelihoods, and collective action 

in biodiversity management, in O’Riordan, T., and StollKleemann, S., eds., Biodiversity, sustainability and human 

communities: Cambridge, UK., University Press, p. 61–86.

In an almost entirely farmed landscape, nature is as much 

a product as it is an input. The assumption that conservation of 

natural resources is only possible through exclusion of human 

interference is erroneous. Modern development of ecosystems 

was based on simplification, but modernism led to arrogance 
Agricultural Conservation Policy 17

about social ties with the natural world and the assumption 

that technology will furnish universal solutions to environmental problems. Regulations and economic incentives are 

commonly used to encourage changes in behavior. Although 

such incentives may be effective in changing management 

practices, they rarely result in a positive change in attitudes 

and farmers commonly revert to old practices when regulations are no longer enforced. When people are organized in 

groups and their knowledge is sought in answers to environmental problems, they are more likely to sustain desirable 

activities following project completion. Five core components 

of successful biodiversity programs promote sustainable management of natural resources: conceptualization of sustainability being of high social value, recognition that rural people can 

improve agro-ecological understanding, increased understanding derived from farmers engaging in their own experimentation supported by professionals, ideas for improvement in 

management are more likely to spread from farmer to farmer 

rather than group to group, and recognition that social learning 

process should be an important focus for all natural resource 

management programs. 

Ray, D.E., De La Torre Ugarte, D.G., and Tiller, K.J., 2003, 

Rethinking U.S. agricultural policy—Changing course to 

secure farmer livelihoods worldwide: Knoxville, Tenn., 

Agricultural Policy Analysis Center, University of Tennessee, 59 p.

Authors put forth the case that a deliberate shift in American agricultural policy in the 1990s resulted in depressed 

crop prices, due to the elimination of several traditional 

safeguards for managing supply and supporting prices. The 

report explores why changes in agricultural policy in the 1996 

Farm Bill resulted in declining farm revenues; the report also 

introduces a policy blueprint that could raise crop prices and 

contribute to a worldwide healthy agricultural industry. Prices 

of primary agricultural imports have declined by over 40 percent since 1996. Farmers in the United States continue to be 

forced out of the industry despite the large infusion of government payments intended to compensate for lower prices. The 

authors conclude that government must help manage excess 

capacity if prices are to be held at levels to benefit both producers and consumers. 

Even with enormous sums of federal funding provided 

to farmers as emergency payments, many small farm operations continue to fail and disappear. These payments have not 

closed the gap between production costs and market prices and 

further reinforce the bias in U.S. agriculture for bigger, less 

diversified farms. Although the number of farms and farmers 

continues to decline, the amount of cropland in production 

remains fairly constant. Unchecked, this trend will result in an 

agricultural industry dominated by large, highly mechanized 

farms. Through contract production, large agribusiness firms 

may control many of the remaining small farms. The authors 

believe that no one policy instrument is key to resolving this 

crisis, but a set of options and policies may increase market 

prices to sustainable levels. Used effectively, the authors 

believe, these options could reduce U.S. government outlays by more than $10 billion/yr and contribute to a healthy 

agricultural industry on a global scale. These options include 

greater use of short- and long-term set-aside programs, farmerowned food security reserves, and price supports. Authors 

advocate greater use of CRP to curb excess productive 

capacity. Both short- and long-term acreage retirement would 

reduce excess production and improve environmental performance. Short-term set-aside programs would induce farmers 

to idle a portion of their working cropland. 

Reichelderfer, K., 1990, Environmental protection and agricultural support—Are trade-offs necessary? in Allen, K., ed., 

Agricultural policies in a new decade: Washington D.C., 

Resources for the Future and National Planning Association, p. 201–230.

Traditional means of supporting farm income tend to 

exacerbate environmental problems. Under current programs, 

agricultural and environmental protection reflect conflicting 

societal preferences. Public reaction to environmental problems suggests that the non-farm population believes it has a 

right to a clean, safe, and healthy environment, which may be 

infringed upon by farming activities. Long-run environmental goals of the American public conflict with the short-run 

profit objectives of individual farmers. The adoption of new 

technologies requires capital investment, high-adjustment 

cost, increased operating costs, or some forfeiture of yield, 

any of which can reduce farm income, at least in the short 

run. Efforts must focus on increasing the cost-effectiveness of 

current or reduced levels of funding to meet policy objectives. 

The Farm Bill has furnished consistency between environmental and agricultural policy objectives, but it could be better. 

For over 50 years, programs supporting commodity prices 

and the transfer of income to the farm sector have formed the 

core of U.S. agricultural policy. Until recently, these programs 

included no explicit conservation objectives. Main objectives 

of agricultural policy are to support farm income and ensure 

a stable and reasonably priced food supply. These multiple 

objectives are achieved through a system of farm programs 

that insulate the farm sector from the market economy by 

artificially supporting certain commodity prices and managing 

their supplies. Each mechanism used to achieve farm and supply control has unique secondary and unintentional effects on 

environmental quality.

Riddel, M., and Skold, M., 1997, Cropland retirement and 

supply control in the Great Plains: Journal of Production 

Agriculture, v. 10, no. 1, p. 106–110.

Supply control has been an important component of agricultural commodity policies for the past 60 years. The primary 

instrument to provide supply control through agricultural legislation has been cropland annual and long-term (for example, 
18 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Soil Bank, CRP) retirement. Authors conclude that annual 

cropland retirement programs for wheat have no effects on 

the amount of wheat produced in the Great Plains, and that 

long-term programs, such as CRP, have only limited supply 

control effectiveness. Rationale for continuing CRP includes 

increased reliance on the program for supply control. However, effectiveness for CRP to control wheat supply from the 

Great Plains is, at best, limited. Within the Great Plains CRP 

enrollment, approximately 57 percent of 34.6 million acres 

is enrolled in the program. Wheat was approximately 50 

percent of base reduction in Great Plains accounting for 36 

percent of total long-term land retirement in the Great Plains.

The Great Plains has experienced increased yields over 

the entire life of land-diversion programs due to greater use 

of chemical and physical inputs, better management practices, and improved cultivars. But Great Plains yields vary 

by 38 percent during the period of analysis—this makes 

effects of land retirement programs difficult to determine. 

Authors conclude that increasing trends in production, yield, 

and acres under production outweigh the consequences of 

reductions in wheat derived from short- and long-term setaside programs. To be effective, supply control programs 

must be more directly linked to output rather than how much 

input is used in production. Since long-term land-retirement 

programs are relatively ineffective for supply control, other 

benefits such as reduced soil erosion, wildlife habitat, and 

water quality must be used to a greater degree to justify 

such programs. 

Roberts, M.J., and Bucholtz, S., 2005, Slippage in the 

Conservation Reserve Program or spurious correlation? 

A comment: American Journal Agricultural Economics, 

v. 87, no. 1, p. 244–250.

Authors put forward the argument that slippage due 

to CRP reported by Wu (see below) is not supported by the 

data and method used by the author to estimate unintended 

stimulus by the program to convert non-cropland to cropland. The authors conclude that Wu’s assertion is erroneous. Wu presents the idea that slippage might arise through 

a price-feedback effect caused by shift in crop prices due to 

CRP enrollment due to substitution of land from noncropping 

to crop production. Wu’s findings are based on the regression of data across crop-reporting districts—the data relate 

new cropland to CRP enrollment. These authors state that 

Wu’s data cannot be used to estimate slippage arising from a 

price feedback effect and conclude that there is no convincing evidence of slippage due to CRP. Roberts and Bucholtz 

completed an additional analysis and found a net-slippage 

estimate that is statistically indistinguishable from zero. The 

authors conclude, however, that even their model and estimates are not reliable and suggest future estimates could be 

derived using data representing a longer and more frequent 

sample period. 

Robertson, G.P., and Swinton, S.M., 2005, Reconciling 

agricultural productivity and environmental integrity—A 

grand challenge for agriculture: Frontiers in Ecology and the 

Environment, v. 1, no. 3, p. 38–46.

Current trends point to continued human population 

growth and higher levels of consumption as the global economy expands. The main challenge of agriculture in coming 

decades will be to produce sufficient food and fiber for a 

growing population at acceptable costs to the environment. 

This challenge requires an ecological approach to agriculture 

production that is largely missing from current management 

and related research. Crop and livestock production must be 

managed as ecosystems with decisions based on environmental 

costs and benefits. Too little is known about important ecological interactions in agricultural systems and landscapes and 

about the economic and social values of ecosystem services 

associated with agriculture. Sustainable agriculture must be 

managed for multiple services (in addition to food production) 

that will require ecological and social research, public education, and innovative agricultural policies.

Agriculture is the world’s largest industry whose future 

impact depends on how effectively we understand and manage 

both the social and ecological elements of ecosystems dominated by the industry. Agricultural ecosystems are as ecologically complex as most other ecosystems on earth. Row crop 

agriculture is essentially a form of early ecological succession 

in which intentional disturbance annually sets back succession. Management typically focuses only on the production 

of marketable commodities but this production comes at the 

expense of other ecosystem services and long-term productivity of agriculture itself. Clean air, water, wildlife habitat, C 

storage, pollination, and disease suppression are all services 

important to human health, ecosystem health, and long-term 

sustainability of agriculture itself. Active management for 

maintaining environmental services associated with agriculture is a concept receiving too little attention in the past and is 

supported by too little science. Science should provide options 

and a sound basis for decision-making by producers, consumers, and those making policies. It is important for the public to 

be aware that choices have alternative consequences and that 

choices can be optimized. A focus on full ecosystem services is 

missing in ongoing research related to agricultural production 

and ecology.

Understanding how organisms are distributed and ecological process within and across landscapes is crucial for designing management practices that optimize trade-offs. Solutions to 

problems in one part of the landscape may become a problem 

elsewhere when management is based on reactive problem 

solving rather than ecosystem management. Social research 

in agricultural ecosystems is just as needed as is ecological 

research. Economic analysis and other social sciences are 

needed to evaluate environmental services associated with agriculture and promote their importance to society. Agriculture 

must adopt a systems-oriented outlook that incorporates social 

and environmental services. This will require input from social 
Agricultural Conservation Policy 19

science and economists and a strong approach toward education of the public about their future and trade-offs between 

management decisions. 

Effective management of agricultural ecosystems requires 

ecosystem understanding of properties and processes that 

include human needs. Socioeconomic research in agricultural 

ecosystems is as much needed as is ecological research. The 

long-term environmental costs of agriculture will be avoided 

only if policy recognizes and rewards environmental stewardship early in the process. Challenges to be faced include 

identification of ecosystems services furnished and affected 

by agriculture, understanding trade-offs between options, 

valuing ecosystem services so they can be prioritized and 

linked to policy decisions, and creating an environmentally 

literate public. Agricultural policy must adopt a more forwardlooking, systems-oriented outlook towards management of 

agricultural ecosystems. 

Robertson, G.P., Broome, J.C., Chornesky, E.A., Frankenberger, J.R., Johnson, P., Lipson, M., Miranowski, J.A., 

Owens, E.D., Pimentel, D., and Thrupp, L.A., 2004, 

Rethinking the vision for environmental research in U.S. 

agriculture: Bioscience, v. 54, no. 1, p. 61–65.

Authors conclude that environmental research related to 

agriculture is largely reactive, focused on problems at small 

scale (for example, field, farm) and conducted within narrow 

disciplinary boundaries. This approach fails to resolve most 

of the more serious environmental issues associated with 

agricultural production. Economic and social costs of agricultural production are high and mostly external to producer 

decisions. Solutions to environmental issues have not been 

adopted for lack of incentives or other socioeconomic reasons, 

or solutions have been inadequate because they fail to fully 

consider the complexity of agricultural ecosystems. Often, 

how well solutions work is unknown because there have been 

inadequate follow-up assessments and monitoring. Appropriate incentives must go beyond production of food and fiber to 

address environmental benefits increasingly demanded by the 

public. Basic environmental research associated with agriculture must address the system at multiple scales and locations 

and be based on development of environmental performance 

standards. Descriptions of environmental services and understanding how they can be quantified and appropriately valued 

is an emerging research need with important implications for 

agriculture and land-use planning.

Ribaudo, M.O., Hoag, D.L., Smith, M.E., and Heimlich, R., 

2001, Environmental indices and the politics of the Conservation Reserve Program: Ecological Indicators, v. 1, 

p. 11–20.

Use of Environmental Benefits Index (EBI) helped the 

USDA increase and broaden the CRP’s environmental benefits 

beyond erosion reduction, which was the primary focus of 

the early program. The paper provides examples about how 

integration and assessment for the purpose of managing public 

resources requires more than natural science disciplines. 

Social science can help explain how public values influence what information is collected and how it is interpreted. 

Examples are furnished to show how EBI was used to integrate science, politics and social values. 

Schertz, L.P., and Doering III, O.C., 1999, The making of the 

1996 Farm Act: Ames, Iowa, Iowa State University Press, 

190 p.

An insightful assessment of the trials and tribulations 

in the formulation and passage of the Federal Agriculture 

Improvement and Reform Act of 1996. Although seen as some 

as the beginning of the end of federal transfers of funds to 

farmland producers by 2002, the authors correctly foresaw 

continuation of such support to the agricultural community. 

Of particular interest are perceptions about the growing 

political power that environmental interests have in shaping 

new legislation based on mounting evidence of the negative impacts of agricultural production on the landscape and 

environmental services. 

Soil and Water Conservation Society, 2006, Conservation 

Effects Assessment Project—Final Report from the Blue 

Ribbon Panel Conducting an External Review of the U.S. 

Department of Agriculture: Ankeny, Iowa, Soil and Water 

Conservation Society, 25 p.

A blue ribbon panel of academic, state, tribal, and 

nongovernmental organization leaders furnishes review and 

recommendations for improvement in the USDA CEAP. The 

panel concludes that a coherent and science-based assessment and evaluation system is urgently needed to ensure that 

conservation programs produce environmental gains that 

taxpayers and agricultural producers expect. The underlying 

conclusion provided by the panel is that the current direction 

of CEAP must change. The panel questions the validity of 

generalized estimates of environmental effects derived from 

simulation models and extrapolation of data derived from 

conservation practices. Quantifying effects and evaluating 

effectiveness are very different types of results. The panel 

concludes simulations cannot, and should not, be seen as a 

substitute for on-the-ground monitoring designed to determine 

if anticipated conservation benefits are being furnished. 

The panel recommends that Congress mandate that at 

least one percent of funding for each authorized program, 

about $40 million, be specifically set aside to support monitoring and evaluation of USDA conservation programs. It is recommended collaborative efforts be expanded between governmental and nongovernmental agencies around geographically 

specified outcomes such as soil quality, water quality, wildlife 

habitat and air quality. Development of approaches to “smart 

monitoring” and assessment of unmet needs and opportunities 
20 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

are needed. The panel also recommends that the USDA look 

more to regional-level assessments rather than a broad-scale, 

national-level evaluation. 

The panel believes the most important, and troubling, 

piece missing from the existing CEAP is the absence of 

plans for on-ground monitoring of changes in environmental 

indicators and outcomes. There is an urgent need for USDA 

to strengthen plans for on-ground monitoring to evaluate 

progress toward specific environmental goals. Simulation 

models and extrapolations of data cannot be a substitute for 

on-the-ground monitoring. It is likely that additional funds and 

staff resources will be needed to support necessary monitoring and inventory systems. On-ground monitoring need not be 

overwhelming and should be based on a suite of indicators that 

can be used to tell a story of what is happening in the environment as a consequence of conservation practices and policies. 

The fundamental unit of assessment should be based upon 

watersheds or other salient geographic scales. The national 

scale currently being used as a foundation for CEAP was 

determined by the panel to be unsatisfactory due to the lack of 

ability to describe local benefits of conservation policies. 

Soil and Water Conservation Society, 2004, Realizing the 

promise of the Farm Security and Rural Investment Act of 

2002: Ankeny, Iowa, Soil and Water Conservation Society, 

36 p.

The report furnishes a summary of progress on implementation of the 2002 Farm Security and Rural Investment 

Act as well as four major recommendations to make the 

Farm Bill live up to its full potential. The report requests that 

Congress provide full funding for all USDA conservation 

programs. Unfortunately, the 2005 presidential budget does 

not keep that promise. 

Full support of conservation technical service infrastructure is cited as the single greatest opportunity to realize the 

full potential of the 2002 Farm Bill. USDA should produce a 

plan to construct a viable technical-services infrastructure for 

the 21st century. Funds from the Commodity Credit Corporation (CCC) should be used to a greater degree to fund 

conservation. Conservation programs must be structured to 

meet the challenge of managing agricultural impacts on the 

environment. The CSP should become the primary agricultural 

conservation program across the country. The report presents 

numerous detailed recommendations on realizing the full 

potential of the 2002 Farm Bill and making conservation a top 

priority for USDA and improvement of environmental quality. 

Stem, C., Margoluis, R., Salafsky, N., and Brown, M., 2005, 

Monitoring and evaluation in conservation—A review of 

trends and approaches: Conservation Biology, v. 19, no. 2, 

p. 295–309.

Monitoring and evaluation furnish public and internal 

accountability that demonstrates the impact of programs, 

which has become increasingly important in the current 

climate of budgetary constraints. Effective projects incorporate well-designed monitoring and evaluation, but monitoring 

and evaluation often suffer from a failure to take advantage 

of lessons already learned from previous monitoring efforts. 

Monitoring efforts require different approaches that must be 

based on consistent language and incorporation of aspects in 

addition to biological variables. Qualitative and social variables are necessary to provide comprehensive assessments of 

conservation-program effectiveness. 

Evaluation approaches vary by stakeholder interests, 

and often serve overlapping purposes that include knowledge 

generation, program improvement, accountability, resource 

allocation, and impact assessment. To understand our environment and protect resources, managers need to be able to 

measure what they are trying to preserve or enhance. Monitoring changes in wildlife populations is generally too time 

consuming and expensive to be feasible for most program 

and site-level assessments. In addition, multiple years of data 

are typically required for a reliable assessment of changes 

in animal populations. A more practical alternative of rapid 

assessment is characterization of vegetation types and species 

but this approach is often limited in approach and reliability of 

results is imperfect. Approaches to measuring the effectiveness 

of conservation programs are best when preceded by a strong 

planning process and clear identification of goals and objectives as well as by measures to gauge progress toward achieving those goals. 

The monitoring of conservation has traditionally focused 

on quantitative indicators of biological health. but engaging 

stakeholders in project management and assessment of social, 

economic, political, and cultural aspects and impacts of a 

program are essential. Conservation takes place in a complex 

context influenced by human populations. It is important to 

involve key stakeholders in monitoring processes because 

stakeholders may offer greater and unique insights to what is 

actually happening as a consequence of conservation practices. 

The authors conclude by recommending there is a greater 

need for collaboration among conservation interests. Diverse, 

numerous approaches to monitoring and evaluation only 

lead to confusion, duplication, and competition, usually for 

limited funds. It would be beneficial to seek greater agreement 

on short lists of potential indicators for common conservation goals. Strategic selection of programmatic indicators of 

success that clearly relate to goals and show progress toward 

desired conservation objectives should be a principal goal of 

monitoring and evaluation.

Taylor, M.R., 2001, The emerging merger of agricultural and 

environmental policy—Building a new vision for the future 

of American agriculture: Virginia Environmental Law Journal, v. 20, no. 1, p. 169–190.

Agriculture is one of society’s most pervasive and consequential environmental interventions. As environmental values 

have become part of mainstream public concern, fundamental 
Agricultural Conservation Policy 21

questions are asked about impacts of agriculture on the environment and welfare of society. Consequently, agriculture will 

continue to be a legitimate subject of public policy. Conservation and environmental protection have moved to the center 

of farm-policy debates. Over the past decade, USDA has 

annually spent on average about $13.5 billion on economic 

assistance for farmers with peaks as high as $28 billion/yr 

in response to emergency conditions. Americans continue to 

culturally identify themselves with farms and farmers, and a 

substantial majority of Americans believe it is in the country’s 

interest to preserve small-family farms. U.S. farm policies 

have played an important role in the emigration of families 

from the farm community. Agricultural policy is global, and 

the impact of U.S. policies has to be understood and evaluated from both global and domestic perspectives. The 1985 

Farm Bill brought conservation and environmental issues 

into the farm-bill debate and created linkages between farmconservation practices and the economic support that operators 

received from the government. The importance of the 1996 

Freedom to Farm Act is that it furnished an opportunity to 

devise policies linking financial assistance to the achievement 

of other objectives, including environmental quality. Public 

dollars will continue to be invested in agricultural support with 

an emphasis on maintaining environmental quality and sustainable farming practices. Farmers and society at large share 

common interests in ensuring sustainable land use by lessening the environmental impacts of agriculture. Farmers are, 

however, unlikely to respond to issues (for example, wildlife 

habitat) that influence their farm’s future productivity if there 

are no economic returns or incentives. 

Theobald, D.M., Spies, T., Kline, J., Maxwell, B., Hobbs, 

N.T., and Dale, V.H. 2005, Ecological support for rural 

land-use planning: Ecological Applications, v. 15, no. 6, 

p. 1906–1914.

Enhanced decision making about rural lands requires 

consideration of how ecological information can enhance 

planning and policy needs. Ecologists must understand tradeoffs between various environmental and social objectives and 

the importance of integrating local knowledge with landscape 

level information. Authors describe four primary challenges 

in improving rural land-use planning: the mismatch between 

spatial and temporal scales in which ecological processes 

occur; scales and tempos of land use and planning; the need 

to develop comprehensive land-use framework to extrapolate 

results of ecological studies to larger landscape context; and 

development of environmental indicators to directly inform 

local, rural land-use planning.

Four factors affect development in rural landscapes: 

urbanization; conversion of natural areas to agriculture or 

intensive forestry; abandonment of agricultural land; and exurban or rural development of resorts, second homes, vacation 

homes, or ranchettes. Exurban development is increasingly 

stimulated by environmental and recreation amenities. Ecological consequences of land-use change are rarely considered. 

Improvement in access to scientific information could help 

identify potential changes resulting from land use. Realistically, it may take decades to centuries to clearly demonstrate 

consequences of natural resource policies.

Complex policies at all levels of government regulate 

natural-resource use throughout the United States, but consideration of ecological effects of land-use change generally does 

not fit well within traditional governmental hierarchy. Policy 

makers often lack high-quality regional-scale information 

about existing ecological conditions and potential implications 

of land-use change. Although governments, in particular the 

federal government, want to judge success of environmental 

policies based on quality outcomes, adoption of “performancebased” environmental policy have been hampered by lack of 

reliable scientific information. 

Landowners must be involved and empowered if landuse planning is to be effective. Planning must be regional, but 

problems are exacerbated as planning areas become large. 

Major problems arise from the lack of institutional establishment to conduct eco-regional or cross-ownership planning. It 

is often difficult to demonstrate the effects of individual landuse changes which may have significant impact on long-term 

ecological issues. A significant challenge is to integrate data 

from a variety of agencies into a cohesive, consistent database 

to make information accessible and useable. Credibility of 

projects or programs is at risk if sufficient amounts of data 

showing results do not meet stakeholder expectations. Farmers and ranchers often have abundant knowledge of ecological 

conditions and use of natural resources in local areas. This 

information is often richer than information furnished by 

governmental agencies. Integrating this information is critical 

to improve the quality of decisions. 

Authors conclude there are few examples of organized 

and systematic efforts to evaluate and learn from applied 

projects in regional land-use planning. There is a mismatch 

of spatial and time scales where ecologists have the greatest 

understanding and those upon which land use occurs. Systematic evaluations of how land-use decisions are influenced 

by ecological information is needed. Improving the relevance 

of ecological science requires critical evaluation. The critical 

component of adaptive management is missing in land-use 

planning, monitoring, and evaluation. 

U.S. Department of Agriculture, 2001, Food and Agricultural 

Policy— Taking stock for the new century: Washington, 

D.C., U.S. Department of Agriculture, 120 p.

Meeting society’s demands for improved environmental 

quality requires a broad definition of output, including environmental amenities represented by rural landscapes, wildlife, 

wetlands, and improved water/air quality. Currently, 92 cents 

of every dollar spent on conservation payments are associated with idling environmentally sensitive land. Farming no 

longer anchors most rural economies. The economic foundations in seven out of eight rural counties are now dominated 

by mixes of manufacturing and other non-farming activities. 
22 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography 

How farming and agricultural policies address environmental 

issues is a matter of both public and private concern. While 

agricultural production has doubled over the past 50 years, 

farm numbers dropped by more than two-thirds. Program 

crops were grown on almost every farm in the 1930s but 

account for only 20 percent of total value of all agricultural 

sales today. 

Farmers and farm households have goals representing differing stages of business development. The smallest 

economic sales class of farms (27 percent) view farming as 

a primary occupation and the rest are either retired or consider farming as a secondary occupation. In 2001, there were 

175,000 commercial farms with sales above $250,000/year. 

This group of producers (8 percent of all farms) accounts for 

68 percent of total farm output. Sixty-two percent of farmers 

combine non-farm income with farm income or are retired 

and view farming as in investment opportunity and a way to 

enjoy rural life. About 650,000 farms consider farming the 

primary occupation and share goals with both commercial 

farms and rural-residence farms. Commercial farms account 

for 68 percent of production and 29 percent of land use. Most 

farms fall in the rural-residence category and occupy 71 percent of land owned by farmers. 

Public expectations reflect concerns about environmental 

preservation and enhancement. Government price-support 

programs have encouraged unneeded output from the most 

efficient producers and have pushed surpluses higher and 

prices lower. Current program benefits still are directed to 

specific commodity producers resulting in only 40 percent 

of farms being recipients. In 1999, 47 percent of payments 

went to large commercial farms, which contributed nearly 

half of commodity production and had average household 

income of $135,000. The impact of income from any source 

on land values depends on whether that income is viewed as 

permanent or transitory. Private farmers and ranchers own 

and manage two-thirds of the Nation’s land. Stewardship 

costs are borne by land managers, but benefits serve society 

at large. Meeting society’s demands for environmental quality 

demands a broad definition of agricultural output to include 

environmental amenities. Conservation programs can provide 

incentives and compensate land managers for all products, 

including environmental benefits. Conservation programs are 

an important source of income for small or intermediate ruralresidence farms. Issues of growing public concern include 

open space, nutrient management, pesticide use, greenhouse 

gas emissions, water quality, wildlife habitat, pathogens, 

and antibiotic resistant bacteria. The greatest challenges in 

formulating the next generation of conservation policy are to 

address multiple environmental problems, support rural communities, and make efficient use of funds. The benefits and 

costs of removing land from production must be in balance 

with conservation and environmental performance on lands 

that remain in production.

U.S. Government Accountability Office, 2004, Environmental 

indicators—Better coordination is needed to develop environmental indicator sets that inform decisions: Washington, 

D.C., U.S. Government Accountability Office GAO–05–52, 

115 p.

Despite decades of activity and billions of dollars spent, 

the United States is incapable of producing a comprehensive 

picture of environmental or natural-resource conditions or 

trends. Challenges include selecting the most appropriate 

indicators and sustaining a balanced long-term effort to obtain 

data of sufficient quality that link environmental outcomes 

to obtain a comprehensive assessment of environmental 

conditions. Individual federal agencies are missing opportunities to improve data quality by not integrating work with 

similar objectives.

Environmental indicators are powerful tools for communicating information on complex environmental issues—these 

tools make information comprehensible and accessible. The 

development of indicators requires investments of time and 

resources as well as sustained leadership and commitment. It 

is not a short-term process. Issues that present challenges to 

the development of indicators include assuring that a sound 

process is used. The development of indicators can be an 

intensive political process; therefore, it should be a collaborative course of action. Obtaining data of sufficient quality is a 

major challenge. Coordinating and integrating various indicator sets is necessary to maximize results. The federal government lacks an organizational framework to provide a consistent basis for working with state or non-governmental sources 

of information. A major difficulty is linking management 

actions and environmental resources and trends that address 

the time lag between management actions and measurable 

results. To address this issue, a focused long-term commitment 

is needed. 

Indicators must be measurable, relevant, of appropriate geographic scale, understandable, based on data that are 

available and of sufficient quality, reflect appropriate temporal scale, and yield information that is comparable to other 

sources of data. In the United States, for example, hundreds 

of agencies collect water-quality data, but there is not enough 

information to furnish a comprehensive assessment at the 

national level because various ways are used to collect the 

data. The lack of coordination, communication of common 

goals, and integration of data constrains the effectiveness 

of monitoring efforts and is a long-standing problem yet to 

be solved. 

Warner, R.E., Etter, S.L., David, L.M., and Mankin, P.C., 

2000, Annual set-aside programs—A long-term perspective of habitat quality in Illinois and the Midwest: Wildlife 

Society Bulletin, v. 28, no. 2, p. 347–354.

Authors conclude that although the CRP has been beneficial, its future is uncertain because of its high cost. Long-term 

conservation strategies must include grassland preserves and 
Agricultural Ecosystems 23

development of relatively sustainable farming systems that 

accommodate needs of grassland dependent species. Shortterm contracts must be at least 3 years and support vegetative 

cover that is present from year to year. The relative benefits 

of native versus introduced grasses are presented as being 

unknown. The authors believe there is growing evidence that 

fields of cool-season grasses or forage legumes may be more 

attractive to nesting birds than are CRP grasslands planted 

to native species. Emphasis on native species may not be 

warranted when, for the typical landholder, seeding of native 

species requires specialized equipment and several years for 

the stand to become established. 

Wu, J., 2005, Slippage effects of the Conservation Reserve 

Program—Reply: American Journal Agricultural Economics, v. 87, no. 1, p. 251–254.

In response to the review, reanalysis, and criticism stated 

by Roberts and Bucholtz (see above) Wu states conceptual 

problems with his original analysis (see below) do not exist. 

He argues their central point of regional variation in CRP acreage being a non-influencing external variable is inconsistent 

with CRP implementation rules and data. Wu believes their 

misidentification of slippage effects arise from acceptance of 

a wrong assumption that the CRP has no impact on cropland 

values and price feedback effect is affecting only a small 

region. Wu points out the analysis of Roberts and Buchotz 

indicates a slippage rate in the Corn Belt ranging between 

13 and 45 percent. Wu provides further arguments defending 

conclusions drawn in his original analysis.

Wu, J., 2000, Slippage effects of the Conservation Reserve 

Program: American Journal Agricultural Economics, v. 82, 

no. 4, p. 979–992.

An unintended impact of conservation easements in 

agricultural ecosystems is the entry of non-cropland into crop 

production. This slippage effect is believed to result in 20 

acres of land put into production for each 100 acres of land 

enrolled in the CRP offsetting water and wind erosion benefits 

by 9 percent and 14 percent respectively. Substantial slippage 

effects described in this analysis suggest the issue should be 

targeted in future conservation policies. The author suggests 

relaxing program rules to allow inclusion of non-cropland 

that offers large environmental benefits, but would otherwise be converted to crop production, would reduce slippage 

effects and improve performance of conservation programs. 

Reduction of slippage effects would improve environmental 

performance of land retirement programs and increase supply 

control of commodities produced. 

Yost, M, 2005, The quest for quantifying Conservation 

Reserve Program benefits, in Transactions of the North 

American Wildlife and Natural Resources Conference, 69, 

Spokane, Wash., March 16–20, 2004, Proceedings: Washington, D.C., Wildlife Management Institute, p. 20–29.

The report contains a discussion by the Associate Administrator of the FSA about the importance of farmland conservation and FSA attempts to improve the CRP and the need to 

document and quantify environmental benefits brought by the 

program. A discussion of how the CRP has evolved is presented. The argument is made that to insure future funding and 

the existence of the program, results will have to be measured 

and communicated beyond the agricultural and conservation 

communities. The author states that agencies that cannot effectively show results of their programs cannot justify budget 

requests and will be less likely to be funded. Descriptions of 

existing and proposed FSA funded projects to assess the environmental effects of the CRP are provided.

Zinn, J., 1993, The next generation of U.S. agricultural conservation policy: Ankeny, Iowa, Soil and Water Conservation 

Society, 40 p.

White paper based on results from National Soil and 

Water Conservation Society forum (March 14–16, 1993) 

of stakeholders and interest groups to assess how current agricultural policies are working. The paper provides 

detailed summaries of current strong and weak points pertaining to the effects of agricultural policies on environmental 

issues. Regional focus-group results present a summary of 

problems and potential solutions to agriculturally related 

environmental issues.

Agricultural Ecosystems

Allen, A.W., 1995, Agricultural ecosystems, in LaRoe, E.T., 

Farris, G.S., Puckett, E.E., Doran, P.D., and Mac, M.J., 

eds., Our living resources—A report to the Nation on the 

distribution, abundance, and health of U.S. plants, animals, 

and ecosystems: Washington, D.C., U.S. Department of the 

Interior, National Biological Service, p. 423–426. 
24 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography 

A summary of the historical effects of agricultural production on the quality and distribution of wildlife habitats is 

presented. The brief report includes a discussion of preliminary results of multi-state monitoring of grassland characteristics in undisturbed fields in Southern Plains and Midwestern 

CRP fields. An overview of CRP benefits to wildlife populations associated with agriculturally dominated landscapes 

is presented. 

Banks, J.E., 2004, Divided culture—Integrating agriculture 

and conservation biology: Frontiers in Ecology and Environment, v. 2, no. 10, p. 537–545.

High-production agriculture with associated simplification of ecosystems, dependence upon chemical inputs, and 

emphasis on yield often appears at odds with conservation, but 

they share a common ecological foundation. Communication 

and cooperation between the two fields is vital to lessening 

environmental impacts associated with agriculture. Holistic 

approaches to incorporating landscape perspectives are needed 

to define better integration of conservation and agriculture. A 

better understanding of how spatial scale interacts with biotic 

and abiotic processes is needed. Real progress in reaching 

a more sustainable level of agriculture will require a shift 

from large-scale agriculture, heavily dependent upon chemical inputs, to medium-scale farming with greater reliance 

on nature-mimicking processes. The ultimate challenge is 

to maximize yields while minimizing environmental costs. 

The greatest opportunities for improving relations between 

agriculture and conservation are gathering information across 

several spatial scales, understanding values and motives of 

stakeholders, defining biotic and abiotic forces and cycles 

at the landscape level, and understanding how policies and 

incentives influence relations between production and conservation at various scales. 

Boody, G., Vondracek, B., Andow, D.A., Krinke, M., Westra, 

J., Zimmerman, J., and Welle, P., 2005, Multifunctional 

agriculture in the United States: Bioscience, v. 55, no. 1, 

p. 27–38.

Potential changes in farming practices are evaluated 

in two Minnesota watersheds to determine how changes in 

farm policy may affect environmental, social, and economic 

outcomes. Authors conclude that environmental and economic 

benefits from farming can be attained through change in 

agricultural land management without increasing public costs. 

Benefits include improved water quality, healthier populations 

of fish, increased C sequestration, decreased greenhouse gas 

emissions, and greater farm profitability. Policy transitions that 

emphasize environmental functions and products in addition to 

food production are essential. Suggestions for redirecting farm 

payments toward “green box” issues could lead to substantial 

environmental change and public benefits. 

Minnesota residents indicate they are willing to provide incentives for significant changes in environmental 

benefits associated with agricultural production. Members 

of the public who were surveyed indicate a desire to develop 

public policy, research, education, and marketing strategies to 

promote greater diversification of food and fiber production 

that will lead to environmental and social benefits. Many current government programs and land-grant university systems 

focus too closely on too few crops and reinforce production 

of traditional commodities. Local institutions need to change 

along with farmers. Focus groups state that present commodity programs discourage diversification in farming. U.S. farm 

policy should support agricultural diversity and nonmarket 

ecosystem services. Future programs should reward farmers 

for environmental benefits. Authors conclude that we cannot 

afford to sacrifice future agricultural productivity for the sake 

of short-term increases in commodity production. Dealing 

with worldwide food shortages will require a future agriculture 

that produces rather than consumes ecosystem benefits.

Brady, S.J., 1985, Important soil conservation techniques that 

benefit wildlife, in Technologies to Benefit Agriculture and 

Wildlife—Workshop Proceedings: Washington, D.C., U.S. 

Congress, Office of Technology Assessment, OTA–BP–F–

34, p. 55–62.

Relations between increasing row-crop production, 

rates of soil erosion, nonpoint sources of water pollution and 

decreasing wildlife associated with farmlands are presented. 

Two principal reasons for degradation of wildlife habitats are 

identified as intensive use and management of agricultural 

lands and extensive cultivation of ever-enlarging fields resulting in demise of needed vegetative covers. Important soil-conservation management practices (for example, conservation 

tillage, grassed terraces, crop rotation) and their implications 

for wildlife are discussed.

Brady, S.J., and Flather, C.H., 2001, Estimating wildlife habitat trends on agricultural ecosystems in the United States, 

in Agriculture and Biodiversity—Developing indicators for 

Policy Analysis: Organization for Economic Co-operation 

and Development expert meeting, Zurich, Switzerland, 

November 2001, Proceedings: Zurich, Switzerland, Organization for Economic Co-operation and Development, 

p. 156–167.

Wildlife response to the management of habitat exhibits 

great variability over time and space. There remains much to 

be learned about ecological process and functions, particularly 

as they relate to wildlife associated with agricultural ecosystems. Consequently, effective management of wildlife habitat 

remains a combination of both science and art. Land use is the 

principal factor determining the base level of abundance of 

indigenous species, which in most cases has a greater impact 

of species abundance than does management of land. Land 
Agricultural Ecosystems 25

use has both direct and indirect effects on wildlife. While 

use of land is relatively easy to document, assessment of 

wildlife habitat quality and wildlife numbers is more problematic. Population density is often an inaccurate estimator of 

habitat quality.

Authors present Natural Resources Inventory (NRI) data 

by USDA Farm Resource Regions and USGS hydrologic 

units. The effects of land use, cover type, spatial patterns, 

USDA conservation programs, and agricultural activities on 

wildlife are discussed. Authors conclude that the CRP has 

been one of the most beneficial programs for enhancement of 

wildlife in the United States, citing data that wildlife habitats 

created by the program are twice as large as the combined area 

of the National Wildlife Refuges System and all state-owned 

wildlife areas in the contiguous United States. The environmental effects of other USDA conservation programs (EQIP, 

WHIP) are discussed briefly. The authors note the effects of 

other conservation practices (conservation tillage, grass terraces, grass border strips, etc.) on lands remaining in active 

production of crops have beneficial effects to wildlife but 

are not immediately obvious or easy to quantify. The authors 

conclude by recommending a landscape-level approach to 

the quantification of wildlife-habitat indicators. As indicators of habitat quality are developed for monitoring purposes, 

they must be tested and refined based on empirically derived 

patterns of biodiversity and basic verification of the presence/

absence of a species on the landscape.

Brown, D.G., Johnson, K.M., Loveland, T.R., and Theobald, 

D.M., 2005, Rural land-use trends in the conterminous 

United States, 1950–2000: Ecological Applications, v. 15, 

no. 6, p. 1851–1863.

Though land-use trends affect ecological systems, spatially explicit data on these changes are difficult to obtain. The 

authors provide an evaluation of land-use trends in the United 

States during the latter half of the 20th century. Agricultural 

land use has had important effects on ecological systems 

throughout the history of North American European settlement. Agricultural land has declined in the United States in the 

20th century due to the conversion to other uses and abandonment of marginally productive land. The goal of the report is 

to summarize patterns of change in settlement and croplands 

in the United States between 1950 and 2000. 

Although the focus of the report is on the eastern and 

southeastern United States, data are furnished for the entire 

country. Population gains in the last 50 years were smallest 

in the Northeastern forest region, Eastern Temperate forest 

region, and Great Plains. Western regions have grown at rates 

well above the national average. The agricultural heartland, 

including the Great Plains, experienced widespread population losses during this 50-year period. Other areas experiencing loss included the Mississippi Delta and the Appalachians. By 2000, 81 percent of the U.S. population resided in 

metropolitan areas. 

Across the United States, cropland area decreased by 

11 percent between 1950 and 2000. Decreases in cropland 

were most consistent in eastern regions; cropland declined by 

nearly 50 percent in the Northern Forest region. Cropland area 

stayed relatively consistent in the Corn Belt and Great Plains, 

although both regions experience substantial declines in 

human population. Declines in cropland areas can be partially 

explained by increases in productivity and intensification in 

remaining agricultural lands but decreases were most dramatic 

in metropolitan counties where cropland was lost to urban 

expansion. In northern forest regions cropland also went back 

into more natural covers. The Great Plains and other western 

areas did have pockets of agricultural expansion in the last 

half of the 20th century due to irrigation. These areas were 

primarily along the Columbia River, Snake River, and high 

plains of western Kansas. Cropland decreased by 22 percent 

east of the Mississippi River. The trends in exurban growth 

and conversion and abandonment of agricultural lands, especially in the eastern United States, have important ecological implications as they affect large areas and functioning of 

ecological systems.

Büchs, W., 2003, Biodiversity and agri-environmental indicators—General scopes and skills with special reference to the 

habitat level: Agriculture, Ecosystems, and Environment, 

v. 98, p. 35–78.

The author furnishes a discussion of biodiversity and 

habitat concepts in relation to development of environmental 

quality indicators in agricultural ecosystems. The presentation 

is based largely on the assumption that biodiversity equates 

to species richness. Requirements for use of indicators are 

presented (using mostly invertebrates as examples) as well 

as issues pertaining to development and use of indicators, 

baseline data, sample size, selection of species, and frequency of surveys. Using specific examples, the author shows 

biodiversity can be a misleading indicator of environmental 

quality. A discussion on the use of indicators by administrators 

is furnished which describes administrators’ expectations that 

indicators are easy to assess, understand, and predictions are 

easy and can be expressed by numerical measures. Generally, 

an expectation is that one biotic indicator is able to represent 

an entire ecosystem. Administrators tend to aggregate data and 

favor reduction in number of indicators used. This tendency 

increases with administrative level, often resulting in use of 

highly aggregated indicators with weak representation of ecosystem characteristics or conditions. 

Carpenter, J., Felsot, A., Hammig, M., Onstad, D., and 

Sankula, S., 2002, Comparative environmental impact of 

biotechnology-derived and traditional soybean, corn, and 

cotton crops: Ames, Iowa, Council for Agricultural Science 

and Technology, 189 p.
26 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography 

Report furnishes a literature review on environmental 

impacts of biotechnology-derived soybean, corn, and cotton 

crops. In 2001, biotechnology derived seed was planted on 

46 percent of global soybean acres, 7 percent of corn acres, 

and 20 percent of cotton acres. Of all biotech crops planted in 

2001 (52.6 million acres globally), 77 percent were tolerant 

of specific herbicides, 15 percent resistant to selected insects, 

and 8 percent were resistant to both herbicides and insects. 

Major reasons for the adoption of biotech crops are lowered 

production costs, reduced crop injury, and flexibility in weed 

management. Biotech herbicide-tolerant soybean production 

has facilitated adoption of conservation tillage. No-till soybean 

acreage in the United States has increased by 35 percent since 

the introduction of herbicide-tolerant soybeans. No-till soybean acreage has also resulted in a decrease of soil erosion and 

dust and favored more efficient land use by more narrow-row 

spacing of crops. Biodiversity in the authors’ state is maintained by adoption of biotech crops as soil microbes, beneficial insects, and bird populations—these methods were not 

different from those observed in conventionally tilled fields. 

Biotech varieties of corn and cotton allow a less persistent use 

of herbicides in the environment and reduce risks of herbicide 

run-off into surface waters. Adoption of biotech crops generally decreases production costs and enhances range of management options available for whole-farm planning.

A detailed review and discussion of potential impacts 

and benefits of biotech crops are presented. While the authors 

conclude that biotech crops have been economically, environmentally, and socially beneficial, they do recommend 

large-scale and farm-scale studies be completed to document 

long-term environmental effects related to the growing use of 

these crops. 

Cassman, K.G., Dobermann, A., Walters, D.T., and Yang, 

H., 2003, Meeting cereal demand while protecting natural 

resources and improving environmental quality: Annual 

Review of Environment and Resources, v. 28, p. 315–358.

Food-production systems have a large influence on 

associated environmental quality. Lands used for crop production and pasture account for 38 percent of world land base. 

Irrigation accounts for 80 percent of all fresh water use on 

global scale. Conversion of natural ecosystems to agricultural 

production results in simplified agroecosystems with resultant 

reduction in bio-diversity and decreased availability of habitats. Maize, rice, and wheat account for about 60 percent of all 

human calories consumed either as direct food for indirectly 

as feed grains. Worldwide demand for cereal grains (largely 

for use in animal feeding) is projected to increase by about 

1.3 percent annually until 2025. Recent trends and future 

trajectories in crop yields, land, fertilizer use, C sequestration, 

and greenhouse-gas emissions in are discussed, as are key 

issues and challenges in meeting growing demands for foods. 

Authors conclude that lessening the expansion of cultivation into remaining natural ecosystems, more efficient use of 

N, and techniques to improve soil quality will be key issues 

in agricultural sustainability. The authors also conclude that 

maintaining the sustainability of agricultural ecosystems will 

depend upon increasing the yield potential of cereal crops 

which is an elusive goal. 

Authors believe a socially acceptable, proactive agriculture will be required to sustain demands for food and environmental quality on a global scale. Policies will have to be 

directed toward the intensification of production on existing 

prime agricultural land while avoiding further depletion of 

natural ecosystems. Substantial investment in research to support scientific advances of new technologies will be required.

Castrale, J.S., 1985, Responses of wildlife to various tillage 

conditions, in Transactions of North American Wildlife 

and Natural Resources Conference, 50, Washington, D.C., 

March 15–20, 1985, Proceedings: Washington, D.C., Wildlife Management Institute, p. 142–156.

The report provides a discussion of minimum tillage 

practices on wildlife use of agricultural fields, (primarily 

corn and soybeans). Three factors are major contributors to 

wildlife use of fields, food availability, vegetation structure, 

and disturbance. Under most circumstances, the availability of 

insects probably does not limit wildlife populations in agricultural fields. Preferred foods may be readily available in corn 

and soybean fields, but a lack of adequate cover or vegetation characteristics may prevent some species from using 

resources present. 

Carroll, C.R., 1992, The interface between natural areas and 

agroecosystems, in Carroll, C.R., Vandermeer, J.H., and 

Rosset, P., eds., Agroecology: New York, McGraw-Hill, 

p. 365–383.

Farming systems generate weedy phenotypes including plants, animals, and pathogens that may become invaders 

of natural areas. Furthermore, crops may become important 

food sources for certain pest species, which contributes to the 

distortion of their impact on other populations of wildlife (for 

example, crows, jays, and raccoons whose enhanced populations seriously threaten other less abundant species of nesting 

birds). Landscapes dominated by agricultural production may 

have a significant effect on the ability of embedded natural 

areas to support endemic species. Natural ecosystems become 

fragmented, which increases boundary phenomena and results 

in the elevation of edge impacts. Loss of natural areas generally means that remaining patches are increasingly isolated; 

consequently, re-colonization is difficult—this increases the 

likelihood of local extinctions. Most of these impacts are 

cumulative and proceed as a consequence of many independent decisions made without regard to possible combined 

effects of changing land use. 

In absence of active management, most small natural 

areas begin to degrade and become less representative of 

the original ecosystem. Small sites typically require more 
Agricultural Ecosystems 27

management effort per unit area than required for large areas. 

The long-term security of natural areas in agricultural landscapes will depend strongly on the way the land surrounding the natural area is used. Beneficial use of surrounding 

lands must be economically sustainable, socially equitable, 

and explicitly linked with management objectives in the 

embedded natural area. Design of agricultural areas should 

be clearly related to the ecological management goals of 

the natural area. Buffer zone activities should be able to be 

modified to meet new contingencies and sufficiently flexible 

so changes can be made without drastically disrupting local 

economy. Buffers should not be sensitive to rapid change in 

market prices, rising production costs, decreasing returns, nor 

should they rely on intensive use of agrochemicals, fire, or 

other methods that may strongly impact nearby natural areas. 

Danielson, B.J., 1992, Habitat selection, interspecific interactions and landscape composition: Evolutionary Ecology, 

v. 6, no. 5, p. 399–411.

The author describes three types of habitat: (1) source: 

reproduction exceeds mortality, (2) sink: limited reproduction 

but will not, on average, compensate for mortality, and (3) 

unusable: comprises the matrix of all habitats never exploited 

by the species. Patches of source and sink habitat are embedded in unusable habitat. By restoring landscapes to natural 

state, it is seldom possible to preserve population and community characteristics that have evolved under natural conditions. It may be possible to compensate for fragmentation 

where unusable habitats have increased by clustering patches 

of usable habitat and connecting patches with dispersal corridors. Spatial dimensions of landscape must be defined by the 

ecology of the species in question and management concern. 

Doak, D.F., Marino, P.C., and Kareiva, P.M., 1992, Spatial 

scale mediates the influence of habitat fragmentation on 

dispersal success—Implications for conservation: Theoretical Population Biology, v. 41, no. 3, p. 315–336.

Habitat heterogeneity has different and conflicting 

effects on animal movement at various scales. Explicit 

consideration of scale is essential in discussion of habitat 

fragmentation and identification of optimal conservation 

strategies. A major impact of fragmentation is the disruption 

of animal dispersal. Fragmentation is dependent upon two 

scales: relative size of the habitat fragments and the spatial 

scale at which these fragments are arranged. When fragmentation is unavoidable, clustering habitat fragments may 

minimize dispersal mortality. The spatial scale of clustering 

must be defined. Clustering seems to have a positive influence 

on dispersal success. Scale effects risks of mortality, degrees 

of connectedness or independence among patches and the 

influence of environmental catastrophes. 

Duelli, P., and Obrist, M.K., 2003, Biodiversity indicators—

The choice of values and measures: Agriculture, Ecosystems, and Environment, v. 98, p. 87–98.

Ideally, a linear relationship exists between an indicator 

and this relationship accurately reflects an aspect of biodiversity under evaluation. Unfortunately, this is rarely the case, 

as it a difficult relationship to establish and problematic to 

prove. Motivations for assessing biodiversity aspects are based 

on different value systems. Because the total evaluation of 

biodiversity on even small areas is logistically and economically prohibitive, scientifically reliable and repeatable indicators must be identified. Use of biodiversity as an indicator 

requires clear definitions of terms, use, and objectives. There 

is no single indicator for biodiversity. Difficulties and concepts in choosing biodiversity indicators for several levels of 

assessment (protection of rare species, ecosystem functioning, pests and biological control) in agricultural ecosystems 

are discussed. To achieve greater reliability and acceptance, 

indicators must be tested to determine their correlation with 

the ecological values they are supposed to represent.

Egbert, S.L., Park, S., Price, K.P., Lee, R.Y., Wu, J., and Nellis, M.D., 2002, Using Conservation Reserve Program maps 

derived from satellite imagery to characterized landscape 

structure: Computers and Electronics in Agriculture, v. 37, 

p. 141–156.

The report describes multi-seasonal Landsat thematic 

imagery used to produce maps of cropland and grassland for 

1987 and 1992 for Finney County, Kansas. A spatial-analysis 

program was used to calculate number of patches, mean patch 

size, patch density, edge density, shape index, nearest neighbor 

distance, and interspersion index. Total grassland area and percent area in grassland as a consequence of CRP was also measured. Results imply species requiring large areas of contiguous grassland habitat have experienced gains in habitat quality. 

Maps of CRP using this methodology are cost-effective for 

mapping large areas and sufficiently accurate for use in modeling environmental effects of CRP. Techniques described in 

the study could be used in monitoring landscape changes over 

time as CRP enrollments and distribution change.

Farris, A.L., and Cole, S.H., 1981, Strategies and goals for 

wildlife habitat restoration on agricultural lands, in Transactions of North American Wildlife and Natural Resources 

Conference, 46, Washington, D.C., March 21–25, 1981, 

Proceedings: Washington, D.C., Wildlife Management 

Institute, p. 130–136.

Indicators of negative changes in farmland wildlife habitat quality include increased urbanization of agricultural land, 

enlarged size of farms, increasing acres devoted to row crops, 

decreased production of small grains, diminished area in wild/

tame hay and pasture, larger field size, continued loss of edge, 

fence rows, farmsteads, wetland, and idle lands. All these 
28 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography 

factors have contributed to reductions in numbers and diversity of wildlife. Agricultural policy is the primary influence 

on agricultural land use and farmland wildlife habitat. Native 

grasses, while taking more care and time to establish, provide 

excellent erosion control with significantly lower cost and 

energy expenditure than introduced species. Long-term benefits of native grasses over introduced, cool-season grasses are 

significant. In most cases, cutting for hay should be delayed 

until after July 15 when the majority of avian species have 

their young off the nests. Cost sharing for farmers that devote 

a minimum percentage of cropped acreage to permanent cover 

capable of supporting wildlife should be adopted. Authors 

suggest that 4 to 5 percent of the landscape in permanent cover 

probably is sufficient to bring benefits to many wildlife species 

associated with agricultural landscapes. 

Felix, J., and Owen, M.D.K., 2004, Weed seedbank comparison in Conservation Reserve Program and adjacent fields 

under continuous cultivation: Weed Technology, v. 18, 

no. 1, p. 45–51.

The report describes soil samples (n=1,260) collected 

in 63 Iowa counties to describe weed seedbanks in CRP and 

adjacent fields under continuous cultivation. CRP fields were 

described as being planted to orchardgrass (Dactylis glomerata), smooth bromegrass (Bromus inermis), big bluestem 

(Andropogon gerardii), and switchgrass (Panicum virgatum). 

Cultivated fields were planted with either corn (Zea mays) or 

soybeans (Glycine max). Five annual grasses and 13 broadleaf 

weed species were identified in both CRP and cultivated fields. 

Weed species diversity was not significantly different between 

CRP and cultivated fields. Sweetclover (Medicago sativa) seed 

populations were consistently higher in CRP because it was 

included as part of cover seeding when stands were established. Overall, broadleaf weeds comprised 90 percent of the 

seedbanks in both types of fields. CRP grassland cover probably reduced weed seedbanks due to suppression of weeds and 

seed production. Annual seed production, differences in biology, and herbicide performance in cultivated fields may have 

contributed to higher production of weeds in these fields. 

Study results describe larger seedbank of weeds in 

cultivated fields than found in CRP. Successful establishment 

of CRP grassland cover likely played a significant role in the 

reduction of weed-seed densities in program fields. Consequently, farmers returning CRP land to crop production are not 

likely to experience a shift in weed-species composition and 

may see lower populations of weeds than found in adjacent 

cultivated fields. The lower population density of weeds in 

former CRP could be an advantage to farmers switching to 

organic farming or reduced usage of herbicides.

Freemark, K., 1988, Agricultural disturbance, wildlife, and 

landscape management, in Moss, M.R., ed., Landscape 

ecology and management: Guelph, Ontario, Canadian Society for Landscape Ecology and Management Symposium, 

p. 77–84.

The report provides a discussion of an investigation of 

bird-species richness and reproduction in forested habitats 

impacted by agriculture. Wildlife in agricultural landscapes 

is subject to disturbances such as habitat fragmentation and 

pesticides, which affect spatial and temporal distribution of 

wildlife. Understanding relations between landscape structure, 

disturbance, and distribution of wildlife is needed to develop 

better management strategies to minimize impacts and enhance 

the persistence of wildlife communities in agriculturally 

dominated landscapes. 

Freemark, K., 1995, Assessing effects of agriculture on terrestrial wildlife—Developing a hierarchical approach for the 

U.S. EPA: Landscape and Urban Planning, v. 31, p. 99–115.

Given the intensive and extensive effects of agriculture, 

there is a need to develop a conceptual and scientific basis to 

promote sustainable agricultural practices that enhance environmental priorities associated with agricultural ecosystems. 

Retrospective analysis may provide insights into the range 

of possibilities for future landscape design and management 

scenarios in a given area. A major limitation of many previous 

studies of wildlife associated with farmland has been the focus 

on detailed studies of small plots with little regard to larger 

spatial scales.

Fry, G.L.A., 1991, Conservation in agricultural ecosystems, in 

Spellerberg, I.F., Goldsmith, F.B., and Morris, M.G., eds., 

The scientific management of temperate communities for 

conservation: Oxford, Great Britain, Blackwell Scientific 

Publications, p. 415–443.

Protected areas alone cannot achieve conservation goals 

such as the maintenance of biological diversity. Incorporation 

of conservation measures in farm management will demand 

clear recommendations based on sound theory and evidence 

gained through practical trials. Maintenance or enhancement 

of habitat quality for a wider range of plants and animals will 

require better understanding of ecological processes at site, 

field, and landscape levels. Lack of understanding of processes 

involved in animal distribution, ways in which species use 

corridors, and what constitutes barriers is a constraint in effectively designing and managing habitats. One limitation of many 

investigations of habitat and wildlife on farmland is a lack of 

regard for management of adjacent fields or the surrounding 

landscape. The abundance of many species comprising animal 

communities on farmland is controlled largely by few environmental factors. Both the timing and severity of agricultural 

practices are important factors governing the potential of agricultural lands as wildlife habitat. Extending the width of field 

margins farther into the cropped fields is one way of increasing 

habitat diversity on arable lands. In many situations management decisions will need to be implemented without thorough 

assessment of the impacts on wildlife.
Agricultural Ecosystems 29

Gall, G.A.E., and Orians, G.H., 1992, Agriculture and biological conservation: Agriculture, Ecosystems and Environment, v. 42, p.1–8.

Agriculture is the dominant form of land management on all continents. There has been a dramatic increase 

in the intensity of management and capital investment in 

agriculture following WWII. Prior to the latter half of the 

1940s, agriculture was sufficiently inefficient that habitats 

were inadvertently provided for many species of wildlife. 

As management intensity increases, multiple uses of land 

decline. As prices of agricultural commodities increase, there 

is a corresponding decrease in recreational, aesthetic uses 

and values associated with agricultural lands. Adoption of 

more intensive agriculture on suitable lands enables more 

food to be produced per unit area. As a result, pressures on 

marginal agricultural land could be reduced, making the 

land available for conservation practices that contribute 

not only to on-site habitat but enhancement of downstream 

environmental quality. 

Gilpin, M., Gall, G.A.E., and Woodruff, D.S., 1992, Ecological dynamics and agricultural landscapes: Agriculture, 

Ecosystems and Environment, v. 42, p. 27–52.

Many parts of society see conflict between conservation 

of biological resources and agricultural production. Agriculture is an essential element of society which can provide 

stewardship of biological resources, but interdisplinary 

efforts are needed in development of strategies for conservation. Agriculture and conservation are not mutually exclusive 

and can be positively linked on local, regional, and global 

scales. Governmental policies that support agriculture often 

deny true economic costs and environmental consequences.

Gliessman, S.R., 1984, An agroecological approach to 

sustainable agriculture, in Jackson, W., Berry, W. and 

Coleman, B., eds., Meeting the expectations of the land—

Essays in sustainable agriculture and stewardship: San 

Francisco, Calif., North Point Press, p. 160–171.

The underlying theme of this paper is “can research 

address questions of how agriculture can be more in balance 

with the natural environment and depend less upon costly 

chemical inputs?” A framework for long-term sustainability 

of agricultural systems and environmental values must be 

established. Agricultural ecology is based on the premise that 

the short-term, mainly economic focus of food production 

must be redirected toward long-term management based on 

cycles and interactions found in natural systems. 

Hansen, A.J., Knight, R.L., Marzluff, J.M., Powell, S., Brown, 

K., Gude, P.H., and Jones, K., 2005, Effects of exurban development on biodiversity—Patterns, mechanisms, and research 

needs: Ecological Applications, v. 15, no. 6, p. 1893–1905.

Exurban development is a pervasive, rapidly growing form 

of land use understudied by ecologists which has large potential to alter biodiversity patterns over extensive areas. Exurban 

development, defined as low-density housing in landscapes 

dominated by native vegetation, is now the fastest growing form 

of land use in the United States. Since 1974, area in exurban 

land use has increased at rates in excess of area in urban or 

agricultural land use. Knowledge of exurban effects on land use 

and homeowner effects on biodiversity are poorly known, but 

potential impacts appear to be substantial. The richness of native 

species generally declines with increased exurban densities. 

Exotic species and native species adapted to human presence 

generally increase with the intensity of human development. 

These relations are generally nonlinear. Biodiversity trends are 

still likely responding to changes in development that began in 

the 1950s. Over time, exurban development often develops into 

suburban and urban forms of land use. 

Higgins, K.F., Naugle, D.E., and Forman, K.J., 2002, A case 

study of changing land use practices in the northern Great 

Plains, U.S.A., An uncertain future for waterbird conservation: Waterbirds, v. 25, p. 42–50.

The northern Great Plains is one of the most economically 

depressed sectors of the United States. Current provisions of 

the Farm Bill are often weighted to commodity production; this 

furnishes incentives to bring more marginal land into production. High rates of wetland drainage in the northern Great 

Plains, especially in the prairie pothole region, remain a threat 

to wetland bird populations. Loss of wetlands and associated 

upland covers threaten production of the 50 to 80 percent of the 

continental waterfowl population produced here. Thirty-nine 

species of shorebirds use Prairie Pothole Region (PPR) wetlands during migration or as breeding habitat. Eleven additional 

species of obligate wetland-breeding birds rely on PPR wetlands for nesting. Wetland losses have had a negative impact on 

migratory habitats. Native mixed-grass prairies historically used 

for grazing are under social and economic pressure to be put in 

tillage. Until recently, loss of mixed-grass prairie had occurred 

more slowly than conversion of tallgrass ecosystems to agriculture. About 60 percent of all native mixed grass prairies in the 

Dakotas and Montana have been converted to cropland. The 

productivity of waterbirds has declined dramatically in response 

to grassland losses. 

The conversion of grassland to cropland has increased 

grazing intensity on South Dakota rangelands. From 1977 to 

1997 1.4 million hectares (3.5 million acres) were converted 

to cropland and other developments in South Dakota. Loss of 

native rangelands, combined with decreases in number of farm 

families and conversion to larger more efficient equipment, 

has led to “cleaner” farming practices wherein idle non-farmed 

areas are eliminated and small wetlands areas are drained. 

These changes are expected to continue as more operators shift 

from diversified grain and livestock operations to monoculture 

grain production. A continuing trend to replace small graincrops with soybeans and corn also has a negative effect on the

quality of wildlife habitat. Development of drought-resistant, 
30 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography 

genetically modified soybeans has accelerated conversion of 

native grassland to cropland. New crop varieties have enticed 

producers to farm low-quality, drought-prone soils. Although 

wildlife benefits of the CRP have been impressive and well 

documented, data indicate native grassland continue to be 

tilled at the same time as lands are being enrolled in the CRP. 

More than one million acres have been converted to cropland 

in the Dakotas and Montana since 1985, despite conservation 

provisions of the Farm Bill. Since 1987, about 168,000 acres 

of grassland have been converted to cropland in eastern South 

Dakota due to western expansion of soybeans. Nearly 18 million acres of CRP in the northern Great Plains are almost the 

same area of native prairie converted to cropland in this area 

since the 1960s. 

The loss of grassland and wetland habitats continues to 

expand westward. Current land use and demographic factors 

indicate that the habitat protection programs most likely to 

succeed are those that encourage livestock ranching. Authors 

believe the most effective approach to preservation of waterbird habitat in the northern Great Plains is a broad suite of 

short and long-term programs and incentives that encourage 

preservation of family ranching operations. 

Jackson, D.L., and Jackson, L.L., 2002, The farm as natural 

habitat—Reconnecting food systems with ecosystems: 

Washington, D.C., Island Press, 297 p.

This book contains eighteen essays pertaining to common values shared by environmentally concerned non-farmers 

and agricultural producers. The essays address effects of 

agricultural policies (existent and proposed) on wildlife and 

environmental quality in agricultural ecosystems. Topics deal 

with sustainable agriculture, environmental restoration of 

agricultural ecosystems, and defining goals for landscape and 

ecosystem management. The text provides description and 

implications of industrialized agricultural effects on environmental quality and alternatives for ecosystem management in 

agricultural landscapes. An underlying theme throughout text 

is that farm policies need to address and promote nonmarket 

as well as market benefits in long-term policies. 

Jeanneret, P., Schüpbach, B., and Luka, H., 2003, Quantifying 

the impact of landscape and habitat features on biodiversity 

in cultivated landscapes: Agriculture, Ecosystems and Environment, v. 98, p. 311–320.

There are no general models relating overall species 

diversity to landscape diversity. A single statistic containing 

all information about the assembly of objects that a landscape 

represents is an unrealistic expectation. Although biodiversity 

is conceptually defined, its measurement remains controversial and largely defined by specific objectives, organisms 

examined, financial constraints in sampling, and observation 

techniques. Authors suggest arthropods are good candidates 

to represent biodiversity. However, species richness of one 

single group or of a small set of organisms is not sufficient to 

measure the different composition of species and comparisons 

between habitats, the species diversity function in ecosystems, and the impact of environmental explanatory factors 

on biodiversity. One single taxonomic group likely does not 

represent more than one or two functions in ecosystems. 

Groups of species are unlikely to react in the same way as 

other groups of species to ecosystem changes. The assessment 

of species composition and assemblages is a more appropriate 

approach to quantifying influence of environmental changes 

in agricultural landscapes. Spatial and temporal distribution of 

suitable habitats is the key variable in assessment of biodiversity in agriculturally dominated landscapes. Constraints and 

limitations in definition and use of species used as indicators are presented. Habitats and landscape parameters have 

varying impacts on measures of biodiversity depending upon 

which evaluation species are chosen. Consequently, one single 

indicator cannot summarize the biodiversity response. The 

authors argue that examination of species assemblages allows 

for a more comprehensive assessment of habitat and landscape 

effects on biodiversity measures.

Kessler, W.B., Salwasser, H.C., Cartwright Jr., W., and 

Caplan, J.A., 1992, New perspectives for sustainable natural 

resources management: Ecological Applications, v. 2, no. 3, 

p. 221–225.

Management of public lands and resources requires 

knowledge about ecosystems, including interrelations of 

human values, activities, and patterns of use; closer partnerships with managers to complete large-scale studies; and 

adaptive management of public lands and resources. Managers must respond to more complex views of public lands and 

their roles in meeting human needs and aspirations. Managers 

need to define objectives that relate to ecological and aesthetic 

conditions of the land stating a desired future condition to 

sustain land uses and resource yields. Grasslands are sustainable in nature by dynamic forces such as fire, flood, and grazing. These forces continually change vegetation patterns and 

processes that have major effects on biological diversity, water 

quality, and other values. The public must be well informed 

about the conditions, capabilities, and options for lands and 

resources and share in the knowledge that professionals accrue 

through research and management experience. Science must 

take into consideration the values and needs of people rather 

than concluding and dictating conclusions about what is 

good or bad for society from a strictly scientific and technical 

perspective. Changes in perspectives must address cumulative 

effects of management and landscape fragmentation. Systems 

must be looked at as whole rather than individual parts.
Agricultural Ecosystems 31

Kleijn, D., and Báldi, A., 2005, Effects of set-aside land on 

farmland biodiversity—Comments on Van Buskirk and 

Willi: Conservation Biology, v. 19, no. 3, p. 963–966.

Worldwide wildlife populations have suffered due to 

expansion and intensification of agricultural production. 

Policy developers in Europe and the United States have 

responded by initial attempts to reduce over-production and 

costs of price support and storage as well as specific attempts 

to address biodiversity and environmental quality. Long-term 

(for example, multi-year) removal of cropland from production has been a commonly used tool to reach these goals. The 

significant expenditures associated with this approach can, 

however, be justified only if scientific evaluations indicate that 

objectives are being met. 

These authors furnish criticism of a meta-analysis evaluation of biodiversity benefits of set-aside land completed by 

Van Buskirk and Willi (2004) (see below for their response) 

in North American and Europe where Van Buskirk and Willi 

reported increases in biodiversity and a positive relationship 

between biodiversity and the age and area of set-aside lands. 

These authors further conclude the work by Van Buskirk and 

Willi was inadequate in design of assessment of ecological 

benefits of agri-environmental policies and suggest a more 

rigorous evaluation within the geographic, agronomic, and 

socioeconomic context of individual countries. An ambiguous 

definition of set-aside land and analysis of data from limited 

geographic areas are identified as flaws and limit the authors’ 

ability to correctly extrapolate data to much larger geographic 

areas. While the criticisms of these authors focus on European 

conditions where agricultural land use has been the predominant form of land use for centuries, they stress the importance 

of agri-environmental policies being evaluated in the ecological and social context of the countries within which the policies are implemented. The authors caution against overextension in extrapolation of data and conclusions.

Koford, R.R., and Best, L.B.,1996, Management of agricultural landscapes for the conservation of neotropical migratory birds, in Thompson, F.R., III, ed., Management of 

midwestern landscapes for the conservation of neotropical 

migratory birds: St. Paul, Minn., U.S. Department of Agriculture Forest Service General Technical Report NC-781, 

p. 86–88.

Thirty-eight neotropical migratory birds are common 

in Midwest agricultural landscapes. Most species depend 

on herbaceous or wooded habitats, which are declining as 

the average size of farms increases. Recommendations for 

improving diversity of avian habitats include: minimize 

cultivation, encourage moderate grazing, delay spring mowing of hay, increase acres in grassed waterways and roadsides, 

avoid nighttime mowing, encourage longer intervals between 

mowings, avoid fall mowing and annual mowing of grassed 

waterways and roadsides, retain fencelines, maintain idle land, 

and change configuration of idle land to enhance species richness and nesting success. An immediate short-term effect of 

tillage is the exposure of arthropods and other prey to foraging 

birds; a long-term effect is the reduction in abundance of litterdwelling arthropods. Conventionally tilled fields have lower 

arthropod abundance than no-till or idle areas. Herbicides 

can affect birds by reducing availability of seeds. Insecticides 

reduce abundance and diversity of foliage-dwelling arthropods. Strip cover, such as grassed waterways, terraces, fencerows, roadsides, and windbreaks/shelterbelts usually provide 

habitat more long-term than provided by areas enrolled in 

crop-retirement programs. Strip cover has decreased in recent 

years. Orientation of crop rows relative to grassed waterways 

influenced disturbance. Nest densities were greater when rows 

were parallel to waterways. 

The authors recommend preservation of remnants of prairie and savannah. Large-scale restoration of these cover types 

is impractical, but remnants can be saved for education and 

research. Other recommendations include: increase presence 

of crop residues, continue and manage CRP, minimize tillage, 

diversify crops, encourage moderate grazing of pastures with 

prescription for species needs of those in most trouble, delay 

spring mowing of hay as long as possible, avoid night mowing, increase intervals between mowing, maintain idle land in 

blocks rather than strips, and increase species composition of 

vegetation. On terraces habitat, improvements can be made 

through flattening of back-slopes and improvement of grass 

stands and planting alternative vegetation. The burning of all 

ditches or roadsides areas in same year should be discouraged. 

Establishment of fencerows greater than 3 meters (m) (10 ft) 

wide should be encouraged. 

Krapu, G.L., Brandt, D.A., and Cox Jr., R.R., 2004, Less waste 

corn, more land in soybeans, and the switch to genetically 

modified crops—Trends with important implications for 

wildlife management: Wildlife Society Bulletin, v. 32, no. 1, 

p. 127–136.

Growing efficiency in corn harvest (greater than 99 

percent under ideal conditions) and widespread replacement 

of corn and other crops by soybeans less capable of supplying nutritional needs of wildlife represent a growing risk to 

wildlife that are dependent upon waste grain for energy and 

weeds for the foods and cover they provide. Nearly 25 percent 

of total cropland in the United States is used to produce soybeans. In 2002, approximately 75 percent of soybean crop was 

planted with genetically modified (GM) herbicide resistant 

soybeans. Increased efficiency of weed-control results in a 

decline in the amount of weeds present—this represents a 

decline in foods and cover for wildlife in agricultural landscapes. Implications may be particularly severe on seeddependent wildlife of lower mobility, smaller home ranges, 

and migratory species with seasonally high nutritional needs.

Prior to development of genetically modified (GM) strains, 
32 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography 

herbicides were less efficient or selective resulting in some 

weed species continuing to thrive in cropland. Genetically 

modified crops appear to be on the verge of greater acceptance 

by farm operators; this would directly or indirectly broaden 

negative impacts on wildlife that is dependent upon weeds. 

Aggressive control of weeds in CRP fields and other private 

lands further impact seed-eating wildlife when weed seeds 

and other high-quality grain foods are becoming less available 

across agriculturally dominated landscapes. 

Authors suggest that more research is needed to determine impacts of weed control on CRP and other lands and 

that more studies are needed to better document effects of GM 

crops on quality of wildlife habitat across regions. Authors 

believe that beneficial effects of the CRP in providing perennial cover for wildlife may be negated by more highly efficient 

and intensive weed control on lands remaining in production. 

It is suggested that producers could be offered incentives to 

grow high-energy food plots, intentionally leave greater crop 

residues, and use less intensive weed-control methods to 

ensure that adequate sources of food are available for wildlife 

in landscapes dominated by row crop production. 

Kuehl, A.K., and Clark, W.R., 2002, Predator activity related 

to landscape features in northern Iowa: Journal of Wildlife 

Management, v. 66, no. 4, p. 1224–1234.

Research in agriculturally dominated landscapes in 

northern Iowa provides further support for providing large 

blocks of grass-dominated cover. Corridors and moderately 

sized patches of habitat near large blocks of cover support 

elevated activity by predators. Focused management of cover 

within patches and exclusion or eradication of predators may 

still play a role in predator control, but the best long-run 

approach is landscape-level planning to furnish needed habitats of sufficient quality and quantity to lessen the impact of 

predator populations.

Milchunas, D.G., Vandever, M.W., Ball, L.O., and Hyberg, 

S., 2011, Allelopathic cover crop prior to seeding is more 

important than subsequent grazing/mowing in grassland 

establishment: Rangeland Ecology & Management, v. 64, 

no. 3, p. 291–300

 Sorghum is known to be allelopathic and is used in row 

crop agriculture rotations to suppress weeds and increase crop 

yields. The effects of grazing, mowing, and type of cover crop 

were evaluated in a previous winter wheat/fallow cropland 

seeded to grassland under the CRP in eastern Colorado. Prior 

to seeding, fallow strips were planted in alternating strips 

of sorghum or wheat as cover crops. Grazing treatments (no 

grazing, moderate to heavy grazing, and mowing) four years 

after planting, which were studied for three years, showed 

that strips previously in wheat had more annual and exotic 

species than sorghum strips. Sorghum strips showed greater 

abundances of perennial native grasses and native species. 

Grazing had relatively minor effects on basal and canopy 

cover of annual or exotic species versus perennial native 

grasses or native species. Mowing was a less effective weedcontrol practice than grazing. Common management practices 

for revegetation/restoration, commonly use herbicides and 

mowing as weed-control practices, and restrict grazing in all 

stages of development. Results suggest allelopathic cover crop 

selection and opportunistic grazing can be effective alternative 

grass establishment and weed control practices. 

 O’Connell, M.A., and Noss, R.F., 1992, Private land management for biodiversity conservation: Environmental Management, v. 16, no. 4, p. 435–450.

For the purpose of conservation, ecosystem diversity 

must be defined on the basis of geographically recognizable, 

mappable units representing commonly associated flora and 

fauna. Species profiting from habitat diversification are generally those least in need of conservation efforts. Managers have 

customarily enhanced local species diversity by maintaining 

numerous edges between habitat types, which is usually to 

the detriment of endemic species. Maintenance of diversity 

from regional and global perspective permits more flexibility in land-use options than a strategy that considers sites in 

isolation. Loss of a species from a specific site may not have 

detrimental effects on biodiversity if the species is regionally 

abundant. Regional biodiversity management does not preclude habitat manipulation to favor certain species; however, 

standards for private land management consistent with goal of 

conserving biodiversity are not simple to delineate. This paper 

provides specific steps and guidelines for identification of 

biodiversity priorities on private lands. 

O’Neill, R.V., Hunsaker, C.T., Jones, K.B., Riitters, K.H., 

Wickham, J.D., Schwartz, P.M., Goodman, I.A., Jackson, 

B.L., and Baillargeon, W.S., 1997, Monitoring environmental quality at the landscape scale: Bioscience, v. 47, no. 8, 

p. 513–519.

Authors argue that ethical environmental stewardship 

requires monitoring and assessment of landscape changes on a 

national scale. Individual owners make changes in landcover, 

but the impacts of these changes have cumulative impacts 

as spatial patterns change. Landscape changes have direct 

impacts on ecological processes. Determination of status and 

trends in patterns of landscape composition can be useful for 

understanding the conditions of ecological resources. The most 

important cause of declines in species numbers and diversity 

is loss of habitat. Authors present discussion on how remote 

imagery, GIS, and principles from landscape ecology can be 

used to monitor environmental quality over large regions. 

Descriptions to assess biotic integrity and diversity, watershed integrity, and landscape resilience and fragmentation are 
Agricultural Ecosystems 33

presented. The importance of landscape-scale assessments is 

highlighted by the frequency of political decisions made at the 

landscape scale. The authors point out that landscape-scale 

assessments will only be viable if developed on a foundation 

of sensitivity testing to determine reliability of methods supported by smaller scale field studies.

Parton, W.J., Gutman, M.P., Williams, S.A., Easter, M., and 

Ojima, D., 2005, Ecological impact of historical land-use 

patterns in the Great Plains—A methodological assessment: 

Ecological Applications, v. 15, no. 6, p. 1915 – 1928.

Authors report the use of historical county-level agricultural data to develop an ecosystem model for grassland, dryland cropping, and irrigated cropping to determine ecological 

effects of prevailing land use. Results indicate that cultivation 

of grasslands results in large losses of soil C and an increase 

in soil N mineralization for the first 20 years of cultivation 

followed by low soil C loss and N mineralization for 50 years 

after the initiation of cultivation. 

Peterjohn, B.G., 2003, Agricultural landscapes—Can they 

support healthy bird populations as well as farm products?: 

The Auk, v. 120, no. 1, p. 14–19.

Intensification of agricultural production appears to 

underlie most declines in grassland bird species numbers and 

distribution. Conservation on a local scale can reverse local 

negative trends, but landscape-level patterns of population 

decline will require solutions that remain undefined. Our 

understanding of ecology and habitat requirements of many 

farmland species during the non-breeding season remains 

rudimentary, limiting the ability to develop effective conservation strategies. Until a more thorough understanding of 

the entire annual cycle of habitat use is provided, the risk of 

inefficient or ineffective conservation strategies remains high. 

Single-species management may not be an effective approach 

for the entire farmland bird community but may be needed for 

species of immediate conservation concern. Effective conservation of avian species associated with agricultural landscapes 

will require innovative solutions based on current agricultural 

practices. Reliance on reverting to less intensive agricultural 

practices across North America is an unrealistic expectation. 

Some combination of variables including grassland 

species composition, structural diversity, patch size, habitat 

fragmentation, and management activities define relations 

between grassland birds and their habitat. Each species 

responds differently and studies at smaller spatial scales are 

needed to clarify these relations. Simple, all-encompassing 

conservation solutions will not reverse all declines in farmland 

bird populations. Recent declines in grassland birds probably 

reflect factors other than simple habitat loss and include fragmentation, increased mowing, and other detrimental practices 

associated with intensification of agricultural production. 

The negative relationship between population trends of avian 

species and CRP (see Murphy 2003 in Grassland Birds; p. 

171 of this report) is surprising and may reflect the fact that 

CRP fields constitute only 3.6 percent of the overall landscape and that negative factors operating on the remaining 

96.4 percent of landscape have a greater influence on avian 

population trends. Five of seven negative associations reported 

by Murphy (2003) were for avian species associated with 

shrub-dominated habitats, and the two negative relations were 

for grassland species that regularly nest in less densely vegetated covers including row crops. The relatively small area of 

land devoted to CRP and its uneven distribution in the United 

States probably also had an influence on this relationship.

Pimentel, D., and Pimentel, M., 2003, Sustainability of meatbased and plant-based diets and the environment: American 

Journal of Clinical Nutrition, v. 78, p. 660–663.

Authors conclude that the heavy dependence on fossil 

energy used by the United States’ food system is not sustainable. The United States’ food-production system uses about 

50 percent of the total area in the country, 80 percent of the 

fresh water, and 17 percent of the fossil energy. The United 

States’ population doubled in the last 60 years and is expected 

to double again in 70 years. Differences in energy requirements needed to produce vegetarian and meat-based diets 

are discussed. 

In the United States, more than 9 billion livestock are 

maintained to supply the animal protein consumed each 

year. These animals consume about 7 times more grain than 

consumed by the entire American population. The amount of 

grain fed to livestock is sufficient to feed about 840 million 

people who follow a plant-based diet. For each kilogram of 

animal protein produced livestock are fed about 6 kg of plant 

protein. The average fossil energy input for all animal protein 

production systems studied is 25 kilocalories (kcal) of energy 

per 1 kcal of protein produced; this is more than 11 times that 

of grain protein production.

More than 99.2 percent of food in the United States 

comes from terrestrial production, whereas 0.8 percent comes 

from oceans or aquatic ecosystems. Continued use of land is 

of concern due to the rapid rate of soil erosion and degradation 

of associated ecosystems. Each year over 90 percent of cropland loses soil at 13 times sustainable rate of 1 ton/hectare/

year. Authors conclude the major threat to future survival and 

U.S. natural resources is rapid growth of human population. 

Ribic, C.A., Warner, R.E., and Mankin, P.C., 1998, Changes in 

upland wildlife habitat on farmland in Illinois 1920–1987: 

Environmental Management, v. 22, no. 2, p. 303–313.

Authors developed an index to evaluate changes in agricultural ecosystems as they affect wildlife habitat. Indices at 

county level have potential to be used in multi-scale analysis 
34 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography 

to investigate effects of policy changes on large-scale areas 

and to develop regional documentation of agricultural impacts 

on upland wildlife and habitats.

Shackleton, R., 2009, Potential impacts of climate change in 

the United States: Washington D.C., Congressional Budget 

Office, Congress of the United States, 25 p.

The report presents a concise overview of the current 

understanding of potential effects of climate change in the 

United States. The synopsis of climate-change issues presents potential impacts including changes in weather patterns, 

precipitation, storms, ocean acidity, and sea level, as well as 

potential alterations to ecosystems and biodiversity, agriculture, fisheries, and human health. Climate-change responses 

to emissions and changes in land use are complex with both 

rapidly and slowly evolving responses. Uncertainly in projecting changes is great. Responses will not be uniform; they will 

vary across regions and seasons. A changing climate is likely 

to result in alterations of regional and seasonal temperatures, 

rainfall and snowfall, as well as change in frequency and 

severity of extreme events such as heat waves, droughts, and 

floods. Regional U.S. climates are expected to become more 

variable with more intense and frequents extremes of high 

temperature and rainfall.

Agricultural impacts are driven by changes in temperature and rainfall. Enhancement of plant growth resulting from 

higher concentrations of carbon dioxide, more destructive 

effects of ground-level ozone, and changes in susceptibility 

to fire and pests are potential consequences of global warming. Warming trends will be relatively greater at high latitudes 

in the Northern Hemisphere. Warming will be greater in the 

interior of continents. An average increase of 7°F (by the end 

of the 21st century) in global temperature will shift average 

annual temperatures two states north. This means that North 

Dakota will have a climate similar to Nebraska of today. At the 

high end of estimated temperature change (11°F) climate patterns would shift three states north. Kansas would be similar 

to Texas. Northerly regions of the United States would tend to 

warm most in the winter due to declining snow and ice cover. 

Most models project that almost any amount of warming will 

cause much of the Southwest to become more arid over the 

course of the 21st century. Warmer winters in northern regions 

will be wetter. Summers will be drier in southern regions. 

Periods of intense rainfall will tend to be interspersed with 

longer dry periods. Rising sea levels will cause gradual, progressive inundation of shorelines; erosion of coastal wetlands 

will increase.

Risks to U.S. agriculture are described as comparatively 

modest. Farmers will have to adapt to changing climate 

conditions by shifting cultivation of specific crops northward 

and altering timing of planting. In some regions, changes 

in rainfall rather than changes in temperature will be more 

unfavorable. Northern regions may have longer growing season and greater precipitation, but southern regions are likely 

to be more sensitive to higher temperature and decreased 

rainfall. Declining supplies of water could affect agriculture in 

western states.

Studies generally conclude that warming and higher 

concentrations of carbon dioxide will boost global growth of 

forests. The area of shrub and steppe in the American southwest is expected to expand. Ranges of mixed forests in the 

northernmost regions and in colder boreal regions will shift 

northward and cover less land area. Treeline could shift 250 

mi north over the course of the 21st century. A greater risk 

of wildfires can be expected. Rising temperatures will shift 

geographic ranges of many fish species northward. Warmwater species are more likely to prosper and expand ranges. 

Western states will find it difficult to meet current levels of 

water demand.

Swanson, T.M., 1992, Wildlife and wildlands, diversity and 

development, in Swanson, T.M., and Barbier, E.B., eds., 

Economics for the wilds: Washington, D.C., Island Press, 

p. 1–14.

Diversity and economic development need not be mutually exclusive. Maintaining diversity of wild resources is a 

necessary condition for sustainability. Wild resources should 

be treated as an input to the development process and cannot 

be excluded. The conservation of biodiversity implies the need 

to conserve not only a given stock of wildlife but the capacity for the species to mix and evolve in an ongoing interactive 

process. In other words, the habitat must be provided that 

will meet the needs of the targeted species across the physical 

landscape as well as through time. It is important to integrate 

wildlife/biodiversity values into the economic process rather 

than shield them from it. Ultimately, the economic value of 

resources will be the key to their survival.

Szentandrasi, S., Polasky, S., Berrens, R., and Leonard, J., 

1995, Conserving biological diversity and the Conservation 

Reserve Program: Growth and Change, v. 26, p. 383–404. 

Effective protection of wildlife resources often will take 

place on land used primarily for purposes other than wildlife habitat. CRP lands currently are targeted to regions (for 

example, Midwest and Great Plains) having relatively few 

threatened and endangered species when compared to other 

regions of the country. This paper describes a method to retarget CRP enrollment to address threatened and endangered 

(T&E) species’ concerns in Oregon or other regions where 

there are greater numbers of these species. The justification 

for improved targeting of CRP is to enhance provision of 

important environmental benefits. Primary agencies involved 

in management and monitoring of CRP (USDA) do not have 

a traditional wildlife-oriented mission. Consequently, species 

preservation and habitat protection received minimal attention 

in program design. 
Agricultural Ecosystems 35

Tilman, D., Fargione, J., Wolff, B., D’Antonio, C., Dobson, 

A., Howarth, R., Schindler, D., Schlesinger, W.H., Simberloff, D., and Swackhamer, D., 2001, Forecasting agriculturally driven global environmental change: Science, v. 292, 

no. 13, p. 281–284.

Description of potential nonclimatic global environmental impacts of agriculture for the coming 20 to 50 years 

is presented. The forecasts presented are described not as 

predictions but estimates of environmental impacts, should 

agriculture continue on trajectories experienced over the past 

35+ years. Authors warn that unforeseen changes in population, economic growth, agricultural policies, climate and other 

factors may affect their projections. Agriculture affects ecosystems by use and release of resources that influence ecosystem 

functioning (N, Phosphorus (P), water), release of pesticides, 

and conversion of natural ecosystems to crop production. 

These sources of global change may rival climate change in 

environmental and social impacts. About 70 percent of harvested crops are fed to livestock in developed countries. A 50 

percent increase in population and demand for diets richer in 

meat are projected to double global food demand by 2050.

 The report states that global N fertilization is forecast 

to be 1.6 times greater than present amounts by 2020 and 2.7 

times greater by 2050. Phosphorus fertilization is forecast to 

be 1.4 times current amounts in 2020 and 2.4 greater by 2050. 

Projected increases in N and P fertilization will have substantial environmental consequences that include eutrophication 

of surface waters, loss of biodiversity, and changes in species 

composition in terrestrial and aquatic ecosystems; groundwater pollution; increases in greenhouse gases; and acidification of soils and freshwaters. If past patterns persist, global 

pesticide production would be 1.7 times that of present levels 

by 2020 and 2.7 times greater by 2050, resulting in elevated 

exposure to humans and ecosystems.

If trends continue, global cropland would increase by 

350,000,000 hectares (742 million acres) by 2050. The majority of this would be in developing countries, primarily in Latin 

America and sub-Sahara Africa. It would amount to about half 

of all potentially suitable land for agriculture, which would 

lead to loss of about one third of remaining tropical and temperate forests, savannas, and grasslands. Conversely, agricultural land use in developed countries is projected to decline as 

the more productive land is farmed more intensively.

An environmentally sustainable revolution is needed 

based on the total costs and benefits of agriculture, including 

agriculture-dependent gains and losses in values of ecosystem services that include biodiversity, recreation, C storage, 

drinkable water, fisheries, and pollination. Use of cover crops 

and of buffers on drainages and surface waters need to be 

expanded. Comprehensive land-use planning is needed to 

minimize fragmentation and protect wetlands and surface 

waters. Methods to quantitatively forecast changes in ecosystem functioning are desperately needed.

Trenbath, B.R., Conway, G.R., and Craig, I.A., 1990, Threats 

to sustainability in intensified agricultural systems—

analysis and implications for management, in Gliessman, 

S.R., ed., Agroecology—Researching the ecological basis 

for sustainable agriculture: New York, Springer-Verlag, 

p. 337–365.

Agricultural intensification typically results in a greater 

proportion of more intensively farmed available land, elevated 

levels of technological input, and more frequent use of land. 

In combination, these variables are often accompanied by 

damage to the natural resource base. Agricultural intensification may damage associated nonagricultural systems within or 

outside the farmed area as well as other agricultural systems 

downstream. Intensive exploitation of available areas has 

led to increases in productivity but also declines in wildlife 

populations associated with less intensive use. Where wildlife 

viability is dependent upon relatively large patches of lessdisturbed habitat, sensitive populations may disappear. 

More frequent use of land is a common aspect of intensification that is potentially exhaustive of land capability. With 

shorter fallow periods between crops, natural-soil processes 

may be unable to regenerate fertility and there may be a 

buildup of pests. Both require greater use of agrochemicals to 

alleviate problems. Use of pesticides may lead to spectacular 

increase in yield, but experience shows that after a number of 

years of application, pesticides progressively lose effectiveness. This decline is due to an increased proportion of pest 

genotypes in a population becoming resistant to chemicals. If 

use continues, especially with higher dosages, the proportion 

of resistant genotypes increases rapidly to the point where 

existing pesticides must be replaced by new, more successful 

chemicals. Emergence of pesticide resistance reduces profitability through crop losses and need for different, inevitably 

more expensive chemical. The less obvious, and sometimes 

delayed, effects on the environment may be substantial, particularly to wildlife. 

Van Buskirk, J., and Willi, Y., 2004, Enhancement of farmland 

biodiversity within set-aside land: Conservation Biology, 

v. 18, no. 4, p. 987–994.

Although it may seem obvious that withdrawal of 

farmland from intensive production would provide benefits to 

wildlife and biodiversity associated with agricultural landscapes, there remain serious questions about the cost effectiveness and benefits of such programs. Some suggest set-aside 

programs are inefficient and relatively unsuccessful in providing wildlife habitat. Agroecologists monitoring these programs 

have reported conflicting results. Because these programs 

are costly, politicians may be unwilling to continue approving payments in North American and the European Union 

without clear evidence of program benefits. Because general 

conclusions about the impact of set-aside programs cannot be 

supported by a few isolated monitoring studies, the authors of 
36 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography 

this report completed a literature review of over 500 studies in 

agricultural landscapes. 

The authors’ meta-analysis indicates numbers of bird species, insects, spiders/harvestmen, and plants were significantly 

higher on set-aside land than on nearby control areas under 

conventional agricultural production. Authors believe their 

analysis unequivocally resolves controversy of biodiversity 

benefits of set-aside land at last at local level. Results of study 

show larger, more permanent units of land enrolled in set-aside 

have greater benefits than do smaller sites of short duration. 

Authors identify a need for more information on how land in 

these programs function in the context of the entire landscape 

and how species react to these programs.

van der Werf, J.P., and Petit, J., 2002, Evaluation of the 

environmental impact of agriculture at the farm level—A 

comparison and analysis of 12 indicator-based methods: 

Agriculture Ecosystems & Environment, v. 93, p. 131–145.

This report furnishes an assessment of 12 indicator-based 

approaches to assessing the environmental impact of agriculture at the farm level. Indicators are alternative measures used 

to identify the status of a concern when, for technical or financial reasons, the impact cannot be measured directly. Indicators of environmental impact may be based on either farmer 

production practices or effects these practices have on the 

environment. Indicator methods of assessment should account 

for a range of objectives covering both local and global 

effects. Indicators based on environmental effects of farming 

practices are preferable to indicators based on farm practices 

as the link with the objective. Indices describing impact both 

per unit surface area and per unit of product are preferable. 

The method of assessment should be validated prior to use. 

Veech, J.A., 2006, A comparison of landscapes occupied by 

increasing and decreasing populations of grassland birds: 

Conservation Biology, v. 20, no. 5, p. 1422–1423.

Twenty years of Breeding Bird Survey (BBS) data were 

used to identify stable, increasing, and decreasing populations 

of 36 grassland bird species in relation to physical features 

of the landscape adjacent to survey routes using USDA NRI 

data. Populations that were increasing were associated with 

landscapes that contained significantly more restored grassland and rangeland but less forest land and urban land than 

landscapes inhabited by decreasing populations. There was 

no significant difference in proportion of cropland within 

landscape of increasing and decreasing population, although 

cropland composed greater than 30 percent of many of these 

landscapes. Restored grassland typically was a very small 

proportion (less than 3.5 percent) of total land cover but was 

significantly more common in landscape of increasing than 

decreasing populations of grassland birds. Rangeland and CRP 

land held the greatest potential for having a positive effect 

on grassland birds. CRP was typically a low component of 

landscape composition (2.9–3.2 percent). The author concludes that the amount of grassland habitat within a landscape 

can affect population trends in grassland birds regardless of 

spatial configuration of individual grassland parcels. 

Warner, R. E., 1994, Agricultural land use and grassland habitat in Illinois—Future shock for midwestern birds: Conservation Biology, v. 8, no. 1, p. 147–156.

During periods of intensive agricultural production, 

grasslands existed only as linear edges with resultant low density and diversity of grassland nesting birds. Nest densities and 

species diversity were highest where grassland was nearby, 

cover types were heterogeneous, and where corridors connected grasslands in surrounding landscape. The percentage 

of ring-necked pheasant (Phasianus colchicus) nests hatched 

annually from 1973 to 1981 was positively correlated with 

the amount of grassland per hen in spring, where grassland 

consisted of both edge habitats (including roadsides) and fields 

of hay and small grain. Nest densities and species diversity 

increased relative to the degree of spatial heterogeneity and 

to how well plots were connected to surrounding landscape 

by corridors. There is potential for enhancing use of grassy 

farmland edges by establishing filter strips, field borders, existing edges, and by locating hay and small grains near wider 

grassland corridors. 

It is too simplistic to conclude all linear habitats compared to fields (blocks of cover) are predator traps. Nest 

destruction was high in years when both predators and nesting 

pheasants were concentrated in relatively little grass-dominated cover. Predation rates vary with predator-prey assemblages, density of birds in nesting habitats, and the extent to 

which other cover and prey attract predators away from relatively attractive nest sites. Overall, landscape-level phenomena 

affecting farmland wildlife populations are poorly understood 

at this time.

Weber, W.L., Roseberry, J.L., and Woolf, A. 2002, Influence of 

the Conservation Reserve Program on landscape structure 

and potential upland wildlife habitat: Wildlife Society Bulletin, v. 30, no. 2, p. 888–898.

The report is an evaluation and quantification of CRP 

effects on Illinois agricultural-landscape composition within 

bobwhite quail (Colinus virginianus) range (southwestern and 

southern Ill.). Considering all land-cover types, CRP landscapes are characterized by smaller acreages, greater edge 

density and greater fragmentation compared to landscapes 

without CRP. Farmland enrolled in CRP tended to be located 

in areas with proportionately less row crop and more grassland and woodland than non-CRP landscapes. Landscapes 

surrounding CRP fields were more diverse than non-CRP 

landscapes. Enrollment criteria required CRP to be located in 

areas that were less productive and more likely to have smaller 

patch size and greater diversity than the composition of overall 
Biomass, Energy 37

landscape. Multiple fields enrolled by landholders also might 

account for some aggregation. Basically, authors conclude that 

CRP is being established in landscapes that already contained 

grassland and woodland cover types. 

To further enhance CRP benefits, land managers and 

wildlife biologists must collaborate to identify objectives and 

maximize landscape-level approaches to cover management. 

As enrollment criteria presently exist, opportunities to improve 

wildlife habitat are limited. Communication and information 

exchange between NRCS personnel and program participants 

needs improvement. Administration of CRP, as well as other 

conservation programs, need greater emphasis on landscape 

level planning to meet wildlife objectives. 

Wu, J., Ransom, M.D., Nellis, M.D., Kluitenberg, G.J., Seyler, 

H.L., and Rundquist, B.C., 2002, Using GIS to assess 

and manage the Conservation Reserve Program in Finney 

County, Kansas: Photogrammetric Engineering & Remote 

Sensing, v. 68, no. 7, p. 735–744.

This evaluation used soil, land use, groundwater, and 

other environmental layers in a GIS to evaluate distribution 

and planning for CRP enrollment. Aquifer thickness, coinciding with gas or oil fields, was closely associated with distribution of CRP. Soil, aquifer depth, physiography, or slope had 

little apparent relation to distribution of CRP. The data layer 

was developed using a soil erosion index used to identify areas 

best suited for enrollment of new CRP lands. Methods and 

approaches to identification of priority data themes and use 

of GIS in land-use planning for CRP and other conservation 

programs are discussed.

Biomass, Energy

Adler, P.R., Sanderson, M.A., Weimer, P.J., and Vogel, K.P., 

2009, Plant species composition and biofuel yields of conservation grasslands: Ecological Applications, v. 19, no. 8, 

p. 2202–2209.

In an investigation of the potential of CRP grasses as a 

source of biofuel, the report found that species richness and 

composition are key determinants in biomass and ethanol 

yields. As species composition increased, potential yields 

decreased. Warm-season grasses were evaluated from 34 sites 

in New York, Pennsylvania, New Jersey, Maryland, and Virginia. Grasses were dominated by switchgrass (Panicum virgatum), big bluestem (Andropogon gerardii), and Indiangrass 

(Sorghastrum nutans). Conservation grasslands with higher 

numbers of plant species had lower biomass yields and lower 

ethanol yield per unit of biomass. Biofuel yield decreased 

by 77 percent as plant-species richness increased from 3 to 

12.8 species per square meter (m2). Ethanol yields vary with 

plant species as a consequence of cell-wall chemistry affecting carbohydrate composition and efficiency of enzymatic 

hydrolysis. Plant-species composition affected concentration 

of lignin, cellulose, and hemicellulose in biomass; this affected 

the potential yield of conservation grasslands. Biomass yield 

per unit area also decreased in response to greater richness in 

plant species. Conservation grassland dominated by tall warmseason grasses had more aboveground biomass, few species 

of plants present, higher ethanol yield per unit biomass, and 

higher ethanol yield than for other sites. Authors conclude that 

sites with higher plant-species richness will yield undesirable 

fermentation characteristics diminishing ethanol yield.

Best, L.B., and Murray, L.D., 2005, Bird responses to harvesting switchgrass fields for biomass, in Transactions North 

American Wildlife and Natural Resources Conference, 69, 

Spokane, Wash., March 16–20, 2004, Proceedings: Washington, D.C., Wildlife Management Institute, p. 224–235.

One alternative use of CRP land as contracts expire is 

production of switchgrass (Panicum virgatum) for biofuel. 

Switchgrass appears to be a viable method of biofuel production due to its high production of biomass and its requirement 

of minimal maintenance once established. Switchgrass is 

harvested in fall and winter; breeding birds are not affected 

directly, but changes in vegetation abundance and structure 

may influence bird abundance and nest success the following spring. Winter abundance of avian species may also be 

affected. Authors believe that switchgrass production could 

furnish environmental benefits similar to the CRP, but removal 

of residual vegetation in harvested fields had a negative effect 

on nest success and nest/brood parasitism. Nest success was 

greater in unharvested fields (59 percent) than in total-harvested (40 percent) and strip harvested (33 percent) fields. 

Because grassland-bird species differ in habitat needs, 

maintaining both harvested and nonharvested switchgrass 

fields would benefit the greatest number of species. This can 

be accomplished by leaving some fields idle during a harvest 

rotation. Harvesting switchgrass fields in alternating cut and 

uncut strips is believed to be more beneficial to the winter 

bird community than is harvesting entire fields. Because 

the establishment of extensive switchgrass fields for energy 

production may affect availability of foods, the authors further 
38 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography 

recommend establishment of food plots in biomass-production 

areas. A discussion of future research needs in relation to field 

size, field configuration, juxtaposition of habitats, and landscape-level effects is presented. 

Bies, L., 2006, The biofuels explosion—Is Green Energy good 

for wildlife: Wildlife Society Bulletin, v. 34, no. 4, 

p. 1203–1205.

A concise appraisal of biofuel types, production methods, 

energy costs, and potential environmental effects of growing 

demand for these products. 

In early 2006, domestic ethanol production capacity was 

about 4.4 billion gallons per year. Approximately 95 percent of 

United States bioethanol comes from corn. About 20 percent of the U.S. corn production goes to ethanol. Iowa alone 

has two dozen ethanol plants with more under construction. 

Bioethanol can be created from cellulosic biomass derived 

from grasses, agricultural residues, straw, and woody biomass. 

Cellulosic ethanol production is often seen as more environmentally desirable due to lower greenhouse emissions and 

higher energy balance. Production and use of cellulosic ethanol results in fewer greenhouse-gas emissions and produces 

more energy per unit of input. A large portion of the economic 

and environmental costs in production of corn ethanol is the 

investment in fossil fuels needed to plant, tend, and harvest 

corn and convert it to ethanol. Three gallons of water are 

required to produce one gallon of corn ethanol. At this time, 

the processes to produce commercial cellulosic ethanol are not 

economically viable.

The extent of losses in wildlife habitat and other environmental impacts of biofuel production depend on the scale 

of production and the type of land used. Compared to land 

planted to corn, grasslands devoted to biomass production 

could still maintain some availability of habitat. Strip harvesting of switchgrass (Panicum virgatum) appears to offer viable 

options of a balance between production and perseveration of 

habitat values. Production methods of cellulosic ethanol are 

still in development. At present, the technology for processing 

a mixture of different grasses is unavailable. Potential effects 

of legislation, tax credits, and subsidies of production of 

biofuels are discussed. One can only conclude that biofuels are 

going to be a major source of agricultural production for years 

to come, and likely only going to get bigger. The author concludes that work must continue to evaluate and design biofuel 

production so it furnishes green energy and wildlife benefits.

Florine, S.E., Moore, K.J., Fales, S.L., White, T.A., and 

Burras, C.L., 2006, Yield and composition of herbaceous 

biomass harvested from naturalized grassland in southern 

Iowa: Biomass and Energy, v. 30, p. 522–528.

The paper addresses issues related to use of grass biomass for cofiring (burning herbaceous biomass with coal) to 

produce energy. Switchgrass (Panicum virgatum) is seen as an 

ideal energy crop due to relatively high yield with moderate to 

low inputs; adaptability to marginal soils; and favorable fuel 

characteristics of high net energy, ash content, and chemistry. 

However, other grasses may also be viable alternatives for 

production of biomass. Authors identify use of CRP lands for 

biofuel production as an alternative to returning these lands 

to production of commodity crops. Many CRP lands in Iowa 

have been planted to cool season grasses (for example, smooth 

brome [Bromus inermis]) but little is known of their potentials 

as a source of biofuel. 

The authors sampled 10 sites planted to cool season 

grasses, and report that biomass yield varied within and among 

locations with yields ranging from 0.75 tons per hectare (t ha) 

(0.3 tons per acre [t ac]) to 8.24 t ha (3.3 t ac). Average yield 

was 4.2 t ha (1.7 t ac). The majority of biomass yield variation 

occurred within sites, not among them. Authors conclude that 

some locations are better than others for biomass production 

due to lower ash, sulfur, and chlorine content in vegetation. 

Chemical composition of sample vegetation is provided. The 

majority of cool season pastures sampled had higher levels 

of ash than recorded in switchgrass. The major component of 

ash is silica. Warm-season grasses typically have lower silica 

content than do cool-season grasses because they use water 

more efficiently. Authors conclude cool-season grasses (for 

example, smooth brome, orchardgrass [Dactylis glomerata], 

and tall fescue [Festuca arundinacea]) can serve as alternative 

sources of herbaceous biomass for fuel production. Biomass 

accumulation in cool-season grasses is greatest in spring and 

early summer while switchgrass and other warm-season species is greatest in late spring and summer. Authors suggest 

cool-season grasses could be harvested earlier in the season if 

stored supplies of switchgrass become limiting. 

Higgins, K.F., Osborn, R.G., Naugle, D.E., and Bakker, K.K., 

2005, Contrasting the potential effects of biomass fuel, soybase fuel, ethanol, and wind energy developments on northern Great Plains Wildlife, in Transactions North American 

Wildlife and Natural Resources Conference, 69, Spokane, 

Wash., March 16–20, 2004, Proceedings: Washington, D.C., 

Wildlife Management Institute, p. 199–214.

Four renewable energy sources are receiving greater 

attention and being developed in the northern Great Plains: 

wind turbines, fuel from grass biomass (typically switchgrass 

[Panicum virgatum], ethanol from corn [Zea mays], and fuels 

from soybean [Glycine max]) products. Histories and social 

and environmental advantages/disadvantages of each method 

of energy production are discussed. Authors recommend 

construction of windplants near breeding, staging or wintering 

areas, migration corridors, or other areas with large concentrations of birds or bats should be avoided until further research 

is conducted. Although most past investigations report 

relatively small amounts of mortality due to turbines, these 

results should not be taken lightly due to the large number of 

windfarms being proposed for development. Perhaps one of 

the most negative impacts of wind power will be development 
Biomass, Energy 39

of large, aboveground transmission lines which have been 

shown to cause significant avian mortality in areas with a high 

density of wetlands. Greater development of row crop acreage 

for ethanol and soy fuels has potential to accelerate conversion 

of wetland and native grasslands into croplands throughout 

the northern Great Plains. Development of drought-resistant, 

genetically modified soybeans has already accelerated conversion of remaining native prairie to cropland. Authors conclude 

that of the four approaches, only biomass fuels have potential 

to bring benefits to Great Plains wildlife. However, if remaining native grasslands and CRP grasslands are converted to 

biomass production, effects will be negative. 

Hoover, S.L., and Morrison, M.L., 2005, Behavior of redtailed hawks in a wind turbine development: Journal of 

Wildlife Management, v. 69, no. 1, p. 150–159.

Authors describe flight behavior of red-tailed hawks 

(Buteo jamaicensis) and their flight/foraging characteristics in 

relation to topography and wind speed that may make them 

susceptible to mortality from collisions with wind turbines. 

Authors recommend that assessment of topographic features 

and weather variables (typical wind speed and direction) of the 

site and behavioral evaluations for common avian species be 

completed prior to installation of new wind farms to identify 

potentially dangerous situations and conditions. Windfarm 

managers can power down turbines at top of hazardous slopes 

when winds are strong and facing perpendicularly to the slope 

to lower likelihood of collision to lessen potential mortality to 

avian species. 

Jarnevich, C.S., and Laubhan, M.K., 2011, Balancing energy 

development and conservation—A method utilizing species 

distribution models: Environmental Management, v. 47, 

p. 926–936.

Authors modeled Lesser Prairie Chicken (LPC; Tympanuchus pallidicinctus) habitat suitability using Maximum 

Entropy (Maxent) as a tool to assist energy development in 

Kansas. The LPC has experienced loss of habitat and population decreases and is considered an indicator of grassland 

conditions. Kansas is ranked third in potential wind energy 

and companies have established 6 wind facilities and proposed 

44 more facilities. Avoidance from further negative impacts to 

wildlife (habitat loss and fragmentation) in areas developed for 

energy production are needed, but agencies often do not have 

the resources to delineate distribution of wildlife or suitable 

habitat at necessary scales.

Authors identified two land use/land cover classes 

(grasslands, CRP), areas of topographic relief, and anthropogenic variables (highways, transmission lines, etc.) as inputs. 

Grasslands represented pasture, rangeland, and lands with 

greater than 50 percent cover of trees or grasslands. Normalized difference vegetation index (NDVI) was used to provide 

estimates of vegetation productivity (low values indicative of 

fallow cropland, high values indicative of lush vegetation). 

Lek locations of both LPC and Greater Prairie Chicken (GPC; 

T. cupido) were collected by Kansas Wildlife and Parks and 

incorporated into the model. 

Lek habitat suitability was positively correlated with 

increasing land cover use/classes. Average NDVI was the 

best indicator of habitat suitability across all models. Low 

NDVI values correlated with greater lek habitat suitability. 

Elevation was the third most important variable in all models 

except for mixed lek (LPC and GPC) models. Mixed leks 

models that included anthropogenic features showed distance 

from roads to be more important than standard deviation in 

elevation. Anthropogenic variables increased uncertainty in 

the models but generally had low relative contributions to 

habitat suitability. 

Maxent models do not determine causal relationships, 

and while evidence of relationship between habitat suitability 

and anthropogenic variables exist and aid in siting energy 

development, the authors caution that additional testing is 

needed to confirm causal relationships.

Jensen, K., Clark, C.D., Ellis, P., English, B., Menard, J., 

Walsh, M., de la Toree Ugarte, D., 2007, Farmer willingness 

to grow switchgrass for energy production: Biomass and 

Bioenergy, v. 31, p. 773–781.

A survey of farmers in Tennessee to determine willingness to grow switchgrass (Panicum virgatum) for potential 

energy markets is reported. In 2005, a survey was sent to 

19,684 Tennessee farmers with a reported income of over 

$10,000. Response rate was 23.9 percent. Of those responding, 

20.8 percent previously heard of growing switchgrass as an 

energy option. Only 29.6 percent of respondents indicated an 

interest in growing switchgrass if it were profitable. Producer 

opinions about switchgrass production are presented. The 

study results suggest that many farmers are still not familiar 

with switchgrass opportunities. The availability of technical 

assistance and poorly defined markets were factors limiting 

adoption of the practice. Land owners with off-farm income 

were more likely to convert land to switchgrass production. 

Control of soil erosion had no influence in interest in growing 

switchgrass but improvement of wildlife habitat quality did.

Johnson, G.D., Perlik, M.K., Erickson, W.P., and Strickland, 

M.D., 2004, Bat activity, composition, and collision mortality at a large wind plant in Minnesota: Wildlife Society 

Bulletin, v. 34, no. 4, p. 1278–1288.

Bat activity examined in southwest Minnesota indicates 

most mortality associated with turbines involves migrating bats. Most mortality was hoary bats (Lasiurus cinereus), 

although fatalities of other species were recorded. Authors 

conclude it is unlikely that resident bats would spend significant time foraging near wind turbines situated within interiors 

of crop fields, pastures, or CRP fields away from woodlands. A 
40 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography 

significant decrease in bat activity was recorded with increasing distance from woodland. Results of this and other studies 

cited lead authors to conclude that populations of breeding 

bats near wind plants are not highly susceptible to collision 

with turbines. However, mortality rates for migrating species are higher. Increased mortality due to safety lighting on 

turbines was not recorded.

Leddy, K.L., Higgens, K.F., and Naugle, D.E., 1999, Effects 

of wind turbines on upland nesting birds in Conservation 

Reserve Program grasslands: Wilson Bulletin, v. 111, no. 1, 

p. 100–104.

CRP grasslands without turbines and areas located 180 

m (215 yards [yd]) from turbines supported 4 times higher 

densities of grassland birds than areas within 80 m (95 yd) of 

turbines. Authors recommend turbines be placed in cropland 

that supports lower densities of grassland passerines rather 

than placing them in CRP grasslands where greater numbers 

of birds are present. Associated human disturbance, turbine 

noise, and physical movements of turbines may have disturbed 

nesting birds.

McLaughlin, S.B., and Walsh, M.E., 1998, Evaluating environmental consequences of producing herbaceous crops for 

bioenergy: Biomass and Bioenergy, v. 14, no. 4, p. 317–324.

The choice of switchgrass (Panicum virgatum) for biomass production is based on potentially high yields, high nutrient use efficiency, and wide geographic distribution. Other 

attributes include positive effects on soil quality and stability, 

potential value as wildlife cover, and relatively low requirements for energy, water, and agrochemical inputs. Estimates 

of the efficiency of energy production show that switchgrass 

can exceed corn (bioethanol) by as much as 15 times. Carbon 

sequestration may exceed those of annual crops by as much as 

20–30 times. These differences can have implications for both 

the rate and efficiency with which fossil fuels can be replaced 

by cleaner burning biofuels. Obvious environmental benefits 

of switchgrass production include improved soil conservation, enhanced energy gain, and reductions in emission of 

carbon dioxide. 

Moreira, N., 2005, Growing expectations—New technology 

could turn fuel into a bumper crop: Science News, v. 168, 

no. 14, p. 218–220.

This is a short but informative article describing the 

potential use of biofuels. Various options and shortcomings 

of alternatives are presented. Green fuels are becoming more 

attractive as fuel prices climb and the end of an oil-based 

economy is projected in future decades. The Energy Policy Act 

of 2005 requires 7.5 billion gallons of ethanol and biodiesel to 

be part of the nation’s fuel supply by 2012, providing 5.75 percent of the country’s fuels supply. Ethanol is the most common 

plant-to-fuel product currently available. Green fuels have 

lower emissions of greenhouse gases, but these fuels do have 

negative consequences, which include high costs of energy 

required to produce them as well as elevated use of fertilizer 

and erosion of soil. Ethanol production from biomass currently 

requires more fuel-derived energy than it saves. Ethanol from 

corn consumes 29 percent more fuel than it saves. Estimates 

indicate that replacing the entire U.S. fuels supply with corn 

ethanol will require at least 60 percent of the nation’s available 

cropland. Cellulosic biomass, rather than corn, appears to be 

a more environmentally friendly approach. Thermochemical 

production of biofuels (production of gas and eventual liquid 

of wood, grass, manure) cannot compete with petroleum on 

the open market. 

Using waste plant material (corn husks, wood chips) may 

avoid these problems, but there is no commercially viable process yet to make large amounts of cellulosic biofuel. However, 

work is progressing on bringing down costs of fuel production 

from cellulase by using bioengineered organisms to break 

down cellulose and produce ethanol. In the United States, the 

greatest opportunities for competitive biofuels may lie in combining biochemical and thermochemical methods. The article 

quotes Larry Russo (Department of Energy) as saying “Agriculture in the 21st century will become our oil wells.”

Mulkey, V.R., Owens, V.N., and Lee, D.K., 2006, Management 

of switchgrass-dominated Conservation Reserve Program 

lands for biomass production in South Dakota: Crop Science, v. 46, p. 712–720.

Successful perennial grass-based energy production 

requires reliable establishment and persistence of grass, high 

yielding cultivars, and appropriate conversion technology. 

In some regions of the United States, switchgrass (Panicum 

virgatum) can produce up to 14 Milligram (Mg) of dry matter 

(DM) per hectare of which over 60 percent is lignocellulose, 

the desirable component for biomass production. At similar 

stages of maturity, warm-season grasses have higher lignocellulose concentrations than cool-season grasses and legumes. 

Lignocellulose concentrations increase as switchgrass matures 

as a result of a decrease in the leaf-to-stem ratio. Growth characteristics and past descriptions of harvest effects on switchgrass yield are provided.

An investigation of management strategies for conversion 

of CRP land planted to switchgrass is presented. Objectives 

were to determine effect of harvest timing, N application rate 

effects on biomass production, and effects of harvest management on species composition and persistence. Authors recommend harvesting switchgrass once per year after a killing frost 

and applying low to moderate amounts of N to maximize 

energy yield. Older stands of switchgrass may be more sensitive to harvest timing than younger stands. Silica content is 

lowest in grass stems and highest in leaves; therefore, harvesting switchgrass with high stem content is desirable because 

biomass quality for combustion purposes is improved. Delaying harvest until after killing frost maximizes canopy cover 
Biomass, Energy 41

length and decreased proportion of broadleaved weeds in harvested biomass. Switchgrass tends to be sensitive to frequent 

harvest. Authors conclude that in 9-yr-old stands, persistence 

of switchgrass declined rapidly when harvested annually during the growing season. Competition between switchgrass and 

other grasses and broadleaved weeds was also greater when 

switchgrass was harvested during growing season. 

Murray, L.D., and Best, L.B., 2003, Short-term bird response 

to harvesting switchgrass for biomass in Iowa: Journal of 

Wildlife Management, v. 67, no. 3, p. 611–621.

An alternative to returning expiring CRP fields to row 

crop production is biomass production through growth of 

switchgrass (Panicum virgatum). Grass biomass is typically 

harvested during fall and winter thereby not directly affecting 

breeding birds during harvest. However, resultant changes in 

vegetation structure will have impacts on the quality of breeding habitat in the subsequent spring. Authors conclude that 

switchgrass biomass fields can retain breeding habitat value 

for some avian species and an interspersion of harvested and 

non-harvested fields would be the best alternative over total 

harvest of all fields or partial harvest of all fields. However, 

the number of avian species using biomass switchgrass fields 

may be reduced due to a greater dependence on herbicides and 

fertilizers to maximize production. Applications of agrochemicals may directly cause nest failures and reduction in habitat 

structure, which would diminish the quality of reproductive 

habitat. Switchgrass fields grown for biomass production 

will generally be of greater value to generalist avian species 

than those with more restrictive habitat requirements that are 

of management concern in Iowa (for example, sedge wren 

[Cistothorus platensis], grasshopper sparrow [Ammodramus 

savannarum], and northern harrier [Circus cyaneus]). 

Murray, L.D., Best, L.B., Jacobsen, T.J., Braster, M.L., 2003, 

Potential effects on grassland birds of converting marginal 

cropland to switchgrass biomass production: Biomass and 

Bioenergy, v. 25, p. 167–175.

Report describes results of Geographic Information System analysis of converting row crop and CRP grass-dominated 

fields to biomass production and effects on 13 selected avian 

species in Rathun Lake watershed in Iowa. Bird-abundance 

values for each habitat were used to model avian abundance 

in watershed before and after conversion to biomass production. Scenarios using total harvest of fields and strip-harvest of 

fields were completed. 

Authors conclude conversion to switchgrass (Panicum 

virgatum) biomass production would create habitat for some 

avian species of management concern (for example, bobolink [Dolichonyx oryzivorus], dickcissel [Spiza americana], 

and field sparrow [Spizella pusilla]). Abundance of these 

species increased under both total field and strip harvesting 

of biomass. A mixture of both total harvest and non-harvest 

would have the greatest benefits to the largest number of avian 

species. Rotations of fields in non-harvest status through harvest period would allow buildup of vegetation litter required 

by early-season ground nesting birds. Authors suggest that 

the establishment of row crop food plots in areas dominated 

by biomass production could mitigate loss of foods provided by typical row crop production. Future monitoring of 

switchgrass biomass production effects on avian populations 

is recommended.

Pineiro, G., Jobbagy, E.G., Baker, J., Murray, B.C., and Jackson, R.B., 2009, Set-asides can be better climate investment 

than corn ethanol: Ecological Applications, v. 19, no. 2, 

p. 277–282.

To meet targets of the Energy and Independence and 

Security Act of 2007, corn production will need to increase by 

improving yields, replacing other crops, and bringing additional uncultivated land into production. The authors state that 

converting natural ecosystems and set-aside lands, including 

lands currently enrolled in the CRP, to corn can result in large 

shifts in C storage. Many past investigations suggest corn 

ethanol reduces greenhouse gas (GHG) emission by displacing use of fossil fuels, but most of these studies do not include 

the implications of changes in net C balance brought through 

changes in soil C content.

Evidence is furnished that C release from soil after planting corn for ethanol may completely offset C gains attributed 

to biofuel generation. The extent to which GHG emissions 

can be reduced through corn ethanol depends strongly on how 

and where the corn is produced. The authors’ assessment of 

142 prior investigations shows soil C sequestered by setting 

aside agricultural land was greater than C credits generated by 

planting corn for ethanol on the same land. Because cropland 

soil has substantial potential to sequester C when restored to 

grassland, conversion of land under long-term cultivation to 

CRP has a more positive greenhouse gas balance than corn 

ethanol production. 

When it becomes commercially viable, cellulosic ethanol 

from biomass is likely have the most beneficial GHG emissions balance of all production options. The authors conclude 

if grasslands are established on cropland the production of 

cellulosic ethanol does not reduce, and actually may increase, 

soil C stocks if corn were planted on the same land. Extending 

current CRP contracts or enrolling new lands in CRP appears 

to more economical strategies for sequestering GHG emissions than converting these lands to corn ethanol production.

Appropriate C accounting of biofuel production requires 

a complete analysis of impacts to the environment. Estimating 

the value and public costs of reducing GHG emissions through 

time is critical for evaluation of alternatives in U.S. Farm and 

Energy bills. The authors conclude cellulosic ethanol produced 

on set-aside land should provide the most efficient tool for 

GHG reductions. At present, conversion of CRP and other setaside lands is an inefficient and expensive alternative for mitigation of greenhousegases. The authors conclude conversion 
42 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography 

of CRP lands or other set-aside lands for production of ethanol 

should not be encouraged through greenhouse-gas policies.

Robel, R.J., Harrington, Jr., J.A., Hagen, C.A., Pitman, J.C., 

and Reker, R.R., 2005, Effect of energy development and 

human activity on the use of sand sagebrush habitat by 

lesser prairie chickens in southwestern Kansas, in Transactions North American Wildlife and Natural Resources 

Conference, 69, Spokane, Wash., March 16–20, 2004, Proceedings: Washington, D.C., Wildlife Management Institute, 

p. 251–266.

Lesser prairie chickens (Tympanuchus pallidicinctus) 

occupy xeric grasslands across much of the southern Great 

Plains dominated by sand sagebrush (Artemisia filifolia) or 

shinnery oak (Quercus havardii). In southwestern Kansas, 

populations have generally declined due to deterioration of 

sandsage habitat. This is largely due to the conversion to 

center-pivot irrigation for production of corn. While most 

of this development occurred in mid 1980s, prairie-chicken 

populations continue to decline. Low nest success and survival 

of chicks appear to be factors contributing to decline. Authors 

conclude the presence of anthropogenic features (for example, 

buildings, roads, wellheads, electric transmission lines) have 

reduced suitability of habitat beyond direct loss of habitat 

area to cropland. Vegetative characteristics between used and 

non-used areas were identical. The animals’ avoidance of 

habitat is believed associated with movement and noise from 

infrastructure related to energy development and agriculture. 

Adult birds used habitat near roads, wellheads, buildings, and 

transmission lines less than areas further from those features. 

Negative impacts were greater for buildings and transmission lines than for wellheads and roads. Estimates of buffers 

around roads and energy features where habitat use is affected 

are given. Buffered areas representing habitat of lower quality 

represent 58 percent of the sand sagebrush habitat remaining 

in 2001. Loss of suitable habitat for nesting is believed to be 

even greater, leaving only 26 percent of remaining habitat 

available for nesting.

Roth, A.M., Sample, D.W., Ribic, C.A., Paine, L., Undersander, D.J., and Bartelt, G.A., 2005, Grassland bird 

response to harvesting switchgrass as a biomass energy 

crop: Biomass and Bioenergy, v. 28, p. 490–498.

Switchgrass (Panicum virgatum) grown as a biofuel has 

potential to furnish a cash crop for farmers and quality nesting 

cover for grassland birds. The study investigates how harvest 

of switchgrass for bioenergy impacts community composition 

and abundance of southwestern Wisconsin grassland bird species. Regrowth of vegetation following mid-summer harvest of 

switchgrass was not observed. Within harvested sites, residual 

vegetation was shorter and litter layer reduced in the year 

following harvest. Grassland bird species preferring vegetative cover of short height and low to moderate density were 

found in harvested areas (for example, grasshopper sparrow 

[Ammodramus savannarum], eastern meadowlark [Sturnella 

magna]). Unharvested switchgrass furnished tall, dense vegetation attractive to species such as sedge wren (Cistothorus 

platensis) and Henslow’s sparrow (A. henslowii). Management plans that maintain some fields unharvested each year 

are recommended as a good compromise to maintain habitat 

for grassland avian species of management concern. August 

harvest furnished habitat the following year favoring species 

preferring vegetation of moderate height and low to moderate 

density. Authors believe a mid-August harvest would allow for 

at least 90 percent of nests to fledge.

Sanderson, M.A., Reed, J.C., and Reed, R.L., 1999, Harvest 

management of switchgrass for biomass feedstock and forage production: Agronomy Journal, v. 91, p. 5–10.

The paper describes harvest management recommendations for switchgrass (Panicum virgatum) as a biomass energy 

crop. Most research on perennial warm-season grasses for 

energy has emphasized a single harvest of very mature stands 

which is suitable for a biomass dedicated only to biomass 

fuels. Authors focus on an alternative that may allow use 

as forage as well as biomass source. Total seasonal yields 

decreased as frequency of harvest increased. Highest yields 

occurred with a single harvest in mid-September. Delay of harvest until November reduced yields. A single, mid-September 

harvest is recommended for maximum biomass yield in the 

south-central United States. A two cut (spring-autumn) alternative may allow farmers to use spring growth as forage and 

the regrowth for biomass but yield would be reduced. More 

frequent harvest would result in reduced yields—perhaps 

these yields would be so reduced as to not be economical for 

machine harvest for biofuel purposes. 

Sanford, M.P., 2005, Extirpating the agriculture versus conservation dichotomy: Conservation Biology, v. 20, no. 1, 

p. 253–254.

Private farm and ranch lands are disappearing at an 

alarming rate. In the United States, more than 12 million hectares (46,333 mi2) were converted to exurban development in 

the 1990s. Private lands in the United States cover 72 percent 

of the land base, support biodiversity equal to or exceeding 

protected areas, contain habitat for 60 percent for of threatened 

and endangered species exclusively, and represent habitat for 

nearly 95 percent of all threatened and endangered species. A 

failure by scientists and practitioners to embrace partnershipbased conservation on private lands remains. Factors affecting 

partnership-based conservation include public opposition/fear, 

negative prior experiences, lack of support from agencies/

institutions, and governmental policies. Agriculturalists and 

conservationists are often polarized on these issues. 

The current conservation era is transitioning from limiting losses due to agricultural practices toward decreasing 
Biomass, Energy 43

losses resulting from urban sprawl which will demand both 

local and global solutions. The author believes many past 

conservation efforts have failed due to the failure to recognize 

(1) the role of local communities in conservation and (2) local 

residents have one of the strongest influences on maintaining 

biodiversity and integrity of the land. Conservation is partly a 

social science which needs to continue a focus on elimination 

of barriers between professionals and landowners. 

Secchi, S., Gassman, P.W., Williams, J.R., and Babcock, B., 

2009, Corn based ethanol production and environmental 

quality—A case of Iowa and the Conservation Reserve Program: Environmental Management, v. 44, p. 732–744.

Increasing demands for corn ethanol has elevated concerns about environmental costs to lands in the CRP if they 

are returned to production. The authors investigate linkages 

between potential corn production on existing CRP. The 

investigation was competed using Iowa data because nearly 

750,000 hectares (18.5 million + ac) are in CRP and the state 

produces more ethanol than any other. The Environmental 

Policy Integrated Climate model is used to investigate changes 

in distribution and abundance of CRP lands relative to potential changes in corn prices.

While the authors admit many variables affect decisions 

about enrollment, they estimate based on a price of $118.10/

ton, almost 400,000 hectares (988,400 ac) of CRP, almost 

half the acreage in the state, would go back into production. 

As corn prices increase a greater percentage of CRP land 

would return to production. Authors estimate, at this price 

it would cost over $277 million through higher payments to 

keep less than 70,000 hectares (173,000 ac) from returning to 

production. The findings show lands leaving the CRP will be 

distributed according to land quality and productivity. Conservation benefits are likely to undergo substantial losses unless 

significant budget increases are provided. One consequence 

of changing land use may be more CRP in buffer strips, field 

borders, and grassed waterways rather than whole field enrollments. Higher payments are likely to be required to enroll or 

maintain whole fields.

Tilman, David, Hill, Jason, and Lehman, Clarence, 2006, 

Carbon-negative biofuels from low-input high-diversity 

grassland biomass: Science, v. 314, p. 1598–1600.

Authors conclude biofuels derived from low-input highdiversity mixture of native grassland perennials can furnish 

more useable energy, greater reductions in greenhouse gases, 

and less pollution from agrichemicals than can production of 

energy from corn ethanol or soybean biodiesel. High diversity 

grasslands provided 238 percent higher energy yields than 

monocultures after 10 years. Currently, biofuel production 

competes for fertile land needed for production of food and 

increases pollution due to greater dependence on chemical 

inputs to maintain productivity. Doubling of global demand 

for food and energy is projected in next 50 years and growing 

use of food crops for energy have elevated concerns about biodiversity loss as remaining natural lands are converted to these 

uses. Authors believe low input highly diverse grasslands to 

meet energy needs can be produced on abandoned agricultural 

lands and suggest with proper management these grasslands 

can produce a sustainable product, renew fertility of the soil 

and provide wildlife and cleaner water. 

Usgaard, R.E., Naugle, D.E., and Osborn, R.G., 1997, Effects 

of wind turbines on nesting raptors at Buffalo Ridge in 

southwestern Minnesota: Proceedings of the South Dakota 

Academy of Science, v. 76, p. 113–117.

Authors report raptors (chiefly red-tailed hawk [Buteo 

jamaicensis], northern harrier [Circus cyaneus], and kestrel 

[Falco sparverius]) were absent from 32 km2 (12.5 mi2) wind 

plant facility despite presence of potentially suitable forested 

and riparian woodland nesting habitat. Although no direct 

mortality due to windmills was recorded, wind turbines may 

be indirectly affecting local populations of raptors by decreasing availability of nesting sites. Authors suggest key habitats 

believed important to raptors should be excluded from development of windfarms until more information is available.

Venuto, B.C., and Daniel, J.A., 2010, Biomass feedstock harvest from Conservation Reserve Program land in northwestern Oklahoma: Crop Science, v. 50, p. 737–743.

Six CRP grasslands were harvested for three consecutive years to determine biomass production in northwestern 

Oklahoma and describe effects on plant growth, and soil 

characteristics. CRP fields were planted to old-world bluestem 

(Bothriochloa spp.) monocultures and native mixed species 

comprised of big bluestem (Andropogon gerardii), Indiangrass 

(Sorghastrum nutans), silver bluestem (B. laguroides), sideoats grama (Bouteloua curtipendula), little bluestem (Schizachyrium scoparium), and sand lovegrass (Eragrostis trichodes). 

Authors conclude, at least in the short-term, old world 

bluestem monocultures are a more productive source of 

biomass feedstock than are CRP fields planted to a mix of 

native species. Old world bluestem productivity declined more 

quickly over time than did productivity of native grass CRP 

fields. This implies greater long-term productivity for native 

species. Authors conclude an annual set-aside approach were 

implemented to extend overall productivity harvest yields 

would increase but total biomass available annually within the 

region would decrease. The consequence of this incorporation 

of rotations would require a greater amount of land to support 

a biomass processing facility. For a bioenergy industries to be 

viable from these CRP grasslands the authors conclude harvest 

strategies (resting/rotation) and nutrient replacement would 

be required to sustain productivity. There was no change in 

species composition or soil characteristics as a consequence 

of harvesting.
44 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography 

Economics

Adam, B.D., Hong, S.J., and Dicks, M.R., 2004, Effects of the 

Conservation Reserve Program on elevator merchandising 

margins in Oklahoma: Journal of Agricultural and Applied 

Economics, v. 36, no. 1, p. 83–96.

As a consequence of the CRP taking land out of production for 10 or more years, grain supplies available to elevators 

are reduced. Study results suggest the CRP has had negative 

effects on local elevator merchandising margins and profits but 

elevators adjusted to changes within one year. Authors conclude the program has had only minor national and regional 

economic impacts but reduced economic activities stemming 

from the CRP may be as high as 20 percent locally. Grain 

elevators have faced several sources of economic strain that 

include CRP, ARP set asides, modification in production due 

to technological changes, and competitive pressures associated 

with storage and merchandising capabilities. Effect of CRP 

on elevator economic stability varies but has been significantly reducing margins an average of 16 percent in 1989 in 

Oklahoma. Elevators were able to make economic or physical 

adjustments to CRP related declines in production in a relatively short period of time. However, these adjustments (for 

example, mothballing or sale of physical assets) may be costly 

to reverse if local productivity increases. These economic 

impacts should be considered as new agricultural policies are 

formulated. Authors recommend that agricultural policies be 

scrutinized carefully to adjust for local impacts on agribusiness because local negative effects can be substantial. Future 

research is recommended that addresses relationships between 

changes in land use, increasing size of farms, and losses in 

market share of local and regional agribusiness.

Bangsund, D.A., Leistritz, F.L., and Hodur, N.M., 2002, Rural 

economic effects of the Conservation Reserve Program in 

North Dakota: Fargo, N.D., Department of Agribusiness and 

Applied Economics, Agricultural Experiment Station, North 

Dakota State University, Agribusiness and Applied Economics Report No 497, 105 p.

While long-term crop retirement programs generally 

produce, in varying degrees, negative effects on those businesses and sectors providing agricultural inputs, those same 

programs generate positive economic effects in other areas of 

the economy. The CRP has greatly enhanced wildlife habitat 

in the northern Great Plains. Increased wildlife habitat has 

directly led to substantial increases in upland bird, waterfowl, 

and big game populations. Enhanced wildlife populations have 

in turn led to increases in wildlife-based recreation, primarily 

hunting, and to a lesser extent, wildlife viewing.

Few studies have attempted to include recreational revenues in the economic assessment of the CRP. Although this 

study examined gains and losses in rural economic activity 

due to the CRP, the analysis should be viewed cautiously, as 

assessing the program’s net economic effects remains sensitive to several key factors and a number of assumptions were 

incorporated due to a lack of data. In addition, the analysis 

was based on a single point in time, and the results may not 

accurately predict future economic effects of the program. The 

future ability of rural areas to offset CRP-based agricultural 

losses with wildlife-related recreational expenditures will 

largely be dependent upon pheasant and waterfowl hunting. 

Pheasant and waterfowl hunting accounted for over 80 percent 

of all CRP-based hunting expenditures, and current data indicates even major increases in deer hunting expenditures will 

likely only offset small reductions compared to ring-necked 

pheasant and waterfowl hunting expenditures. Consequently, 

not all areas of North Dakota will be able to equally offset 

agricultural losses with recreational revenues. Future wildlife 

population levels, policies, and hunting trends, which affect 

pheasant and waterfowl hunting, will have the greatest effect 

on the level of recreational revenues captured in rural areas.

Collectively, resident hunter expenditures were a substantially higher source of new wealth than nonresident hunters. 

However, both resident and nonresident hunter expenditures 

are important sources of recreational revenues in most areas 

of the state. The future ability of rural areas to offset CRPbased agricultural losses will be dependent upon expenditures 

from both resident and nonresident hunters and factors, which 

substantially affect either group, will have implications on the 

amount of recreational spending captured in those rural economies. The degree to which CRP-based hunting revenues in 

rural areas are offsetting agricultural losses varied throughout 

the state. In several cases, hunting expenditures offset a substantial portion of the agricultural losses, while in other areas, 

the net economic loss from the program remains high. The net 

economic effects of the program in the western and central 

areas of the state were most favorable, since those areas had 

the highest levels of CRP-based hunting expenditures and relatively lower amounts of lost agricultural revenues. However, 

the net effect of recreational and agricultural revenues in eastern areas of the state was not nearly as favorable. Those areas 

captured little additional hunting-related expenditures from 

the program and had relatively high levels of lost agricultural 

revenues. In North Dakota, the net economic effect of losses in 

agricultural revenues and gains in hunting-based recreational 
Economics 45

revenues indicated the CRP is not the economic burden several 

in areas of the state previous research has suggested.

Cahill, K.N., Kucharik, C.J., and Foley, J.A., 2009, Prairie restoration and carbon sequestration— difficulties quantifying 

C sources and sinks using a biometric approach: Ecological 

Applications, v. 19, n. 8, p. 2185–2201.

Two southwest Wisconsin CRP fields and adjacent 

croplands were evaluated for C cycling and ecosystem characteristics. Greenhouse gas emissions have been targeted by 

the Kyoto Protocol yet no standardized or widely adopted 

methodology for quantifying C credits exist. Grasslands cover 

20 percent of the earth’s terrestrial surface and store 10-30 

percent of its soil C stocks yet they do not receive the attention 

that forests do in the context of global change. 

Study site entailed a CRP field previously in maize and 

enrolled into the program in 1987. Three treatments were 

evaluated: a warm season grass planting (C4), a cool season 

grass planting (C3), and a disk planted unfertilized continuous no-till rotation of crops (maize and soybeans). The most 

abundant grass in the C4 treatment was switchgrass (Panicum 

virgatum) and in the C3 treatment smooth brome (Bromus 

inermis). Both treatments had patches of non-seeded species in 

them and some seeded species failed to establish. 

Total soil respiration was highest in the C3 treatment and 

not significantly different between the C4 and cropland treatment. Annual soil C flux was significantly higher than the C4

and cropland treatment. Forty of 45 estimates showed the C3

treatment to be a net annual source of C and fifteen out of 45 

estimates showed the C4 treatment to be a C sink. Cropland 

treatment was estimated to be a C source. Both grassland treatments had significantly higher soil C in the top 5 cm of soil 

than the crop treatment. 

Net ecosystem productivity estimates varied widely in 

magnitude and by methodology. Authors caution when using 

only one estimate for annual net primary production, belowground net primary production (ANPP, BNPP) or microbial 

respiration as the results may misrepresent the certainty 

assigned to the result. Authors also caution that great abundance of forbs planted in the CRP treatments may not be 

representative of a typical CRP planting. Forbs are important 

components of a diverse planting for wildlife habitat but 

involve a tradeoff by reducing C sequestration. 

De La Torre Ugarte, D., and Helwinckel, C., 2006, Analysis 

of the economic impacts on the agricultural sector of the 

elimination of the Conservation Reserve Program: Knoxville, Tenn, Agricultural Policy Analysis Center, University 

of Tennessee, 18 p.

The CRP was not designed to be a supply management 

program but it clearly has an impact on supply and crop 

prices. As of 2006, the 34.7 million acre program has reduced 

planted and harvested acres of most farm programs. Changes 

in CRP enrollment will have impacts on markets should the 

program lose legislative or budgetary support. The Agricultural Policy Analysis Center estimates 37 percent of today’s 

CRP acres will return to crop production as contracts expire 

by 2015 if legislation for budget priorities eliminates the CRP. 

It is estimated 71 percent of expiring acres (9 million acres) 

will be used to grow corn, soybeans, and wheat. Added acres 

devoted to these crops will reduce prices received by farmers to lower than USDA projected baseline prices resulting 

in an estimated $6.6 billion loss in net market returns if CRP 

acres are returned to crop production. Increased plantings and 

lower prices will have a positive effect on export volume with 

corn exports estimated to increase by 183 million bushels, 7.7 

percent above the USDA baseline projection. APEC estimates 

federal payments (direct payments, loan deficiency payments, 

etc.) for eight major program crops will rise nearly 34 percent 

($3.8 billion) over USDA estimates. It is estimated from 2007-

2015 the net effect of eliminating the CRP program would 

result in an additional cost to the government of $32.6 billion.

Economic Research Service. 2004. Conservation Reserve 

Program: Economic and Social Impacts on Rural Counties. 

ERS Report to Congress. U.S. Department of Agriculture, 

Economic Research Service, Washington D.C. 143 p.

This report provides an evaluation of CRP on economic 

and social impacts on rural counties. Report concludes that 

high enrollment of CRP was associated with some loss of 

jobs in rural counties between 1986-1992 but the negative 

effect did not persist through the 1990s. Regional impacts of 

the CRP vary widely with both economic winners and losers. 

Economic effects were found to vary over time, geography, 

and economic trends affecting rural economies. No statistical 

significant evidence was found that high levels of CRP participation affected local government services or tax burdens. 

Proportion of whole-farm enrollees, relative to partial-farm 

enrollees did not have strong impacts on employment or 

provision of local government services. Rural counties with 

modest populations (small towns serving as local agricultural 

centers) were likely to lose jobs when 20 percent or more 

of the area’s cropland was enrolled in CRP but job growth 

rebounded as time passed. More densely populated rural 

counties with diverse, local economies were rarely affected by 

CRP enrollment in either the short or long term. Counties with 

low population density (without small towns) were unaffected 

by level of CRP enrollment. Authors conclude that release of 

CRP back to production could have a small positive effect on 

national output but incomes of medium-income households 

(those receiving most of CRP payments) could decline.

Authors report because of the stable source of income 

provided by the program the CRP helped many financially 

vulnerable farm operators stay within their communities rather 

than leave in search of employment elsewhere. In addition, 

improvements in wildlife populations and provision of cleaner 

more scenically appealing environment, CRP may have made 

some rural communities more attractive places to live. 
46 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography 

CRP enrollment tends to be greatest in rural, agricultural areas with a long history of population decline. Post 

population trends were largely unaffected by high levels of 

CRP enrollment. Relative to consequences of technological advances, market trends and other federal policies, CRP 

effects on beginning farmer trends is minor. No statistically 

significant evidence was found that CRP participation encourage absentee ownership of farmland. While a full measure 

of the economic benefits associated with improved environmental quality and resultant recreation stemming from CRP is 

unavailable, conservative estimates are recreational activities 

exceed $700 million/year.

Feather, P., Hellerstein, D., and Hansen, L., 1999, Economic 

valuation of environmental benefits and the targeting of 

conservation programs— the case of the CRP: Washington, 

D.C., USDA Economic Research Service, Agricultural Economic Report No. 778, 56 p.

Report documents how nonmarket valuation can be used 

in targeting CRP by examining environmental targeting to 

specific environmental benefits and recreational opportunities created by conservation programs. Ecosystem health and 

many recreation activities have substantial social and economic worth but typically have no explicitly identified price 

or market value. Report discusses development, application 

and alternatives in use of the EBI devised to score land parcels 

to determine potential environmental and economic benefits 

of individual contracts. Specifically discussed in this analysis are alternative applications to address greater attention to 

freshwater-based recreation, wildlife viewing, and ring-necked 

pheasant (Phasianus colchicus) hunting. Noteworthy findings 

include conclusion switching CRP targeting from soil erodibility to the EBI doubles benefits to freshwater-based recreation 

and wildlife viewing; CRP wildlife recreation benefits are 

significantly larger than fresh-water based recreation benefits. 

Natural resources near populated areas are likely to generate 

larger recreation use benefits simply because they are more 

easily accessible. Authors conclude valuation based targeting 

of CRP is feasible and may improve performance of the program, especially if public preferences are known and explicit.

Feng, H., Kling, C.L., Kurkalova, L.A., Secchi, S., and 

Gassman, P.W., 2005, The Conservation Reserve Program 

in the presence of a working land alternative— Implications for environmental quality, program participation, and 

income transfer: American Journal Agricultural Economics, 

v. 87, no. 5, p. 1231–1238.

The United States has invested large amounts of money 

in agricultural conservation programs over the past century 

with the largest and most ambitious program being the CRP. 

Although the CRP has evolved to target an array of environmental issues the program operates strictly through land 

retirement. One issue that has not received much attention in 

evaluation is consequences of working land programs (for 

example, Environmental Quality Incentives Program, Conservation Security Program) that compete for the same parcels of 

land. As the 2007 Farm Bill approaches it will be important 

to understand the potential complementarities and conflicts 

between these types of programs (that is retirement vs. working land programs).

Increasingly farmers are faced with decisions to retire a 

piece of land, cultivate it with conservation practices, or not 

to participate in either type of program. This paper provides 

analysis and estimates of how these programs might affect the 

CRP in terms of land enrolled, income transfers to farmers, 

and the extent of environmental improvement as measured by 

C sequestration, reduction in soil erosion, and reduction of N 

runoff. Authors conclude compared to where land retirement 

is the only option the economic and environmental results of 

land retirement programs are very different when working 

land programs are available. The same unit payments for land 

retirement in presence of subsidies for conservation tillage will 

enroll only about 50 percent of acreage that can be enrolled in 

absence of working land programs. 

Authors conclude working land and retirement program 

are mutually exclusive since a single piece of land can be 

enrolled in only one of these two options. Therefore, these 

types of programs compete and landowner decisions can have 

significant consequences for performance of each program. 

The authors point out one type of program is not superior to 

the other but the impact of one program on another is critical 

for conservation policy. Assessments of conservation program 

performance without taking these interactions into account 

could produce inaccurate performance and potential outcomes. 

Authors believe (based on simulation analysis) the presence of 

a working land program for conservation tillage would result 

in significantly lower signups for the land retirement program 

at a given rental rate. The presence of both a large working 

land and land retirement programs can result in more environmental benefits and income transfers than possible with only a 

land retirement program.

Fleming, R.A., 2004, An econometric analysis of the environmental benefits provided by the Conservation Reserve 

Program: Journal of Agricultural and Applied Economics, 

v. 36, no. 2, p. 399–413.

Author investigates extent of crop acreage enrollment in 

the CRP and effects on environmental conditions. A spatial 

econometric model is used to assess if CRP enrollments are 

greater in counties with poorer environmental quality. Findings are in 7 of 10 regions evaluated, CRP enrollment is 

higher in counties with an environmental concern and the CRP 

is targeting environmental concerns that will lead to future 

improvement in environmental quality. 

Author concludes in counties with higher productivity, thus higher economic returns from crop production, the 

CRP rental rate is not high enough to encourage operators 

to enroll in the program. Program expenditures have been 
Economics 47

highest in counties with poorer environmental quality suggesting enhancement of environmental quality as a result of 

the CRP. Even though CRP expenditures at the regional level 

may not indicate major environmental benefits extending from 

the program this does not mean there have not been beneficial 

micro or local impacts. Author concludes CRP has and will 

continue to benefit environmental conditions across the lower 

48 states justifying expenditures and supporting continuation 

of agricultural conservation programs. Expansion of studies to 

document benefits to wildlife, soil quality/erosion, and water 

quality are suggested to document and assess the economic 

and social value of the CRP. 

Gascoigne, W.R., Hoag, D., Koontz, L., Tangen, B.A., Shaffer, T.L., and Gleason, R.A., 2011, Valuing ecosystem and 

economic services across land-use scenarios in the Prairie 

Pothole Region of the Dakotas, USA, v.70, p.1715-1725

Authors quantify ecosystem services across three land 

uses (native prairie, CRP/WRP, and cropland) in the PPR of 

North and South Dakota by modeling four future land-use predictions and subsequent changes in ecosystem service values. 

Hypothetical land-use changes dubbed “aggressive conservation,” “CRP mitigation,” “market forces,” and “extensive conversion” were evaluated for ecosystem and economic service 

tradeoff analysis. Some of the scenarios were purposefully 

designed to extend programs past their current contract periods 

to more fully capture the dynamics of the ecological impacts 

(that is C sequestration). 

Aggressive conservation forecasts the effects of a 50 

percent increase in CRP/WRP lands at the expense of cropland 

while preserving native prairie. CRP mitigation estimates the 

effects of mitigating conversion of native prairie to cropland 

by enrolling additional lands into CRP/WRP. Market forces 

estimate environmental and economic consequences of losing 

native prairie to cropland while maintaining CRP/WRP lands 

at current levels. Extensive conversion estimates effects of 

losing native prairie acreage compounded with a 25 percent 

reduction in CRP/WRP acreage. 

Aggressive conservation would lead to gains in the PPR 

of $69 million annually and $1 billion over the twenty years 

and would substantially increase both soil and vegetation 

organic C and duck fledglings while reducing soil loss by 80 

million Mg. CRP mitigation would sustain an estimated loss of 

nearly $200 million annually or $2.5 billion over twenty years. 

Authors indicate that CRP/WRP lands cannot entirely mitigate 

the loss of native prairie. The market-forces scenario estimated 

net annual losses valued at over $281 million. Additional 

income from increased cropping could not offset decreases in 

C stocks. In the final scenario, extensive conversion showed 

enormous losses in C, soil and waterfowl tantamount to over 

$271 million annually and $4 billion over the twenty-year 

policy period.

Hansen, L., Feather, P., and Shank, D., 1999, Valuation of agriculture’s multi-site environmental impacts—An application 

to pheasant hunting: Agricultural & Resource Economics 

Review, v. 28, no. 2, p. 199–207.

Authors report ring necked pheasant (Phasianus colchicus) hunting benefits of the CRP were approximately $80 million in 1991 in states where the program appears most critical 

to the provision of pheasant habitat. Using a multi-site demand 

model, national survey on recreation, and environmental data 

process through GIS environmental benefits of CRP acreage 

can be compared across locations permitting change in policies affecting design and operation of the program. Total consumer surplus associated with pheasant hunting was estimated 

at $184 million/yr. Of this amount, $80 million was attributed 

to environmental benefits brought by the CRP. Redistribution 

of CRP acreage to address other environmental priorities could 

reduce pheasant hunting benefits but economic losses would 

be more than offset by benefits brought by nonconsumptive 

wildlife recreation and water-based recreation.

Hodur, N.M., Leistritz, F.L., and Bangsund, D.A., 2002, 

Local socioeconomic impacts of the Conservation Reserve 

Program: Fargo, N. Dak., Department of Agribusiness and 

Applied Economics, Agribusiness and Applied Economics 

Report No. 476-S, 58 p.

Findings document a number of apparent benefits in 

Northern Great Plains of the CRP. Enhanced habitat for wildlife has contributed to growth in populations of upland game 

birds, growth in numbers of resident and non-resident hunters, 

and increase in recreation-related expenditures in rural areas. 

The program has helped stabilize revenue of participating 

landowners during a period when the region’s farmers and 

landowners experienced adverse weather and poor market 

conditions. Program is very popular with ND landowners 

with continued participation expected to remain high. Some 

survey respondents, upon which report is based, attribute rural 

depopulation and general decline in farm and rural economy to 

CRP. However, most respondents indicated CRP did not affect 

transfer of property either to next generation or unrelated buyers. Other benefits attributed to the program include decreased 

soil erosion, improved water quality, and reduction in flooding. See Leistritz, Hodur, and Bangsund (2002) for an abbreviated presentation of study findings.

Hoppe, R.A., and Banker. D.E., 2006, Structure and finances 

of U.S. Farms—2005 family farm report: Washington D.C., 

U.S. Department of Agriculture, Economic Research Service, Economic Information Bulletin, no. 12, 42 p.

In 2003, 98 percent of American farms were family 

owned and organized as proprietorships, partnerships, or 

family corporations. Very large family farms and non-family 

farms account only for a small percentage of all farms but 
48 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography 

account for a growing share of farm sales. Small family farms 

represent most farms in the country but produce only a modest 

share of farm output. Median income for farm households is 

10 percent higher than median for all U.S. households with 

small farm households receiving a substantial portion of 

income from non-farm sources. Small family farms account 

for 91 percent of U.S. farms holding about 71 percent of farm 

assets including 70 percent of farmland. Consequently, these 

farms and operators potentially have a large role in the effectiveness of natural resource and environmental policy. Small 

farms account for about 82 percent of the land enrolled in the 

CRP and WRP.

Production has shifted largely to large and very large 

family and non-family farms since the 1980s (9 percent of 

farms in 2003) and such farms now account for 73 percent 

of production. This trend is likely to continue due to growing 

share of operators 65 years old and older and negative operating profit margin of small farms. Medium sales and large 

sales farms received about 75 percent of commodity related 

governmental payments. Retirement, residential and low-sales 

small farms received 64 percent of conservation (CRP, WRP) 

payments in 2003.

Ibendahl, G., 2004, Risk-adjusted comparison of Conservation 

Reserve Program payments versus production payments for 

a corn-soybean farmer: Journal of Agricultural and Applied 

Economics, v. 36, no. 2, p. 425–434.

Author reports on simulation-model output to compare 

farming income to payments under CRP program. The study 

was conducted based on data from three farms in Kentucky. 

The report concludes that CRP payment provides a competitive return relative to active farming, especially in areas with 

poor productivity of soil. Author believes the CRP should be 

considered by many farmers as a management and economic 

option especially on those farms with variable soils and less 

productive lands.

Isik, M., and Yang, W., 2004, An analysis of the effects of 

uncertainty and irreversibility on farmer participation in the 

Conservation Reserve Program: Journal of Agricultural and 

Resource Economics, v. 29, no. 2, p. 242–259.

Authors examine determinants of farmer participation 

in the CRP. Option values play a significant role in farmer 

decisions to retire land having implications for the design 

and implementation of conservation programs by improving 

design and cost-effectiveness. With CRP participation, farmers 

face a decision between uncertain farm income due to fluctuating crop prices and yield, and uncertain payments from one 

signup period to another. A decision-making model based on 

data from 100 Illinois counties was developed analyzing land 

benefits, land characteristics, and owner attributes. 

Study results indicate uncertainty and irreversibility of 

the CRP impact farmer decisions to participate in the program. 

The bid cap has a positive impact on CRP participation, as do 

increases in production costs and decreases in crop revenues. 

Lands with higher EBI indices have higher probability of 

participation. Counties with higher proportions of cropland 

suitable for production tend to have lower enrollment rates 

in the program. Older farmers tend to participate more in the 

CRP than do younger farmers. 

Success of land-retirement programs depends on appropriate design of rental payment, EBI instruments, and effective 

targeting of environmentally sensitive cropland. The program 

design should consider effects of costs to participants and 

uncertainty about outcomes. In environmentally sensitive 

regions, additional financial incentives would help increase 

participation in conservation programs. 

Johnson, R.L., McKean, J.R., Sandretto, C.L., 1992, Increased 

recreational hunting can offset negative economic impacts 

of the Conservation Reserve Program: Washington, D.C., 

U.S. Department of Agriculture, Economic Research Service Technical Bulletin TB92-4, 23 p.

An input-out analysis using National Survey of Fishing 

and Hunting data completed for northeastern Colorado estimates negative economic effects of the CRP and an increase 

in small-game and migratory-bird hunting needed to offset 

it. Offsetting CRP-related employment loss would require 

recreation hunting to rise by 1.8times, but offsetting the loss 

in sales would require an increase of 2.5. The negative impact 

and required offsetting rise in recreational hunting increases 

sharply if farmers who place land in CRP leave the region. 

Keith, K.W, 2005, Perspectives of the National Grain and 

Feed Association, in Allen, A.W., and Vandever, M.W., 

eds., The Conservation Reserve Program—Planting for the 

future—Proceedings of a National Conference, Fort Collins, 

Colo., June 6–9, 2004: U.S. Geological Survey, Biological Resources Discipline, Scientific Investigations Report 

2005–5145, p. 38–45.

Perspectives of the National Grain and Feed Association 

(NGFA) on the future of the CRP and suggested refinements of 

the program are provided. Recommendations the NGFA would 

like to see adopted include exclusion of whole-farm enrollment in CRP and reconsideration of the 25 percent cropland 

cap because of a dependence on inaccurate data and a tendency for CRP enrollment to become concentrated in specific 

geographic regions. Also recommended is a reduction in the 

overall enrollment cap for the CRP, as NGFA sees an increase 

in demand for more acres in production to address growing 

demands for production. NGFA believes there should be a 

greater focus on CRP addressing soil and water quality issues 

and would like to see some CRP lands put back into production prior to the large expiration of existing CRP contracts in 

2007 and 2008. Overall, NGCA believes there are other opportunities to address conservation without idling land. Excerpts 
Economics 49

from several letters from grain-related industries from the 

Great Plains are presented that describe severe detrimental 

impacts of the CRP on local businesses. 

Losey, J.E., and Vaughan, M., 2006, The economic value of 

ecological services provided by insects: Bioscience, v. 56, 

no. 4, p. 311–323.

Authors estimate ecological services (dung burial, pest 

control, pollination, and nutrition for wildlife) provided by 

insects in the United States to be at least $57 billion. Economic estimates for each service are: dung burial $0.38 billion, pollination $3.07 billion, pest control $4.49 billion, and 

wildlife-related recreation $49.96 billion. These are believed 

to be conservative estimates of the ecological values furnished 

by insects within the United States. Other environmental 

services provided by insects include suppression of weeds and 

other exotic herbivorous species, facilitation of dead plant and 

animal decomposition, and improvement of soil condition. 

The value of any of these services could add billions of dollars 

to these estimates.

The predominant benefit of insects is concentrating 

and moving nutrients through the food web. Economic and 

ecological benefits of dung beetles (primarily Scarabaeida) 

are discussed with benefits including improvement in soil, 

volatilization of N, diminished fouling of forage, and control 

of livestock parasites and pests. Pollination is the most widely 

known benefit of insects, with 15 to 30 percent of diet within 

the United States directly or indirectly dependent upon pollination by insects. Available information suggests control of 

insect pests costs the U.S. economy billions of dollars each 

year. This is only a fraction of the economic impact if beneficial insects did not keep most pests below economically 

damaging levels. U.S. citizens spend over $60 billion a year 

on hunting, fishing, and observing wildlife. Insects are a critical food source for much of this wildlife. 

The authors conclude that an annual investment of 

tens of billions of dollars could be economically justified to 

maintain ecological services provided by insects. There has 

been a steady decline in beneficial insects associated with 

diminishing biodiversity accompanied by severe declines 

in the quality of environments heavily impacted by human 

activities. Authors recommend a diversity of plant species 

in restoration or conservation projects to support viable and 

diverse populations of insects. Authors recommend USDA 

conservation programs pay specific attention to insects and the 

roles they carry out in ecosystem functioning. Insects and their 

needs should be considered in land-management decisions. 

A diverse community of forbs should be included with any 

restoration projects. 

Lynch, L., and Brown, C., 2000, Landowner decision making 

about riparian buffers: Journal of Agricultural and Applied 

Economics, v. 32, no. 3, p. 585–596.

Understanding farmer decision making in regards to 

property and conservation practices is crucial to effective conservation programs. Determination of conditions that influence 

farmer decisions when most benefits accrue to society (for 

example, establishment of riparian buffers) and not directly 

to the landowner is important in setting program incentives 

and policies. Authors conclude non-agricultural opportunity 

costs affect farmer decisions. If environmentally sensitive, but 

high-value, land is desired for enrollment additional incentives 

will be required. Upfront costs for adoption of conservation 

practices were important determinants in land owner decisions. Farmers were more sensitive to the cost-share rates to 

establish conservation practices than they were to relative 

incentive rates. Authors conclude increasing cost-share rates 

may be more effective in increasing enrollment in specific 

conservation practices than are increasing rental rates and upfront signing bonuses. Increasing cost-share rates may encourage more participation than does an increase in annual rental 

payments. Land values, rental rates, and crop prices affect 

farmer decisions about participation. In areas with high land 

values or low rental rates, additional incentives such as higher 

annual rates or signing bonuses may be needed to achieve 

enrollment goals.

Mortensen, T.L., Leistritz, F.L., Leitch, J.A., Coon, R.C., and 

Ekstrom, B.L., 1990, Socioeconomic impact of the Conservation Reserve Program in North Dakota: Society and 

Natural Resources, v. 3, p. 53–61.

Economic impacts of the CRP are estimated for North 

Dakota. Net reductions in production expenditures and household income totaled $55 million of which about 62 percent 

occurred in the retail sector of the economy. The total impact 

of the program affected about 0.5 percent of the state’s baseline economic activity. Local areas with high concentrations of 

CRP and businesses dependent on farm inputs may be affected 

the most. The most significantly impacted region had a 0.91 

percent reduction in economic activity due to CRP. Positive 

economic impacts also were documented. Longer-term beneficial aspects could result from achievement of CRP conservation objectives. (See Bangsund and others, 2002, and Leistritz 

and others, 2002, for more recent analysis of economic effects 

of CRP on North Dakota economies.)

Parrish, D.R, 2005, The Conservation Reserve Program—

Through the Farm Bureau Window—An outline, in Allen, 

A.W. and Vandever, M.W., eds., The Conservation Reserve 

Program— Planting for the future—Proceedings of a 

National Conference, Fort Collins, Colo., June 6–9, 2004: 

Reston, Va., U.S. Geological Survey, Biological Resources 

Discipline, Scientific Investigations Report 2005–5145, 

p. 37.

Perspectives of the Farm Bureau related to the CRP 

are presented. Support is described as being generally broad 
50 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography 

because the program provides stable source of income, opportunities to improve soil, air, water, and wildlife resources, 

but at times some view the program as a direct competitor 

for limited farmland and a threat to the economic stability of 

agricultural areas. Farm Bureau supports limiting CRP enrollment to 25 percent of cropland acres, maintaining base history, 

reevaluation of rental rates, control of noxious weeds on CRP 

acres, control of fire hazards, and leasing CRP for recreation 

but opposes emergency use of CRP acres and practices that 

jeopardize drainage or flood control. Farm Bureau would 

like to see a more landscape level approach to conservation 

policies as well as more integrated approach between various 

USDA conservation programs. 

Pimentel, D., Acquay, H., Biltonen, M., Rice, P., Silva, M., 

Nelson, J., Lipner, V., Giordano, S., Horowitz, A., and 

D’Amore, M., 1992, Environmental and economic costs of 

pesticide use: Bioscience, v. 42, no. 10, p. 750–760.

Approximately 600 different types of pesticides are 

used annually in the U.S. Roughly 160 million ha/yr (greater 

than 395 million ac/yr) receive a heavy pesticide application, 

averaging 3 kg/ha (2.7 lb/ac). Without pesticides, pests would 

account for 10 percent of crop loss with specific crop losses 

ranging from 0 to nearly 100 percent. Despite widespread use 

of pesticides, insects, plant pathogens, and weeds destroy 37 

percent of all potential food and fiber crops. Tenfold increase 

in insecticide use from 1945 to 1989 but total crop losses 

from insect damage have nearly doubled from 7 to 13 percent. 

Rise in insect damage is, in part, due to changes in agricultural practices. Natural predators play a major role in keeping 

populations of many insect pests under control. Pesticides 

directed toward pest species adversely affect these beneficial 

species disrupting natural biological control. Fungicides can 

contribute to pest outbreaks when they reduce fungal pathogens naturally parasitic on many insects. An estimated $520 

million/yr can be attribute to costs of additional pesticide 

applications and increased crop losses following destruction of 

natural enemies by pesticides applied to crops. 

The three most common pesticides found in groundwater 

are aldicarb, and herbicides alachlor, and atrazine. Estimates 

are that nearly one-half of groundwater and well water in the 

United States has potential to be contaminated. Adding monitoring and cleaning costs the total cost of pesticide polluted 

groundwater is approximately $1.8 billion/yr. High pesticide 

concentrations in water directly kill fish. Low-level doses 

kill susceptible fry and essential foods of fish are eliminated. 

Pesticides washed into aquatic systems by runoff and soil 

erosion cause few if any widespread pesticide poisoning dramatic enough to be observed. Therefore most poisonings go 

unrecognized and unreported yet have significant ecological 

impacts. A low estimate of annual losses is $24 billion/yr. The 

actual cost is probably several times this amount.

Roberts, R.S., 1987, Rural population loss and cropland 

change in the Southern Plains—Implications for cropland 

retirement policy: Professional Geographer, v. 39, no. 3, 

p. 275–287.

A major obstacle constraining adoption and implementation of cropland retirement programs has been fear that such 

programs will threaten viability of rural communities. Author 

concludes short-term cropland idling under post-1960 pricesupport programs appears to furnish a greater threat to rural 

communities than do long-term cropland-retirement programs. 

Despite their intuitive appeal, cropland retirement programs 

have never been popular among farmers and have met stiff 

political opposition from regional and local rural interests. The 

combination of farm financial stress and continuing population 

loss from farming regions will continue to provide a basis for 

political contention. Author cites studies that determined the 

Soil Bank (1956–1972) did not increase downward trend in 

rural population losses and that the financial cushion furnished 

by the program actually allowed many farm families to remain 

farming or transition into off-farm jobs as a major source 

of income.

Based on an analysis of data from 1930 to 1970, the 

author concludes that a small long-term negative impact on 

rural populations in the Southern Plains can be attributed to 

cropland retirement but massive structural shifts in the agricultural community have had a much greater effect on rural 

population change. There may be economic stress placed on 

individual farms, or farm supply and service businesses in 

rural areas, as a result of cropland retirement, but there is little 

evidence the changes have long-term effects on total rural and 

service center populations. The author further concludes, there 

is no major direct threat to rural population or retail change 

from change in cropland area. 

Soutiere, E.C., 1984, Farm wildlife production—What does it 

cost?, in Transactions of North American Wildlife and Natural Resources Conference, 49, Boston, Mass., March 23–28, 

1984, Proceedings: Washington, D.C., Wildlife Management Institute, p. 159–163.

Issues that negatively influence farmers’ willingness to 

produce wildlife: harassment and problems associated with 

increased hunting pressure and demand, increased crop damage, and loss of income from diverted lands. Economic effects 

of delayed haying include lower tonnage as well as lower 

digestibility and protein content. Dairy cows fed late-cut hay 

will require 1.5–2 times more grain supplement containing an 

additional 5 percent protein.

Can it be expected that farmers will carry the cost of 

providing wildlife habitat? The answer is reflected in the 

continued removal of wetlands, idle areas, and fencerows. If 

the costs of wildlife are compared to the costs of agricultural 

products (grain, hogs) the costs of production on prime farmland are very high. Raising pen-reared birds is a comparative 
Economics 51

bargain at these prices. Compensation to the farmer for 

wildlife habitat would probably need to be at least equal to 

75–80 percent of the market value of the yield per acre of crop 

normally produced on set-aside land. To obtain a meaningful 

increase in wildlife numbers it would probably require at least 

5 percent of land area be devoted to wildlife habitat.

Any solution to production long-term of wildlife on 

farmland must include acceptance of farming practices that 

produce wildlife as a no-cost byproduct of production. Agencies need to aggressively advocate and demonstrate farming 

technologies that help both the farmer and wildlife. The best 

approach for farmland wildlife management is to deal with 

resources and programs that encourage sound land use for all 

resources over the long term. Wildlife’s only hope on prime 

farmland is farm practices, programs, and policies that bring 

reduced costs or added income to the individual farmer.

Sulivan, P., Hellerstein, D., Hansen, L., Johansson, R., Koenig, 

S., Lubowski, R., McBride, W., McGranahan, D., Roberts, 

M., Vogel, S., and Bucholtz, S., 2004, The Conservation Reserve Program— Economic implications for rural 

America: Washington, D.C., U.S. Department of Agriculture, Economic Research Service, Agricultural Economic 

Report No. 834, 106 p.

The report estimates economic impacts of high levels of 

enrollment in the CRP in rural counties since the inception of 

the program. Results indicate no discernible impact by CRP on 

county population trends. Employment growth was believed 

to have been temporarily slowed in counties with high CRP 

enrollment, but negative effects were short lived. High levels 

of enrollment appear to have affected farm-related businesses 

over the long run but growth in other nonfarm businesses 

moderated the negative impact on total employment. If CRP 

had ended in 2001, study results suggest 51 percent of land 

in program would have returned to production. Spending 

on outdoor recreation related to CRP would have decreased 

by as much as $300 million/yr in rural areas. Economic 

impacts of CRP on employment and income vary widely 

among regions having similar CRP enrollment due to local 

economic conditions. 

Authors found no statistically significant evidence to 

support the assumption CRP encourages rural outmigration. 

Nor did high levels of CRP enrollment affect beginning farmer 

trends or absentee ownership of farmland. Nationally, it was 

estimated that economic effects of allowing CRP land to return 

to production would be very small with both positive and 

negative effects largely canceling each other out. However, 

economic effects could be more substantial locally where 

enrollment is high. 

Van Buskirk, J., and Willi, Y., 2004, Enhancement of farmland 

biodiversity within set-aside land: Conservation Biology, 

v. 18, no. 4, p. 987–994.

Although it may seem obvious that withdrawal of 

farmland from intensive production would provide benefits to 

wildlife and biodiversity associated with agriculturally dominated landscapes, there remain serious questions about the cost 

effectiveness and benefits of such programs. Some suggest 

set-aside programs are inefficient and relatively unsuccessful 

in providing wildlife habitat. Agroecologists monitoring these 

programs have reported conflicting results. Because these 

programs are costly, politicians may be unwilling to continue 

approving payments in North American and the European 

Union in absence of clear evidence reporting benefits of these 

programs. Because general conclusions about the impact of 

set-aside programs cannot be supported by few isolated monitoring studies the authors of this report completed a literature 

review of over 500 studies in agricultural landscapes. Of these, 

127 reports met criteria of at least two treatments of lands-use 

types and measures of variation among replicates of at least 

one plant or animal taxon. 

Authors report that meta-analysis indicates numbers of 

bird species, insects, spiders/harvestmen, and plants were significantly higher on set-aside land than on nearby control areas 

under conventional agricultural production. Authors believe 

their analysis unequivocally resolves controversy of biodiversity benefits of set-aside land at least at local level. The simple 

result of the study is that larger, more permanent units of land 

enrolled in set-aside have greater benefits than do smaller sites 

of short duration. Authors identify need for more information 

on how land in these programs functions in the context of the 

entire landscape and how species react to these programs.

Van Buskirk, J., and Willi, Y., 2005, Meta-analysis of farmland 

biodiversity within set-aside land—Reply to Kleijn and 

Báldi: Conservation Biology, v. 19, no. 3, p. 967–968.

In response to criticism by Kleijn and Báldi (2005) these 

authors defend their original investigation where they reported 

positive effects of set-aside land on density and species richness of birds, insects, spiders and plants. The authors state, in 

response to disparagement from Kleijn and Báldi, that their 

criticism is based only on their findings in Netherlands and 

that Kleijn and Báldi must realize variation from individual 

investigations is to be expected and local results reveal only 

part of the picture in the larger multi-national (127 studies 

assessed) evaluation. Van Buskirk and Willi argue that the 

level of heterogeneity in their study strengthens their results 

as it illustrates that biodiversity benefits of set-aside programs 

are quite general and at least a fraction of farmland biodiversity can be restored by temporarily setting aside land from 

conventional production. They suggest a reasonable initial 

plan would be to set aside a mosaic of plots, as large as possible, of different ages. This approach would have limited 

effects in a landscape dominated by traditional agriculture 

(for example, relatively small fields, production of multiple 

crops) but would be increasingly appropriate as the landscape 

became more dominated by modern, chemically-intensive 

industrialized farming. 
52 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Williams, C.F., and Mjelde, J. W., 1994, Conducting a 

financial analysis of quail hunting within the Conservation 

Reserve Program: Wildlife Society Bulletin, v. 22, 

p. 233–241. 

Upsurge in outdoor recreation has strained the public land 

system. Public hunting lands remain in short supply and growing demand for use. The greatest opportunities to supply quality hunting lie in development of opportunities on private land.

U.S. Department of Agriculture, 1993, Conservation Reserve 

Program—Cost-effectiveness is uncertain: Washington, 

D.C., U.S. General Accounting Office, GAO/RCED–93–

132, 14 p.

Precise balance between the costs and environmental 

benefits of CRP cannot be calculated because dollar value 

of the environmental benefits cannot be precisely assessed. 

The USDA has not quantified the effect on the environment 

of removing enrolled acres from production. USDA will pay 

more than $91 billion to remove 63.5 million acres from production over ten-year life of program. Environmental benefits 

are perceived to be only temporary. USDA goals of program 

were to reduce commodity production, support farm income 

and lastly to provide environmental benefits. As a result of 

these priorities, land with fewer environmental benefits was 

initially allowed into the program. Other USDA programs 

(Conservation Compliance, Agricultural Conservation Program, and Small watershed Program) were identified as covering more acres of cropland, costing less, and providing more 

long-term environmental benefits. However, these programs 

are not intended to curb excess production and only indirectly 

support farm incomes. Advantage of these programs is they 

do not take land out of production. (Implications to wildlife; 

less land set aside in permanent cover = probability of lower 

overall wildlife benefits).

General Accounting Office, 1989, Farm programs—Conservation Reserve Program could be less costly and more effective: Washington, D.C., Committee on Agriculture, Nutrition, and Forestry, U.S. Senate, GAO/RCED–90–13, 79 p.

USDA could improve effectiveness of CRP by targeting 

cropland eroding at the highest rates where most contributions 

to surface water and groundwater contamination are greatest. CRP costs will be offset to some extent as farmers enroll 

acres otherwise used for growing crops covered by price and 

income support programs. USDA incurred additional cost in 

tree planting initiative by furnishing greater rental rates in 5 

southeastern states. Higher rental rates were paid to all farmers 

whether or not they planted trees. USDA instructions to county 

offices allowed CRP rental rates in many areas to exceed local 

rental rates. Report recommends USDA implement competitive bid system and modify the 25 percent limit on acreage to 

allow more flexibility in program enrollment.

Grassland Management 

Baer, S.G., Kitchen, D.J., Blair, J.M., and Rice, C.W., 2002, 

Changes in ecosystem structure and function along a chronosequence of restored grassland: Ecological Applications, 

v. 12, no. 6, p. 1688–1701.

Evaluation of change in vegetation, roots, and soil characteristics in 12-year-old CRP fields in Nebraska (Gage and 

Saline counties) planted to native warm season grasses (that is, 

big bluestem [Andropogon gerardii], little bluestem [Schizachyrium scoparium], sideoats grama [Bouteloua curtipendula], 

switchgrass [Panicum virgatum], and Indiangrass [Sorghastrum nutans]). The evaluation was completed across CRP 

fields of varying age (0–12 yr). Percent cover of grasses and 

forbs changed across time represented by CRP fields of varying age. Most recently planted fields (2 yr) contained legumes 

in seed mixture; legumes represented less than 1 percent of 

total plant cover in these grasslands. In fields less than 4 years 

old, vegetative cover was dominated by early successional 

annual species and planted grasses contributed less than 10 

percent of total plant cover. Although species dominance varied, in fields greater than 6 years old grasses dominated plant 

cover and forbs were negligible. Root biomass and C storage 

in roots increased across time sequence. Total root biomass 

significantly was higher in grasslands restored for 10–12 years 

than in 2-year-old restored sites. Carbon storage in roots was 

greatest in grasslands restored for 10 or more years. Significant changes in soil physical and chemical properties occurred 

only within 10 cm (4 in) of surface. 

The objective of CRP was not to restore native grasslands and pre-agricultural diversity. Near exclusion of forbs 

in CRP fields greater than 6 years old points to major difference between native tallgrass prairie and CRP (unmanaged) 

fields. Fields in this study were ungrazed and infrequently, or 

never, burned. Authors conclude, however, that revegetation 

of former croplands with historically dominant native grasses 
Grassland Management 53

Comparisons showed an increase in the proportion of 

native species after the first growing season. First growingseason restorations were composed mainly of annual and 

biennial plant species, many of which were non-native. Perennial native composites were common in the second growing 

season. By the third growing season a significant portion 

(38–57 percent) of vegetative cover became dominated by 

native warm-season grasses. Associated with increased cover 

of warm season grasses was an increase in belowground net 

primary production, litter mass, and C mineralization rates. 

Total soil C and N were not significantly different between 

native prairie and restored grassland on agricultural sites. 

Authors conclude, with time, vegetative diversity in restored 

agricultural sites (for example, CRP) can support community 

and system-level conditions comparable to native prairie.

Campa III, H., and Winterstein, S.R., 1992, Wildlife and 

vegetative response to diverted agricultural land in Gratiot 

County, Michigan: East Lansing, Mich., Department of 

Fisheries and Wildlife, Annual Report, December 1992, 

26 p.

Several significant differences for vegetation variables 

(for example, percent canopy cover, height, total canopy, percent grass canopy, percent litter cover) among grasslands were 

reported, but none were found to be consistently related to 

field age. Older fields tended to be characterized by a greater 

percentage cover of grass and litter. Younger fields tended to 

have greater forb and live canopy cover. Younger fields supported greater avian densities and diversities. Avian productivity, however, was higher in older fields, which may have been 

result of older fields providing more suitable nesting sites due 

to greater diversity in vegetation structure.

Collins, S.L., Glenn, S.M., and Gibson, D.J., 1995, Experimental analysis of intermediate disturbance and initial floristic composition—Decoupling cause and effect: Ecology, 

v. 76, no. 2, p. 486–492.

This paper reports results of disturbance from long-term 

studies in tallgrass prairie (Konza Prairie Kansas).The hypothesis richness will be highest in communities with moderate 

levels of disturbance and at intermediate time spans following 

disturbance has been widely accepted. If disturbance occurs 

frequently, richness is assumed to decrease because species 

intolerant of disturbance become locally extinct. If disturbances are infrequent, richness decreases because dominant 

species outcompete weaker competitors. Richness should be 

greatest at intermediate frequencies of disturbance when conditions favor competitive species and those that tolerate disturbance. A second prediction of the intermediate disturbance 

hypothesis is that species richness will be highest at intermediate time spans following disturbance because late successional 

species will competitively displace early successional species 

lowering richness later in succession. 

facilitates recovery of some key ecosystem properties and processes in trajectory toward reestablishment of native prairie. 

Barker, J.R., Baumgarder, G.A., Turner, D.P., and Lee, J.J., 

1996, Carbon dynamics of the Conservation and Wetland 

Reserve Programs: Journal of Soil and Water Conservation, 

v. 51, no. 4, p. 340–346.

Data from Conservation and Wetland Reserve Programs 

analyzed to quantify C dynamics of cropland converted to 

grassland or forestland. Cropland converted to forestland 

gained C at a rate about 7 times greater than cropland converted to grassland. Maintaining existing CRP grassland will 

provide substantial C sequestration on a national scale due to 

large area enrolled in long-term set aside. 

Berger, J.J., 1993, Ecological restoration and nonindigenous plant species—A review: Restoration Ecology, v. 1, 

p. 74–82.

Merely re-creating the physical form or appearance of an 

ecosystem without restoring naturally occurring functions does 

not constitute complete restoration. The key question to ask is 

not whether one can eradicate an invading species but whether 

its establishment can be impeded, its growth restricted, and 

its reproduction restrained, thus keeping it from becoming a 

worse pest. Ecosystems most susceptible to invasion by nonindigenous plant species are generally those with breaks in the 

natural plant cover. Typically, mechanical or chemical weed 

removal or control is required before restoration can begin. An 

appropriate question is: can restoration prevent reinfestation 

of the ecosystem by the nonindigenous species? Restoration is 

not likely to be successful in excluding invading species once 

propagules of the invader are well dispersed throughout the 

system. Control rather than exclusion may be the more attainable goal. If restoration is not accompanied by a successful 

eradication or other on-going management program restored 

native flora will remain at risk. 

Camill, P., McKone, M.J., Sturges, S.T., Severud, W.J., Ellis, 

E., Limmer, J., Martin, C.B., Navratil, R.T., Purdie, A.J., 

Sandel, B.S., Talukder, S., and Trout, A., 2004, Community 

and ecosystem-level changes in a species-rich tallgrass prairie restoration: Ecological Applications, v. 14, no. 6, 

p. 1680–1694.

The objective was to examine differences in ecosystem 

characteristics between restored prairies and restored grasslands on adjacent agricultural fields in southern Minnesota to 

determine changes in plant community and ecosystem properties. Objectives were to examine how plant groups and ecosystem properties change through time, if ecosystem processes 

may be plant species dependent, and if ecosystem processes 

differ from lands in CRP. 
54 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

 Authors report significant decline in species richness 

with increasing disturbance frequency. Average number of 

species and number of grass, forb, and annual species were 

lowest on annually burned sites compared to unburned sites 

and those burned every 4 years. Species richness reached a 

maximum at an intermediate time interval since disturbance. 

A disturbance event can reduce or maintain species richness 

but does not in itself increase richness; it does, however, create conditions necessary for increased richness. Disturbance 

regimes are characterized by variation in size, frequency, and 

intensity of disturbance. Results indicate species richness is 

consistently lowest on frequently burned sites with lower fire 

intensity compared to infrequently burned sites where fires 

are hotter.

Coppedge, B.R., Engle, D.M., Fuhlendorf, S.D., Masters, 

R.E., and Gregory, M.S., 2001, Landscape cover type and 

pattern dynamics in fragmented southern Great Plains grasslands, USA: Landscape Ecology, v. 16, p. 677–690.

Cover and land-use change between 1965 and 1995 

related to the CRP are discussed for an area of northwestern 

Oklahoma. The original grassland ecosystem has been fragmented by agricultural land use. Due to exclusion of fire, remnant grasslands have experienced invasion by eastern redcedar 

(Juniperus virginiana) having further negative consequences 

for endemic species of wildlife and remaining southern Great 

Plains grasslands. Even small amounts of encroachment by 

woody vegetation into remnant grassland can have substantial effects of these species. The authors conclude Oklahoma 

grasslands, as well as grasslands across the Southern Plains, 

will continue to lose their value to wildlife unless substantial 

modifications are made to existing land management policies 

and practices.

Coppedge, B.R., Fuhlendorf, S.D., Harrell, W.C., and Engle, 

D.M., 2008, Avian community response to vegetation and 

structural features in grasslands managed with fire and grazing: Biological Conservation, v. 141, p. 1196–1203.

The study reports management of tallgrass prairie in 

north central Oklahoma on avian community response. 

Grasses in the study area is dominated by big bluestem 

(Andropogon gerardii), little bluestem (Schizachyrium scoparium), Indiangrass (Sorghastrum nutans), and switchgrass 

(Panicum virgatum). Portions of pasture were burned each 

year to create a mosaic of grassland patches in varying stages 

of recovery from disturbance. Results indicate woody edges, 

ponds, and roads were more negative than positive influences on abundance of several grassland avian species. The 

study provides evidence of ecological advantages of rotating 

disturbance patterns in tallgrass prairie via patch-burning. 

Patch burning affected the avian community by decreasing 

abundance of the brown-headed cowbird (Molothrus ater), 

increased overall species richness, enhanced grassland obligate 

richness, and provided habitat for the Henslows’s sparrow 

(Ammodramus henslowii) a species of management concern. 

Fritcher, S.C., Rumble, M.A., and Flake, L.D., 2004, Grassland bird densities in seral stages of mixed grass prairie: 

Journal of Range Management, v. 57, no. 4, p. 351–357.

Authors believe seral stages of grassland may have 

effects on declining bird populations in grassland ecosystems, but resource managers lack sufficient information to 

assess how avian species are affected by changes in grassland 

composition. Report evaluates bird density, species diversity 

and species richness in four seral stages of western wheatgrass 

(Pascopyrum smithii), green needlegrass (Nasella viridula) 

associations in central South Dakota. Species richness did 

not differ between seral stages, but diversity was greater in 

early seral stages of grassland composition. Birds with habitat 

requirements of tall vegetation and residual cover were more 

abundant in later seral stages (for example, grasshopper 

sparrow [Ammodramus savannarum], bobolink [Dolichonyx 

oryzivorus]). Early seral stages were more beneficial to species 

needing short grass and sparse vegetative cover (for example, 

chestnut-collard longspur [Calcarius ornatus], horned lark 

[Eremophila alpestris]). Authors recommend management 

prescriptions furnishing a mosaic of seral stages to maximize 

grassland bird species diversity and abundance across the 

landscape. Authors conclude seral stage was an effective predictor of density for many grassland birds and its assessment 

can furnish a framework for development of management 

plans and prediction of effects of management decisions.

Gauthier, D. A. and Wiken, E.B., 2003, Monitoring the conservation of grassland habitats, prairie ecozone, Canada: Environmental Monitoring and Assessment, v. 88, p. 343–364.

Canadian prairie ecozone represents 5 percent of Canadian area and 16 percent of North American Great Plains. 

Authors estimate only 25–30 percent of Canadian grassland 

remaining habitats are concentrated in southeastern Alberta 

and southwest Saskatchewan. This report furnishes an overview of ecosystem, land cover, administrative, and conservation area databases useful for evaluation and monitoring 

grasslands in North America with a specific focus on Canadian 

prairie ecozone. Fragmentation of grasslands habitats and 

implications for grassland conservation are discussed. Authors 

recommend that monitoring programs incorporate quantitative 

and qualitative evaluations of habitat conditions that include 

amount of specific types of habitat, landscape patterns, indicators of habitat quality, spatial metrics, and rates of change in 

habitat conditions. 

George, R. R., Farris, A.L., Schwartz, C.C., Humburg, D.D., 

and Coffey, J.C., 1979, Native prairie grass pastures as nest 

cover for upland birds: Wildlife Society Bulletin, v. 7, no. 1, 

p. 4–9.
Grassland Management 55

Lands seeded to pure stands of switchgrass (Panicum virgatum), Indiangrass ( Sorghastrum nutans), and big 

bluestem (Andropogon gerardii) and properly managed as 

warm season livestock forage provide suitable nest cover for 

ring-necked pheasants (Phasianus colchicus) and other upland 

nesting birds. In contrast, alfalfa and orchardgrass hay fields 

produced no successful nests due to early-season hay cutting. Switchgrass furnishes quality cover because it maintains 

leaves, resists burial/lodging by snow, and provides good 

residual spring cover. Passerine densities were highest in big 

bluestem. The three grasses listed above are recommended 

for warm-season livestock forage and wildlife nesting cover. 

Little bluestem is best nesting cover but it produces less forage 

and is more difficult to establish than other native grasses. Tall 

native grasses should not be grazed below 8-10 in. Grazed 

grasses should be left undisturbed as much as possible in order 

to provide maximum residual cover in spring. Prescribed 

burns every 4–5 years will remove excess litter and prevent 

woody invasion. 

Germano, D.J., Rathbun, G.B., and Saslaw, L.R., 2001, 

Managing exotic grasses and conserving declining species: 

Wildlife Society Bulletin, v. 29, no. 2, p. 551–559.

Evaluation of introduced grasses on fauna in San Joaquin 

Valley, Calif. Herbaceous cover of introduced grasses and 

forbs often creates an impenetrable thicket for small grounddwelling vertebrates. Authors believe some years moderate 

to heavy grazing by livestock is the best way to decrease the 

dense cover created by exotic grasses. Many plant and animals 

are adapted to relatively open habitats and are morphologically, behaviorally, and physiologically ill equipped to live in 

dense stands of grass. Control of exotic grasses may be possible by removing plants mechanically or by herbicides. These 

methods, however, generally are too costly to be effective over 

large areas.

Gibon, A., 2005, Managing grassland for production, the 

environment and the landscape—Challenges at the farm and 

landscape level: Livestock Production Science, v. 96, 

p. 11–31.

Agricultural systems are increasingly recognized by 

society and science as complex systems supporting a variety 

of environmental and social benefits. Written from a European 

perspective, this paper addresses issues appropriate to the 

future of grassland management and environmental issues in 

the United States. Grasslands are currently regarded as a land 

used to enhance and preserve based on growing recognition 

of their many environmental services. However, the scientific 

understanding required to achieve multifunctional benefits still 

remains poor. Spreading understanding of the need to consider 

grassland management beyond the grassland itself is needed 

at farm and landscape levels. The first requirement is a greater 

understanding of the diverse services grasslands provide 

and knowledge about the way their functions can conflict or 

complement other farm operations. Grasslands are increasingly recognized for their contributions to C sequestration, 

regulation of nutrients, soil quality, water cycle balance, flood 

reduction, and contributions to biodiversity.

 As in the United States, European grassland has experienced huge reductions area and quality in the 20th century. 

High yielding row crops reduced area devoted to grasslands 

resulting in significant negative environmental impacts. There 

is a growing awareness of the need to care for grasslands 

on the farm and landscape level to maximize environmental 

services. Enhancement of semi-natural grassland and the 

recreation of landscape heterogeneity is being considered as a 

key in sustaining biodiversity across agricultural ecosystems. 

Aesthetics and natural heritage may lead to specific objectives 

with respect to grassland restoration and their spatial arrangement in the landscape. Pressure for delivery of environmental 

and public goods by agriculture has increased. Monitoring will 

be key in documentation of benefits, effectiveness of policies, 

and efficient adoption of desired management changes by fine 

tuning financial support to farmers. Success will require management at a variety of scales and cooperation with ecological 

sciences, economics, and social sciences. 

Gill, D.E., Blank, P., Parks, J., Guerard, J.B., Lohr, B., 

Schwartzman, E., Gruber, J.G., Dodge, G., Rewa, C.A., and 

Sears, H.F., 2006, Plants and breeding bird response on a 

managed Conservation Reserve Program grassland in Maryland: Wildlife Society Bulletin, v. 34, no. 4, p. 944–956.

Paper describes plant and breeding bird responses to 

CRP grassland establishment and management in northeastern Maryland. Fields were planted with five mixtures of 

warm-season native grasses representing various growth-form 

heights with mowing and herbicide applications to control 

weeds and encourage stand establishment. In six years, plantspecies richness increased following a third season prescribed 

burn to remove excessive litter and control encroachment of 

woody vegetation. Several at-risk bird species (for example, 

grasshopper sparrow [Ammodramus savannarum]) colonized 

restored grasslands and established sustainable breeding populations. These populations declined in absence of burning but 

these fields did attract several shrubland associated species. 

Avian habitat preferences were determined more by vegetation 

structure than plant species composition. Authors recommend 

grassland management include rotation of prescribed fire 

and herbicide to favor desirable physical diversity in vegetation structure. No one management protocol will work for all 

targeted species. 

Study results demonstrate eastern native grasslands 

can be “reassembled” on heavily degraded lands within a 

time frame of 2 to 4 years. “Reassembled” means increasing 

species diversity in a managed habitat so the area becomes 

capable of supporting sustainable populations of plant and 

animal species. In six years of management (for example, 

mowing burning), cumulative plant-species richness increased. 
56 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Several at-risk bird species (for example, grasshopper sparrow 

[Ammodramus savannarum], dickcissel [Spiza americana]) 

colonized the restored grassland and established sustainable 

breeding populations. Large blocks of habitat were fundamental to the positive response by grassland obligate species 

in contrast to narrow linear grass-buffer strips (that is, CP21) 

which attracted very few grassland specialist bird species. 

Prescribed burning is identified as the least expensive management tool for maintaining grasslands. Switchgrass (Panicum 

spp.) was found to be too aggressive in this region and no 

longer recommended for native grassland seeding mixtures. 

Management of restored grasslands should include spatial and 

temporal rotation of prescribed fire and herbicide applications 

to sustain desirable vegetative physical structure rather than 

species composition.

The authors conclude mowing, during establishment, 

prescribed burning on a 3-year rotation, and application of 

herbicides for noxious weed control established and maintained a species rich grassland habitat valuable to grasslandobligate species. Results of this study demonstrate many of 

the management prescriptions recommended by USDA and 

others work. Conservation effort of CRP and CREP are valid 

approaches to benefit multiple conservation objectives.

Grant, T.A., Madden, E., and Berkey, G.B., 2004, Tree and 

shrub invasion in northern mixed-grass prairie—Implications for breeding grassland birds: Wildlife Society Bulletin, 

v. 32, no. 3, p. 807–818.

Study reports investigation effects of invasion by aspen 

(Populus tremuloides), willow (Salix spp.) and other woody 

vegetation on avian grassland bird species habitat quality in 

north-central North Dakota. Grassland study area dominated 

by needlegrass- wheatgrass (Stipa-Agropyron) intermixed 

with smooth brome (Bromus inermis) and Kentucky bluegrass 

(Poa pratensis). Probability of occurrence of 11 of 15 species decreased as percent woodland, tall shrub, or brush cover 

increased. Grasslands became largely unsuitable for 9 species 

of grassland birds as woody cover exceeded 25 percent. Only 

vesper sparrow (Pooecetes gramineus), clay-colored sparrow (Spizella pallida), and common yellowthroat (Geothlypis 

trichas) occurred more frequently as woody cover increased. 

Savannah sparrow (Passerculus sandwichensis), bobolink 

(Dolichonyx oryzivorus) and grasshopper sparrow (Ammodramus savannarum) reached maximum occurrence in open treeless grasslands with probability of occurrence declining to 50 

percent when woody cover ranged from 10–25 percent. Number of species negatively affected by woody cover increased as 

vertical structure changed to tall shrub and aspen woodland.

Authors judge even nominal increases in woody vegetation will compromise use of grasslands by several avian species. Occurrence of most woodland-sensitive species declined 

rapidly as woodland cover increased to only 5–20 percent. 

Recommend restoration efforts on grasslands be focused 

where woody cover is less than 20 percent for management to 

have most beneficial effects. Authors urge discontinuance of 

programs that encourage introduction of native and non-native 

trees and shrubs into northern Great Plains grasslands.

Henderson, D.C. and Naeth, M.A., 2005, Multi-scale impacts 

of crested wheatgrass invasion in mixed-grass prairie: Biological Invasions, v. 7, p. 639–650.

Crested wheatgrass (Agropyron cristatum) in the most 

widespread alien perennial forage grass across the North 

American Great Plains. The species has invaded native 

grasslands and raises concerns about its ecological impact. 

Intentionally introduced from Eurasia as a forage crop due 

to its ability to resist grazing and become established under 

drought conditions it has often spread into remaining natural 

grasslands. The species tends to out-compete native species 

and dominate communities for decades following establishment. Rate of spread can be as much as 1–2 m/yr (3–6 ft/yr). 

Because it is so adaptable, crested wheatgrass is intentionally 

seeded into semiarid regions to prevent invasion of even less 

desirable species like cheatgrass (Bromus tectorum) and knapweed (Centaurea spp.).

 An assessment of impacts of crested-wheatgrass invasion is reported at multiple scales of evaluation. At population level, native cool season mid-grasses and forbs were less 

abundant in invaded grassland. Native cool season and warm 

season short grasses species abundance was not affected. At 

community and landscape levels, vegetative diversity was 

lower in invaded grasslands due to lower species richness 

and cover of forbs. At ecosystem level vegetation and litter 

biomass were greater in invaded grasslands but belowground 

organic matter, soil organic C, N, and P were not affected. 

Crested wheatgrass incursion into mixed-grass prairie communities appears to simplify composition of prairie landscapes. 

Crested wheatgrass pastures are less diverse and have less 

soil organic matter than native grasslands on formerly cultivated land. Once established, crested wheatgrass dominates 

vegetation composition and the seedbank. Control of crested 

wheatgrass requires suppression of seed production, elimination of existing plants, and introduction of native grass and 

forb seeds.

Hirsch, S.A. and Leitch, J.A., 1998, Impact of leafy spurge on 

post-Conservation Reserve Program land: Journal Range 

Management, v. 51, no. 6, p. 614–620.

Authors state leafy spurge (Euphorbia esula) infests 

some of the 1.2 million hectares (greater than 2.9 million ac.) 

of CRP in North Dakota. (However, no quantifiable data on 

presence of leafy spurge are presented.) Authors believe, once 

established, leafy spurge will out-compete established grasses. 

Resultant spurge monocultures will reduce benefits of the 

CRP and diminish economic returns to some post-CRP land 

use. Again, they offer no documentation of spurge replacing established grasses. Post-CRP impacts on grazing and 
Grassland Management 57

crop production are estimated in the “absence of actual data.” 

Authors speculate, using a North Dakota input-output economic model, that post-CRP economic losses on grazing lands 

(that is, CRP lands used for grazing after contract expiration) 

would be $3.6 million annually. Authors believe if CRP lands 

facilitate spread of leafy spurge the ecological and environmental benefits of the CRP are overestimated. Justifiably, the 

authors advocated more precise inventories of spurge infestation to more accurately evaluate effects of the invasive species 

on land use and economic impacts. 

Hofmann, M., and Isselstein, J., 2005, Species enrichment 

in an agriculturally improved grassland and its effects on 

botanical composition, yield, and forage quality: Grass and 

Forage Science, v. 60, p.136–145.

Effects of different management practices on botanical 

development and productivity of a species-poor, intensively 

managed grassland are reported for a 4-year period. Half of 

study plots were sown with a mixture of forb (wildflower) 

species to investigate effects of cutting regimes on vegetation composition, stand development and dry-matter yield. 

Frequent cutting resulted in the greatest number of established 

plants and three-times greater harvested dry-matter yield of 

introduced species when compared to infrequent cutting. 

Introduced forbs increased the crude protein concentration but 

decreased digestibility of forage. Although this investigation 

took place in Germany, the implications and discussion presented are applicable to grassland management issues in North 

America, particularly as they relate to lands enrolled in grass 

covers in USDA conservation programs.

The report documents that it is possible, under appropriate management, to establish a range of wildflower species 

into grasslands. All cutting treatments resulted in some degree 

of establishment of forbs. Stands subjected to more severe disturbance prior to seeding (for example, plowing) had the greatest response to forb establishment. Other studies cited show 

over-sowing by broadcast seeding without severe mechanical 

disturbance was ineffective. Greater biomass of seeded species 

in cut plots was result of higher number and growth of introduced plants. Appropriate management measures are necessary to ensure initial increase in vegetation composition is 

maintained over the long-term. Authors conclude herbage production can be maximized by increasing diversity in vegetation. This can be partly explained by establishment of N-fixing 

legumes (for example, clover) as well as species with different 

temporal and spatial growth patterns than that of grass-dominated stands. Herbage from treated plots (mowed) with higher 

abundance of introduced forbs had higher N concentration 

than plots without such species. Authors conclude introduction of forbs can increase forage quality with respect to protein 

concentration but may lead to a reduction in digestibility.

Lee, K.H., Isenhart, T.M., Schultz, R.C., and Mickelson, S.K., 

1999, Nutrient and sediment removal by switchgrass and 

cool-season grass filter strips in central Iowa, USA: Agroforestry Systems, v. 44, no. 2-3, p. 121–132.

In the short term, switchgrass (Panicum virgatum) and 

cool-season grass filter strips (smooth brome [Bromus inermus], timothy [Phleum pratense], and fescue [Festuca spp.]) 

removed about the same amount of sediment. Long-term 

effectiveness of cool season grass filter strips may be limited; 

however, due to sediment accumulation in this low stature, 

less resilient vegetation. Switchgrass may offer higher longterm effectiveness because it produces large amount of litter, 

has stiff stems, strong root systems, and growth pattern more 

uniform and erect than cool-season grasses.

Lemaire, G., Wilkins, R., and Hodgson, J., 2005, Challenges 

for grassland science—Managing research priorities: Agriculture Ecosystems & Environment, v. 108, p. 99–108.

Although written for application in the European agricultural ecosystem, concepts presented are applicable to the agricultural/environmental situation in the United States as well. 

Production-oriented research in the last century made significant contributions to greater yields and productivity of the 

agricultural industry but these advancements have contributed 

to serious long-term negative effects on the stability of the 

world’s land and water resources. Grasslands are an essential 

component of integrated land use affecting resource stability, 

biodiversity and global-level changes in environmental quality. The authors argue there is need for funding of research on 

land-use strategies and grassland management in particular. 

There is need for inter-disciplinary research with emphasis on 

large-scale, long-term land use on both regional and national 

scales. To be effective, some research projects will require 

funding for at least 10 years.

Grassland ecosystems have to be managed with multipurpose objectives related to their environmental, biodiversity, 

landscape ecology, agricultural, and social implications. The 

expansion of industrial agriculture largely has reduced the 

importance of grasslands in mixed farming systems. Because 

continued specialization of farming may be inescapable, new 

strategies of mixed-land use have to be promoted at landscape and regional levels. Implications for new approaches to 

research and management are discussed from perspectives of 

local, landscape, and regional scales. Grassland conservation 

and integration into a more diversified, sustainable agricultural 

land use must take into account the socio-economic forces that 

affect land use. The enhancement of conservation issues must 

be undertaken in an approach that recognizes the landscape 

as being an assembly of farmers who respond individually 

to their own social/economic constraints. Explicit contradictions between socio-economic goals of farmers and ecological 

goals of other components of society need to be recognized 

and defined.
58 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Madison, L.A., Barnes, T.G., and Sole, J.D., 2001, Effectiveness of fire, disking, and herbicide to renovate tall fescue 

fields to northern bobwhite habitat: Wildlife Society Bulletin, v. 29, no. 2, p. 706–712.

Fields dominated by tall fescue (Festuca arundinacea) 

furnish poor habitat for bobwhite quail (Colinus virginianus) 

due to unsuitable vegetation structure, depleted vegetation 

composition, and a lack of food producing plants of sufficient 

quality. Fescue grass forms a dense sod that decreases bare 

ground and may prevent bobwhite from efficient movement 

and foraging. This study examined effectiveness of controlled 

burning, disking, and herbicide (Roundup®) to improve habitat quality for quail. Spring herbicide application most effectively reduced fescue coverage. Fescue cover was reduced for 

one year following disturbance by fall, spring, and summer 

disking, but became similar to control plots and pre-treatment 

conditions by the second year post-treatment. Fall, spring, 

and summer burning did not prove to be effective in reduction 

of fescue. 

Martin, A.R., Moomaw, R.S., and Vogel, K.P., 1982, Warmseason grass establishment with Atrazine: Agronomy Journal, v. 74, p. 916–920.

Competition from weeds is a major factor limiting establishment of warm-season grasses often delaying the first use 

for forage by 2 or 3 yr. Seeding year forage yields of big bluestem (Andropogon gerardii) and switchgrass (Panicum virgatum) were significantly increased following atrazine application. Warm season perennial grasses are particularly slow to 

become established from seed often requiring up to 4 years 

before they can be grazed or harvested for hay. Cool season 

weed species are especially competitive with native species. 

Milchunas, D.G., Vandever, M.W., Ball, L.O., and Hyberg, 

S., 2011, Allelopathic cover crop prior to seeding is more 

important than subsequent grazing/mowing in grassland 

establishment: Rangeland Ecology and Management, v. 64, 

no. 3, p. 291–300

Sorghum is known to be allelopathic and is used in crop 

agriculture rotations to suppress weeds and increase crop 

yields. This study evaluated the effects of grazing, mowing, 

and cover crop in a winter wheat–fallow cropland seeded to 

grassland under the CRP in eastern Colorado. Fallow strips 

planted to forage sorghum as a cover crop and wheat strips 

with wheat stubble were treated as grazed moderate, grazed 

heavy, ungrazed, and mowed. After four years of grazing 

and mowing treatments, results showed that plots previously 

in wheat had more annual and exotic species than sorghum 

plots. Concomitantly, there were much greater abundances of 

perennial native grass and all native species in sorghum strips 

than in wheat cropped areas. Grazing treatments had relatively 

minor effects on basal and canopy cover composition of 

annual or exotic species versus perennial native grass or native 

species. Mowing was a less effective weed control practice 

than grazing. Results suggest that allelopathic cover crop 

selection and opportunistic grazing can be effective alternative 

grass establishment and weed control practices.

Murray, L.D., Best, L.B., Jacobsen, T.J., Braster, M.L., 2003, 

Potential effects on grassland birds of converting marginal 

cropland to switchgrass biomass production: Biomass and 

Bioenergy, v. 25, p. 167–175.

Report describes results of GIS analysis of converting 

row crop and CRP grass-dominated fields to biomass production on 13 selected avian species in Rathun Lake watershed 

in Iowa. Bird-abundance values for each habitat were used to 

model abundance in watershed before and after conversion 

to biomass production. Scenarios using total harvest of fields 

and strip-harvest of fields were completed. Authors conclude 

that conversion to switchgrass (Panicum virgatum) biomass 

production would create habitat for some avian species of 

management concern (for example, bobolink, dickcissel, field 

sparrow). Abundance of these species increased under both 

total field and strip harvesting of biomass scenarios. A mixture 

of both total harvest and non-harvest would have the greatest 

benefits to the largest number of avian species. Rotations of 

fields in non-harvest status through harvest period would allow 

buildup of vegetation litter required by early-season ground 

nesting species. Authors suggest establishment of row crop 

food plots in areas dominated by biomass production could 

mitigate loss of foods provided by typical row crop production. Future monitoring of switchgrass biomass production 

effects on avian populations is recommended.

Oberheu, D., Mitchell, R., Dabbert, B., and Davis, S., 1999, 

Observations of avian nesting activity in burned and nonburned weeping lovegrass CRP: Texas Journal of Agriculture and Natural Resources, v. 12, p. 14–17.

More than 1 million acres of weeping lovegrass 

(Eragrostis curvula) has been planted in Texas as part of the 

CRP. The planting has been criticized as being of little value 

to wildlife. Although numbers of nests found were small, this 

report documents nesting in weeping lovegrass by Cassin’s 

Sparrow (Aimophila cassinii) a species in decline throughout 

its range. Nests of mourning doves (Zenaida macroura) and 

common nighthawk (Chordeiles minor) also were located in 

CRP lovegrass fields. Although not the best cover for wildlife 

due to a lack of structural diversity and insufficient thermal 

cover, weeping lovegrass may be the best multiple-use cover 

for soil conservation, and forage production on sandy soils in 

the southern High Plains. Because nesting seemed to be inhibited for at least two seasons following burning, the authors 

suggest application of prescribe fire should be conducted in a 

mosaic fashion to maintain diversity in vegetative cover. 
Grassland Management 59

Porkorny, M.L., Sheley, R.L., Svejcar, T.J., and Engle, R.E., 

2004, Plant species diversity in a grassland plant community—Evidence for forbs as a critical management consideration: Western North American Naturalist, v. 64, no. 2, 

p. 219–230.

An evaluation of plant species diversity and composition 

in southwestern Montana grassland dominated by Idaho fescue 

(Festuca idahoensis) and bluebunch wheatgrass (Agropyron 

spicatum) is presented. Authors report that forbs represented 

a majority of species richness and biomass in the grassland 

community. Maintenance of diversity in vegetation composition should be a primary objective of land managers because 

increased diversity results in greater stability in vegetation 

community and decreases risk of invasion by undesirable 

species. Periodic sampling in spring and in summer at peak 

standing crop is recommended to better understand and define 

contribution of forbs in grassland community. Sampling in 

mid-summer captured only 76 percent of community diversity 

as compared to 95 percent when sampled in spring and summer. Management recommendations for maintenance of forb 

diversity are presented. 

Renfrew, R.B., Ribic, C.A ., and Nack, J., 2005, Edge avoidance by nesting grassland birds—A futile strategy in a 

fragmented landscape: The Auk, v. 122, no. 2, p. 618–636.

An evaluation of edge effects is described for avian 

species (Savannah sparrow [Passerculus sandwichensis], 

grasshopper sparrow [Ammodramus savannarum], bobolink 

[Dolichonyx oryzivorus] and meadowlark [Sturnella spp.]) in 

grazed pastures in Wisconsin. Authors conclude edge avoidance by grassland passerines will not necessarily reduce predation in actively grazed pastures within fragmented agricultural 

landscapes. Authors recommend patches with larger core area 

will likely enhance productivity of these species. Removal of 

trees and shrubby hedgerows recommended when practical 

but this approach may be practical only when few wooded 

areas are nearby and removal increases connectivity of larger 

pastures or grassland covers. Presence of adequate height, density, and structural variability is believed key in conservation 

of grassland birds. Decreased rates of stocking could favorably 

maintain vegetation height density making it more difficult for 

predators to locate nests. Proper management of cattle may 

have as much an effect on grassland bird populations as management of patch and landscape characteristics. 

Rucker, A.D., 2001, Conversion of tall fescue pastures to tallgrass prairie in southeastern Kansas— Kansas Department 

of Wildlife and Parks Annual Progress Report: Manhattan, 

Kans., Kansas State University, 56 p.

Conversion of existing stands of tall fescue (Festuca 

arundinacea) completed by removing cattle from fescue 

pastures, discontinuation of fertilization, and application of 

spring burning one year following removal of cattle. Study is 

focused on response of small mammals to changes in vegetation diversity and structure. Positive response and greater 

diversity of small mammals in restoration sites suggest greater 

diversity in plant species and structure had positive effects on 

mammal populations. 

Ryan, M.R., 1986, Nongame management in grassland and 

agricultural ecosystems, in Hale, J.B., Best, L.B., and Clawson, R.L., eds., Management of nongame wildlife in the 

Midwest—A developing art: Chelsea, Mich., BookCrafters, 

p. 117–136.

Acquisition, reclamation, and proper management of 

grassland resources must become a priority to conserve the 

genetic diversity of native prairie flora and fauna. The role of 

agriculture in prairie wildlife conservation must be defined 

to develop effective management strategies. The remaining 

grassland tracts that are too small to show characteristic variability of natural prairie ecosystems may distort modern views 

of grasslands. Grasslands contain substantial habitat diversity, 

primarily in the horizontal plane. View of grassland ecosystem 

as a mosaic of habitat types influenced by soil moisture and 

grazing intensity are the primary controlling factors and set 

the stage for development of wildlife management goals and 

strategies. Opportunities to manage remaining prairie tracts of 

sufficient size to include all aspects of the prairie vegetation 

continuum are rare. Alternative is to manage smaller tracts as 

components of overall prairie mosaic. Goal of nongame grassland management should be conservation of wildlife species 

native to prairie habitats. Management actions must be defined 

on a state or region-wide level. If richness of species indigenous to prairie ecosystems is objective, the management plan 

must be developed on large scale and implemented through 

integrated management.

A large block of similar habitat will contain and conserve 

more species than a small unit. However, there is controversy 

around the question of whether a large tract will maintain 

more species than several small tracts that, combined, equal 

the area of the larger tract. Ranking of sites for selection: (1) 

sites, regardless of size, containing rare species or habitats 

that could support them; (2) large tracts containing a variety 

of habitat conditions furnishing a mosaic of habitat types; (3) 

clusters of small tracts that provide, or can be managed for, a 

variety of components of the prairie mosaic; (4) large homogeneous blocks of grassland; and (5) small highly isolated units 

of grassland. Monotypic seeded fields are less likely to be of 

value to nongame wildlife than multi-species fields. 

Sampson, F., and Knopf, F., 1994, Prairie conservation in 

North America: Bioscience, v. 44, no. 6, p. 418–421.

Since European settlement, regional declines in area of 

native prairie range as high as 99.9 percent. In addition to 
60 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

direct loss to cropland, overgrazing and recreation add to the 

stress on remnant tracts of prairie. Fifty-five grassland species currently are threatened. Paper advocates inventory and 

monitoring of remaining prairie ecosystems, discouragement 

of establishment of woody plants and woody corridors within 

prairie dominated ecoregions, and realignment of administrative and ecoregion borders to increase efficiency in inventory 

and monitoring.

Seefeldt, S.S., Conn, J.S., Zhang, M., and Kaspari, P.N., 2010, 

Vegetation changes in Conservation Reserve Program lands 

in interior Alaska: Agriculture, Ecosystems and Environment, v. 135, p. 119–126.

Results of an investigation of plant communities within 

CRP fields established in Delta Junction, Alaska, is presented. 

The CRP fields included in the study were originally planted 

to smooth brome (Bromus inermis), red fescue (Festuca 

rubra), and the native common horsetail (Equisetum arvense). 

As time progressed, abundance of these species decreased 

being replaced by the native grass, bluejoint (Calamagrostis 

canadensis), native forbs, shrubs and tree species. Plant 

diversity in the CRP fields increased by more than 2 species 

per 1000 m2/year. The authors conclude plant succession in 

the CRP fields is following patterns similar to that of natural systems despite multiple years of having been farmed. If 

these fields are left undisturbed, the resultant plant community 

would be indistinguishable from surrounding undisturbed 

bottomland forest. As frequency and abundance of woody species increase through time, it will be difficult to meet USDA 

compliance standard that CRP fields must be maintained in a 

condition that permits easy conversion to cropland. Authors 

believe that these CRP fields will be non-compliant 32 years 

after establishment in CRP, but the fields will be providing 

excellent erosion control and wildlife habitat. Although the 

CRP fields included in the study were not specifically evaluated for their quality as wildlife habitat, young CRP fields 

furnished “good” habitat for bison (Bison bison). The older, 

shrub-dominated fields were believed to furnish “good” habitat for moose (Alces alces).

Sieg, C.H., Flather, C.H., and McCanny, S., 1999, Recent 

biodiversity patterns in the Great Plains— Implications for 

restoration and management: Great Plains Research, Fall 

1999, p. 277–313.

Public policies that focus on ecosystem protection and 

furnish private landowners with incentives to manage their 

property to meet conservation objectives are needed to assure 

long-term sustainability of Great Plains ecosystems. Ninetyfive percent of land in the U.S. portion of the Great Plains is in 

private ownership making private lands in this region particularly important to the conservation of imperiled species and 

habitats. Grassland nesting birds had the highest overall rate of 

loss. The proportion of grassland species that declined (greater 

than 44 percent) was greatest in the Southern Plains. An average of 9 percent of the wetland bird species have declined 

across the region between 1966 and 1996. 

There is much uncertainty associated with plans to restore 

and maintain Great Plains biodiversity. For most aspects of 

biodiversity we lack a comprehensive understanding of past 

and current status as well as a relatively poor understanding of 

the role disturbances (drought, fire, grazing, flooding) played 

in shaping various prairie types and their landscape components. Less is known about how to incorporate disturbances 

into landscapes vastly altered by intensive land use, fragmentation, and the introduction of dozens of exotic species. Properly planned grazing regimes are appropriate components of 

a strategy to restore biodiversity throughout the Great Plains. 

Grazing systems should be tailored to a particular ecosystem 

and include variation in grazing duration and intensity. Restoration of fire in management plans should be considered with 

prescriptions based on historical patterns including burning at 

varying intervals in different seasons. Management designed 

to conserve biodiversity should focus on provision of habitats 

with varying successional and structural stages. Monitoring 

and evaluation of management actions will be critical in developing future management options and policy guidelines. 

Tilman, D., Reich, P.B., and Knops, J.M.H., 2006, Biodiversity and ecosystem stability in a decade-long grassland 

experiment: Nature, v. 441, no. 1, p. 629–632.

Authors report on results and implications of a 10-year 

investigation of ecosystem stability finding year-to-year variation in abundances of plant species and productivity. Greater 

numbers of plant species led to greater temporal stability of 

annual aboveground plant production. Stability of ecosystem 

was found to be significantly greater at higher diversity levels 

of plant species and tended to increase as study plots matured. 

Authors conclude greater diversity in vegetation leads to 

greater ecosystem stability.

Vinton, M.A., and Goergen, E.M., 2006, Plant-soil feedbacks 

contribute to the persistence of Bromus inermis in tallgrass 

prairie: Ecosystems, v. 9, p. 967–976.

A greater understanding of factors supporting success and 

persistence of invasive plants in native ecosystems is needed. 

Over the past 30 years, grass smooth brome (Bromus inermis) and cool season (C3

) introduced and potentially invasive 

species have been spreading throughout North America’s 

central grasslands resulting in displacement of native species including tallgrass species such as switchgrass (Panicum 

virgatum). Smooth brome was introduced in the 1880s and 

was widely planted for forage and soil stabilization along 

roads and waterways. The presence of smooth brome is especially problematic in the Northern Plains and Midwest where 
Grassland Management 61

it forms monocultures. This investigation reports smooth 

brome had greater tiller density, mass and canopy interception 

of light on N enriched soils suggesting smooth brome may 

have a competitive advantage on soils with higher rates of N. 

Smooth brome was also found to have a higher C-N ratio and 

greater rate of decomposition than did switchgrass possibly 

contributing to more rapid cycling of nitrogen which may 

result in a competitive advantage that enables brome to persist 

in remnant or restored grasslands. The authors conclude the 

increased human-induce nitrogen deposition on terrestrial 

ecosystems will likely make control of smooth brome a 

continuing challenge.

Washburn, B.E., Barnes, T.G., and Sole, J.D., 1999, No-till 

establishment of native warm-season grasses in tall fescue 

fields: Ecological Restoration, v. 17, no. 3, p. 144–149.

A relatively new herbicide, Plateau may be especially 

useful in establishment of native warm season grasses because 

several key species and forbs are tolerant of the herbicide. 

Best control of tall fescue (Festuca arundinacea) was on plots 

with a spring burn followed by a single application of Plateau 

in early May. Glyphosate (Roundup®) is a foliar-acting herbicide with no residual effects. Plateau has a 40–45 day residual 

effect and plant uptake occurs both through leaf surfaces and 

roots. Plots treated with Roundup had few visible signs of 

native grasses. Spring burning followed by a pre-emergence 

application of Plateau at 12 oz/acre and seeding native grasses 

effectively eliminated tall fescue within a single growing season. This treatment also provided residual weed control that 

allowed native grasses to become established during the first 

growing season. 

Wilson, S.D., and Gerry, A.K., 1995, Strategies for mixedgrass prairie restoration—Herbicide, tilling, and nitrogen 

manipulation: Ecological Restoration, v. 3, no. 4, 

p. 290–298.

Evaluation of converting crested wheatgrass (Agropyron 

cristatum) and smooth brome (Bromus inermis) to native species. Three levels of tillage, none, intermediate and complete. 

Plots sprayed with glyphosate had density of native seedlings 

20 times that of unsprayed plots. Native seedling density 

was significantly higher in plots receiving the highest intensity of tilling. Native vegetation in north American prairie is 

frequently replaced with Eurasian grasses. One of greatest 

obstacles to seedling establishment is elimination of current vegetation. Most effective method for removing may be 

treatment with herbicides such as glyphosate. Tilling prior to 

seeding may provide sufficient time for seedlings to establish 

before the regrowth of introduced vegetation.

Wilson, S.D., 1989, The suppression of native prairie by alien 

species introduced for revegetation: Landscape and Urban 

Planning, v. 17, p. 113–119.

Introduced species did not aid revegetation. Plots seeded 

with introduced species did not produce significantly higher 

standing crop or below-ground biomass than did unseeded 

plots. Unseeded plots had the lowest frequency of bare 

ground. Allowing prairie to revegetate without sowing introduced species produced both the highest cover of bare ground 

and the greatest abundance of native species. Effect of sowing 

commercial seed mixtures of introduced species was to suppress native flora. Total frequency of native species was lowest 

where crested wheatgrass (Agropyron cristatum) and smooth 

brome (Bromus inermis) were sown indicating that these species dominate native as well as introduced flora.

Willson, G.D., and Stubbendieck, J., 1996, Suppression of 

smooth brome by Atrazine, mowing, and fire: The Prairie 

Naturalist, v. 28, no. 1, p. 13–20.

Neither burning nor mowing resulted in significant reductions of abundance of smooth brome (Bromus inermis). Sod 

seeded big bluestem (Andropogon gerardii) failed in all treatments. Restoration efforts to should be focused on enhancing 

the vigor of remnant warm-season grasses or suppress existing 

sod forming grasses before seeding native species. Authors 

recommend that the application of atrazine should be avoided 

if enhancement of forb diversity is a primary objective. Single 

mowing in May had no significant effect on smooth brome 

tiller density. The absence of significant effect of mowing 

may have been due to mowing above a majority of the tiller 

growing points. 

Willson, G.D., and Stubbendieck, J., 2000, A provisional 

model for smooth brome management in degraded tallgrass 

prairie: Ecological Restoration, v. 18, no. 1, p. 34–38.

In warm season, grass-dominated pastures and native 

prairies smooth brome (Bromus inermis) is considered a 

highly competitive weed because of its rhizomatous sod-forming root system and prolific seed production. Brome exhibits 

two predominant periods of tiller emergence and development. Most active period is after flowering in June continuing 

into fall. The less active period of tiller emergence occurs 

from about mid-March through early May. Tiller elongation 

begins in early May in the central Great Plains and Midwest in 

response to greater day length.

Management: Clipping during its active period of 

growth will lower production of aboveground biomass of 

brome. Mowing and raking in an Illinois prairie in late April 

resulted in significant decrease in seasonal growth of brome. 

A 50-percent reduction in smooth brome tiller density was 

recorded after a prescribed burn in early May at time of tiller 
62 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

elongation. Early spring burns appear best to limit biomass 

production of brome. Herbicides also are effective in elimination of brome. Atrazine applied in late April at 1.9 lbs/ac 

reduced smooth brome by 91 percent and shifted dominance 

from cool to warm season grasses. Only atrazine was effective in reducing brome tiller density, possibly because the 

herbicide killed the whole plant. Burning at emergence does 

not affect secondary tiller (after treatment growth) density in 

years when precipitation is normal or below normal although 

in years with above normal precipitation brome increases 

dramatically. Burning during other three growth stages significantly reduces both tiller density and biomass, especially when 

repeated annually.

Two factors are particularly important in smooth brome 

management: post fire competition and seasonal timing of 

fire. A single, spring application of atrazine restored a pasture 

dominated by smooth brome when big bluestem (Andropogon 

gerardii) and Indiangrass (Sorghastrum nutans) comprised 

only 20 percent of pre-treatment vegetation. It appears that 

warm-season grasses must comprise more than 20 percent 

of species mix of degraded site before a prescribed burn 

will effectively reduce brome. Fire alone will not restore 

a degraded tallgrass site dominated by smooth brome. At 

severely degraded sites (CRP, former cropland) other methods 

must be used such as herbicide applications followed by seeding of warm season grasses. Annual spring burning can lower 

species diversity by eliminating, or preventing establishment 

of cool-season forbs. A single burn before tiller elongation 

that removes most litter may increase growth of brome due to 

increased light reaching growing leaves. 

In situations where smooth brome is the dominant species 

and warm-season grasses are absent, burning will have no 

long-term negative effect on smooth brome and may actually increase its abundance. Burning of smooth brome during 

spring tiller elongation provides the most immediate and 

persistent reduction in both tiller density and biomass.

Grazing, Haying, Mowing

Allen, A.W., Cade, B.S., and Vandever, M.W., 2001, Effects 

of emergency haying on vegetative characteristics within 

selected Conservation Reserve Program fields in the northern Great Plains: Journal of Soil and Water Conservation, 

v. 56, no. 2, p. 120–125.

This study compared vegetative characteristics of 

undisturbed and hayed CRP fields in North and South Dakota. 

Fields used in the study were of same age and planted with 

similar mixes of cool-season, introduced grasses and forbs. 

Emergency haying had little long-term effect on vegetation 

height/density, percent cover of live grass, or forb cover when 

compared to undisturbed fields. The presence of legumes 

primarily alfalfa increased in response to haying, whereas 

abundance of noxious weeds (predominantly Canada thistle 

[Cirsium arvense]) decreased. Implications for long-term management of CRP grasslands to meet avian habitat requirements 

are discussed.

Boyles, S.L., Stoll, B.W., and Dobbles, T.L., 2001, The use 

of Conservation Reserve Program land for grazing cattle: 

Journal of Sustainable Agriculture, v. 18, no. 4, p. 113–120.

Evaluation of intensive rotational grazing of CRP grassland in Ohio is reported. Grassland was planted to orchardgrass (Dactylis glomerata), timothy (Phleum pratense), and 

red clover (Trifolium pratense) in 1987. Investigation evaluated potential of grazing CRP grasslands if the lands are 

removed from the conservation program at a seasonal annual 

stocking rate of 3.5 head/ha (1.5/ac). Based on measures of 

nitrate and nitrogen run-off from grazed CRP met Environmental Protection Agency conservation compliance demands 

needed for participation in other USDA programs. 

Cade, B.S., Vandever, M.W., Allen, A.W., and Terrell, J.W., 

2005, Vegetation changes over 12 years in ungrazed and 

grazed Conservation Reserve Program grasslands in the 

Central and Southern Great Plains, in Allen, A.W. and 

Vandever, M.W., eds., The Conservation Reserve Program—Planting for the future— Proceedings of a National 

Conference, Fort Collins, Colo., June 6–9, 2004: U.S. Geological Survey, Scientific Investigations Report 2005–5145, 

p. 106–119.

Report describes changes, over a 12-year period, in 

vegetation composition and density in CRP grasslands as 

the result of no disturbance and emergency use (grazing) 

of well-established CRP grasslands. Introduced (CP1) and 

native (CP2) CRP fields were classified into introduced warm 

season grasses (for example, plains bluestem [Bothriochloa 

ischaemum], weeping lovegrass [Eragrostis curvula]), native 

warm season grasses (for example, Indiangrass [Sorghastrum 

nutans], switchgrass [Panicum virgatum], little bluestem 

[Schizachyrium scoparium]), and cool season grasses [for 

example, smooth brome (Bromus inermis), and intermediate 

wheatgrass (Thinopyrum intermedium). 

All grass plantings exhibited an increasing dominance 

of grass cover over time with a corresponding reduction in 

the proportion of forbs in the stands. Results indicated that a 

single year of emergency grazing of CRP fields with wellestablished cover had minimal impacts on vegetation structure and composition two and four years after grazing. These 

results, however, do not apply to grazing of incompletely 

established fields or grazing in multiple sequential years. 

Selection of grasses for planting of conservation covers should 

be based on synchronous benefits for habitat, erosion control, and potential use as forage. Introduced grasses generally 

outcompeted native species and formed monotypic stands or 

developed stands so dense as to have minimal value as habitat 

for some species of wildlife. It is suggested management prescriptions for CRP fields should be based on clear objectives 
Grassland Management 63

with measurable criteria for definition of success. Universal 

management guidelines across large spatial areas may simplify 

policy guidelines but fail to address differences among grass 

seedings and management objectives. 

Collins, S.L., Knapp, A.K., Briggs, J.M., Blair, J.M., and 

Steinauer, E.M., 1998, Modulation of diversity by grazing and mowing in native tallgrass prairie: Science, v. 280, 

no. 5364, p. 745–747.

Long-term experiments on effects of N addition, mowing, 

and burning on tallgrass prairie lead to conclusion fire alone is 

not sufficient for restoration of biodiversity. Frequent burning 

dramatically increased dominance of warm season grasses but 

reduced plant species diversity. Grazing by bison or cattle is 

recommended for maintenance of vegetation diversity. Grazing increased abundance of forbs under conditions that would 

have otherwise promoted dominance of warm-season grasses. 

Richness of cool-season species was lowest on watersheds 

burned but not grazed. Richness of warm-season species was 

greatest on sites grazed and burned. Mowing prevented loss 

of cool-season grasses under conditions that otherwise would 

have led to elimination of these species. Increase in light penetration may be a major mechanism by which species richness 

is maintained.

Fuhlendorf, S.D., Zhang, H., Tunnell, T.R., Engle, D.M., and 

Cross, A.F., 2002, Effects of grazing on restoration of southern mixed prairie soils: Restoration Ecology, v. 10, 

no. 2, p. 401–407.

An analysis of grazing effects of cultivated lands 

reseeded to native grasses under CRP and native prairies never 

cultivated, but managed similarly, undertaken in Oklahoma. 

Vegetation monitored in study is typical of southern mixed 

prairie perennial species with dominant species varying 

depending on physical conditions and past land use. Common 

mid-grasses were sideoats grama (Bouteloua curtipendula), 

purple threeawn (Aristida purpurea), and silver bluestem 

(Bothriochloa laguroides). Dominant short grasses included 

blue grama (B. gracilis) and hairy grama (B. hirsuta). Less 

common tall grasses included little bluestem (Schizachyrium 

scoparium), yellow Indiangrass (Sorghastrum nutans), and big 

bluestem (Andropogon gerardii).

Management of domestic livestock on rangelands, including land planted to grasses but no longer actively part of the 

CRP program, can have variable effects on soil fertility, vegetation composition, and structure, thereby influencing the rate 

of recovery of restored grasslands. Grazing may also influence 

amounts, spatial pattern, and composition of nutrient accumulation in soil. Authors conclude that regardless of cultivation 

history, soils and vegetation on heavily grazed sites differed 

significantly from that on moderately grazed sites. On restored 

(CRP) sites soil N and C were higher with moderate grazing 

than with heavy grazing. On native prairie sites, grazing only 

minimally affected soil nutrients. Heavy grazing on formerly 

CRP sites reduced litter accumulation and abundance and 

increased bare ground, which led to reduction in accumulation 

of organic matter and nutrients. Results of this study suggest 

heavy grazing on native mixed prairie has little influence but 

heavy grazing on restored mixed grasslands (CRP) actually 

reduces rate of soil nutrient and organic matter accumulation. 

Authors state data support USDA policies that limit grazing 

on CRP grasslands if the objective is restoration of grassland 

ecosystems or building soil C pools. 

Gilley, J.E., Patton, B.D., Nyren, P.E., Simanton, J.R., 1996, 

Grazing and haying effects on runoff and erosion from a 

former Conservation Reserve Program site: Applied Engineering in Agriculture, v. 12, no. 6, p. 681–684.

Comparisons of runoff and erosion are made from a 

former CRP field with treatments including undisturbed CRP, 

twice-over rotational grazing, season-long grazing, haying, 

and burning. The experimental field was formerly in CRP and 

planted to 40 percent intermediate wheatgrass (Agropyron 

intermedium), 50 percent smooth brome (Bromus inermis), 

and 10 percent alfalfa (Medicago sativa). Runoff and erosion 

were based on simulated rainfall. No significant difference was 

found between season-long grazing and burned treatments. 

Similar amounts of erosion were recorded from twice over 

rotational grazing, season-long grazing and hayed treatments. 

Use of CRP for grazing or haying resulted in a significant 

increase in runoff when compared to leaving the site in undisturbed grass-dominated cover. Grazing and haying operations 

resulted in significantly reduced infiltration rates for surface 

waters. The authors determine, however, grazing and haying 

of this CRP site would not result in “excessive” erosion if 

adequate canopy and soil surface cover were maintained.

Ignatiuk, J.B. and Duncan, D.C., 2001, Nest success of ducks 

on rotational and season-long grazing systems in Saskatchewan: Wildlife Society Bulletin, v. 29, no. 1, p. 211–217.

Rotational grazing systems implemented to increase duck 

production in the Canadian prairie pothole region have had 

only limited success. A comparison of waterfowl production 

recorded in once-over rotational systems and season-long 

pastures in Saskatchewan failed to reveal differences in nest 

survival between grazing systems. Rotational systems could 

be more beneficial if they preserve or improve grassland areas, 

attract more ducks from less productive habitats, or increase 

duck survival. Strong evidence pastures have high success 

of nest compared to most other habitat types including small 

plots of planted cover. Conversion of cropland to pasture and 

retaining existing pastures was recommended to improve 

duck production.

Kantrud, H.A., 1981, Grazing effects on avifauna of North 

Dakota: Canadian Field Naturalist, v. 95, p. 404–417.
64 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Avian species richness tends to decrease in response to 

greater intensity of grazing, but total density of birds increased 

due to higher numbers of a few common species. Total bird 

density was always highest on idle or lightly grazed sites. In 

general, distribution and abundance of most grassland bird 

species in North Dakota have been negatively affected by 

agricultural activities. Fragmentation of grasslands by agriculture resulted in extirpation of some avian species, but cultivation of eastern tallgrass prairie has destroyed habitat for more 

bird species than in the shorter, western grasslands. Protection 

should be given to larger remaining areas of grassland representative of various types found throughout state. Long-term 

preservation of grassland habitat quality will require periodic 

management of vegetation.

Kantrud, H.A., and Kologiski, R.L., 1982, Effects of soils and 

grazing on breeding birds of uncultivated upland grasslands 

of the northern Great Plains: Washington, D.C., U.S. Fish 

and Wildlife Service Wildlife Research Report 15, 32 p.

Livestock grazing on lands set aside for wildlife can be 

used as a management measure to increase populations of 

game species and increase diversity of plant or animal species. Light to moderate grazing resulted in increased species 

richness. However, heavy grazing in the northern Great Plains 

significantly reduced species richness. Grazing by domestic 

livestock generally decreased average vegetative height and 

increased exposure of bare soil. In lightly grazed plots height 

of vegetation seemed to decrease because of shading effect 

of large amounts of litter. Increased avian species richness 

was associated with plots in which height of vegetation was 

not appreciably reduced and percentage of bare soil was not 

greatly increased by excessive grazing. 

Luttschwager, K.A., 1991, Effects of two haying provisions on 

duck nesting in Conservation Reserve Program (CRP) fields 

in South Dakota: Brookings, S. Dak., South Dakota State 

University, M.S. thesis, 51 p.

This report provides an evaluation of 1988 and 1989 

release of eastern South Dakota CRP fields for emergency 

haying on duck-nest density and success. Nest densities in 

idled (non-hayed) strips and non-hayed fields were significantly greater than recorded within hayed strips. Nest densities in idled and hayed blocks were similar. Nest success was 

lowest in idled strips, which apparently attracted predators 

as well as ducks. Author recommends leaving a minimum of 

25 percent of hayed fields in non-hayed cover in contiguous 

blocks rather than strips.

McClaran, M.P. and Anable, M.E., 2006, Spread of introduced 

Lehmann lovegrass along a grazing intensity gradient: Journal of Applied Ecology, v. 29, no. 1, p. 92–98.

An evaluation of the spread of lovegrass (Eragrostis 

lehmanniana) in Arizona in relation to various levels of grazing intensity is presented. Lovegrass density increased with 

time but was not affected by grazing intensity. Native grasses 

decreased while relative abundance of lovegrass increased 

with time and grazing intensity. Lovegrass has been used commonly in the southwest to prevent soil erosion and to furnish 

forage for livestock where native grasses have declined. 

Lovegrass can become the dominant herbaceous cover within 

15 yr following planting with resultant lower faunal diversity 

associated with such stands. Authors conclude lovegrass will 

spread regardless of presence or absence of grazing and the 

only way to control the spread of the species is to reduce availability and distribution of seed from established plants. 

McCoy, T.D., Kurzejeski, E.W., Burger Jr., L.W., and Ryan, 

M.R., 2001, Effects of conservation practice, mowing, and 

temporal changes on vegetation structure on CRP fields in 

northern Missouri: Wildlife Society Bulletin, v. 29, no. 3, 

p. 979–987. 

During 1989–1995, 154 cool-season and warm-season 

grass CRP fields between 1 and 9 yr old were monitored in 

Northern Missouri to describe differences and changes in 

vegetation. Within 3 to 4 yr, perennial grasses with substantial accumulation of litter dominated fields. Annual weed and 

legume component and abundant bare ground was characteristic of fields 3 yr, or younger. As fields aged, annual weeds 

declined and perennial grasses and litter increased reducing amount of bare ground. Once established, warm-season 

grasses (switchgrass monocultures) were taller and had more 

bare ground than cool-season grass plantings. Excessive 

height and density of vegetation in warm-season grass fields 

may limit use by many wildlife species, even those associated 

with tallgrass habitats. Mowing (vegetative material left in 

field vs. removal by emergency haying) had short-term effects 

on vegetation structure and led to accelerated succession and 

litter accumulation. Depending on species of wildlife of interest habitat quality can be expected to vary across time as fields 

age. Periodic management of CRP grassland recommended for 

setting back succession, increasing vegetation diversity, and 

enhancing habitat quality.

Renner, R.W., Reynolds, R.E., and Batt, B.D.J., 1995, The 

impact of haying Conservation Reserve Program lands on 

productivity of ducks nesting in the Prairie Pothole region 

of North and South Dakota in North American Wildlife and 

Natural Resources Conference 60, Proceedings: Washington, D.C., Wildlife Management Institute, p. 221–229.

Report provides a comparison of duck-nest success and 

production in hayed versus non-hayed portions of CRP fields. 

Duck production was higher on non-hayed portions of CRP 

fields. Authors suggest that haying effects on litter depth and 

vegetation structure may have detrimental effects on quality 
Grassland Management 65

of nesting cover through entire year following haying of CRP 

cover. The report recommends haying be allowed no more 

than once every 5 yr to maintain vegetation quality, habitat 

diversity and quality of nesting cover.

Rogers, W.M., Kirby, D.R., Nyren, P.E., Patton, B.P., and 

Dekeyser, E., 2005, Grazing intensity effects on Northern 

Plains mixed-grass prairie: Prairie naturalist, v. 37, no. 2, 

p. 73–83.

The effects of long-term (1988–2000) grazing on mixedgrass prairies in south central North Dakota are described. 

Authors did not detect difference in herbaceous basal cover 

between grazing intensities following 12 consecutive years 

of season-long moderate (50-percent removal) and heavy 

(80-percent removal of aboveground biomass) grazing. Stocking rate for moderate and heavy intensity grazing averaged 

0.4 and 1.1 animal unit month (aum)/ha (1 and 2.75 aum/ac), 

respectively. Both intensities did, however, reduce aboveground herbaceous standing crop, total root biomass, and 

soil organic carbon. Grasses on study sites were dominated 

by Kentucky bluegrass (Poa pratensis), needle-and-thread 

(Hesperostipa comata), blue grama (Bouteloua gracilis), 

western wheatgrass (Agropyron smithii), and sun sedge 

(Carex heilophila). 

Authors conclude that in Kentucky, bluegrass-dominated 

mixed grass prairie basal cover was relatively independent of 

grazing intensity. Grass cover and total aboveground herbaceous biomass was greatest in the non-grazed treatment. 

The study does not support the hypothesis that aboveground 

productivity is maximized at a moderate intensity of grazing. 

Root biomass was greatest in the non-grazed treatment with 

study concluding long-term moderate and heavy season-long 

grazing reduced root biomass in the upper soil profile. 

Truett, J.C., 2003, Migrations of grassland communities and 

grazing philosophies in the Great Plains—A review and 

implications for management: Great Plains Research, v. 13, 

p. 3–26.

An assessment of implications of grazing by large herbivores on east-west migration of major grassland communities 

and discussion of changes in philosophies and implications 

of grazing regimes on grassland types and distributions are 

presented. The conclusion is that grazing does not necessarily 

“degrade” grasslands; it just alters structure and composition of the vegetative community. These changes are either 

favorable or detrimental to the extent they affect erosion of 

soil and the “desired” biological community. Author concludes increasing numbers of range scientists advocate grazing 

management shift from traditional model of light to moderate, uniform grazing to a regime based more on evolutionary 

grazing patterns. Such a management agenda would favor 

patchier grazing at various intensities to promote more diversity in grassland species, diversity in structural composition, 

and potential eastward expansion of short-grass ecosystems. 

The author bases his argument largely on the belief that such 

intensive grazing patterns may result in greater profitability 

for livestock producers and short-grass systems are intrinsically of more value than are mixed grass systems in Great 

Plains ecosystems. 

Van Dyke, F., Van Kley, S.E., Page, C.E., and Beek, J.G., 

2004, Restoration efforts for plant and bird communities 

in tallgrass prairies using prescribed burning and mowing: 

Restoration Ecology, v. 12, no. 4, p. 575–585.

Report provides description of mowing and burning management strategies for restoration and rejuvenation of tallgrass 

prairie (dominated by big bluestem [Andropogon gerardii], 

Indiangrass [Sorghastrum nutans], switchgrass [Panicum 

virgatum], and goldenrod [Solidago spp.]) in fragmented landscapes in Iowa. Many species of grassland birds are not area 

sensitive but are vegetation sensitive, responding to vegetation 

structure, diversity and habitat heterogeneity. Management 

treatments such as mowing and burning cannot change size, 

shape or areas of grassland but can alter grassland vegetation 

density and structure and can be important management tools. 

Response of vegetative and bird communities to management practices are discussed. Mowing did not affect species 

richness and diversity in plant communities but mowed sites 

were lower in total plant coverage and total forb coverage 

than burned or untreated sites. Untreated (unmowed and nonburned) sites had more coverage by shrubs suggesting mowing 

and burning did retard encroachment by woody vegetation.

Authors conclude that overall abundance and diversity 

of plants and birds were generally insensitive to management. Small fragmented sites may not respond in short term to 

management treatments nor be capable of supporting highly 

diverse communities regardless of how intensively they are 

managed. Diversity of native prairie communities can be 

enhanced only through long-term management, acquisition of 

large units of land capable of supporting stable populations, 

and intentional reintroduction of priority species. Management recommendations for increasing vegetative diversity 

are presented.

Warren, K.A., and Anderson, J.T., 2005, Grassland songbird 

nest-site selection and response to mowing in West Virginia: 

Wildlife Society Bulletin, v. 33, no. 1, p. 285–292.

Former hayfields and pastures are becoming a common 

component of the landscape in the eastern United States due 

to changing farming and land use practices as well as purchase 

of farmland for other uses. Authors report investigation of 

grassland bird nest site selection and success between idle and 

mowed pastures and hayfields. Dominant vegetation on study 

fields included orchardgrass (Dactylis glomerata), mountain 

oatgrass (Danthonia compressa), sweet vernalgrass (Anthoxanthum odoratum), quackgrass (Elymus repens), and timothy 
66 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

(Phleum pratense). Avian nests monitored included bobolink 

(Dolichonyx oryzivorus), eastern meadowlark (Sturnella 

magna), red-winged blackbird (Agelaius phoeniceus), and 

savannah sparrows (Passerculus sandwichensis).

Authors conclude management that increases vertical 

structure and density should be promoted for grassland birds 

through mowing, grazing, and prescribed burning to set back 

grassland succession. These management techniques are 

recommended to prevent encroachment of woody vegetation 

and excessive litter developing in undisturbed fields. Leaving 

blocks of cover idle for 1–4 yr is recommended to maintain 

overall diversity in vegetation composition. 

Williams, D.W., Jackson, L.L., and Smith, D.D., 2007, 

Effects of frequent mowing on survival and persistence 

of forbs seeded into a species-poor grassland: Restoration 

Ecology, v. 15, no. 1, p. 24–33.

Enhancement of vegetation diversity in established 

communities is often difficult because established vegetation 

is resistant to colonization. Many attempts at restoration of 

tallgrass prairie have failed to achieve high diversity in species present. Survival of new or introduced species seedlings 

is generally restricted to larger openings in canopy due to 

greater availability of physical space, light, moisture, and 

nutrients. Authors report very frequent mowing in first and 

second year after introduction of forbs in established stands 

of grass to allow conditions favoring their establishment to 

enhance vegetative diversity in a 25-yr-old prairie planting 

site in northern Iowa. Study site was initially dominated 

by smooth brome (Bromus inermis), Quackgrass (Agropyron repens) and planted to perennial (C4

) grasses consisting of big bluestem (Andropogon gerardii), little bluestem 

(Schizachyrium scoparium), switchgrass (Panicum virgatum), sideoats grama (Bouteloua curtipendula) and Indiangrass (Sorghastrum nutans) in 1973.

Forb seedlings in mowed plots grew larger and matured 

more quickly than did those in control plots (unmowed). 

Forbs in mowed plots had greater root and shoot mass than 

did those in control plots. Forbs in control plots began to 

decline as canopy of warm-season grasses increased. Four 

years after introduction, forbs twice as abundant in mowed 

plots as recorded in control plots. By year five, forbs were 

only half as abundant in unmowed plots as compared 

to treated plots. Seeded forbs in treated plots gradually 

increased in size over years becoming more visually dominant and eventually producing seed. Authors conclude addition of seed and a single year of managed mowing could turn 

species-poor grasslands into more diverse plant communities. 

Grazing may also be a useful approach in enhancement of 

vegetation diversity. In contrast to new seedings, succession/

restoration does not require intensive management beyond 

the first growing season.

Zukerberg, B., and Vickery, P.D., 2006, Effects of mowing 

and burning on shrubland and grassland birds on Nantucket 

Island, Massachusetts: Wilson Journal of Ornithology, 

v. 118, no. 3, p. 353–363.

Paper reports results of management directed toward 

preservation and enhancement of early successional grasslands 

to maintain habitat quality for avian species dependent upon 

early stage grasslands. Habitat management was accomplished 

through burning and mowing (brush cutting). Over a 3-yr 

period songbird response varied among avian species as well 

as type of management applied. In shrublands mowing was the 

most effective method for restoring grassland habitat. Burning 

was reported to have little effect on abundances of shrubland 

birds and vegetation structure. Both burning and mowing were 

successful in restricting encroachment of shrubs into grasslands. Authors conclude effects of grassland restoration on 

generalist species will vary with management type and subtle 

habitat preferences of affected species. While several generalist species may inhabit the same habitat type differences in 

vegetative characteristics define the presence of each species. 

Habitat preferences for several species (for example, Eastern 

towhee [Pipilo erythrophthalmus], common yellowthroat 

[Geothlypis trichas], song sparrow [Melospiza melodia]) 

are described. Authors suggest a dynamic and diverse set of 

strategies should be integrated into management that furnishes 

some grassland areas in later stages of succession to maintain 

overall diversity in avian species. 

Pollinators, Invertebrates, and 

Miscellaneous Wildlife

Aizen, M.A., Garibaldi, L.A., Cunningham, S.A., and Klein, 

A.M., 2009, How much does agriculture depend on pollinators? Lessons from long-term trends in crop production: 

Annals of Botany, v. 103, no. 9, p. 1579–1588.

Photo credit: Sweat bee, David Leatherman
Pollinators, Invertebrates, and Miscellaneous Wildlife 67

Animal pollination contributes to the integrity of most 

terrestrial ecosystems and has direct effects on biodiversity. 

The production and diversity of agriculture depends on biotic 

pollination. The productivity of many agricultural crops 

worldwide depends upon pollination by insects and other 

animals. Worldwide, the production and diversity of agriculture depends on biotic pollination particularly on the services 

provided by the honey-bee (Apis mellifera). The demand for 

pollination is rising at the same time pollinator populations are 

declining in abundance and diversity. Stocks of honey bees are 

experiencing many diseases. In North America, the number 

of managed honey-bee hives has declined almost 60 percent 

since the 1940s due to parasitic mites and other unidentified factors. Populations of wild pollinators species are also 

in decline, largely due to destruction of habitat, resulting in 

concerns that a potential global “pollination crisis” threatens 

food production. 

While pollinator-dependent crops represent a larger 

proportion of total agricultural production in the developing world, future pollinator shortage is projected to result in 

expansion in cultivated area to compensate for lost production. 

Authors estimate that the percentage of cropland devoted to 

pollinator-dependent crops in the developed world increased 

from 18.2 percent in 1961 to 34.9 percent in 2006. In the 

developing world, pollinator-dependent crops increased from 

23.4 to 32.8 percent in the same period. The developing 

world represents more than two-thirds of global agricultural 

production with production 50 percent more dependent on 

pollinators than that of developed countries. Losses of habitats 

and pollinator populations, particularly in the tropics, may 

accelerate deforestation and intensify pressures on remnant 

natural ecosystems as demand for agricultural land to compensate for these losses in production increases. The authors 

conclude that losses in pollinator benefits caused by human 

impacts will have direct effects on the quantity and diversity 

of food production. Attempts to compensate for these losses 

will accelerate habitat destruction and may cause even further 

losses in pollinators.

Bauer, D.M., and Wing, I.S., 2010, Economic consequences of 

pollinator declines—A synthesis: Agricultural and Resource 

Economics Review, v. 39, no. 3, p. 368–383.

The paper finishes a literature review of pollinator 

declines with resultant economic impacts, declines in ecological services, and concerns regarding global food security. Pollination is a priceless ecosystem service that furnishes a variety of benefits including food, fiber, plant derived medicines, 

genetic diversity, and overall ecosystem resilience. While 

recent declines in honey bees (Apis mellifera) have received 

much attention global declines in pollinator populations and 

species diversity raise concerns regarding risks to food security and economic development. Pollinator losses bring risks 

to ecosystem stability, biodiversity loss of pollinator species, 

and the plants they pollinate. Agricultural intensification, 

pests, disease, pesticides and habitat destruction have been 

linked to declines of both managed and wild insect pollinators. 

Even in plants that are wind and self-pollinated insect pollination can increase quantity and quality of production. Globally, 

75 percent of primary crop species and 35 percent of crop 

production rely on some level of animal (insects, bats, birds) 

pollination. Within the United States, more than 50 percent 

of primary crops and 20 percent of crop production depend 

on animal pollination. Honey bee pollination in the United 

States has an economic value of $14.6 billion/yr. Pollination 

by wild insects raises the economic value an unknown, but 

substantial, amount.

Wild pollinators are important for agricultural production whose importance varies by plant species, geographical 

location and time of year. Although most attention on pollinator declines has focused on impacts to agriculture implications reach into the structure of food webs, ecosystem health, 

and population dynamics of wild plants. Due to diminishing 

numbers and availability of honey bees, reliance on wild 

pollinators for agricultural production is projected to increase 

both globally and in the United States. The authors conclude 

wild pollination services will be under-provided without some 

type of government program or policy intervention. Loss of 

pollinator habitat is an issue of major concern. The authors 

further recommend development of conservation-based 

strategies for both on-farm and off-farm conservation of wild 

pollinator habitats.

Branson, D.H., 2005, Effects of fire on grasshopper assemblages in a northern mixed-grass prairie: Environmental 

Entomology, v. 34, no. 5, p. 1119–1113.

Grassland fires are capable of having positive or negative 

effects on grasshopper (Gomphocerinae) population densities. 

The timing and intensity of fire can have an important influence on population characteristics. The objective of this study 

was to examine effects of a late-fall wildfire on grasshopper 

density and community composition in a mixed-grass prairie. 

Common grasses on study sites included blue grama (Bouteloua gracilis), western wheatgrass (Pascopyrum smithii), and 

needle and thread grass (Hesperostipa comata). Authors report 

no statistically significant effect of fire on numerical species 

richness or an impact on grasshopper community structure. 

Mean grasshopper density was 5.2/m2 in burned plots and 

5.4/m2 in unburned plots. Although fire did negatively affect 

grasshopper population densities, effects were short-lived. 

Burger, L.W. Jr., Kurzejeski, E.W., Dailey, T.V., and Ryan, 

M.R., 1993, Relative invertebrate abundance and biomass in 

Conservation Reserve Program plantings in northern Missouri, in Church, K.E., and Dailey, T.V., eds., Quail III—

National Quail Symposium: Jefferson City, Mo., Missouri 

Department of Conservation. 

CRP fields were planted to a red clover (Trifolium 

pratense)/timothy (Phleum pratense) mix and dominated 

by red clover had highest recorded levels of invertebrate 
68 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

abundance and biomass. Mean abundance and biomass of 

invertebrates in CRP fields were four times that of soybean 

fields. CRP fields could provide quality brood habitat if structural characteristics are consistent with quail brood foraging 

needs. Incorporation of a legume in CRP planting may produce higher invertebrate densities and improve value of these 

fields to avian broods. 

Carroll, S.C., Rummel, D.R., and Segarra, E., 1993, Overwintering by the Boll Weevil (Coleoptera Curculionidae) in 

Conservation Reserve Program grasses on the Texas High 

Plains: Ecology and Behavior, v. 86, no. 2, p. 382–393.

The study objective was to determine if CRP grasses 

increased probability of development of resident boll weevil 

(Anthonomus grandis grandis) populations. CRP grasses furnished marginal over-wintering habitat for the species. Total 

winter survival and emergence of the species was consistently 

lower in CRP than recorded in native sand shinnery oak 

(Quercus havardii) habitats that served as a standard of comparison. Study results imply CRP grasses (weeping lovegrass, 

[Eragrostis curvula]) furnish marginal winter habitat for the 

boll weevil. Small numbers of the weevil did survive winter 

in CRP grasses; therefore, if surviving winter populations are 

large, potentially damaging populations could occur affecting 

adjacent cotton crops. 

Cederbaum, S.B., Carroll, J.P., and Cooper, R.J., 2004, Effects 

of alternative cotton agriculture on avian and arthropod populations: Conservation Biology, v. 18, no. 5, p. 1272–1282.

Land devoted to cotton (Gossypium hirsutum) production 

is intensively managed with resultant poor habitat potential 

for wildlife. Application of pesticides is usually frequent and 

intensive. Under modern conventional methods of cotton production, lands devoted to this crop are of little value to wildlife. Sustainable farming methods of conservation tillage and 

intercropping hold promise as approaches to creating a more 

diverse agroecosystem and reducing costs for farmers. Report 

presents effects of clover (Trifolium spp.) strip cover cropping with conservation tillage with conventional methods of 

cotton production and conservation tillage methods on avian 

and arthropod species composition and field use in east-central 

Georgia. Fields where strip cover had been incorporated had 

higher densities of birds and higher relative abundance of 

arthropods than found within both conservation tillage and 

conventional fields. During periods of migration and breeding, 

total densities of birds on strip cover fields were 2–6 times and 

7–20 times greater than on conservation tillage and conventional fields, respectively. Findings suggest both conservation 

tillage and strip cropping will improve avian habitat conditions in cotton production systems with strip cropping furnishing superior habitat. Reduction in inputs with clover systems 

could allow lower production costs by $282–$317/ac.

Davros, N.M., Debinski, D.M., Reeder, K.F., and Hohman, 

W.L., 2006, Butterflies and Continuous Conservation 

Reserve Program filter strips—Landscape considerations: 

Wildlife Society Bulletin, v. 34, no. 4, p. 936–943.

Paper describes investigation of effects of filter strips 

along southwestern Minnesota waterways on abundance and 

diversity of butterfly communities. Row crops dominated the 

study area accounting for an average of 85 percent of landscape cover. Herbaceous dominated cover accounted for 9 percent of landscape. Butterfly use of filter strips was influenced 

by local and landscape level variables. Butterfly abundance 

and density were generally positively associated with greater 

width of filter strips. Authors recommend establishment of 

filter strips of maximum width possible with plantings comprised of diverse species composition and structure. 

Davis, S.S., 1998, Effects of prescribed fire on small mammal 

and beetle assemblages in Conservation Reserve Program 

(CRP) grasslands: Lubbock, Tex., Texas Technical University, M.S. thesis, 55 p.

Author examines effects of prescribed fire on small 

mammal and beetle populations in CRP fields dominated by 

weeping lovegrass (Eragrostis curvula) in Lynn County, Tex. 

Twelve sample sites were stratified by canopy cover of vegetation. Small mammal species collected included: deer mouse 

(Peromyscus maniculatus), hispid pocket mouse (Chaetodipus 

hispidus), Cotton rat (Sigmodon hispidus), western harvest 

mouse (Reithrodontomys megalotis), northern grasshopper 

mouse (Onychomys leucogaster) and, spotted ground squirrel 

(Spermophilus spilosoma). Results suggest that rodents living in weeping lovegrass monocultures select different cover 

based on microhabitat conditions. Lovegrass habitats following fire are continually being optimized by changing groups of 

rodents even when vegetative cover returns to pre-burn conditions. Although small mammals are typically not considered 

important in decisions for CRP management, their presence 

can be important by increasing diversity of wildlife and supporting avian and mammalian predators. 

Sampling showed 13 different families of beetles present 

in lovegrass CRP fields. June and dung beetles (Scarabaeidae), darkling beetles (Tenebrionidae), and blister beetles 

(Meloidae) were not affected by fire. Ground beetles (Carabidae) and tiger beetles (Cicindelidae) beetles show population increase in response to fire. Author concludes beetle 

families most affected by fire are those dependent upon litter 

and detritus for suitable habitat. Author concludes species 

dependent on thick layer of litter are reduced by application of 

prescribed fire. 

Dievert, E.J., and Utter, R.A., 2003, Earthworm (Lumbricidae) 

survey of North Dakota fields placed in the U.S. Conservation Reserve Program: Journal of Soil and Water Conservation, v. 58, no. 1, p. 39–45.
Pollinators, Invertebrates, and Miscellaneous Wildlife 69

Twenty-three sites in ND CRP fields (5–8 yr old) were 

surveyed for presence and type of earthworms. Sites with 

earthworms were associated with organic matter levels greater 

than 2.5 percent. Sites without earthworms were characterized 

as having high content of sand (67 plus or minus 13 percent) 

with soil containing sharp crystals or grains that might not 

be suitable for inhabitation by earthworms. Total earthworm 

population estimates from five sites average 6.3 million/

ha (2.5 million/ac). Presence of wetlands or tree-dominated 

habitats in fields could not be used as criteria for determining 

presence of earthworms.

Doxon, E.D., and Carroll, J.P., 2007, Vegetative and invertebrate community characteristics of Conservation Reserve 

Program fields relative to gamebirds in western Kansas: 

American Midland Naturalist, v. 158, no. 2, p. 243–249.

Vegetative and invertebrate characteristics are examined 

in Kansas CRP fields planted to: Native grass (CP2), Established Grass (CP10), and Rare and declining habitat (CP25). 

CP10 fields were 7–10 yr old. CP2 and CP25 fields were 

3-5 years old. None of the fields evaluated had been hayed, 

burned, or grazed in the 3 yr previous to the study. Fields 

were planted to native grasses including western wheatgrass 

(Pascopyrum smithii), Indiangrass (Sorghastrum nutans), 

switchgrass (Panicum virgatum), sideoats grama (Bouteloua 

curtipendula), little bluestem (Schizachyrium scoparium), and 

big bluestem (Andropogon gerardii). CP2 fields were seeded 

with alfalfa (Medicago saliva). CP25 mixes were comprised of 

native grasses and wildflowers such as Maximilian sunflower 

(Helianthus maximiliani) purple prairie clover (Dalea purpurea), prairie coneflower (Ratibida columnifera), and Illinois 

bundleflower (Desmanthus illinoensis). 

Wheat (Triticum aestivum) fields were found to support 

less invertebrate biomass than CRP fields. Bare ground in CRP 

fields averaged 10 percent while forb cover was generally less 

than 20 percent. Invertebrate abundances were not significantly different among the CRP types evaluated. Conservation 

practices that incorporated some forbs in the planting mix had 

more stable, even increases, in invertebrate biomass and abundances. Unharvested wheat and CP10 fields had the greatest 

number of insect-prey. CRP produced more quality insect-prey 

than did wheat except when compared to unharvested wheat 

fields. Because invertebrate abundance varied within field 

types throughout the growing season, the authors suggest a 

mix of CRP practices across the landscape. Most fields were 

believed to provide excellent brood-rearing and feeding opportunities for gamebird chicks.

Fox, T.B., Landis, D.A., Cardoso, F.F., and Difonzo, C.D., 

2004, Predators suppress Aphis glycines Matsumura population growth in soybean: Environmental Entomology, v. 33, 

no. 3, p. 608–618.

The soybean aphid (Aphis glycines) is an invasive species 

first discovered in Wisconsin in 2000. Currently distributed 

across 19 states and parts of Canada, the species interacts 

with both native and naturalized predators present in soybean 

ecosystems. In the United States, populations of this aphid 

have been reported to cause up to 40 percent decline in seed 

yield and up to 50 percent reduction in photosynthetic rates for 

soybean leaves infested. The aphid can also introduce other 

diseases (for example, soybean dwarf, tobacco ringspot, and 

yellow mosaic viruses) into soybean fields. These aphids also 

cause indirect damage by excreting honeydew which promotes 

growth of molds that reduce productivity of plants. 

The purpose of this investigation was to determine if 

native predators had an effect on population dynamics of this 

potentially economically significant invasive species. The 

evaluation shows natural predators play an important role in 

control of A. glycines. By attacking aphids before they reached 

high numbers even a low density of natural (native) predators 

was able to suppress this pest. 

Although the authors do not specifically state this, the 

implication of this study is preservation of native vegetative 

communities that support indigenous invertebrate predatory 

species, interspersed with lands in soybean production can be 

an effective means to control this pest species. 

Haysom, K.A., McCracken, D.I., Foster, G.N., and Sotherton, 

N.W., 2004, Developing grassland conservation headlands—Response of carabid assemblage to different cutting 

regimes in a silage field edge: Agriculture, Ecosystems and 

Environments, v. 102, p. 263–277.

European agricultural landscapes have experienced the 

same intensification of production as seen in the United States. 

Increased use of nitrogenous fertilizers, wide-scale application of pesticides, simplification of the agricultural landscape, 

and replacement of small scale mixed farming with larger 

specialized farming operations have had substantial impacts on 

availability of wildlife habitats and biodiversity in agriculturally dominated landscapes. Authors discuss development and 

implementation of conservation headlands in croplands and 

their relation to improving availability of invertebrate foods for 

avian species. Butterflies, small mammals and songbirds have 

also shown positive response to creation of headland habitats 

in arable fields. Authors evaluate and advocate use of headland concept in grass-dominated crop (pastures, silage) where 

margins of fields are established by sowing a grass/herb mix or 

allowing natural regeneration to proceed. In addition to changes 

in vegetation structure, frequent harvest of grass crops can 

modify substrate characteristics affecting invertebrate composition. Carabid beetle assemblages increased in uncut margins and 

in margins cut only once each summer. Result of low intensity 

management in margins was increase in effective area of intercrop habitat. Authors recommend use of headland concept in 

grass-dominated croplands is a useful tool for improvement of 

habitat quality in agriculturally dominated landscapes.
70 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Hendrix, P.F., Parmelee, R.W., Crossley Jr., D.A., Coleman, 

D.C., Odum, E.P., and Groffman, P.M., 1986, Detritus food 

webs in conventional and no-tillage agroecosystems: Bioscience, v. 36, no. 6, p. 374–380.

Conservation tillage-crop planting systems leave 30 percent or more of crop residues on soils surface. Area in conservation tillage is 24–36 million hectares (9.4–14 million ac) or 

about one-third of the Nation’s cropland. Conservation tillage 

creates conditions similar to those of undisturbed ecosystems 

when compared to conventional tillage. No-till soils usually 

are physically and chemically stratified with more nutrients 

near the surface. Plowed soils often show increased organic 

matter decomposition and nutrient mineralization. Nutrient 

uptake by crops and weeds is often higher in conventionally 

tilled systems. In natural ecosystems, both direct and indirect 

interactions among soil biota are involved in decomposition 

of organic matter. No-till abundance and activity of fungivorous fauna increase in surface layers, and mineralization 

proceeds more slowly, thereby enriching soil. Decomposing 

residue plus microbes and microconsumers serve as food 

for macroconsumers. Organic pool should grow larger over 

time under no-till management. No till appears to increase 

importance of fungi relative to bacteria as primary decomposers, which provide a resource base for the detritus food web. 

Plowing creates conditions favorable to bacteria based food 

webs composed of disturbance-adapted organisms with high 

metabolic rates causing faster decomposition of organic matter 

and nutrient mobility. 

Hoernemann, C.K., Johnson, P.J., and Higgins, K.F., 2001, 

Effects of grazing and haying on arthropod diversity in

North Dakota Conservation Reserve Program grasslands, 

in Proceedings of the South Dakota Academy of Science: 

Mitchell, S. Dak., South Dakota Academy of Science, v. 80, 

p. 283–308.

Authors report that the majority of arthropod fauna was 

not adversely affected in abundance or diversity when subjected to moderate levels of grazing or haying. Maintenance of 

diverse arthropod populations ensures food for wildlife species 

in CRP habitats and prevents population outbreaks by insect 

pest species. Results suggest that grazing and haying of CRP 

lands are viable post-contract uses with regard to maintaining 

diverse arthropod populations.

Hull, S.D., Robel, R.J., and Kemp, K.E., 1996, Summer avian 

abundance, invertebrate biomass, and forbs in Kansas CRP: 

Prairie Naturalist, v. 28, no. 1, p. 1–12.

Invertebrate biomass and avian abundance evaluated in 

six Kansas native grass CRP fields. Analysis did not detect 

a statistically significant relationship between forb abundance and invertebrate biomass or avian abundance. Avian 

community assemblages in CRP fields with low and high 

forb abundances were similar. Authors suggest that a lack of 

statistically significant relationship does not mean assumption 

of greater abundance of forbs relates to greater availability of 

food for avian species is invalid. Half of invertebrate biomass 

collected was grasshoppers but not identified as to being grass 

or forb-dependent species. None of sampled fields had forb 

coverage exceeding 24 percent, which may have been below 

canopy coverage threshold to detect significant differences. 

Authors conclude different results may have been found with 

a larger sample size and greater spread in forb canopy cover 

(for example, 0–80 percent rather than 0–23 percent). Future 

research should address these shortcomings. 

Jonas, J.L., Whiles, M.R., and Charlton, R.E., 2002, Aboveground invertebrate responses to land management differences in a central Kansas grassland: Environmental Entomology, v. 31, no. 6, p. 1142–1152.

Invertebrate community diversity and dynamics are 

tightly associated with plant communities. Incorporation 

of invertebrate communities into assessment programs can 

enhance sensitivity at smaller spatial and temporal scales 

than can assessment for larger avian or mammalian species. 

Invertebrate diversity is often related to plant species diversity, 

structural diversity, patch size, and density. Author provides 

justification of why Coleoptera (beetles) and Orthoptera 

(grasshoppers, crickets, mantids, katydids, walkingsticks) are 

invertebrate groups with characteristics suitable for monitoring grasslands. Study objective was to examine responses of 

invertebrates to different land management practices in a Great 

Plains grassland system. Evaluation completed in smooth 

brome (Bromus inermis) and mixture of tallgrass and mixedgrass prairie and old-field sites. Dominant grasses in oldfield sites were Kentucky bluegrass (Poa pratensis) and big 

bluestem (Andropogon gerardii) in prairie sites. Forb species 

cover was 11 percent in brome, 15 percent in old fields, and 7 

percent in prairie sites. Old-field sites had significantly higher 

plant species richness than brome or prairie sites. 

Invertebrates in general and Orthoptera and Coleoptera 

responded to differential land use and appeared most related to 

plant structural diversity and native plant species abundance. 

Coleopteran richness and diversity were generally lowest in 

brome fields. Orthopteran abundance and diversity was negatively correlated to native plant species abundance. Author 

speculates orthopteran distribution patterns of distribution may 

be related to land use and mechanical disturbance. Grasshopper distribution may be more related to accumulated surface 

and standing plant litter than to plant species composition. All 

prairie sites in study had been annually hayed which greatly 

reduced vegetative litter that may have negatively affected 

habitat quality for eggs and early instar nymphs. Brome and 

old fields, where orthopteran values were greatest were not 

regularly hayed. 
Pollinators, Invertebrates, and Miscellaneous Wildlife 71

Kremen, C. N., Williams, M., and Thorp, R.W., 2006, Crop 

pollination from native bees at risk from agricultural intensification: Proceedings National Academy of Science, v. 99, 

no. 26, p. 16812–16816.

Ecosystems services are critical to human survival, which 

often is a strong argument for preservation of biodiversity. 

However, economic and ecological benefits furnished by these 

services are poorly understood and rarely incorporated into 

landscape management plans. American farmers have been 

dependent upon European honey bees (Apis mellifera) to 

furnish pollination services in agricultural production. These 

colonies are becoming scarce due to diseases, pesticides, and 

other impacts. Native bees also provide essential pollination, but 

the amount provided and effects of land use are poorly defined. 

Native bees can provide full pollination services; however, 

diversity in landscape vegetation composition is essential for 

sustaining this service. Continued degradation of the agricultural and natural landscape interface will continue to have negative impact on the benefits brought by these species. 

Animals, particularly bees, pollinate over 66 percent of 

the world’s 1,500 crop species. Currently, agriculture relies 

on only 11 of the 20,000 to 30,000 species of bees worldwide. 

Economic worth of honey bee pollination in the United States 

is $5–14 billion per year. Invasion by the Africanized race of 

A. mellifera continues to spread north, creating loss of efficiency and liability concerns for bee keepers. 

Authors believe native bee communities can provide 

equivalent services to that of managed honey bees if habitats of sufficient quality and distribution are maintained in 

association with agricultural land use. Isolation of floral and 

nesting resources in wildlands (for example, non-cultivated) 

is likely a key factor affecting the numbers and distribution of native bees. Native bee diversity and abundance is 

significantly related to the proportional area of uncultivated 

habitat associated with agricultural land. Use of insecticides 

and herbicides in conventional agriculture are also likely to 

negatively impact bee populations. The preservation of native 

vegetation in small fragments of habitat within larger context 

of agricultural landscape would benefit bees as well as other 

insect species. Authors suggest the CRP could play a significant role in enhancement and lessening costs for provision of 

needed habitats for these species. Restoration of bees and their 

habitats could benefit native plants and promote conservation 

of biodiversity across the agro-natural landscape. 

Landis, D.A., Wratten, S.D., and Gurr, G.M., 2000, Habitat 

management to conserve natural enemies of arthropod pests 

in agriculture: Annual Review Entomology, v. 45, 

p. 175–201.

As a result of frequent disturbance, intensity of land 

use, and growing dependence on agrochemicals, agricultural 

landscapes are particularly difficult environments to maintain 

indigenous species furnishing biological control of cropland 

plant pests. This document furnishes a review of recent literature focused on management of vegetation covers to favor 

natural enemies of agricultural pests by integrating suitable 

covers spatially and temporally in agricultural landscapes. 

Manipulation favoring biological control is focused on provision of suitable covers to favor survival, fecundity, longevity, 

and behavior of natural predators to increase their effectiveness 

in control of crop pests. Management of habitats may occur at 

within-field, within-farm, or at landscape scales. Establishment 

of non-farmed sites supporting perennial flowering plant species 

interspersed with croplands is a fundamental concept in this 

approach to enhancing biodiversity and control of insect pests. 

Simply increasing diversity of plant covers, however, can 

increase pest problems. Consequently, it is important to identify key elements of plant diversity needed by natural enemies 

of crop pests. Key elements include improving availability of 

alternative foods such as nectar, pollen, providing shelter or 

microclimates in which natural enemies overwinter, and furnishing habitats in which alternative hosts or prey can survive. 

Successful implementation of natural predator conservation 

involves evaluation of disturbance in agricultural landscapes. 

Cover cropping, intercropping, and reduced tillage are alternatives to lessening disturbance. Habitat management may not 

always require radical changes in farming practices and may 

not require taking land totally out of production. Alternatives 

and examples of approaches to enhance agricultural landscapes to make pest management more effective and production systems more sustainable are presented. 

Lewis, T., 1969, The diversity of insect fauna in a hedgerow 

and neighboring fields: Journal of Applied Ecology, v. 6, 

no. 3, p. 453–458.

Hedgerows contribute to enriched insect fauna in 

neighboring fields. In terrestrial insect communities, diversity 

was greatest in hedge, lower in beans, and least in pasture. 

Diversity of aerial insects decreased in response to increasing 

distance from the hedge. Presence of hedge enriched aerial 

population for a distance from trees to 10 times tree height 

on downwind side and one to two times on upwind side 

of hedgerow. 

Losey, J.E., and Vaughan, M., 2006, The economic value of 

ecological services provided by insects: Bioscience, v. 56, 

no. 4, p. 311–323.

Authors estimate ecological services (dung burial, pest 

control, pollination, and nutrition for wildlife) provided by 

wild insects in the United States to be at least $57 billion. 

Economic value estimates for each service are: dung burial 

$0.38 billion, pollination $3.07 billion, pest control, $4.49 

billion, and wildlife-related recreation $49.96 billion. These 

are believed to be very conservative estimates of the ecological values furnished by insects within the United States. 

Other environmental services provided by insects include 
72 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

suppression of weeds and other exotic herbivorous species, 

facilitation of dead plant and animal decomposition, and 

improvement of soil condition. The correct value of any of 

these services could add billions of dollars to these estimates.

Economic and ecological benefits of dung beetles (primarily Scarabaeidae) are discussed with benefits including 

improvement in soil, volatilization of nitrogen, diminished 

fouling of forage and control of livestock parasites and pests. 

Pollination is the most widely known benefit of insects with 15 

to 30 percent of the diet of U.S. citizens directly or indirectly 

dependent upon pollination by insects. Available information 

suggests that control of insect pests costs the U.S. economy 

billions of dollars each year, but this is only a fraction of the 

economic impact if beneficial insects did not keep most pests 

below economically damaging levels. U.S. citizens spend over 

$60 billion a year on hunting, fishing and observing wildlife. 

Insects are a critical food source for much of this wildlife. The 

predominant benefit of insects is concentrating and moving 

nutrients through the food web. 

The authors conclude annual investment of tens of billions of dollars could be economically justified to maintain 

services provided by insects. There has been a steady decline 

in beneficial insects associated with diminishing biodiversity 

accompanied by severe declines in the quality of environments 

heavily impacted by human activities. Authors recommend 

a diversity of plant species in restoration or conservation 

projects to support viable and diverse populations of insects. 

Authors recommend that USDA conservation programs pay 

specific attention to insects and the roles they play in ecosystem functioning. Insects and their needs should be considered 

in land-management decisions. A diverse community of forbs 

should be included with any restoration of habitat or riparian 

bank projects. 

McIntyre, N.E., 2003, Effects of Conservation Reserve Program seeding regime on harvester ants (Pogonomyrmex), 

with implications for the threatened Texas horned lizard 

(Phrynosoma cornutum): The Southwestern Naturalist, v. 

48, no. 2, p. 274–313.

Abundance of harvester-ant nest sites, primary prey 

for endangered Texas horned lizard, are evaluated in CRP 

grasslands and native prairie in Texas panhandle sites. CRP 

fields evaluated were planted to old world bluestem (Bothriochloa ischaemum), weeping lovegrass (Eragrostis curvula), 

or mixtures of native grasses with and without buffalograss 

(Buchloë dactyloides). Native grass CRP plantings were dominated by sideoats grama (Bouteloua curtipendula), blue grama 

(B. gracilis) and switchgrass (Panicum virgatum). (Estimates 

of field age, comparisons of density and other vegetation 

characteristics between seeded and native grasslands were not 

described). The fewest ant mounds were found within fields 

planted to old world bluestem. Native (ungrazed) grassland 

had highest density of ant mounds. However, no significant 

difference between abundance of ant mounds in native and 

exotic CRP plantings were reported. Author concludes there 

is no evidence CRP plots planted to exotic grasses are poorer 

habitat for Texas horned lizards in terms of ant abundance than 

are native plantings. 

McIntyre, N.E., and Thompson, T.R., 2003, A comparison 

of Conservation Reserve Program habitat plantings with 

respect to arthropod prey for grassland birds: American 

Midland Naturalist, v. 150, no. 2, p. 291–301.

Authors compared arthropod abundance in four CRP 

cover types: lovegrass (Eragrostis curvula), old world 

bluestem (Bothriochloa ischaemum), mixed native grasses 

(primarily sideoats grama [Bouteloua curtipendula] and 

switchgrass [Panicum virgatum]) with and without buffalo 

grass (Buchloë dactyloides) and native shortgrass prairie (that 

is, non-CRP) in Texas panhandle. Sampling focus was on adult 

and juvenile spiders (Order Araneae), beetles (Coleoptera), 

grasshoppers and crickets (Orthroptera), and butterflies and 

moths (Lepidoptera). Arthropod diversity was higher on indigenous short grass prairie when compared to CRP. The highest 

diversity in arthropods was recorded in native short grass prairie plot, which had the greatest vegetative diversity of all study 

plots. There were no significant differences in arthropod richness or abundance between types of CRP grasslands. Report 

concludes that CRP grasslands are not equivalent to native 

prairie in terms of vegetation or arthropod diversity but CRP 

lands do support arthropod prey for grassland birds. Results 

indicate plantings established in early years of CRP (old world 

bluestem, weeping lovegrass), as well as, more recently established stands of native grasses provide arthropods and habitat 

for avian species. 

Millenbah, K.F., 1993, The effects of different age classes 

of fields enrolled in the Conservation Reserve Program in 

Michigan on avian diversity, density, and productivity: 

East Lansing, Mich., Michigan State University, M.S. 

thesis, 138 p.

Avian communities and vegetative characteristics examined in 6 age-class fields (1–6 growing seasons) in central 

Michigan to determine relations between field age and characteristics of avian communities. Younger CRP fields, characterized by dominance of forbs and bare ground, supported greater 

avian densities and diversities than older fields. Older fields 

supported greater height of grasses and litter cover. Grassland 

birds may require a diversity of age classes of CRP fields in 

agricultural landscapes to meet habitat requirements. Results 

suggest relationship between age of field and relative avian 

abundance, diversity, and productivity. Younger fields supported greater diversity and density of avian species. Older 

fields with greater litter cover and grass cover supported the 

greatest productivity. One-year-old CRP fields had greatest 

diversity of avian species. As fields aged, avian diversities 

declined but productivity increased. Both the number of active 

nests and successful nests were greatest in older fields. Litter 
Pollinators, Invertebrates, and Miscellaneous Wildlife 73

cover serves as mechanical barrier to seedlings, decreasing 

the amount of light energy available for growth. On new fields 

horizontal cover is sparse. As forb and grass cover increased 

through the fourth growing season, horizontal cover increased. 

As fields became more grass-dominated and sparser during 

years 5 and 6, horizontal cover decreased.

Greater biomass and diversity of insects were available in 

younger fields. Few significant differences were found among 

field-age classes, but mean insect diversities and biomass 

generally decreased as fields aged with younger fields furnishing greater diversity. Seventy percent of surveyed landowners 

gave improvement of wildlife habitat at least some importance 

in enrollment into CRP. Authors recommend controlled disturbance in years 4–6 of typical CRP grassland contract. Disturbances that provide multiple successional stages may best 

provide for concurrent high density, diversity, and productivity 

of avian species. 

Morandin, L.A., and Winston, M.L., 2006, Pollinators provide 

economic incentive to preserve natural land in agroecosystems: Agriculture, Ecosystems and Environment, v. 116, 

p. 289–292.

Globally, conversion of natural ecosystems to agriculture is a major cause for losses in biodiversity. While natural 

patches of vegetation within agricultural landscapes are often 

viewed as a source of weeds, pests, and a hindrance to farming 

operations, these areas furnish biodiversity refuges, habitat 

corridors, and source areas for pollinating insects. Despite 

their economic and environmental benefits, natural pollinators 

are rarely taken into consideration in landscape planning. The 

economic value of natural pollinators remains largely undefined. This paper describes an evaluation completed in Alberta, 

Canada, of wild bee populations on canola (Brassica napus) 

production and yield.

Bee abundance was greatest in canola fields having more 

uncultivated land within 750 m (820 yd) of field edges. Abundance 

of bees increased in response to weed cover within fields and in 

uncultivated areas around canola fields. The authors conclude 

that seed production and crop yield could be increased by greater 

amounts of uncultivated habitats within the vicinity of canola fields. 

Authors estimate that pollination by wild bees could account for 

up to 38 percent increase in profits. The importance of pollinating 

insects to crop yield is not unique to canola implying uncultivated 

land interspersed with cropland has substantial potential to enhance 

natural pollination, crop yields and ultimately economic profits to 

farm operators. 

Ostman, O., Ekbom, B., Bengtsson, J., and Weibull, A., 2001, 

Landscape complexity and farming practice influence the 

condition of polyphagous carabid beetles: Ecological Applications, v. 11, no. 2, p. 480–488.

Authors attribute design of landscape structure in farming ecosystems having an influence on abundance of carabid 

beetles and potential biological control of pests in crop fields. 

Carabid beetles are predators of cereal aphids. Increased abundance of these predatory species could decrease aphid abundance in crop fields. Large degree of variability in physical 

condition of these ground beetles can be attributed to landscape factors including perimeter-to-area ratio of cultivated 

fields. These findings could be due to better feeding conditions 

at field borders, which are relatively more abundant on farms 

with high perimeter-to-area ratio. Beneficial attributes include 

proximity to several alternative habitats. Field borders are 

important to overwintering success of these species. Superior 

overwintering sites may result in reduced energy use during 

winter, which may in turn affect physical condition of beetles 

the following spring and summer. 

Phillips Jr., S.A., Brown, C.M., and Cole, C.L., 1991, Weeping lovegrass, Eragrostis curvula (Schrader) Nees Von 

Esenbeck, as a harborage of arthropods on the Texas High 

Plains: The Southwestern Naturalist, v. 36, no. 1, p. 49–53. 

Evaluation completed in 1984–1985 to determine arthropod fauna harbored by weeping lovegrass due to concern 

insects associated with the grass species extensively planted 

under the CRP would be detrimental to local or adjacent cotton crops. Results indicate large-scale plantings of weeping 

lovegrass will not be detrimental to the agro-ecosystem and 

may be beneficial through provision of habitat for predators 

and parasitoids of cotton pests. 

Reeder, K.F., Debinski, D.M., and Danielson, B.J., 2005, 

Factors affecting butterfly use of filter strips in Midwestern 

USA: Agriculture, Ecosystems and Environment, v. 109, 

p. 40–47.

Authors report results of investigating butterfly abundance and diversity relations to vegetative variables in filter 

strips in an agriculturally dominated landscape in southwest 

Minnesota. Filter strips evaluated were 3–7 yr old and dominated by “non-native” species, switchgrass (Panicum virgatum), and native vegetation. Buffer strips were present on both 

sides of streams and bordered by corn, soybeans, or wheat. 

Variation in management of filter strips was not an issue; none 

were treated with insecticide or fertilized. Filter-strip width did 

not differ significantly among planting treatments and ranged 

from 18 to 167 m (20 to 183 yd) for all plantings. Diversity of 

butterflies was positively correlated with width of filter strips, 

but abundance was not. Abundance and species richness of 

habitat sensitive (area) was positively related to width of filter 

strips. Authors conclude species adapted to tallgrass prairie 

and sensitive to disturbance may not benefit from narrow filter 

strips. The majority of butterflies exhibited a positive relationship to coverage of forbs. Although narrow strips were used 

by butterflies wider planting supported a higher diversity and 

larger abundances of butterflies. Increasing height and vertical 

density of vegetation may also influence richness of habitat 
74 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

sensitive species. Authors believe control of Canada thistle 

(Cirsium canadensis) through use of broad-leaved herbicides kills other beneficial forbs having a negative effect on 

butterfly populations.

Ries, L., and Debinski, D.M., 2001, Butterfly responses to 

habitat edges in the highly fragmented prairies of central 

Iowa: Journal of Animal Ecology, v. 70, p. 840–852.

Remaining natural habitats continue to become fragmented by human activity elevating risks for animal populations occupying these areas to become more isolated and 

vulnerable to processes that may cause local extinctions. 

However, little is known about how animals move through 

diverse landscapes and features of habitat that can enhance 

movements. Prairie ecosystems are considered one of the most 

endangered in the United States with between 82 percent and 

99 percent eliminated. Iowa has suffered from the greatest 

losses with less than 0.01 percent of tallgrass prairie remaining. Row crops, roads, or treelines border the majority of 

prairie remnants. 

 The authors use data collected on behavior of two butterfly species, a habitat specialist, Regal fritillaries (Speyeria 

idalia) and generalist, monarch (Danaus pexippus), in prairie 

cover types to determine the extent to which edges are barriers 

to emigration. Authors conclude edges between habitats can 

act as barriers to movement even when adjacent habitats are 

structurally similar. Prairie remnants in Iowa are small ranging 

from 1 to 10 hectares (0.4 to 4 ac) resulting in a high emigration rate of butterflies. Increased dispersal may have an overall 

negative effect resulting in drain on local populations. Consequently modification of edge structure to reduce dispersal 

may become an important management option but further 

evaluation is needed. Response of butterflies to prairie edges is 

highly variable dependent on species, edge characteristics and 

local environmental conditions. Management plans should be 

based on responses of several species. 

Robel, R.J., Press, B.M., Henning, B.L., and Johnson, K.W., 

1995, Nutrient and energetic characteristics of sweepnetcollected invertebrates: Journal Field Ornithology, v. 66, 

no. 1, p. 44–53.

An evaluation of invertebrate production in CRP grasslands is provided, but authors conclude sweepnet samples do 

not represent an accurate picture of invertebrate biomass available to birds. They do, however, state that the samples reflect 

taxonomic heterogeneity of invertebrate biomass in vegetative 

canopy of grasslands. Efforts to understand interactions of food 

resources and reproductive strategies require more precise data. 

Food resources are highly variable depending on taxonomic 

composition of insect biomass. Factors that influence differences in nutrient and energy contents of invertebrate taxonomic 

groups include genera or species within the samples, proportion of adult and immature individuals in the sample, levels of 

nutrients in food substrate, and life-history characteristics of 

species within taxonomic group. Need to know year-to-year or 

site-to-site differences in characteristics of avian food source to 

define suitability of food resources and predict avian behavior.

Southwick, E.E., and Southwick Jr., L., 1992, Estimating the 

economic value of honey bees (Hymenoptera: Apidae) as 

agricultural pollinators in the United States: Journal of Economic Entomology, v. 85, no. 3, p. 621–633.

Economic value of honey bees (Apis mellifera) to pollination of agricultural crops are presented as are economic gains 

to consumers through lower prices for crops benefited by pollination. Annual social gains are estimated to range between 

$1.6 and $5.7 billion. Demand for pollination services is greatest in monoculture production and where hybrid seed is used. 

Important crops include vegetables, fruits, clovers, oilseeds, 

alfalfa, soybeans, hay, forage crops, nuts, and flowers. In addition to the introduced European honey bee, there are about 

3,500 native species of bees in North America of which many 

play an important role in pollination. About 130 crops in the 

United States are dependent upon pollination by honey bees 

and other native species. It is believed production of fruit, seed 

and nut crops would decline by about 90 percent without the 

pollination services provided by honey bees. Honey bees are 

often credited for pollination actually performed by other bee 

species and insects but the economic value of these species 

remains unknown and largely underappreciated. In addition to 

the services provided to agricultural production, bees pollinate 

vegetation which enhances property values in wilderness, 

urban and watershed areas. 

Several factors have, or will, influence honey bee population that include introduced mites parasitic to honey bees, 

spreading diseases affecting bee populations, northward movement of Africanized honey bees (A. m. scutellata), and the 

negative effects of increased use of pesticides. 

Taylor, R.L., Maxwell, B.D., and Boik, R.J., 2006, Indirect 

effects of herbicides on bird food resources and beneficial 

arthropods: Agriculture Ecosystems & Environment, v. 116, 

p. 157–164.

This paper reports relations between agricultural herbicides and food webs and how changes in the plant community 

affect abundance of arthropods. The study focuses on insects 

eaten by ring-necked pheasant (Phasianus colchicus) and 

gray partridge (Perdix perdix) chicks as well as arthropods 

that prey on insect pests and weed seeds. Beneficial insects 

were more common in weedy vegetation communities found 

within monocultures. Study demonstrates herbicides do affect 

abundance of beneficial insects that are food for avian species and predators of less desirable species. The study confirms herbicides do reduce numbers and biomass of insects 

important to game species, as well as others dependent upon 

insects for food, by altering the beneficial effects of vegetation 
Mammals 75

composition and diversity. Weedy plots contained 12 times the 

biomass of vegetation dwelling insects than did monocultures. 

Vegetation plots with intermediate diversity in vegetation 

held 8 times the biomass of insects found within monocultures. After spraying bromoxynil and imazamethabenz insect 

abundance in weedy plots was diminished to 3 and 2 times 

that recorded in monocultural plots. Authors advocate use of 

headlands, where herbicides are not used, interseeding, and 

greater use of narrow spectrum herbicides to lessen losses of 

beneficial insects in agroecosystems.

Thomas, M.B., Wratten, S.D., and Sotherton, N.W., 1991, 

Creation of island habitats in farmland to manipulate populations of beneficial arthropods—Predator densities and 

emigration: Journal of Applied Ecology, v. 28, no. 3, 

p. 906–917.

Replacement of natural vegetation by crop monocultures 

eliminates presence of many indigenous insects. Diversity in 

habitat structure on both macro and micro scales will enhance 

abundance and diversity of insect populations associated with 

agricultural ecosystems. Decrease in diversity of habitats 

resulting from larger fields results in lower density of insects 

in interiors of larger fields. 

Whitmore, R., 1982, Insect biomass in agronomic crops as 

food for ring-necked pheasant chicks: Lincoln, Nebr., University of Nebraska Lincoln, Ph.D. Dissertation, 64 p.

Corn, soybeans, and alfalfa had significantly lower 

amounts of insect biomass than recorded in wheat, oats, 

sweetclover, and oats-sweetclover. Estimated numbers of 

chicks/ha supported by insect biomass found in specific crops: 

corn, 8; soybeans, 10; sweetclover, 64; oats, 86; and oatssweetclover, 106.

Weibull, A., Bengtsson, J., and Nohlgren, E., 2000, Diversity 

of butterflies in the agricultural landscape—The role of 

farming system and landscape heterogeneity: Ecogeography, v. 23, p. 743–750. 

Variation in landscape heterogeneity is more important 

than composition of the farming system (organic vs. conventional) for butterfly diversity and abundance. Authors 

express the opinion that the belief that organic farming always 

enhances diversity is not necessarily true. Landscape structure, 

but not always farming, practices have effects on diversity. 

Farmers of all kinds should be encouraged to increase the 

small-scale diversity of vegetation associated with farming operations to enhance habitat/species diversity. Simple 

methods such as leaving small habitat islands or strips within 

and between fields, increasing area and distribution of field 

margins should be encouraged. (Study completed in Sweden).

Mammals

Cline, G.A., 1988, Habitat relationships of bobwhite quail and 

cottontail rabbits on agricultural lands in Halifax County, 

Virginia: Blacksburg, Va., Virginia Polytechnic Institute and 

State University, M.S. thesis, 99 p.

Evaluation of a Habitat Suitability Index (HSI) model 

developed for assessment of bobwhite quail habitat. Wooded 

fallow fields, length of pasture/fallow, forest/forest edge, and 

total number of all edges present were positively related to 

quail presence. Management recommendations include maximizing the number of different edges and number of fallow 

fields in early successional stages. Cultivation of field borders, 

corners, waterways and other idle areas should be discouraged. 

A large number of small fields, each with a fallow or brushy 

border, are better than same acreage encompassed in only a 

few fields. Author concludes HSI model can correctly predict 

which habitats are preferred by bobwhite quail. 

Davis, S.S., 1998, Effects of prescribed fire on small mammal 

and beetle assemblages in Conservation Reserve Program 

(CRP) grasslands: Lubbock, Tex., Texas Technical University, M.S. thesis, 55 p.

Author examines effects of prescribed fire on small 

mammal and beetle populations in CRP fields dominated by 

weeping lovegrass (Eragrostis curvula) in Lynn County, Tex. 

Twelve sample sites were stratified by canopy cover of vegetation. Small mammal species collected included: deer mouse 

(Peromyscus maniculatus), hispid pocket mouse (Chaetodipus 

hispidus), Cotton rat (Sigmodon hispidus), western harvest 

mouse (Reithrodontomys megalotis), northern grasshopper 

mouse (Onychomys leucogaster), and spotted ground squirrel 

(Spermophilus spiolsoma). Results suggest rodents living in 

weeping lovegrass monocultures select different cover based 

Photo credit: White-tailed deer fawn, Tom Stehn, U.S. Fish and Wildlife Service
76 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

on microhabitat conditions. Lovegrass habitats following fire 

are continually being optimized by changing groups of rodents 

even when vegetative cover returns to pre-burn conditions. 

Although small mammals are typically not considered important in decisions for CRP management, their presence can be 

important by increasing diversity of wildlife and supporting 

avian and mammalian predators. 

Sampling showed 13 different families beetles present in 

lovegrass CRP fields. June and dung beetles (Scarabaeidae), 

darkling beetles (Tenebrionidae), and blister beetles (Meloidae) beetles were not affected by fire. Ground beetles (Carabidae) and tiger beetles (Cicindelidae) beetles show population increase in response to fire. Author concludes beetle 

families most affected by fire are those dependent upon litter 

and detritus for suitable habitat. Author concludes species 

dependent on thick layer of litter are reduced by application of 

prescribed fire. 

Evard, J.O., Snobl, D.A., Doeneir, P.B., and Dechant, J.A., 

1991, Nesting of short-eared owls and voles in St. Croix 

County: The Passenger Pigeon, v. 53, no. 3, p. 223–226.

High concentration of meadow voles (Microtus pennsylvanicus) in CRP grasslands are attributed to attracting and 

supporting an elevated diversity of predators including shorteared owl (Asio flammeus), red fox (Vulpes vulpes), coyote 

(Canis latrans), and rough legged hawks (Buteo lagopus). 

Two nests of short-eared owls were found in CRP grassland. 

The species rarely has nested in Wisconsin. Presence of nests 

was attributed to CRP habitat supporting high density of 

meadow voles. 

Furrow, L.T., 1994, The influence of field age on mammalian 

relative abundance, diversity, and distribution on Conservation Reserve Program lands in Michigan: Lansing, Mich., 

Michigan State University, M.S. thesis, 118 p.

Results suggest structure and composition of CRP grasslands in various age classes influence mammalian abundance, 

richness, and diversity. Reversion of CRP lands back to 

cropland may have significant impact on diversity of mammalian species depending on these grasslands for habitat. Results 

indicate leaving CRP fields undisturbed during the first 6 yr 

may reduce plant and animal diversity as fields become less 

structurally complex. Author recommends disturbance at 3–6 

yr after establishment of fields. 

Gould, J., 1991, Seasonal use of Conservation Reserve Program fields by white-tailed deer in eastern South Dakota: 

Brookings, S. Dak., South Dakota State University, M.S. 

thesis, 40 p.

CRP lands used by white-tailed deer (Odocoileus virginianus) are recorded in greater proportion than availability of 

cover type during spring, summer, and fall. Deer selected CRP 

during active periods in the spring and summer and during 

bedding periods in summer and fall but avoided CRP during 

fall active periods. CRP land provides important forage and 

cover in all seasons. In most cases, maintenance, mowing, 

and weed control are detrimental to wildlife populations. CRP 

fields must have some type of disturbance every few years to 

maintain quality of habitat. Author recommended vegetation 

disturbance/management every 3–5 yr in late summer subsequent to avian nesting season (usually identified as after July 

15). CRP may not be living up to expectations for provision 

of high quality habitat, however, in comparison with that 

furnished by actively farmed cropland, habitat quality is better 

than on most cropland.

Govenburg, T.W., Jacques, C.N., Klaver, R.W., and Jenks, 

J.A., 2010, Bed site selection by neonate deer in grassland 

habitats on the northern Great Plains: Journal of Wildlife 

Management, v. 74, no. 6, p. 1250–1256.

An investigation of white-tailed deer (Odocoileus virginianus) bed sites in South Dakota. Of all bed sites found 

52.6 percent were in CRP dominated by western wheatgrass 

(Pascopyrum smithii), big bluestem (Andropogon gerardii), 

porcupine grass (Hesperostipa spartea), and little bluestem 

(Schizachyrium scoparium). Authors recommend management 

that encourages the tallest vertical height in grassland cover. 

They also express concern diminishing enrollment in CRP will 

lead to greater mortality of fawns.

Griffin, S.L., 1991, Pronghorn use of agricultural land in 

northwestern South Dakota: Brookings, S. Dak., South 

Dakota State University, M.S. thesis, 63 p.

Pronghorn (Antilocapra americana) observed within CRP 

grasslands 5 percent of monitoring time. CRP grasslands represented 4 percent of study area. Suggests that CRP grasslands 

may furnish high-quality foraging areas and program may 

result in reducing depredation on small grain and alfalfa croplands. Use of CRP by pronghorn was often highest in early 

summer and winter when potential for agricultural conflict was 

greatest. Future research should focus on better definition of 

pronghorn preferences for various grassland plantings permitted in CRP.

Hall, D.L., and Willig, M.R., 1994, Mammalian species composition, diversity, and succession in Conservation Reserve 

Program grasslands: The Southwestern Naturalist, v. 39, 

no. 1, p. 1–10.

Abundance of small mammals and species diversity compared between native shortgrass grasslands and CRP fields in 

southern high plains of Texas. CRP grasslands simulate shortgrass prairies in species diversity but not in species composition. CRP grasslands consist of introduced grasses, primarily 

weeping lovegrass (Eragrostis curvula), which allow CRP to 
Mammals 77

accomplish soil erosion goals but not create “native habitat” 

with respect to plant or animal species composition. Successional changes in vegetational structure occurred in CRP sites. 

First-year sites on average contained more bare ground and 

less cover than older sites. Second-year sites were dense and 

almost homogenous with lovegrass. Third-year sites contained 

dense lovegrass, but it occurred in clusters, or bunches, interspersed with open spaces. CRP grasslands support as great a 

diversity of small mammals as do shortgrass prairie at least 

within initial three years following their establishment. Species composition may be highly dependent on specific physiognomic parameters that are not met in either agricultural sites 

or CRP grasslands. Endemic mammalian species composition 

may be restored if grazing or fire disturbance were incorporated into long-term management of CRP grasslands. 

Horncastle, V.J., Hellgren, E.C., Mayer, P.M., Ganguli, A.C., 

Engle, D.M., and Leslie Jr., D.M., 2005, Implications of 

invasion by Juniperus virginiana on small mammals in the 

southern Great Plains: Journal of Mammalogy, v. 86, no. 4, 

p. 1144–1155.

Authors report changes in southern Great Plains landscape cover is changing in response to expansion and invasion 

of eastern red cedar (Juniperus virginiana) which is having 

effects on local vegetation composition and habitats for small 

mammals. Changes were investigated in tallgrass prairie, old 

field, and cross-timbers forest. In old field and tallgrass sites 

occurrence of grassland mammals decreased in response to 

increasing amounts of red cedar. Results suggest an increase in 

overstory cover from 0 to 30 percent can change species-rich 

prairie community to one dominated by one species (whitefooted mouse, [Peromyscus leucopus]). Losses in mammalian 

species diversity and changes in distribution parallel those 

reported for avian communities affected by invasion of red 

cedar. Authors believe this to be first study documenting 

impacts of red cedar on grassland mammalian communities 

adding to a body of literature describing negative consequences of invasion by this species. Once established, red 

cedar is difficult to remove. Prescribed fire may be best alternative but is limited in use due to costs and social concerns. 

Early detection and selective removal of young seedlings 

through cutting, mowing, or grazing may be most effective 

approach in controlling spread of red cedar.

Kamler, J.F., Ballard, W.B., Fish, E.B., Lemons, P.R., Mote, 

K., and Perchellet, C.C., 2003, Habitat use, home ranges, 

and survival of swift foxes in a fragmented landscape—

Conservation implications: Journal of Mammalogy, v. 84, 

no. 3, p. 989–995.

Study completed in north panhandle of Texas. Habitat 

loss attributed to be one of primary reasons for decline of the 

swift fox (Vulpes velox) in the western Great Plains. Results 

indicate swift foxes are specialized in habitat selection. 

Protection of native shortgrass prairie may be necessary to 

support this species. Unlike habitat generalist species such 

as coyote (Canis latrans), red fox (V. Vulpes) and gray fox 

(Urocyon cinereoargenteus), which benefited from agricultural use and fragmentation of Great Plains habitats, swift fox 

range has declined. Study area composed primarily of irrigated 

cropland, native shortgrass prairie (grazed) and ungrazed 

grasslands enrolled in CRP. Shortgrass prairie was dominated 

by blue grama (Bouteloua gracilis) and buffalo grass (Buchloë 

dactyloides). CRP grasslands were planted to introduced old 

world bluestem (Andropogon spp.) and sideoats grama (Bouteloua curtipendula). Study results show swift foxes selected 

for shortgrass prairie and nearly completely avoided CRP 

grasslands. Although it represented 13–15 percent of study 

area, only 1 of 1,204 recorded locations of swift foxes were in 

CRP grassland. Avoidance of CRP by swift foxes attributed to 

their restricted mobility in taller, thicker vegetation (typical of 

ungrazed old world bluestem), reduced visibility, and possible 

lower abundance of prey in fields dominated by old world 

bluestem. Authors conclude planting of CRP fields to nonnative grasses and prevention of grazing of those grasslands 

may have further restricted available habitat for the swift fox. 

Kamler, J.F., Ballard, W.B., Lemons, P.R., Gilliland, R.L., and 

Mote, K., 2005, Home Range and habitat use of coyotes in 

an area of native prairie, farmland, and CRP fields: American Midland Naturalist, v. 153, no. 2, p. 394–404.

Coyotes (Canis latrans) monitored in northwestern 

Texas to determine habitat use and home range patterns in a 

landscape dominated by native pasture, cropland and CRP 

grasslands. Native prairie cover types were dominated by 

blue grama (Bouteloua gracilis) and buffalograss (Buchloë 

dactyloides) and moderately grazed by cattle. Primary crops 

on agricultural fields were corn and winter wheat. Most CRP 

fields in the study area were enrolled in 1985 and planted 

to warm season grasses dominated by old-world bluestem 

(Andropogon spp.) and sideoats grama (Bouteloua curtipendula). Study area defined by resident coyotes was 30 percent 

native prairie, 40 percent farmland, and 30 percent CRP. 

Habitat composition defined by transient coyote area of use 

was 33 percent native prairie, 48 percent cropland, and 19 percent CRP. Vegetation in CRP fields was thicker and taller than 

recorded in native prairie fields. Resident coyotes selected for 

native prairie sites whereas, transient coyotes selected for CRP 

fields. Resident coyotes used more native prairie and CRP 

and less cropland in winter than summer. Most (80 percent) 

natal dens found occurred in CRP fields. Resident coyotes 

may have selected native prairie because it is believed to 

contain a greater amount and diversity of prey species. CRP 

fields provided the only tall, permanent vegetation in study 

area therefore believed to furnish best available cover for 

transients. During winter resident coyotes selected more CRP 

than used in summer. Native prairie sites generally contained 

large numbers of cattle and had more human activity than did 

CRP fields. Authors conclude CRP provided important cover 
78 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

for coyotes because it was the only tall, permanent vegetation 

within the study area. 

Kamler, J.F., Ballard, W.B., and Swepston, D.A., 2001, Range 

expansion of mule deer in the Texas panhandle: The Southwestern Naturalist, v. 46, no. 3, p. 378–379.

In contrast to population trends in other western states, 

mule deer (Odocoileus hemionus) populations in the Texas 

panhandle region are increasing and expanding. Over-hunting 

and loss of habitat decreased mule deer range substantially 

by the mid-1940s. By 1985, mule deer occurrence increased 

to 48 percent of the panhandle counties due to reintroductions of the species and limited natural expansion of range. 

The species was typically found along major drainages of the 

Canadian River and other steep rugged terrain. From 1985 

to 2000, data show that mule deer populations expanded and 

nearly doubled distribution becoming present in 88 percent 

of panhandle counties. Authors believe expansion of deer is 

related to enrollment of crop fields into the CRP, which has 

provided higher vegetative cover, and greater distribution of 

suitable cover across relatively flat terrain otherwise dominated by cropland and shortgrass prairie. CRP fields provide 

permanent cover of relatively tall and dense grasses such as 

old world bluestem (Bothriochloa ischaemum). Because most 

CRP fields lie adjacent to croplands, mule deer have adequate 

cover adjacent to feeding areas. Authors believe availability 

and distribution of cover had been limiting mule deer distribution until advent of the CRP.

Kamler, J.F., Ballard, W.V., Wallace, M.C., and Gipson, P.S., 

2007, Diets of swift foxes (Vulpes velox) in continuous and 

fragmented prairie in northwest Texas: The Southwestern 

Naturalist, v. 52, no. 4, p. 504–510.

A comparison of swift fox diets in a fragmented landscape (native prairie [40 percent], cropland [39 percent], 

CRP [21 percent]) and grazed native prairie dominated by 

blue grama (Bouteloua gracilis), and buffalograss (Buchloë 

dactyloides). CRP fields were recently enrolled and planted to 

warm-seasons grasses including sideoats grama (B. curtipendula), blue grama, sand dropseed (Sporobolus cryptandrus), 

and buffalograss. Older fields were planted to old world 

bluestem (Bothriochloa spp.). Swift fox diets were dominated 

by insects in the native prairie sites. The diet consisted of 

insects, birds, and mammals [primarily black-tailed jackrabbits (Lepus californicus) and cottontails (Sylvilagus spp.)] in 

the fragmented landscape. Greater edge and habitat diversity 

in the fragmented landscape enhanced habitat diversity and 

prey availability. The higher proportion of edge likely also 

benefited coyotes (Canis latrans) which can suppress swift 

fox populations.

Kaufman D.W., and Kaufman, G.A., 1989, Nongame wildlife 

management in central Kansas—Implication of small mammal use of fencerows, fields, and prairie: Transactions of the 

Kansas Academy of Science, v. 92, no. 3–4, p. 198–205.

Prairie-cropland ecotone provides suitable habitat for 

several native small mammals. Fencerows between prairie and 

cropland are potentially valuable habitats. Fencerows between 

prairie and cropland furnish better habitat than fencerows with 

similar cover type on both sides. Fencerows provide food, 

cover, and access to other cover types as well as dispersal 

corridors. Prairie-cropland fencerows supported an abundant, 

diverse assemblage of native small mammals. The association of these species was apparently dependent on tall, dense 

vegetation, deep litter, and ready access to food in crop fields. 

Interiors of cropland, even when fallow, were insufficient to 

support most species of small mammals. Small, ungrazed 

herbaceous and woody habitats scattered within a matrix of 

cultivated fields would maintain a higher density and diversity 

of small mammals than would be found if these cover types 

were removed.

Mankin, P.C., and Warner, R.E., 1999, Responses of eastern 

cottontails to intensive row-crop farming: Journal of Mammalogy, v. 80, no. 3, p. 940–949.

Eastern cottontail (Sylvilagus floridanus) home ranges 

averaged 2.3 times larger during growing season than in nongrowing season. During non-growing season farm homesteads 

were major component of home ranges. Homesteads were less 

than 2 percent of study area but comprised 23 percent of home 

ranges and 40 percent of rabbit locations. Declines in rabbit 

numbers have been most pronounced in intensively farmed 

regions where row crop agriculture has replaced pasture, other 

early successional permanent vegetation, forage crops, small 

grains, and miscellaneous uncropped land. Loss of cottontail 

habitat in Midwest is also attributed to greater use of herbicides and intensive fall tillage.

Phillips, M.L., Clark, W.R., Nusser, S.M., Sovada, M.A., and 

Greenwood, R.J., 2004, Analysis of predator movement in 

prairie landscapes with contrasting grassland composition: 

Journal of Mammalogy, v. 85, no. 2, p. 187–195.

An investigation of landscape influence on ability of 

predators to locate waterfowl nests focused on planted cover 

(CRP), pasture and hayland in North Dakota. Two 41.4 square 

kilometer (km2) (25 square mile [mi2]) study areas—one of 

low-density grassland (15–20 percent grassland) and the other 

high-density (45–55 percent grassland)—were defined to 

investigate nightly movements of red foxes (Vulpes vulpes) 

and striped skunks (Mephitis mephitis). Authors conclude that 

heterogeneity of cover types at patch and landscape scales can 

affect predator movement. Fox movements were straighter 
Mammals 79

across landscapes with low composition of grassland with 

direct movement between isolated patches of grassland cover. 

Movement of skunks did not differ between study areas with 

high and low density of grassland and were focused along wetland edges. Authors suggest a greater understanding of predator behavior in fragmented landscapes is essential for effective 

management of breeding habitat for grassland birds.

 Sammon, J.G., and Wilkins, K.T., 2005, Effects of an invasive 

grass (Bothriochloa ischaemum) on a grassland rodent community: Texas Journal of Science, v. 57, no. 4, p. 371–382.

Rodent assemblages in native prairie in central Texas 

were compared to determine if non-native grassland supported 

a small mammal fauna different than found in grasslands dominated by native species. Past studies are cited that have shown 

lower diversity, richness, and relative abundance of small 

mammals in pure stands of grass than recorded in more dense 

native prairies. Rodent diversity generally correlates positively 

with plant diversity and cover. Introduced old-world bluestem 

tends to overwhelm and eliminate native species resulting in 

large homogenous stand of exotic grass. Exotic grasses often 

significantly increased the amount of litter present, reduced 

water loss from the soil, and diminished fluctuation in temperature by increasing insulation as a consequence of greater 

litter biomass. These changes often lead to establishment of 

exotic grasses over native grasses. Densities of hispid cotton 

rat (Sigmodon hispidus) were higher in habitats dominated 

by native grasses than recorded in stands of bluestem. The 

authors believe that further expansion of introduced grasses 

threaten to simplify remaining grassland habitats resulting in a 

system much different than native prairie.

Schroeder, M.A., and Vander Haegen, W.M., 2006, Use of 

CRP fields by greater sage-grouse and other shrubsteppe 

associated wildlife in Washington: Olympia, Wash., U.S. 

Department of Agriculture Farm Service Agency, Washington Department of Fish and Wildlife, 39 p.

The CRP is the largest effort to restore grassland and 

shrubsteppe habitat in the Columbia River Basin. About 1.5 

million acres have been planted to CRP grasses in Washington. 

Unlike Midwestern CRP acreage established on land largely 

prairie prior to conversion to cropland, much of Washington 

CRP occurs on lands previously shrubsteppe prior to agricultural use. Declines in northwestern shrubsteppe habitats have 

coincided with declines in endemic populations of wildlife. 

Older CRP fields in the eastern Washington study areas were 

dominated by crested wheatgrass (Agropyron cristatum) while 

newer fields were dominated by the native Sandberg bluegrass 

(Poa ampla). Data suggest mule deer (Odocoileus hemionus) 

and jackrabbits (Lepus spp.) are using CRP fields with deer 

using newer fields and shrubsteppe to a greater degree than 

older CRP fields. 

Schwartz, O.A., and Whitson, P.D., 1987, A 12-year study of 

vegetation and mammal succession on a reconstructed tallgrass prairie in Iowa: American Midland Naturalist, v. 117, 

no. 2, p. 240–249.

The report documents successional changes in plant 

and small mammal communities in hayfield planted to five 

native grass species. Original field was dominated by foxtail 

(Setaria spp.) and alfalfa (Medicago sativa). Native grasses 

planted were big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), Indiangrass (Sorghastrum 

avenaceum), sideoats grama (Bouteloua curtipendula), and 

switchgrass (Panicum virgatum). Three distinct developmental stages were recorded and discussed: herbaceous weed, 

perennial grassland, and early prairie. Reconstructed prairie 

furnished sub-optimal habitat for common prairie mammals 

due to low abundance of forbs, low diversity in vegetation, 

and high biomass of vegetation. As stand aged five perennial 

prairie grasses became dominant with few other herb, forbs, or 

woody plants present. Authors suggest development and management of seeded grasslands should incorporate techniques to 

balance native plant species diversity, especially forbs. High 

abundance of grasses, deficiency in forbs and lack of structural 

diversity furnish poor quality habitat for grassland species. 

Seefeldt, S.S., Conn, J.S., Zhang, M., and Kaspari, P.N., 2010, 

Vegetation changes in Conservation Reserve Program lands 

in interior Alaska: Agriculture, Ecosystems and Environment, v. 135, p. 119–126.

Results of an investigation of plant communities within 

CRP fields established in Delta Junction, Alaska is presented. 

The CRP fields included in the study were originally planted to 

brome (Bromus inermis), red fescue (Festuca rubra), and the 

native common horsetail (Equisetum arvense). As time progressed, abundance of these species decreased being replaced 

by the native grass, bluejoint (Calamagrostis canadensis), 

native forbs, shrubs and tree species. Plant diversity in the 

CRP fields increased by more than 2 species per 1000 m2/

year. The authors conclude plant succession in the CRP fields 

is following patterns similar to that of natural systems despite 

multiple years of having been farmed. If these fields are left 

undisturbed the resultant plant community would be indistinguishable from surrounding undisturbed bottomland forest. As 

frequency and abundance of woody species increase through 

time it will be difficult to meet USDA compliance standard 

that CRP fields must be maintained in a condition that permits 

easy conversion to cropland. Authors believe these CRP fields 

will be non-compliant 32 years after establishment in CRP 

but the fields will be providing excellent erosion control and 

wildlife habitat. Although the CRP fields included in the study 

were not specifically evaluated for their quality as wildlife 

habitat, young CRP fields furnished “good” habitat for bison 
80 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

(Bison bison). The older, shrub-dominated fields were believed 

to furnish “good” habitat for moose (Alces alces).

Slade, N.A, and Crain, S., 2006, Impact on rodents of mowing 

strips in old fields of eastern Kansas: Journal of Mammalogy, v. 87, no. 1, p. 97–101.

Mowing was implemented in strips to prevent invasion 

of woody vegetation in old-field grass dominated covers. 

Effects on numbers and movements of five rodent species are 

described. Numbers of hispid cotton rats (Sigmodon hispidus) 

and prairie voles (Microtus ochrogaster) were reduced temporarily by mowing. Numbers of white-footed mice (Peromyscus leucopus) and deer mice (P. maniculatus), and western 

harvest mice (Reithrodontomys megalotis) were not significantly affected. Changes in numbers and movements were 

of short duration and authors conclude that mowing narrow 

strips when vegetation can recover rapidly had little sustained 

impact on rodent community. Deer mice showed almost no 

response to mowing. Negative effects on cotton rats lasted 4–5 

months. Authors suggest mowing in narrow strips and early in 

the growing season should retain small mammal community.

Sirotnak, J.M., Reese, K.P., Connelly, J., and Radford, K., 

1991, Effects of the Conservation Reserve Program (CRP) 

on wildlife in southeastern Idaho, project W-160-R-18, job 

completion report: Boise, Idaho, Idaho Department of Fish 

and Game, 45 p.

Lands enrolled in the CRP and used by mule deer 

(Odocoileus hemionus) and upland game birds. Continuation 

of CRP contracts was recommended to furnish continuing benefits to wildlife. Sharp-tailed grouse (Tympanuchus phasianellus) population benefited from the program in southeastern 

Idaho. Best-quality habitat was in fields with high levels of 

cover, diversity in vegetation species, and patches of native 

habitat or irregular borders increasing edge habitat. Authors 

concluded establishment of CRP may reduce depredation on 

forage crops by mule deer.

Stanley, T.R., 2010, Land use and small mammal predation 

effects on shortgrass prairie birds: Journal of Wildlife Management, v. 74, no. 8, p. 1825–1843.

An investigation of the potential effects of land use on 

small mammal (for example, thirteen-lined ground squirrel 

[Spermophilius tridecemlineatus], deer mouse [Peromyscus 

maniculatus]) predation on grassland bird nests is described. 

The author states, while benefits to mid- and tallgrass prairies 

are clear, it remains unclear if CRP provides suitable nesting 

habitat for shortgrass prairie birds. Also of interest was what 

effects elevated abundance of vegetation and seed sources 

furnished by CRP had on species richness of potential predators. Native grassland sites were dominated by buffalograss 

(Buchloë dactyloides), blue grama (Bouteloua gracilis) and 

plains pricklypear (Opuntia polyacantha). CRP fields in the 

northeastern Colorado study area were smooth brome (Bromus inermis) and wheatgrass (Agropyron spp.). Age of fields 

was not given. Land uses on shortgrass prairie are found to 

alter small mammal communities. Small mammal densities 

and richness were found to be greater along edges and on 

CRP compared to shortgrass sites. Survival of nests (artificial 

and natural) at edge and CRP sites did not differ from native 

sites. Small mammal communities were found not to affect 

nest survival. 

Non-Game Birds

Allen, A.W., 1994, Conservation Reserve Program (CRP) 

contributions to avian habitat: Fort Collins, Colo., U.S. Fish 

and Wildlife Service Federal Aid Report, National Biological Survey, 19 p. 

This report furnishes a summary of CRP contributions 

to distribution and quality of habitat for game and non-game 

birds affiliated with agricultural ecosystems. The report concentrates largely on species endemic to grassland ecosystems 

and decisions in CRP management that may favor endemic 

grassland species or species more typical of farmland habitats 

(for example, ring-necked pheasants [Phasianus colchicus]). 

The report provides a discussion of identification of CRP 

contracts furnishing greatest potential benefits, landscape 

planning, and management recommendations to enhance 

habitat quality. 

Angelstram, P., 1986, Predation on ground-nesting birds’ nests 

in relation to predator densities and habitat edge: Okios, 

v. 47, p. 365–373.

Author provides discussion of how predators utilize 

different habitats. As the size of habitat islands decrease the 

Photo credit: Western Meadowlark, John and Karen Hollingsworth, U.S. Fish 

and Wildlife Service
Non-Game Birds 81

influences of surrounding cover become increasingly important. Since relative amount of edge increases as patch size 

decreases the predation rate should be inversely related to 

the size of patch. Permanently high densities of generalist 

predators are often a consequence of human activities especially where landscapes become fragmented in terms of cover 

type composition (for example, agriculture land use). The 

author concludes cover type edges in more productive habitats 

will experience greater rates of predation than edges in less 

productive habitats 

Bakker, K.K. and Higgins, K.F., 2009, Planted grasslands and 

native sod prairie— equivalent habitat for grassland birds?: 

Western North American Naturalist, v. 69, no. 2, 

p. 235–242.

A comparison of species richness and density of grassland nesting birds in cool-season exotic grasses, warm-season 

monocultures/mixes, and native sod prairie in eastern South 

Dakota and western Minnesota is reported. Monocultures were 

switchgrass (Panicum virgatum) and intermediate wheatgrass 

(Thinopyrum intermedium). Warm season mixes contained 3 

to 5 plant species (for example, big bluestem [Andropogon 

gerardii], Indiangrass [Sorghastrum nutans], switchgrass) 

while native sod tallgrass prairie contained as many as 119 

plant species. Cool season mixes were dominated by exotic 

species including smooth brome (Bromus inermis) and yellow 

sweetclover (Melilotus officinalis). Planted fields were 4 to 9 

yr old.

Preservation of native prairies furnished habitat not 

available in planted fields. Native sod prairies were found to 

support a richer grassland bird community and higher densities 

of several species. Planted cover types dominated by exotic 

species, intermediate wheatgrass monotypes, and cool-season 

mixes supported depleted grassland bird communities in comparison to native tallgrass prairie. Warm-season grass mixes 

came closest to approximating avian richness found in native 

prairie. Intermediate wheatgrass monocultures and exotic 

cool-season mixes contained 40 to 60 percent fewer bird 

species than did native prairie. Authors recommend including 

additional native plant species into grass plantings for production of biomass fuels or conservation purposes. 

Bassett-Touchell, C.A., and Stouffer, P.C., 2006, Habitat 

selection by Swainson’s warblers breeding in loblolly pine 

plantations in southeastern Louisiana: Journal of Wildlife 

Management, v. 70, no. 4, p. 1013–1019.

Swainson’s warblers (Limnothlypis swainsonii) are typically associated with bottomland hardwood forests but also 

breed in even-age plantations of pine. Authors report investigation of Swainson’s warbler use of loblolly pine (Pinus 

taeda) plantations of various age classes and management 

histories in southern Louisiana to determine stand structure 

preferences of the species. The warblers were found in pine 

stands that had well-developed canopy closure, abundant 

understory vegetation, and sparse ground cover. Swainson’s 

warblers were recorded as using 7 to 24-yr-old, unthinned, 

even-aged loblolly pine stands as breeding habitat. Authors 

conclude that even-aged, thinned stands are not used as breeding habitat by this species. A mosaic of even-aged stands 

within a landscape is recommended to furnish habitats for 

avian species requiring early and mid-successional habitats. 

Use of pine plantations by Swainson’s warblers is believed to 

begin when stands reach 7 yr of age and use will continue only 

if the stands remain unthinned.

Berthelsen, P.S., 1989, Value of the Conservation Reserve Program to birds in the Texas southern high plains: Lubbock, 

Tex., Texas Technical University, M.S. thesis, 106 p.

The author believes the greatest potential benefit of the 

CRP to wildlife in the Southern High Plains is provision of 

secure, high quality nesting and winter cover for avian species. Bird-species composition on CRP lands was represented 

primarily by 2 to 3 dominant species. Seven of 13 species 

observed on CRP lands were considered migrants or winter 

residents. Fields of blue grama/kleingrass (BG/K) (Bouteloua 

gracilis/Panicum virgatum) produced high quality winter 

habitat. This cover type produced the greatest values for 

avian winter densities, avian biomass estimates, nest densities, number of birds observed, and winter cover quality 

for pheasants. BG/K had highest numbers of avian species 

observed, followed by blue grama/sideoats grama (Bouteloua 

curtipendula) and blue grama/plains bluestem (Bothriochloa

spp.). CRP may promote dispersal and increase survival of 

ring-necked pheasants (Phasianus colchicus) through provision of high-quality winter habitat more evenly dispersed over 

agriculturally dominated landscapes. CRP fields in vicinity of 

remaining grain crops may substantially enhance year round 

habitat quality. BG/K grasslands will provide quality passerine 

habitat in southern high plains during winter and reproductive 

seasons. Greatest potential of CRP wildlife habitat in southern 

high plains is to produce secure, high quality, long-term nesting and winter cover for upland game birds. Nest success on 

CRP lands averaged 22 percent. There was no apparent difference in nest success between CRP covers. BG/K had highest 

production of cover types followed by BG/PB and BG/SO. 

Study documents earlier initiation of pheasant nests in CRP 

than reported for the general area, which may be related to 

increase of available nesting habitat, more favorable weather, 

or hens entering breeding season in good physiological condition. CRP lands enable pheasants to distribute from formerly 

concentrated habitats, particularly playa wetlands often unsafe 

or unsuitable habitat due to seasonal flooding. 

Benefits of CRP are dependent upon cover-management 

practices and political pressures. Approximately one-third 

of fields evaluated were hayed or mowed for weed control 

resulting in minimal to no value as habitat for upland nesting 

birds. Mowing of CRP fields for weed control was believed 

unnecessary. As stands age grasses will outcompete forbs and 
82 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

the weed issue will diminish. In addition, weed control may 

reduce compositional quality of vegetation in the field further 

affecting habitat quality. 

Bertherlsen, P.S., and Smith, L.M., 1995, Nongame bird nesting on CRP land in the Texas Southern High Plains: Journal 

of Soil and Water Management, v. 50, no. 6, p. 672–675. 

Evaluation of nongame bird nesting in the most common CRP cover types in Texas High Plains; blue grama/

sideoats grama (Bouteloua gracilis/Bouteloua curtipendula), 

blue grama/Kleingrass (Panicum virgatum), and blue grama/ 

plains bluestem (Bothriochloa spp.). Dominant avian species reported in the evaluation were western meadowlark 

(Sturnella neglecta), grasshopper sparrow (Ammodramus 

savannarum), Cassin’s sparrow (Aimophila cassinii), and 

red-winged blackbird (Agelaius phoeniceus). Nest initiation 

for these species peaked in mid-May. Authors suggest because 

vegetative characteristics of fields change as CRP grasslands 

age their value as nesting habitat for nongame birds may 

decline as age of grasslands progress without disturbance to 

rejuvenate vegetation. 

Best, L.B., Bergin, T.M., and Freemark, K.E., 2001, Influence 

of landscape composition on bird use of row crop fields: 

Journal of Wildlife Management, v. 65, no. 3, p. 442–449.

Bird species abundance in row crop fields was greater 

in landscapes with more grassland block cover and/or more 

wooded block-cover and strip cover. Avian habitat selection 

and use is a multi-scale phenomenon; therefore, landscape 

context should be considered when evaluating avian use 

and conservation management of agricultural ecosystems. 

Although few species nest in row crop fields (corn, soybeans) over 50 avian species have been documented to use 

these cover types during the breeding season. Avian species 

response to landscape composition varied. Habitat affinities of 

avian species influence use of specific habitat patches as well 

as landscape in which patches are located. Use of row crop 

fields by birds depends on within field features (for example, 

residue, crop type, and development) and landscape features in 

which fields are situated. 

Best, L.B., Campa III, H., Kemp, K.E., Robel, R.J., Ryan, 

M.R., Savidge, J.A., Weeks Jr., H.P., and Winterstein, S.R., 

1998, Avian abundance in CRP and crop fields during winter in the Midwest: American Midland Naturalist, v. 139, 

no. 2, p. 311–324.

This report contains results of 1992–1995 comparison of 

avian abundance and species composition in CRP and rowcrop fields during winter from Indiana, Iowa, Kansas, Michigan, Missouri, and Nebraska. Mean annual bird abundance 

ranged from 0.1 to 5.1 birds per km (0.62 mi) of transect in 

CRP fields and 0.1 to 24.2/km transect in row crop fields. Total 

number of species recorded in CRP fields ranged from 6 to 

32 and 8 to 18 in row crop fields. Six of seven most abundant 

species observed in row crop fields are already abundant or 

experiencing long-term increases in populations. Variations 

in numbers and species recorded by state are reported. Total 

bird abundance in CRP and row crop fields was variable 

among states with no consistent pattern evident. A number 

of the most abundant avian species wintering in CRP fields 

have experienced long-term declines in populations. Authors 

document widespread use of CRP by birds in winter and 

conclude the program has potential to mitigate declines in 

avian populations. 

Best, L.B., Campa III, H., Kemp, K.E., Robel, R.J., Ryan, 

M.R., Savidge, J.A., Weeks Jr., H.P., and Winterstein, S.R., 

1997, Bird abundance and nesting in CRP fields and cropland in the Midwest—A regional approach: Wildlife Society 

Bulletin, v. 25, no. 4, p. 864–877.

Comparison of abundance and nesting success of avian 

species in CRP and row crop fields over 5 years (91–95) 

in 6 Midwest states (Indiana, Kansas, Missouri, Michigan, 

Nebraska, Iowa). Bird abundance was 1.4 to 10.5 times greater 

in CRP than found within row crop fields. Nests of 33 bird 

species found in CRP with nests of only 10 species in row 

crops. The number of nests found was 13.5 times greater in 

CRP than within row crops. Nest success was 40 percent in 

CRP. Nest success in row crops similar to that of in CRP, but 

total number of nests found in row crop was only 7.4 percent 

of that in CRP. Predation was greatest cause of nest failure. 

Long-term farm set-aside programs establishing perennial 

grass cover provide benefits for grassland birds including several species for which conservation is of substantial concern. 

Authors recommend further investigation of species-specific 

habitat requirements in relation to planting, management and 

spatial configuration of CRP.

Best, L.B., Freemark, K. E., Dinsmore, J.J., and Camp, M., 

1995, A review and synthesis of habitat use by breeding 

birds in agricultural landscapes in Iowa: American Midland 

Naturalist, v. 134, no. 1, p. 1–29.

Data for this report was collected during breeding season 

(May–July). Total numbers of birds recorded were highest in 

floodplain and upland forests and lowest in small grain fields 

and fencerow dominated by herbaceous vegetation. Abundance of avian species was lowest in agricultural habitats 

(tilled row crops and small grains) and highest in narrow stripcover habitats (railroad rights-of-way, wooded fencerows and 

shelterbelts). Abundance patterns in natural habitats (forest, 

marsh, and prairie) were intermediate between agricultural and 

strip cover habitats. Bird species were more abundant in strip 

cover habitats. At least 30 percent of bird species using these 

habitats are common to very abundant. Abundance and diversity of arthropods was greater in uncropped strip cover habitats 
Non-Game Birds 83

with perennial vegetation than recorded in cultivated cropland. 

Avian foraging was concentrated in and near such areas. Low 

abundance of birds was recorded in agricultural habitat due to 

repeated disturbance by tillage, planting, cultivation, pesticide/

fertilizer application, and mowing. These activities during 

breeding season destroy nests and adversely alter physical 

features of habitat causing disruption of site fidelity behavior 

by birds. Croplands characteristically have low species diversity and generally relatively simple physical structure. Acute 

or toxic exposure to toxic compounds or reduction in food 

sources also influences avian use of croplands. 

Best, L.B., Whitmore, R.C., and Booth, G.M., 1990, Use of 

cornfields by birds during the breeding season—The importance of edge habitat: American Midland Naturalist, v. 123, 

p. 84–99.

Elimination of woody vegetation from fencerows and 

other habitats adjacent to crop fields will affect assemblage 

of bird species found within fields. The amount of linear edge 

relative to field area has a major effect on field use by birds. 

Larger fields are used proportionately less. The proportion of 

linear field edge decreases as fields become larger resulting 

in less overall use of cropland by birds. The trend in recent 

decades has been to consolidate fields and increase size of 

cropping units. Bird abundance was reported to be greater in 

wooded edges than in herbaceous edges. More bird species, 

and about five times more birds, used the perimeters of cornfields than the central area of fields. Continued land-use practices that increase field size and eliminate woody vegetation 

from edge habitats will affect both richness and abundance of 

avifauna affiliated with agricultural ecosystems. 

Blackwell, B.F. and Dolbeer, R.A., 2001, Decline of the redwinged blackbird population in Ohio correlated to changes 

in agriculture (1965–1996): Journal of Wildlife Management, v. 65, no. 4, p. 661–667.

Evaluation of breeding population data of red-winged 

blackbirds (Agelaius phoeniceus) showed decline with population indices decreasing by over 53 percent during period of 

evaluation (1966–1996). Although considered a pest, the 

decline is important from both ecological and damage control 

perspectives. Expansive upland grass dominated habitats furnish substantial potential for red-winged blackbird population 

growth. Decrease in area of non-alfalfa hay harvested likely 

has reduced availability of quality nesting habitat for this species. An associated increase in mechanized agricultural practices and use of chemicals in farming has resulted in a loss of 

traditional and non-traditional nesting habitats with resultant 

declines in grassland associated avian species. The agricultural 

practices that have resulted in decline of red-winged blackbirds likely have had more severe effects on other, less ubiquitous grassland species. Findings lend support to continuation 

of the CRP and other programs providing suitable habitat for 

grassland species. Management regimes should be modified 

by area, season, and crop rotation patterns to increase habitat 

opportunities for grassland avifauna.

Bock, C.E., Saab, V.A., Rich, T.D., and Dobkin, D.S., 1993, 

Effects of livestock grazing on neotropical migratory 

landbirds in western North America, in Finch, D.M., and 

Stangle, P.W., eds., Status and management of neotropical 

migratory birds: Fort Collins, Colo., USDA Forest Service 

General Technical Report RM-229, p. 296–309.

Authors advocate finding ways to make existing CRP 

grasslands economically valuable to owners, possibly encouraging moderate, periodic grazing by livestock or limited 

haying. Authors speculate CRP grasslands would be of greater 

benefit in some situations if they were coupled with creation 

of livestock exclosures in other areas such as National Grasslands. Also recommended by authors was an increase in the 

amount of public rangeland from which all livestock grazing 

is excluded.

Bohning-Gaese, K., Taper, M.L., and Brown, J.H., 1993, Are 

declines in North American insectivorous songbirds due to 

causes on the breeding range?: Conservation Biology, v. 7, 

no. 1, p. 76–86.

Predation on breeding grounds in North America 

is believed to have played a larger role in the decline of 

migratory songbirds than deforestation on tropical wintering grounds. Predation pressure by terrestrial mammals is 

believed to have had a major impact on population trends of 

avian species. Vulnerability traits of low, open nests and high 

parasitism by brown-headed cowbirds (Molothrus ater) have 

additive negative effects on songbird populations. Authors 

suggest even a small effect of cowbird parasitism could be 

enough to push a songbird population experiencing substantial rate of predation to a negative replacement rate and 

decline in population. 

Bollinger, E.K., and Gavin, T.A., 1989, Eastern bobolink 

populations—Ecology and conservation in an agricultural 

landscape, in Hagen, J.M., III and Johnston, D.W., eds., 

Ecology and conservation of neotropical migrant landbirds: 

Washington, D.C., Smithsonian Institute Press, p. 497–506. 

Bobolink (Dolichonyx oryzivorus) abundance reported 

greatest in old hayfields. Abundance of species increased 

exponentially with size of hayfields. Conservation practices 

designed for grassland birds should concentrate on creating, or maintaining, large habitat patches which resemble old 

hayfields. Recommendations: create or maintain patches of 

relatively sparse grass-dominated cover with some broadleaf 

forbs. Fewer, larger patches tend to contain more breeding 

bobolinks than numerous small ones, because nest predation and parasitism by brown-headed cowbirds (Molothrus 
84 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

ater) tends to be higher in small patches of grassland cover. 

Management of grassland should focus on prevention of 

encroachment by woody vegetation. These practices should 

help populations of other declining grassland species as well. 

Eastern meadowlark (Sturnella magna), upland sandpipers 

(Bartramia longicauda), Henslow’s sparrow (Ammodramus 

henslowii), and grasshopper sparrow (A. savannarum), were 

positively correlated with bobolink densities.

Boutin, C., Freemark, K.E., and Kirk, D.A., 1999, Farmland 

birds in southern Ontario—Field use, activity patterns and 

vulnerability to pesticide use: Agriculture, Ecosystems and 

Environment, v. 72, no. 2, p. 239–254.

Three factors are major determinants of bird distribution in agricultural land: type of crops grown, configuration 

and physical structure of adjacent non-crop cover types, 

and frequency and extent of agricultural practices (for 

example, tillage, pesticide application, crop harvest). A lack 

of data on avian use of croplands in dissimilar agricultural 

landscapes is a major obstacle in assessing effects of agriculture on wildlife in many areas of North America. Most 

species surveyed used edge habitat significantly more than 

expected. More arthropods are found in field edges than in 

interior areas of fields. Many field margins, or herbaceous 

borders, are either sprayed directly for control of pests or 

vulnerable to spray drift. Impacts of spraying on edges 

have diminished diversity of plants and insects important 

for young birds. The impacts of agrochemical spraying are 

especially detrimental in intensively farmed landscapes where 

vegetative diversity is already minimal.

Bowen, B.E. and Kruse, A.D., 1993, Effects of grazing on 

nesting by upland sandpipers in south central North Dakota: 

Journal of Wildlife Management, v. 57, no. 2, p. 291–301.

The study results suggest grazing during late spring and 

early summer has a detrimental effect on reproduction of 

upland sandpipers (Bartramia longicauda) in the northern 

Great Plains. Authors recommend delay of grazing until at 

least mid to late June. Traditional season-long grazing (June–

October) should be avoided. Autumn grazing at high stocking 

rates may be an acceptable alternative to season-long grazing. 

In the central Great Plains sandpipers nested in grazed fields 

rather than in ungrazed fields where vegetation was too tall. 

Brady, S.J. and Flather, C.H., 1998, Agricultural land use patterns and grassland nesting birds: Gibier Faune Sauvage, 

v. 15, p. 775–784.

Paper documents association of grassland-nesting avian 

species with nonfederal rural land use and factors related to 

abundance of grassland birds. Natural Resources Conservation 

Service NRI data used to characterize land use patterns and 

BBS data. Authors conclude half of birds responded positively 

to the CRP, remainder of species investigated showed neutral response. Although the CRP has had a positive effect on 

grassland birds, the authors believe the program does not 

appear to be as important as are other habitats occurring on 

larger expanses of range and cropland. Effective management of wildlife habitat in agricultural ecosystems will occur 

only when management practices on all lands are taken into 

consideration on both local and regional levels. The species 

most associated with CRP were western meadowlark (Sturnella neglecta) ring-necked pheasant (Phasianus colchicus), 

lark bunting (Calamospiza melanocorys), and horned lark 

(Eremophila alpestris).

Brennan, L.A., and Kuvlesky Jr., W.P., 2005, North American 

grassland birds—An unfolding conservation crisis?: Journal 

of Wildlife Management, v. 69, no. 1, p. 1–13.

There is no single cause for declines of grassland birds 

but cumulative factors (afforestation in eastern United States, 

fragmentation and loss of prairie ecosystems with agriculture, 

and deterioration of western rangelands) are key factors in 

decline of these species. Authors believe economics of crop, 

fiber, and meat production have overwhelmed ethical use 

of land. Authors describe purpose of North American Bird 

Conservation Initiative as a potential solution for conserving 

grassland bird populations. Coordination of grassland bird 

conservation efforts with initiatives to increase upland game 

bird populations present additional opportunities to positively 

impact virtually all species of North American grassland birds. 

Avian species with affinities for grassland and grassshrub habitats have been in continental-scale population 

declines for decades. Declines probably began about the time 

the steel plow first broke prairie sod in 19th century. Since mid1800s, loss of grassland ecosystems in most of North America 

has exceeded 80 percent. Conversion of prairie ecosystems 

to agriculture remains a key part of problem facing grassland 

birds but problems extend far beyond prairie biome. Widespread deterioration in rangeland habitat quality and industrial 

silviculture that has replaced fire-maintained, open, park-like 

southern pine forests with dense plantations also have contributed to declines in grassland birds. Strategically adding 

CRP lands within highly fragmented agriculturally dominated 

landscapes would likely be of benefit to grassland species by 

reducing predation and brood parasitism rates associated with 

habitat edge. Restoration of ecosystem processes through 

use of fire, restoration of hydrological regime and control of 

invasive plant species will also be required to reverse declines 

in grassland birds. Stabilization and recovery of grassland bird 

populations will require healing of sick landscapes through 

adoption of the North American wildlife management model 

that has been so successful in recovery of other species in 

past decades.

Bryan, G.G., and Best, L.B., 1991, Bird abundance and species richness in grassed waterways in Iowa rowcrop fields: 

American Midland Naturalist, v. 126, p. 90–102.
Non-Game Birds 85

 An evaluation of avian use of grassed waterways planted 

to smooth brome (Bromus inermis) in corn and soybean fields. 

Forty-eight avian species were recorded using grassed waterways compared to 14 species within croplands. No species 

exhibited exclusive use of croplands. Current mowing recommendations are to mow after July 15, however, 53 percent of 

all species observed and all of breeding species were recorded 

at peak abundance in waterways during 4–22 July. Authors 

recommend waterways be mowed in late August or early September to avoid detrimental effects on avian species. Mowing should not be undertaken after mid-September because 

mowing would reduce the amount of winter cover and residual 

vegetation required for early spring nesting. Unmowed waterways furnish important habitat for birds in mid-to-late summer 

because other grass dominated cover types have already been 

mowed, concentrating birds in limited remaining habitat. 

Burger, L.D., Burger, L.W., and Faaborg, J., 1994, Effects of 

prairie fragmentation on predation of artificial nests, Journal 

of Wildlife Management, v. 58, no. 2, p. 249–254.

Artificial nests in smaller prairies were depredated more 

than those in larger prairies (37 percent vs. 13.9 percent). 

Although highest rates of predation were observed in smallest prairie size classes, proximity to woody cover was a more 

important factor affecting predation rates on artificial nests. 

Smallest prairies may have had higher predation rates due to 

higher proportion of area near woody cover. The potential 

effects of prairie size and woody vegetation on success of 

ground-nesting birds should be considered in decisions of 

acquisition and management of prairie habitats. 

Chapman, R.N., Engle, D.M., Masters, R.E., and Leslie Jr., 

D.M., 2004, Tree invasion constrains the influence of herbaceous structure in grassland bird habitats, Ecoscience, v. 11, 

no. 1, p. 55–63.

Authors conclude trees and other woody plants diminish habitat quality for grassland-obligate birds as well as 

biological integrity of grassland ecosystems. Avian species 

associated with North American southern mixed grass prairies 

have declined in abundance while species associated with 

shrub-stage and woodland habitats have increased. Expansion of eastern redcedar (Juniperus virginiana) in southern 

Great Plains explains some of changes in avian assemblages 

in landscapes composed of grassland patches fragmented 

by cropland. As canopy cover of eastern redcedar increased 

variation in abundance of grassland birds decreased. Authors 

believe invasion of woody plants into grassland habitats will 

result in increasingly ineffective management of grassland bird 

abundance and nest success. Redcedar invasion also degrades 

grassland habitat by resulting in greater fragmentation of 

grasslands affecting area sensitive species. Although diversity 

in avian community may increase due to greater abundance 

of woody vegetation, it comes at the expense of the relatively 

few species endemic to grassland ecosystems. 

Chapman, R.N., Engle, D.M., Masters, R.E., and Leslie Jr., 

D.M., 2004, Grassland vegetation and bird communities in 

the southern Great Plains of North America: Agriculture, 

Ecosystems and Environment, v. 104, p. 577–585.

Relations between structure and composition of vegetation and abundance of breeding birds in CRP fields seeded 

to old-world bluestem (Bothriochloa ischaemum) and native 

grasslands in Oklahoma are reported. Study fields were undisturbed, hayed or grazed. Authors conclude seeded grasslands 

were inferior to native mixed prairie in terms of diversity of 

plant species, however differences did not have a meaningful 

effect on vegetation structure that influenced habitat selection 

by breeding birds. Overlap in bird community composition 

showed disturbance (grazing, haying) rather than plant species 

composition creates habitat heterogeneity required to support 

a diverse assemblage of avian species. Authors conclude conservation programs that do not allow for suitable disturbance 

will benefit only a narrow suite of birds regardless of plant 

species composition. 

Clawson, M.R., and Rotella, J.J., 1998, Success of artificial 

nests in CRP fields, native vegetation, and field borders in 

southwestern Montana: Journal of Field Ornithology, v. 69, 

no. 2, p. 180–191.

Artificial nests used to study relations between nest success in CRP, field borders/watercourses, and native vegetation. Nest success was higher in structurally more complex 

CRP fields than other grassland types. Results suggest nests 

surrounded by taller, thicker cover were more likely to survive 

than nests in vegetation furnishing less concealment. Field size 

was directly related to nest success in CRP fields but not in 

other grassland types. 

Conover, R.R., Burger, L.W., Jr., and Linder, E.T., 2006, 

Winter avian community and sparrow response to field border width: Journal of Wildlife Management, v. 71, no. 6, 

p. 1917–1923.

The amount of strip cover, or linear cover, across the 

southeast has diminished. To compensate for these losses 

the national Conservation Buffer Initiative has promoted 

establishment of herbaceous field borders to enhance wildlife 

habitat quality. Effects of warm-season grass field borders 

on avian winter abundance in Mississippi are reported. Field 

borders were 400 m (1,312 ft) in length and planted to a 

mixture of Indiangrass (Sorghastrum nutans), little bluestem 

(Schizachyrium scoparium), big bluestem (Andropogon gerardii) partridge pea (Chamaecrista fasciculate), and Kobe pea 

(Lespedeza striata). Narrow borders were approximately 8 m 

(26 ft) in width while wider borders were approximately 30 m 

(100 ft) wide. 

Wide field margin borders enhanced overall abundance, 

richness and total avian conservation value over non-bordered 

fields and narrow field borders. Detailed information on 
86 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

habitat use by commonly observed avian species is presented. 

It is suggested wider borders furnish increased escape-cover 

quality or reduce predation pressure by increasing distance to 

avian predator perch sites in wooded edges. Field borders also 

enhanced greater use of crop fields by avian species for foraging. The authors conclude field borders performed well as 

winter habitat for birds in the Mississippi Alluvial Valley. The 

authors advocate establishment of field borders on production 

farms as a source of foraging, roosting and escape cover. Strip 

cover widths of 30 m (100 ft) or wider are recommended.

Conover, R.R., Burger Jr., L.W., and Linder, E.T., 2009, 

Breeding bird response to field border presence and width: 

Wilson Journal of Ornithology, v. 121, no. 3, p. 548–555.

Avian density, richness, and conservation value are 

assessed between narrow (8.2 m [26 ft]) and wide (47 m [134 

ft]) field borders on intensively row-cropped field margins 

in the Mississippi Alluvial Valley. Field borders were 400 m 

(1,312 ft) in length and planted to a mixture of Indiangrass 

(Sorghastrum nutans), little bluestem (Schizachyrium scoparium), big bluestem (Andropogon gerardii) partridge pea 

(Chamaecrista fasciculate), and Kobe pea (Lespedeza striata). 

Wide field borders supported twice as many birds than 

did narrow borders, which supported six times as many 

birds as non-bordered fields. Seventy-eight bird species were 

observed in field borders during the study. Birds recorded and 

habitat associations are presented. Greater avian densities in 

and adjacent to wide field borders are attributed to increased 

vegetative diversity, lower perimeter to area ratio, and simply 

greater area of potential habitat. The authors believe greater 

emphasis on grassed borders is a more viable answer than 

whole field enrollment to declining grassland bird populations 

in intensively farmed areas as less land is taken out of production. Field borders should be as wide as possible to bring 

greater benefits to grassland birds. 

Conway, W.C., Smith, L.M., and Ray, J.D., 2005, Shorebird 

habitat use and nest-site selection in the playa lake region: 

Journal of Wildlife Management, v. 60, no. 1, p. 174–184.

Playa lakes provide important habitats for wintering 

waterfowl as well as migrant and breeding shorebirds. Wetland 

scale habitat use and nest-site selection for four dominant 

species [American avocet (Recurvirostra americana), blacknecked stilt (Himantopus mexicanus), killdeer (Charadrius 

vociferus), snowy plover (C. alexandrinus)] nesting in playas, 

saline and man-created lakes, and riparian wetlands are 

described. Only avocets and killdeer nested in playas. No nests 

were found in created wetlands. Authors conclude created 

wetlands cannot compensate for loss of playa wetlands and 

urge greater conservation efforts be directed toward conservation of these natural wetlands. Protection of playa hydroperiod 

should be emphasized for breeding shorebird conservation. 

Most playas have cropland-dominated watersheds and have 

lost their natural vegetative communities. Prairies restoration 

around watersheds will decrease sedimentation rates and serve 

to restore playa hydrological cycles, which will benefit avian 

habitat quality and use. 

Coppedge, B.R., Engle, D.M., Masters, R.E., and Gregory, 

M.S., 2001, Avian response to landscape change in fragmented southern Great Plains grasslands: Ecological Applications, v. 11, no. 1, p. 47–59.

Avian community dynamics were investigated within 

fragmented grasslands in Oklahoma. Avian community structure shifted along gradients of increasing woody plant cover 

and levels of landscape fragmentation. The authors conclude 

invasion of woody plant species into grassland ecosystems 

already fragmented by agriculture represents a conservation 

dilemma because woody vegetation in remnant native prairies 

may provide habitat for some declining neotropical migrants 

while suitability is diminished for many endemic grassland 

birds. Native grassland area and landscape pattern, especially size of grassland patches, were negatively affected by 

encroachment of woody vegetation. 

Authors believe although most of CRP in Oklahoma was 

planted to non-native grass monocultures (primarily old-world 

bluestem [Andropogon spp.] and lovegrass [Eragrostis spp.]) 

grassland avian species have benefited. But positive relations 

exhibited by some species were only in areas most affected 

by encroaching woody vegetation with the lowest levels of 

intact native grasslands leading authors to conclude benefits of 

the CRP may be relevant to and dependent upon, the context 

of the surrounding landscape. Authors recommend increased 

focus on grassland management and continuation of agricultural set-aside programs in areas where grasslands have been 

severely altered by woody vegetation and extensively fragmented by agricultural activity.

Coppedge, B.R., Fuhlendorf, S.D., Harrell, W.C., and Engle, 

D.M., 2008, Avian community response to vegetation and 

structural features in grasslands managed with fire and grazing: Biological Conservation, v. 141, p. 1196–1203.

The study reports management of tallgrass prairie in 

north central Oklahoma on avian community response. 

Grasses in the study area are dominated by perennial grasses 

including big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), Indiangrass (Sorghastrum 

nutans), and switchgrass (Panicum virgatum). Portions of 

pasture were burned each year to create a mosaic of grassland patches of varying stages of recovery from disturbance. 

Results indicate that woody edges, ponds, and roads were 

more negative than positive influences on abundance of 

several grassland avian species. The study provides evidence 

of ecological advantages of rotating disturbance patterns in 

tallgrass prairie via patch-burning. Patch burning affected 

the avian community by decreasing abundance of the brownheaded cowbird (Molothrus ater), increased overall species 

richness, enhanced grassland obligate richness, and provided 
Non-Game Birds 87

habitat for the Henslows’s sparrow (Ammodramus henslowii) a 

species of management concern. 

Cunningham, M.A., 2005, A comparison of public lands and 

farmlands for grassland bird conservation: The Professional 

Geographer, v. 57, no. 1, p. 51–65.

An assessment between avian songbird populations is 

made on southern Minnesota CRP fields and public lands to 

address relative effectiveness of public grasslands and private 

land for conserving songbird populations. Bird abundance 

and diversity were greater on CRP lands by providing more 

and better habitat for avian species. The author concludes 

USDA conservation programs and rules for implementation 

will strongly influence success of biodiversity conservation 

in the region. 

Public lands investigated included restored prairies 

within state parks, waterfowl production areas (WPAs), 

wildlife management areas, and scientific and natural areas. 

The average number of birds observed on public lands was 9.8 

pairs per eight hectare transect with a maximum of 22 and a 

minimum of 0. On CRP fields the average number of pairs was 

13/transect with a maximum of 28 and minimum of 0. Species 

richness was also greater on CRP fields than recorded within 

public lands. Public lands were richer in forbs than CRP fields 

but there were fewer birds found on the more forb-rich fields. 

CRP fields were dominated by a mix of brome (Bromus inermis) and alfalfa (Medicago sativa) or clover (Melilotus spp.) 

followed by monocultures of switchgrass (Panicum virgatum). 

Reed canarygrass (Phalaris arundinacea) and spotted knapweed (Centaurea maculosa), widespread invasive species in 

this region, were found more frequently on public lands than 

on CRP lands. Spatial indicators (mean patch size, proximity, 

and availability of core area) were substantially better for CRP 

lands than for public grasslands. 

The author concludes CRP lands supported a greater 

abundance and diversity of birds than did public lands surveyed. While availability of habitat due to CRP is clearly a 

benefit the program’s variable nature, subject to economic and 

political conditions poses difficulties for long-term management of wildlife and their habitats. Variable funding and 

relatively short (10 yr) contract period may make the CRP an 

unreliable source of habitat in the long-term. Conservationists and the public need to be aware of just how little public 

grassland acres exist and how important USDA conservation 

programs are for wildlife. 

Davis, S.K., 2004, Area sensitivity in grassland passerines—

Effects of patch size, patch shape, and vegetation structure 

on bird abundance and occurrence in southern Saskatchewan: The Auk, v. 121, no. 4, p. 1130–1145.

Information related to area sensitivity and consequences 

of habitat fragmentation on avian species has come largely 

from studies completed in forested and tallgrass-prairie 

habitats. Study reports findings of habitat fragmentation on 

abundance and occurrence of nine species of mixed-grass 

prairie passerines. Sprague’s pipit (Anthus spragueii), Baird’s 

sparrow (Ammodramus bairdii), grasshopper sparrow (A. 

savannarum), and chestnut-collared longspur (Calcarius ornatus) were determined to be area sensitive being more abundant 

or occurred more frequently in larger patches of mixed-grass 

prairie. The ratio of edge to interior habitat was a better 

predictor of areas sensitivity than patch size for these species 

in most cases. Horned lark (Eremophila alpestris), Savannah 

sparrow (Passerculus sandwichensis), clay-colored sparrow 

(Spizell pallida), western meadowlark (Sturnella neglecta), 

and brown-headed cowbirds (Molothrus ater) were insensitive 

to patch size.

Vegetation structure was found to be an important predictor of grassland-bird abundance and occurrence, explaining 

additional variation not accounted for by patch size or ratio of 

edge to interior habitat. While protection of large, contiguous 

tracts of habitat is essential to conservation of endemic grassland birds, the author concludes preservation of small patches 

of grassland with minimal edge also is vital for conservation 

of some grassland species. Grassland patches having a higher 

proportion of interior habitat relative to edge habitat are more 

attractive to area-sensitive species. Restoration efforts in 

grassland habitats should focus on increasing patch size and 

minimizing amount of edge but small patches of grassland 

should not be eliminated from consideration. Physiognomic 

features of habitat such as density of live and residual vegetation, vegetation height and shrub density also affect attractiveness of grasslands for avian species. 

Davis, S.K., and Duncan, D.C., 1999, Grassland songbird 

occurrence in native and crested wheatgrass pastures of 

southern Saskatchewan: Studies in Avian Biology, v. 19, 

p. 211–218.

Songbird occurrence compared in native pasture and 

seeded pastures of pure crested wheatgrass (Agropyron cristatum) and crested wheatgrass/legume mix in southern Saskatchewan. Habitat variables associated with songbird occurrence 

differed among species. Authors conclude that vegetative 

structure is more important than is plant species composition 

in habitat selection for grassland birds. Pure stands of crested 

wheatgrass were found to be as attractive to many avian species as were native pastures. Because many species rarely 

inhabit cropland conversion to pure stands of crested wheatgrass can be beneficial to avian species if sufficient cover and 

structural diversity are furnished. Many avian species were 

more attracted to native pasture than stands of crested wheatgrass. Authors recommend preservation of existing native 

grasslands and restoration of grasslands that more closely 

mimic the structural diversity of native prairie community.

Delisle, J.M., and Savidge, J.A., 1997, Avian use and vegetation characteristics of Conservation Reserve Program fields: 

Journal of Wildlife Management, v. 61, no. 2, p. 318–325.
88 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Comparison of avian use of conservation practice CP1 

(cool season grasses and legumes) and CP2 (warm-season, 

native grasses) in southeastern Nebraska. Total bird abundance 

did not differ between CP1 and CP2 fields. In winter and 

breeding season, CP2 fields had taller, denser vegetation than 

recorded in CP1 fields. Bobolinks (Dolichonyx oryzivorus) 

were more abundant in CP1 whereas common yellowthroats 

(Geothylpis poliocephala) and sedge wrens (Cistothorus 

platensis) more abundant in CP2 fields. American tree sparrows (Spizella arborea) and ring-necked pheasants (Phasianus 

colchicus) were the most abundant species recorded during 

winter with the highest numbers were associated with CP2. 

Meadowlarks (Sturnella neglecta) were most abundant in 

CP1. Sedge wrens preferred fields with structurally complex 

vegetation but disappeared after fields had been mowed or 

burned. Yellowthroats were associated with comparatively 

tall vegetation. Grasshopper sparrows (Ammodramus savannarum) disappeared from fields as litter depth increased and 

amount of dead vegetation accumulated. CP2 fields that maintained relatively consistent numbers of grasshopper sparrows 

were mowed 3 out of 4 yr. CP2 was preferred by pheasants for 

winter cover. Native plantings alone can provide habitat for 

all native birds if some fields were managed more intensively 

to simulate historical disturbances resulting from wildfire or 

grazing. CP1 generally furnished the best habitat for species 

which nest directly on ground and prefer low vegetation height 

and minimal depth of litter. CP2 grasslands were used predominantly by avian species that nest higher in vegetation and 

prefer denser growth. 

Donald, P.F., Pisano, G., Rayment, M.D., and Pain, D.J., 2002, 

The common agricultural policy, EU enlargement and the 

conservation of Europe’s farmland birds: Agriculture, Ecosystems and Environment, v. 89, p. 167–182.

Modern agriculture should be regarded as a major 

threat to biodiversity, comparable to global climate change 

and pollution in their potential to affect vast areas. Authors 

estimate one billion hectares in next 50 yr will be converted 

to agriculture in developing countries resulting in doubling, 

or tripling, of chemical eutrophication of aquatic ecosystems 

and pesticide pollution. Data shows that declines in European 

birds have been most significant in EU countries with the most 

intensive agricultural production. Changes in agricultural production contributing to loss of avian numbers and biodiversity 

are attributed to increased use of pesticides, increase in highinput cereal farming, loss of lower-input grassland systems, 

increase in field size; loss of hedgerows and other “nonproductive” land, changes in times of sowing and harvesting, 

increased stocking levels of livestock, replacement of hay with 

silage, and abandonment of farmland. Data to support nonagricultural causes of avian population changes are generally 

weak or lacking. 

Eggebo, S.L., 2001, Ring-necked pheasant and passerine 

abundance in Conservation Reserve Program grasslands 

of differing age-classes and cover types in eastern South 

Dakota, 1998–2000: Brookings, S. Dak., South Dakota 

State University, M.S. thesis, 96 p. 

Old CRP grasslands (10–13 years old) had higher 

crowing count responses than recorded in young CRP fields 

(0–3 years old). Cool-season grasslands (tall or intermediate 

wheatgrass [Agropyron elongatum, A. intermedium], smooth 

bromegrass [Bromus inermis], and legumes) had higher crowing count responses than did warm-season mixes (switchgrass 

[Panicum virgatum], big bluestem [Andropogon gerardii], 

Indiangrass [Sorghastrum nutans]). Non-game bird grassland 

obligates were more abundant in CRP grasslands dominated 

by cool season grasses. Author concludes it takes at least 3 

yr for CRP fields to provide suitable habitat for ring-necked 

pheasants (Phasianus colchicus). As CRP grasslands become 

older, they may lose some feeding qualities (for example, loss 

of legumes) but gain value as nesting habitat due to greater 

quality of cover. Overall, cool-season grassland generally 

furnished greater habitat quality than did grasslands dominated 

by warm-season species. Warm season grasses appeared to 

furnish better winter cover. The author recommends flexibility 

in CRP planting mixes with greater priority given to providing 

a mix of grassland types in administration of the CRP. Legume 

component may be critical component of the cool season mix. 

Evard, J.O., Snobl, D.A., Doeneir, P.B., and Dechant, J.A., 

1991, Nesting of short-eared owls and voles in St. Croix 

County: The Passenger Pigeon, v. 53, no. 3, p. 223–226.

Elevated concentration of meadow voles (Microtus 

pennsylvanicus) in CRP grasslands was attributed to attracting 

and supporting a diversity of predators including short-eared 

owl (Asio flammeus), red fox (Vulpes vulpes), coyote (Canis 

latrans), and rough legged hawks (Buteo lagopus). Two nests 

of short-eared owls were found in CRP grassland. The species 

rarely has nested in Wisconsin. Authors attribute presence of 

these nests to CRP grassland habitat supporting high density 

of prey species. 

Fletcher Jr., R.J., and Koford, R.R., 2002, Habitat and landscape associations of breeding birds in native and restored 

grasslands: Journal of Wildlife Management, v. 66, no. 4, 

p. 1011–1022.

Evaluation of avian density and species richness in Iowa 

grasslands indicates restored grassland habitats contain bird 

communities generally similar to those in native prairie habitats. Therefore, restored grasslands may furnish similar habitat 

suitability for most grassland birds found in native grasslands. Although diversity of plants was much higher in native 
Non-Game Birds 89

prairies, habitat structure was similar for many habitat variables. Primary exception was percent total cover and percent 

bare ground; both lower in restored grasslands. Restoration 

of grasslands in agricultural landscapes can provide suitable 

habitat for breeding grassland birds even if restoration does 

not mirror composition of native prairie. Habitat structure is 

important predictor of bird density in grasslands; consideration 

of landscape structure provides additional resolution. The 

amount of grassland in a landscape and its shape and structure 

should be important considerations in land acquisition, restoration, and management.

Fletcher Jr., R.J., and Koford, R.R., 2003, Changes in breeding 

bird populations with habitat restoration in northern Iowa: 

American Midland Naturalist, v. 150, no. 1, p. 83–93.

Although habitat restorations of grasslands and wetlands 

inevitably provide breeding habitat for declining avian species 

estimating how restoration efforts have enhanced populations 

and communities in fragmented landscapes is not easy or 

straightforward. Authors estimate many species of management concern have increased in response to restoration of 

habitat, but analysis of spatial processes could be important 

in determining habitat quality for avian species in agriculturally dominated landscapes. Temporal dynamics in avian 

populations can affect estimates of population change because 

populations can change among years. Some populations may 

exhibit changes at regional scales. Changes in restoration 

that restore grasslands from hayland and pasture will likely 

produce less change in avian populations than restoring lands 

in row crop agriculture. However, restoration of hayland and 

pasture will remain valuable because both grazing and mowing can have negative effects on avian populations. 

Fletcher Jr., R.J., Koford, R.R., and Seaman, D.A., 2006, Critical demographic parameters for declining songbirds breeding in restored grasslands: Journal of Wildlife Management, 

v. 70, no. 1, p. 145–157.

Planting and restoration under state and federal conservation programs are investigated to understand consequences on 

grassland bird (dickcissel [Spiza Americana], bobolink [Dolichonyx oryzivorus]) populations in northern Iowa. The study 

area was restored from row crop production using warmseason grasses (27.5 percent) and cool-season grasses (72.5 

percent). Warm-season grasses were typically switchgrass 

(Panicum virgatum) or big bluestem (Andropogon gerardii). 

Cool-season plantings were dominated by smooth brome 

(Bromus inermis). 

No evidence is found for planting type influencing rates 

of nest predation. The authors conclude management focused 

on increasing adult survival or decreasing nest predation could 

produce stable populations of these species. Data suggests 

grasslands in this Iowa study were likely sink habitats for 

dickcissels where populations were unsustainable without 

immigration. Bobolink population growth would occur only 

if annual survival is high. It is recommended conservation 

strategies should concentrate on lessening detrimental effects 

of nest predation. Larger size of fields and greater amount of 

grassland habitat in the landscape is recommended. 

Frawley, B.J., 1989, The dynamics of nongame bird breeding ecology in Iowa alfalfa fields: Ames, Iowa, Iowa State 

University, M.S. thesis, 94 p.

Eight bird species (dickcissel [Spiza americana], red 

winged blackbird [Agelaius phoeniceus], western meadowlark 

[Sturnella magna], common yellowthroat [Geothlypis trichas], 

sedge wren [Cistothorus platensis], grasshopper sparrow 

[Ammodramus savannarum], mourning doves [Zenaida macroura] and vesper sparrow [Pooecetes gramineus]) established 

territories in alfalfa fields before mowing. Mowing reduced 

avian numbers and densities. Only dickcissels, grasshopper sparrows, western meadowlarks, and vesper sparrows 

attempted to nest in second growth alfalfa fields subsequent to 

mowing. Common yellowthroats selected the tallest, densest 

vegetation with relatively high coverage of grass. Grasshopper sparrows used areas of comparatively sparse vegetation. 

Western meadowlark abundance seemed unrelated to changes 

in vegetation.

The needs of ground nesting birds are difficult to integrate with forage management practices. Highest forage 

yields are obtained by harvesting alfalfa in early June in Iowa. 

Alfalfa is typically harvested two more times at 51⁄2-week 

intervals. Forage production on private lands will continue to 

intensify with greater production, new cultivars, and earlier 

mowing. New species of cultivars have permitted earlier 

mowing while still maintaining high yields. CRP provides 

some compensation for losses of habitat in alfalfa. However, 

mowing of CRP in nesting season negates potential benefits 

of CRP.

Freemark, K.E., Probst, J.R., Dunning, J.B., and Heji, S.J., 

1993, Adding a landscape ecology perspective to conservation and management planning, in Finch, D.M., and Stangle, 

P.W., eds., Status and management of neotropical migratory 

birds: Fort Collins, Colo., USDA Forest Service General 

Technical Report RM-229, p. 346–352.

Populations within individual habitat patches can decline, 

become extinct, and become reestablished by dispersal of individuals from other patches. The set of local populations, which 

interact through dispersal, is a meta-population. Within a landscape the probability of local extinction within a habitat patch 

is inversely related to size of the patch population, which is 

proportional to the size and habitat quality within the patch. 

Probability of re-colonization is proportional to proximity 

and connectedness to similar habitat patches and permeability 
90 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

of the intervening matrix of land cover and use. Effective 

conservation of neotropical migrant land birds may require 

preservation of suitable but intermittently unoccupied, habitat. 

Management plans should protect the diversity of habitats and 

landscapes used, not just where the species is most common. 

Fritcher, S.C., Rumble, M.A., and Flake, L.D., 2004, Grassland bird densities in seral stages of mixed grass prairie: 

Journal of Range Management, v. 57, no. 4, p. 351–357.

Authors believe seral stages of grassland may have 

effects on declining bird populations in grassland ecosystems but resource managers lack sufficient information to 

assess how avian species are affected by changes in grassland composition. Report evaluates bird density, species 

diversity and species richness in 4 seral stages of western 

wheatgrass (Pascopyrum smithii), and green needlegrass 

(Nasella viridula) associations in central South Dakota. Species richness did not differ between seral stages but diversity 

was greater in early seral stages of grassland composition. 

Birds with habitat requirements of tall vegetation and residual 

cover were more abundant in later seral stages (for example, 

grasshopper sparrow [Ammodramus savannarum], bobolink 

[Dolichonyx oryzivorus]). Early seral stages were more beneficial to species needing short grass and sparse vegetative cover 

(for example, chestnut-collard longspur [Calcarius ornatus], 

horned lark [Eremophila alpestris]). Authors recommend 

management prescriptions furnishing a mosaic of seral stages 

to maximize grassland bird species diversity and abundance 

across the landscape. Authors conclude seral stage was an 

effective predictor of density for many grassland birds and 

assessment of seral stage can furnish a framework for development of management plans and prediction of effects of 

management decisions.

Gard. N.W., Hooper, M.J., and Bennett, R.S., 1993, Effects of 

pesticides and contaminants on neotropical birds, in Finch, 

D.M., and Stangle, P.W., eds., Status and management of 

neotropical migratory birds: Fort Collins, Colo., USDA Forest Service General Technical Report RM-229, p. 13–413. 

The report provides a summary of potential effects of 

chemicals on migratory birds. More is unknown than known 

and problems or effects of chemical applications and pollution remain difficult to assess. Standardization of monitoring 

programs and selection of specific avian species as indicators 

is recommended. 

Gill, D.E., Blank, P., Parks, J., Guerard, J.B., Lohr, B., 

Schwartzman, E., Gruber, J.G., Dodge, G., Rewa, C.A., and 

Sears, H.F., 2006, Plans and breeding bird response on managed Conservation Reserve Program grassland in Maryland: 

Wildlife Society Bulletin, v. 34, no. 4, p. 944–956.

A report on the first 6 years of studies in experimental 

CRP grasslands designed to evaluate how mixes affect local 

population of grassland obligate birds, appraise avian species response to vegetation management, and define desirable grassland management prescriptions. The investigation 

is based on evaluation of 92.4 hectares (232 ac) of CRP 

grassland in northeastern Maryland. CRP fields were planted 

to native grasses (CP2) in 1998. Designed as a replicable 

experiment, the ultimate management goal of these fields was 

reestablishment of grasslands similar to those dominant on 

the Atlantic seaboard pre-agriculture. Fields were planted to 8 

native warm-season, and 2 cool-season grasses. Within several 

fields prairie flower seeds were added to the planting mix.

Study results demonstrate eastern native grasslands can 

be “reassembled” on heavily degraded lands within a time 

frame of 2 to 4 yr. Reassembled was, increasing species 

diversity in a managed habitat so the area becomes capable 

of supporting sustainable populations of plant and animal 

species. In six years of management (for example, mowing, 

burning) cumulative plant species richness increased. Several at risk bird species (for example, grasshopper sparrow 

[Ammodramus savannarum], dickcissel [Spiza americana]) 

colonized the restored grassland and established sustainable 

breeding populations. Large blocks of habitat were fundamental to the positive response by grassland obligate species 

in contrast to narrow linear grass-buffer strips (that is, CP21) 

which attracted very few grassland specialist bird species. 

Prescribed burning is identified as the least expensive management tool for maintaining grasslands. Switchgrass (Panicum 

spp.) was found to be too aggressive in this region and no 

longer recommended for native grassland seeding mixtures. 

Management of restored grasslands should include spatial and 

temporal rotation of prescribed fire and herbicide applications 

to sustain desirable vegetative physical structure rather than 

species composition.

The authors conclude mowing, during establishment, 

prescribed burning on a 3-yr rotation, and application of 

herbicides for noxious weed control established and maintained a species rich grassland habitat valuable to grasslandobligate species. Results of this study demonstrate many of 

the management prescriptions recommended by USDA and 

others work. Conservation effort of CRP and CREP are valid 

approaches to benefit multiple conservation objectives.

Granfors, D.A., 1992, The impact of the Conservation Reserve 

Program on eastern meadowlark production and validation 

of the eastern meadowlark habitat suitability index model: 

Lubbock, Tex., Texas Technical University, M.S. thesis, 

98 p.

Eastern meadowlark (Sturnella magna) productivity was 

compared between CRP land and rangelands in Lyon county 

Kansas. Nests in CRP fields had lower parasitism by brownheaded cowbirds (Molothrus ater), larger clutch sizes, and 
Non-Game Birds 91

higher hatch rates than nests in pastures. Cowbird parasitism 

appeared to be a major cause of lowered productivity of meadowlark nests. Eastern meadowlarks selected for less dense 

litter and more homogenous vegetation structure in both land 

use types. Nests in CRP fields had higher proportion of grass 

than available in random sites. Residual cover was greater near 

nests in CRP fields. 

Relationships between HSI values and eastern meadowlark densities were poor due primarily to high densities of 

meadowlarks in fields with high coverage of forbs. Relationship improved when HSI values and densities were averaged 

over three years of the study. There appeared to be no discernible relationship between western meadowlark (S. neglecta) 

densities and the output of the eastern meadowlark HSI model. 

Granfors, D.A., Church, K.E., Smith, L.M., 1996, Eastern meadowlark nesting in rangelands and Conservation 

Reserve Program fields in Kansas: Journal of Field Ornithology, v. 67, no. 2, p. 222–235.

Comparison of microhabitat, nest-site selection, and nest 

success on Kansas rangelands and CRP is described. Daily 

nest survival rates and numbers fledged per female did not 

differ significantly between land use types. Mowing CRP 

fields was source of nest failure and induced adults to abandon 

some fields. CRP had significantly higher values for depth and 

density of litter cover, taller herbaceous canopy, less herbaceous cover and more standing dead cover than recorded in 

rangelands. CRP has increased diversity of available nesting 

habitats. Eastern meadowlarks (Sturnella magna) selected 

sites with greater litter cover, higher proportion of grass, more 

uncompacted litter, and greater structural homogeneity than on 

recorded in random plots. Delay of mowing and burning was 

recommended to enhance and maintain habitat suitability in 

CRP fields.

Mowing caused undesirable buildup of litter and, depending on time of year, may cause abandonment of fields and 

direct failure of nests. Authors recommended partial mowing 

of fields over complete mowing. Spot mowing after July 15 

was recommended as best management option. Disadvantage 

of grazing is increased probability of trampling and attracting brown-headed cowbirds (Molothrus ater). Prescribed 

burning can reduce litter and increase proportion and vigor 

of native grasses while decreasing percentage of cool-season 

grasses and forbs. Recommend spring burning every 3–4 yr. 

Prescribed burning may cause temporary early-season loss 

in habitat quality, but resultant increased cover of grass and 

reduction of litter should enhance habitat quality later in growing season and subsequent years. 

Grant, T.A., Madden, E., and Berkey, G.B., 2004, Tree and 

shrub invasion in northern mixed-grass prairie—Implications for breeding grassland birds: Wildlife Society Bulletin, 

v. 32, no. 3, p. 807–818.

Study reports results of investigation of invasion by 

woody plants aspen (Populus tremuloides), willow (Salix

spp.) and others on avian grassland bird species in northcentral North Dakota. Grassland study area dominated by 

needlegrass-wheatgrass (Stipa-Agropyron) intermixed with 

smooth brome (Bromus inermis) and Kentucky bluegrass 

(Poa pratensis). Probability of occurrence of 11 of 15 species decreased as percent woodland, tall shrub, or brush cover 

increased. Grasslands became largely unsuitable for 9 species 

of grassland birds as woody cover exceeded 25 percent. Only 

vesper sparrow (Pooecetes gramineus), clay-colored sparrow (Spizella pallida), and common yellowthroat (Geothlypis 

trichas) occurred more frequently as woody cover increased. 

Savannah sparrow (Passerculus sandwichensis), bobolink 

(Dolichonyx oryzivorus) and grasshopper sparrow (Ammodramus savannarum) reached maximum probability of occurrence 

in open treeless grasslands with probability of occurrence 

declining to 50 percent when woody cover ranged from 10–25 

percent. Number of species negatively affected by woody 

cover increased as vertical structure changed to tall shrub and 

aspen woodland.

Authors judge even nominal increases in woody vegetation compromise use of grasslands by several avian species. 

Occurrence of most woodland-sensitive species declined 

rapidly as woodland cover increased to only 5–20 percent. 

Recommend restoration efforts on grasslands be focused 

where woody cover is less than 20 percent for management to 

have most beneficial effects. Authors urge discontinuance of 

programs that encourage introduction of native and non-native 

trees and shrubs into northern Great Plains grasslands.

Graul, W.D., 1980, Grassland management practices and 

bird communities, in Management of western forests and 

grasslands for nongame birds: Ogden, Utah, USDA Forest 

Service General Technical Report INT-86, p. 38–47.

Grasslands contain relatively few bird species. However, 

within grasslands occur mosaics with different avian species 

restricted to subtypes. Consequently, a general habitat category 

of grassland can contain considerably more avian species than 

may be implied by categorization as a single type. Grassland 

bird communities tend to be numerically dominated by one 

or two abundant, widespread species. Grassland types may 

contain avian species with extremely restricted habitat needs. 

A viable approach to grassland management is to consider the 

habitat requirements of avian species with most restrictive 

needs and maintain enough suitable habitat to support substantial numbers of the species. This management strategy is based 

on assumption species with broader habitat requirements will 

find suitable habitat.

Helmers, D.L., 1992, Shorebird management manual: 

Manomet, Mass., Western Hemisphere Shorebird Reserve 

Network, 58 p.
92 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Disappearance or degradation of migratory stopover 

habitats (many of which are associated with agricultural 

ecosystems) may be detrimental to entire populations of 

shorebirds. Physically and chemically altered wetlands have 

resulted from drainage, impoundment, or alteration of watersheds and water regimes. Associated uplands used by nesting 

shorebirds are dominated by short, sparse vegetation. Twelve 

shorebird species breed within the Great Plains geographic 

region. Nest sites are often on bare sand or gravel substrates 

associated with fresh, alkaline, or saline wetlands. A mosaic of 

wetland types from ephemeral to semi-permanent interspersed 

with short to moderate height grasslands provide reproductive 

and brood rearing habitat for many of shorebirds utilizing the 

Great Plains. 

Henningsen, J.C., and Best, L.B., 2005, Grassland bird use of 

riparian filter strips in southeast Iowa: Journal of Wildlife 

Management, v. 69, no. 1, p. 198–210.

Report documents results of investigation of breeding 

grassland bird use of 33, 3–4-yr-old CRP filter strips. Relative 

abundances of birds and nests were similar between coolseason and warm-season grass plantings. The most abundant 

avian species recorded were red-winged blackbird (Agelaius 

phoeniceus), dickcissel (Spiza americana), song sparrow 

(Melospiza melodia), and common yellowthroat (Geothlypis 

trichas). Nest success was generally low in all treatments 

evaluated with predation being the major cause of nest failure. 

Several differences between vegetation characteristics in 

filter strips planted to cool-season (mixtures of brome [Bromus inermis], orchardgrass [Dactylis glomerata], and timothy 

[Phleum pratense]) and warm-season (switchgrass [Panicum 

virgatum]) were recorded. Generally, warm season planting 

had more vertically dense live vegetation, taller residual vegetation and greater plant species richness (forbs). Grass cover 

was greater on cool-season filter strips. Cool season grass and 

legume plantings are more horizontally dense and more resistant to encroachment from weedy plants. Proximity to woody 

vegetation influenced bird species richness, abundance, and 

nest abundance. Species richness was higher in non-wooded 

sites as grassland bird species tend to be less abundant, or less 

likely, to nest near wooded edges. Nest success estimates were 

generally low in all treatments (planting mixture, edge type) 

and were lower than nest success reported for block-shaped 

CRP fields in Iowa. Authors conclude presence of woody 

vegetation adjacent to filter strips has negative effects on use 

by grassland birds but if enhancement of the overall avian 

community is a goal establishment of filter strips adjacent to 

wooded riparian corridors is a reasonable management option. 

Greater filter strip width potentially can increase use by birds 

infrequently recorded in existing filter strips. 

Herkert, J.R., 1994, The effects of habitat fragmentation on 

midwestern grassland bird communities: Ecological Applications, v. 4, no. 3, p. 461–471. 

Breeding bird species richness patterns significantly 

increase with habitat fragment size. Eight of 15 bird species 

had distributions among fragments influenced by habitat area. 

Estimates of minimal area requirements for five area sensitive avian species range from 5 to 55 hectares (12.5 to 136 

ac). Absence of area sensitive grassland bird species from 

small fragments may be a consequence of limited availability 

of habitat. Both area and vegetation structure significantly 

influence midwestern grassland bird populations. All five area 

sensitive species monitored in this study regularly avoided 

structurally suitable habitat on small grassland fragments. 

Habitat fragmentation is likely to have caused midwestern 

grassland bird declines especially for area-sensitive species. 

Management directed toward minimizing breeding season 

disturbances, controlling features attracting nest predators, 

reduction in amount of woody encroachment into grasslands, 

and attention to needs of area sensitive species would be major 

benefits to midwestern grassland birds. Local or regional 

extinctions are likely if loss and fragmentation of midwestern 

grassland habitat continues.

Large scale, diverse grassland management is needed to 

meet habitat needs of migratory grassland bird species of the 

greatest conservation concern in Midwest region. Habitats of 

highest management concern will vary regionally. Management should focus on providing habitat for large populations 

of area-sensitive species to increase the likelihood of longterm persistence of populations. An excellent discussion on 

effects of grazing and burning is presented. However, results 

can be highly variable depending on extent of management, 

season as well as species of management concern. Mosaic of 

burned and unburned, mowed, un-mowed grasslands provide 

full range of habitat preferences. There still are insufficient 

data regarding individual species and how they respond 

to differing management practices under varying conditions. Information on short-term responses is common but 

there is little available information on long-term effects of 

habitat management. 

Herkert, J.R., 1994, Breeding bird communities of midwestern 

prairie fragments—The effects of prescribed burning and 

habitat area: Natural Areas Journal, v. 14, p. 128–135.

Study competed in Illinois comparing relative importance of habitat area and effects prescribed burning showed 

habitat area had greater influence on breeding bird community 

composition than prescribed burning. Large prairie fragments 

must be managed to provide a mosaic of burned and unburned 

areas to ensure availability of suitable habitat for species 

experiencing significant population declines and predominately restricted to large grassland areas. Benefits of burning 

include increase in aboveground plant biomass, which may 

provide greater concealment for nests thereby decreasing rate 

of nest predation. Higher densities of insects also present in 

burned prairies as compared to unburned sites. Management of 

large fragments of prairie is more complex than that of smaller 
Non-Game Birds 93

fragments due to presence of sensitive avian species. The 

habitat requirements of these species can be addressed by providing a mosaic of habitat types. General guidelines: conduct 

prescribed burns on large prairie fragments (greater than 80 

hectares [198 ac]) on rotation of 20–30 percent of area annually. On small fragments larger percentage may be burned but 

probably should not exceed 50–60 percent of area, especially 

if sensitive species are present. 

Herkert, J.R., 1997, Population trends of the Henslow’s sparrow in relation to the Conservation Reserve Program in 

Illinois, 1975–1995: Journal of Field Ornithology, v. 68. 

no. 2, p. 235–234.

Spring bird count data suggests 78 percent population 

decline for the Henslow’s sparrow (Ammodramus bairdii) in 

Illinois between 1975 and 1995. Analysis indicates grasslands 

established under CRP have been beneficial to the species. 

Population trends in counties with high enrollment in CRP 

were greater than trends in counties with little land enrolled 

in the program. Although the CRP has been beneficial, the 

positive change in populations of Henslow’s sparrows has 

been insufficient to offset long-term, larger scale declines due 

to other factors, particularly loss of suitable habitat. Periodic 

management of CRP grasslands may be needed to maintain 

habitat quality for the species by reducing encroachment of 

woody vegetation into grasslands. 

Herkert, J.R., 2007, Evidence for a recent Henslow’s sparrow 

population increase in Illinois: Journal of Wildlife Management, v. 71, no. 4, p. 1229–1233.

Due to long-term declines in populations the Henslow’s 

sparrow (Ammodramus henslowii) is of high management 

concern. Historical loss of habitat has been the underlying 

reason for the decline in numbers and distribution of the 

species. Using Illinois Spring Bird Count data, the author 

investigates relations between establishment of the CRP and 

population trends for the species. The CRP appears to have 

played a fundamental role in averting federal listing of the 

Henslow’s sparrow in the United States. Data analysis shows 

populations of Henslow’s sparrows in Illinois have increased 

substantially over the last 10 years. This increase is attributed 

to establishment of more than 400,000 hectares (988,440 ac) 

of CRP grasslands within the state. Growing populations of 

the bird in other states (Iowa, North Dakota, South Dakota, 

Minnesota, Michigan, Missouri, and Indiana) also are attributed to increased distribution and quality of habitat brought by 

the CRP. Since haying and grazing diminish habitat quality, 

new USDA rules for allowing managed use of these fields may 

have detrimental effects on the species. Monitoring the effects 

of haying and grazing, especially on three year rotations, 

should be completed to assess impacts to Henslow’s sparrow 

which generally do best within undisturbed grasslands.

Herkert, J.R., 2007, Conservation Reserve Program benefits 

on Henslow’s sparrows within the United States: Journal of 

Wildlife Management, v. 71, no. 8, p. 2749–2751.

The Henslow’s sparrow (Ammodramus henslowii) is one 

of America’s fastest declining grassland songbirds. Establishment of the CRP has been associated with enhancement of 

habitat distribution and quality for this species. Breeding Bird 

Survey data are used to evaluate the impact CRP has had on 

the Henslow’s sparrow throughout their breeding range. Data 

from 170 BBS routes in Illinois, Indiana, Iowa, Kansas, Kentucky, Maryland, Michigan, Minnesota, Missouri, New York, 

Ohio, Oklahoma, Pennsylvania, Virginia, West Virginia, and 

Wisconsin are used in the analysis. CRP data (total percentage land area in CRP) were at the county-level for the 2002 

Census of Agriculture. The author finds Henslow’s sparrow 

populations are influenced by the CRP with greatest increases 

in populations found in areas of high local enrollment in the 

program. This trend was evident throughout the breeding 

range. Prior to CRP populations of this species were declining at a rate of 6.5 percent/yr. Subsequent to establishment 

of CRP grasslands the species is believed to be increasing by 

2.9 percent/yr. Population enhancements experienced by the 

Henslow’s sparrow are at risk due to effects of high commodity prices and expiration of a large number of CRP contracts 

in upcoming years. If many of these lands return to production 

habitat and population gains experienced by this species will 

diminish. The effects of loss in CRP habitats on Henslow’s 

sparrows should be monitored.

Herkert, J.R., 2009, Response of bird populations to farmland 

set-aside programs: Conservation Biology, v. 23, no. 4, 

p. 1036–1040.

The author states the role of agriculturally dominated 

landscapes in biodiversity conservation has been largely 

ignored. U.S. Department of Agriculture set-aside programs 

may offer the most promising conservation opportunities due 

to the large area devoted to these programs. (Note: only lands 

included in the CRP are included in this evaluation. Effects of 

other USDA/State set-aside programs are not addressed). The 

author provides an analysis of set-aside area and changes in 

avian populations following establishment of these programs. 

The assessment is focused on 12 north-central states (Illinois, 

Indiana, Iowa, Kansas, Michigan, North and South Dakota, 

Minnesota, Missouri, Nebraska, Ohio and Wisconsin). Within 

these states is found 62 percent of the total cropland in the 

United States and 6.7 million hectares (16.5 million ac) of land 

enrolled in the CRP (48 percent of total CRP area). The author 

used 21 years of BBS population trend data collected after 

establishment of the CRP to evaluate whether the program 

had influenced population trends of breeding birds within the 

north-central United States.

Results show an association between set-aside (that 

is, CRP) on local abundance and change in regional avian 
94 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

population trends following broad scale implementation of 

the CRP. Avian species whose abundance was most strongly 

influenced by CRP also tended to exhibit regional improvements in populations. Several grassland-obligate birds, whose 

populations were in long-term decline prior to the CRP, have 

had positive population response to the program. Grassland 

species with the greatest positive changes in population trends 

(bobolink [Dolichonyx oryzivorus], dickcissel [Spiza americana]) were also the most common grassland species in CRP 

fields within the region. The author provides a summary of 

population trends for 30 avian species prior to (1966–1986) 

and following initiation of the CRP (1987–2007). The author 

notes avian use of set-aside grasslands vary as vegetation 

structure and composition change through time consequently 

the influence of changes in habitat composition and response 

of bird populations deserves greater research attention. The 

author states there is increasing evidence CRP lands have provided population-level benefits for grassland birds. However, 

there is growing concern over the stability of lands devoted 

to the conservation program. Rising commodity prices may 

influence farm operators to return lands enrolled in the CRP 

to production. The author concludes new policy options may 

be needed to maintain the population profits to grassland birds 

brought by the CRP as acreage in the program declines.

Herkert, J.R., Sample, D.W., and Warner, R.E., 1996, Management of midwestern grassland landscapes for the conservation of migratory birds, in F.R. Thompson, III, ed., Management of midwestern landscapes for the conservation of 

neotropical migratory birds: St. Paul, Minn, USDA Forest 

Service General Technical Report NC-187, p. 89–116.

Avian species of high priority for conservation were 

associated with a variety of grassland habitats including dry 

prairies, pastures, old fields, hayfields, wet prairies, sedge 

meadows, and grasslands with interspersed shrubs. Diverse 

habitat associations of bird species with high management 

concern suggest problems facing grassland birds are widespread and involve variety of grassland habitats. One common 

feature was sensitivity to habitat fragmentation. Declines in 

grassland bird numbers significantly correlate with declines 

in regional acreage of pastures and hay fields. Grassland nest 

success highest 2–3 yr following prescribed fire. Mid-length 

(3–5) year rotational burn program appears to be optimum 

under most circumstances. A greater understanding of winter 

ecology and habitat requirements of grassland bird species is 

needed. Relatively few avian species use fields with monotypic grass cover. Pastures are most abundant grassland habitat 

in the Midwest accounting for 7.8 million hectares (19 or more 

million ac) (5.7 percent of land area). Pastures can furnish 

valuable habitat because, when not over-grazed they can support diverse assemblages of grassland bird species including 

those with declining populations. Area of pasture/hayfield 

reached peak in Midwest in early 1900s but have declined 

since then due to lower presence of farm animals and greater 

dependence upon confine feeding operations.

Hickman, K.R., Farley, G.H., Channell, R., and Steier, J.E., 

2006, Effects of old world bluestem (Bothriochloa ischaemum) on food availability and avian community composition within the mixed-grass prairie: The Southwestern 

Naturalist, v. 51, no. 4, p. 524–530.

An investigation of relations between grassland vegetation structure and species composition in Old-world bluestem, 

native prairie, and CRP pasture to avian community species 

richness and species abundance is reported. The study was 

completed in southwestern Kansas. CRP pastures included 

in the study had expired from enrollment in the program and 

were grazed during the evaluation. Dominant grasses in the 

CRP pastures were sand bluestem (Andropogon hallii), little 

bluestem (Schizachyrium scoparium), Indiangrass (Sorghastrum nutans), switchgrass (Panicum virgatum), sideoats grama 

(Bouteloua curtipendula), and sand lovegrass (Eragrostis 

trichodes). Native pastures had never been under crop 

production with most common grasses being big bluestem 

(Andropogon gerardii), sideoats grama, Indiangrass, and little 

bluestem. Old-world bluestem pastures were monocultures 

planted to two cultivars of the species.

Study findings show abundance of individual bird species richness was significantly lower in old world bluestem 

than both native and CRP pastures. Fewer bird species were 

also recorded in the old world bluestem fields than within 

native fields. No difference in numbers of birds observed 

was recorded between CRP and old world bluestem pastures. 

Grasshopper sparrows (Ammodramus savannarum), dickcissels (Spiza americana), western meadowlarks (Sturnella 

neglecta), eastern meadowlarks (S. magna), and lark sparrows 

(Chondestes grammacus) were the most abundant species 

across all pastures. 

Forb cover was found to be significantly greater in native 

rangelands compared to CRP and old world bluestem fields. 

The old world bluestem pastures had significantly shorter 

vegetation than recorded in other field types. CRP was found 

to have greater litter depth than recorded in old-world monocultures and native pastures. The authors conclude shorter 

vegetation heights and litter depths in old world pastures may 

not have provided sufficient vegetation structural diversity 

for some grassland birds to find suitable for use. Analysis of 

arthropod biomass indicated old world bluestem and CRP 

pastures lacked some attributes necessary to produce an abundance of arthropods. Shorter vegetative cover and low mean 

forb cover in old world bluestem supported lower arthropod 

biomass. In contrast, CRP pastures showed a positive relationship between amount of forbs present and arthropod biomass. 

Insect biomass increased with increasing abundance of forbs. 

Significantly less avian food, as defined by arthropod biomass, 

was found in old world bluestem fields than in native pastures. The authors consider the large area planted to old world 

bluestem monocultures in the southern Great Plains may be 

contributing to declining abundance of grassland birds.
Non-Game Birds 95

Horn, D.J., and Koford, R.R., 2000, Relation of grassland bird 

abundance to mowing of Conservation Reserve Program 

fields in North Dakota: Wildlife Society Bulletin, v. 28, 

no. 3, p. 653–659.

Evaluation of haying of CRP fields in central North 

Dakota. Study compared relative abundance of birds in idled 

and mowed portions of fields one year after mowing. Results 

are consistent with other evaluations which show bird species 

responding to differing characteristics of fields as defined by 

height and structure of vegetation. Some species were more 

abundant in idled portions of fields while others were more 

abundant in hayed portion of field. By late spring of the year 

following mowing portions of fields hayed had vegetation of 

equivalent height of non-mowed portions of fields. Authors 

recommend partial mowing of CRP fields to provide a mosaic 

of grassland habitats with different physical characteristics to 

meet needs of diverse populations of avian species.

Howard, M.N., Skagen, S.K., and Kennedy, P.L., 2001, Does 

habitat fragmentation influence nest predation in the shortgrass prairie?: The Condor, v. 103, p. 530–536.

Effects of habitat fragmentation and vegetation structure of shortgrass prairie and CRP land on predation rates on 

natural and artificial nests were investigated in northeastern 

Colorado. Vegetation seeded under CRP is taller than native 

shortgrass prairie species. Patch size, degree of fragmentation, 

and distance of nest from edge had no influence on mortality rates of artificial or natural nests. Vegetation structure did 

influence predation of artificial nests with predation decreasing with increasing height of vegetation, however, vegetation 

structure did not influence predation rates on natural nests. 

Mortality rates of artificial nests on CRP lands and shortgrass 

sites did not differ. Authors conclude habitat structure is a 

more important determinant of nest predation than is influence 

of landscape. Habitat fragmentation in study area did not result 

in increased predation in remaining patches of shortgrass 

prairie habitat. 

Hughes, J.P., Robel, R.J., Kemp, K.E., Zimmerman, J.L., 

1999, Effects of habitat on dickcissel abundance and nest 

success in Conservation Reserve Program fields in Kansas: 

Journal of Wildlife Management, v. 63, no. 2, p. 523–529.

CRP fields studied were dominated by Indiangrass 

(Sorghastrum nutans), big bluestem (Andropogon gerardii), 

little bluestem (Schizachyrium scoparium), sideoats grama 

(Bouteloua curtipendula), switchgrass (Panicum virgatum), 

and western wheatgrass (Agropyron smithii). These grasses 

comprised over 95 percent of all vegetation recorded in study 

fields. Dickcissel (Spiza americana) abundance was significantly associated with field-level vegetation characteristics, 

field edge characteristics, and land use surrounding CRP 

fields. Nest success was associated with field-level vegetation 

variables only, specifically vegetation volume. The species 

responded positively to increased litter cover but negatively to 

live and grass canopy covers. Forbs have been recognized as 

preferred nesting substrates for dickcissels. Forbs were relatively uncommon in CRP fields evaluated. Efforts to enhance 

dickcissel habitat should focus on modification of vegetation 

structure within fields by encouraging presence and abundance 

of forbs. 

Hughes, J.P., Robel, R.J., and Kemp, K.E., 2000, Factors influencing mourning dove nest success in CRP fields: Journal of 

Wildlife Management, v. 64, no. 4, p. 1004–1008.

An evaluation of mourning dove (Zenaida macroura) 

nesting success in northeastern Kansas CRP fields. Daily 

nest survival rates were associated positively with height of 

live vegetation and negatively with percent grass cover and 

percent live vegetation cover. Management practices producing sparse but tall vegetation may increase success of mourning dove nests in CRP fields. Evaluated fields were planted to 

CP2 native warm season grasses (Indiangrass [Sorghastrum 

nutans], big bluestem [Andropogon gerardii], little bluestem [Schizachyrium scoparium], sideoats grama [Bouteloua 

curtipendula], switchgrass [Panicum virgatum], and western 

wheatgrass [Agropyron smithii]). Dove nests were found in 7 

of 9 fields evaluated in 1994 and 8 of 9 fields in 1995. Nest 

success did not differ between years. Apparent nest success 

was 55.6 percent in both years, representing a superior success rate reported in other studies. Daily nest survival rates 

were influenced by field-level vegetation structure, but not 

field-edge characteristics or surrounding land-use variables. 

Doves appeared to have higher success in fields with tall, live 

vegetation and low amounts of grass and live vegetation cover. 

Authors recommend intermediate level of disturbance providing low amounts of live vegetation and grass cover but high 

height of vegetation. Recommend spring burning every 3 yr.

Hultquist, J.M., and Best, L.B., 2001, Bird use of terraces in 

Iowa rowcrop fields: American Midland Naturalist, v. 145, 

no.2, p. 275–287.

Bird abundance in terraces was less than recorded in 

other strip cover habitats such as grassed waterways and roadsides but greater than recorded in row crops. Authors conclude 

the relative contribution of terraces to grassland bird conservation is minor and changes in current management practices of 

terraces would not likely improve conditions for birds nor be 

economically acceptable. Dominant cover on terraces evaluated was smooth bromegrass (Bromus inermis), the species 

one recommended by NRCS for establishment on terraces. 

Bird species richness and abundance may be lower in terraces 

because terraces are narrower than other strip-cover habitats 

and vegetation is less diverse. Bird densities in terraces were 

higher than recorded in CRP because of greater concentration 

of birds in narrow strip covers than in block-cover CRP.
96 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Igl, L.D., and Johnson, D.H., 1995, Dramatic increase of Le 

Conte’s sparrow in Conservation Reserve Program fields in 

the Northern Great Plains: Prairie Naturalist, v. 27, no. 2, 

p. 89–94.

Substantial increase in Le Conte’s sparrow (Ammodramus leconteii) numbers in CRP recorded in 1994 compared 

to 1990–1993. Changes in habitat associated with drought 

from1989–1993 and above normal precipitation from mid1993 to mid-1994 likely produced favorable breeding conditions for this species in CRP fields. CRP may provide important habitat only under wet conditions. Influence of emergency 

mowing and grazing of CRP fields on breeding bird populations remains poorly understood.

Igl, L.D., and Johnson, D.H., 1999, Le Conte’s sparrows 

breeding in Conservation Reserve Program fields—Precipitation and patterns of population change: Studies in Avian 

Biology, v. 19, p. 178–186.

Breeding Le Conte’s sparrows (Ammodramus leconteii) studied in CRP grasslands from 1990 to 1996. Status 

changed from an uncommon breeding species to one of the 

most abundant species recorded in last two years of study. 

Results emphasize importance of range-wide conservation 

efforts and long-term observations of grassland birds. In 6-yr 

study period, 111 species of birds were recorded using CRP 

grasslands during the breeding season. Dramatic increase 

in populations of this sparrow coincided with occurrence 

of wet conditions in northern Great Plains. Authors believe 

geographically large conservation programs such as the CRP 

are important for long-term conservation of avian species in 

grassland ecosystems and attribute improvements in habitat 

quality and distribution furnished by the program as benefiting 

many species of grassland birds. 

Johnson, D.H., Haseltine, S.D., and Cowardin, L.M., 1994, 

Wildlife habitat management on the northern prairie landscape: Landscape and Urban Planning, v. 28, p. 5–21.

A summary of European settlement impacts to northern 

prairie landscapes and wildlife habitats. Regional management of wildlife cannot be effective on public lands alone. 

Partnerships with private landowners need to be developed 

and expanded. Wildlife managers need to base management 

activities on explicit, quantifiable objectives that furnish 

measures of survival, reproduction, and distribution of species. 

Descriptions of potential landscape-level management options 

are presented.

Johnson, D.H., and Igl, L.D., 1995, Contributions of the Conservation Reserve Program to populations of breeding birds 

in North Dakota: Wilson Bulletin, v. 107, no. 4, p. 709–718.

An evaluation of projected changes in North Dakota 

breeding bird populations if CRP land was taken out of 

conservation covers and brought back to agricultural production is presented. Of 18 avian species common on CRP, crop 

fields, or both, 12 were more abundant in CRP. Six of these 

species had suffered significant decline in populations prior to 

implementation of the CRP. None of the species common in 

cropland cover types had declined significantly. Termination 

of CRP and return of lands to cultivation is projected to cause 

population declines for sedge wren (Cistothorus platensis), 

grasshopper sparrow (Ammodramus savannarum), savannah 

sparrow (Passerculus sandwichensis), dickcissel (Spiza americana) and lark bunting (Calamospiza melanocorys).

Johnson, D.H., and Igl, L.D., 2001, Area requirements of 

grassland birds—A regional perspective: Auk, v. 118, no. 1, 

p. 24–34.

Loss of grassland habitats is only one variable affecting 

avian breeding success. Degradation of remaining grasslands 

due to improper, or inadequate, management, disruption of 

natural disturbance regimes, encroachment of woody and 

exotic vegetation, and fragmentation are other key issues influencing habitat quality for these species. Three fragmentation 

factors affect avian grassland habitat quality: patch-size, edge, 

and isolation. The report provides an evaluation of the influence of fragmentation and isolation of CRP grassland fields 

for grassland breeding bird populations in the northern Great 

Plains. Fields were planted with perennial grasses and legumes 

usually wheatgrasses (Agropyron spp.), bromegrass (Bromus 

inermis), and alfalfa (Medicago sativa). Breeding bird assemblages associated with these fields were similar to those in idle 

native grasslands in the same region. Authors conclude locating a CRP field near existing grassland, or establishing one 

large CRP field would benefit more grassland bird species than 

would creating a larger number of small, isolated CRP fields. 

Johnson, D.H. and Koford, R.R., 1995, Conservation Reserve 

Program and migratory birds in the northern Great Plains, 

in LaRoe, E.T., Farris, G.S., Puckett, C.E., Doran, P.D., 

and Mac, M.J., eds., Our living resources—A report to the 

Nation on the distribution, abundance, and health of U.S. 

plant, animal, and ecosystems: Washington, D.C., U.S. 

Department of the Interior, National Biological Service, 

p. 302–303.

A presentation of nest density and survival rate data 

for selected common birds and waterfowl nesting in North 

Dakota and Minnesota CRP fields, croplands, and WPAs. Data 

supports conclusion federal agricultural programs can have 

beneficial effects on wildlife resources over broad geographic 

areas. As CRP fields age their attractiveness to certain species 

may change.
Non-Game Birds 97

Johnson, G.J., and Temple, S.A., 1990, Nest predation and 

brood parasitism of tallgrass prairie birds: Journal of Wildlife Management, v. 54, no. 1, p. 109–111.

Rates of nest predation and brood parasitism of 5 avian 

species nesting in tallgrass prairie remnants in Minnesota were 

influenced by size of prairie fragment, distance to wooded 

edge, and number of growing seasons since vegetation around 

nest was last burned. Nest predation was lower on larger 

blocks of habitat, further from wooded edge, and in vegetation 

burned less than 3 yr prior to observation. Management activities to maximize nest productivity should focus on provision 

of large fields regularly burned with no nearby wooded edges. 

Species investigated: clay-colored sparrow (Spizella pallida), 

savannah sparrow (Passerculus sandwichensis), bobolink 

(Dolichonyx oryzivorus), grasshopper sparrow (Ammodramus 

savannarum), and western meadowlark (Sturnella neglecta). 

Because of increased abundance of brown-headed cowbirds 

(Molothrus ater) and addition of wooded edges to prairie habitat nest productivity of prairie nesting birds may be declining. 

Recently burned prairie vegetation is usually tall and dense, 

which may restrict visibility to predators and predator activities. Production of seeds and insects was greater in recently 

burned areas permitting birds to spend less time foraging and 

greater amount of time protecting nests.

Kantrud, H.A., 1981, Grazing effects on avifauna of North 

Dakota: Canadian Field Naturalist, v. 95, p. 404–417.

Avian species richness tends to decrease in response to 

greater intensity of grazing, but total density of birds increased 

due to higher numbers of a few common species. Total bird 

density was always highest on idle or lightly grazed sites. In 

general, distribution and abundance of most grassland bird 

species in North Dakota have been negatively affected by 

agricultural activities. Fragmentation of grasslands by agriculture resulted in extirpation of some avian species but cultivation of eastern tallgrass prairie has destroyed habitat for more 

bird species than in the shorter, western grasslands. Protection 

should be given to larger remaining areas of grassland representative of various types found throughout state. Long-term 

preservation of grassland habitat quality will require periodic 

management of vegetation.

Kantrud, H.A., and Higgens, K.F., 1992, Nest and nest site 

characteristics of some ground-nesting, non-passerine birds 

of northern grasslands: Prairie Naturalist, v. 24, no. 2, 

p. 67–84.

Fields with numerous wetlands were more attractive 

to upland-nesting shorebirds than were similar fields where 

wetlands were more distant. All species studied used native 

grassland for nesting. Fourteen species nested in seeded grasslands and croplands. Nest success rates did not differ among 

habitat types for any species. Except for killdeer (Charadrius 

vociferus), few nests were found in annually tilled croplands. 

Current management practices on grasslands devoted to 

wildlife conservation would benefit from occasional management activities to maintain stand vigor. Results suggest 

about one third of bird species studied, mostly shorebirds, 

nested predominantly in shorter sparser cover of pastures 

rather than taller idle grasslands. Few species were attracted 

to recently burned fields. To maintain grassland bird species diversity and abundance large, scattered areas of grasslands in the northern Great Plains should be periodically 

disturbed to reduce vegetation height, litter, and the invasion 

of woody plants. Modern livestock grazing systems can 

increase habitat quality for many species of non-game birds 

on mixed-grass prairies in North Dakota. However, some 

species seem attracted to fields where vegetation height and 

density are reduced by grazing during one or more previous 

growing seasons even though these fields may be relatively 

unattractive when cattle are present. 

Kantrud, H.A., and Kologiski, R.L., 1982, Effects of soils and 

grazing on breeding birds of uncultivated upland grasslands 

of the northern Great Plains: Washington, D.C., USDI Fish 

and Wildlife Service Wildlife Research Report 15, 32 p.

Livestock grazing on lands set aside for wildlife can be 

used as a management measure to increase populations of 

game species and increase diversity of plant or animal species. Light to moderate grazing resulted in increased species 

richness. However, heavy grazing in the northern Great Plains 

significantly reduced species richness. Grazing by domestic 

livestock generally decreased average vegetative height and 

increased exposure of bare soil. In lightly grazed plots height 

of vegetation seemed to decrease because of shading effect 

of large amounts of litter. Increased avian species richness 

was associated with plots in which height of vegetation was 

not appreciably reduced and percentage of bare soil was not 

greatly increased by excessive grazing. 

Kimmel, R.O., Berner, A.H., Welsh, R.J., Haroldson, B.S., and 

Malchow, S.B., 1992, Population responses of grey partridge (Perdix perdix), ring-necked pheasant (Phasianus colchicus) and meadowlarks (Sturnella spp.) to farm programs 

in Minnesota, in Birkan, M., ed., Proceedings of Perdix VI, 

First International Symposium on Partridges, Quails, and 

Francolins: Gibier Fauna Sauvage, v. 9, p.797–806.

Impacts of farm programs on wildlife vary depending on 

vegetation planted, subsequent management of vegetation, and 

length of time cropland was removed from production. Spring 

and summer roadside counts were used to monitor changes 

in grey partridge, pheasant, and meadowlark population 

changes in 15 Minnesota study areas with varying amounts of 

land removed from production. Conservation lands included 

lands enrolled in CRP and Reinvest in Minnesota (RIM) 

program. At the time of evaluation approximately 96 percent 
98 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

of CRP land in Minnesota was planted to tame grasses and 

grass-legume mixtures (CP1 and CP10). Native grass plantings (CP2) accounted for 4 percent of plantings. Grass covers 

planted on 80 percent of RIM lands were tame grasses and 

grass-legume mixtures. Authors estimate it would cost $200 

million/yr for state conservation agency to establish the number of acres of habitat furnished by the CRP. Authors conclude 

there was not an apparent response by gray partridge but the 

abundance of pheasants and meadowlarks was positively correlated with amount of land in CRP/RIM. Wildlife benefits of 

covers provided by conservation programs vary according to 

which habitat components are furnished and how these components affect existing conditions. If winter cover and feeding 

areas are inadequate, the benefits of added reproductive cover 

furnished by CRP/RIM may be reduced. Areas with existing 

low populations of grassland birds may take a longer period of 

time for population responses to improvement in habitat quality to be evident. 

King, J.W., and Savidge, J.A., 1995, Effects of the Conservation Reserve Program on wildlife in southeast Nebraska: 

Wildlife Society Bulletin, v. 23, no. 3, p. 377–385.

Ring-necked pheasant (Phasianus colchicus) numbers in 

southeast Nebraska were higher in areas with approximately 

20 percent of cropland in CRP than in areas with less than 5 

percent of landscape in the program. Meadowlark (Sturnella 

neglecta) numbers and eastern cottontail rabbit (Sylvilagus 

floridanus) numbers did not differ between areas. No differences were found between numbers of birds or avian richness 

between cool-season grass and warm-season grass-cover 

types. Vegetation structure and amount of cover were more 

important in determining bird densities and richness than 

was diversity of vegetation species. No relationship between 

bird numbers and vegetation diversity was found suggesting 

structure may be more important than species composition. In 

general, vegetation was taller in warm-season grass fields than 

recorded within cool-season fields. Authors suggest burning 

grasslands every 3–5 yr to rejuvenate fields. Fields seeded to 

single grass species generally become denser as they mature 

resulting in decline in habitat quality.

Klute, D.S., 1994, Avian community structure, reproductive 

success, vegetative structure, and food availability in burned 

CRP fields and grazed pastures in northeastern Kansas: 

Manhattan, Kans., Kansas State University, M.S. thesis, 

168 p.

Thesis is focused on comparison of avian community 

structure, reproductive success, vegetative structure, and food 

availability in burned CRP fields with local dominant cover 

types, burned, grazed, native grass pastures. During summer, 

relative abundance of avian species was significantly greater in 

grazed pastures than in CRP fields. Differences were primarily 

due to vegetative structure. Vegetative height and biomass 

VOR was greater in CRP than grazed fields. Total invertebrate 

biomass during summer was significantly greater in grazed 

pasture than CRP. Greater forb coverage in grazed pastures 

may have contributed to higher biomass of invertebrate in 

grazed pastures over CRP. During winter relative avian abundance did not differ significantly between CRP and grazed 

pastures. Mean species richness was greater in CRP. Winter 

CRP fields had taller vegetation and more bare ground within 

grazed pastures. Total biomass of available seed did not differ 

significantly between CRP and grazed pastures, however, CRP 

contained more preferred seed for wintering birds. Author 

concludes CRP furnished better winter habitat than provided 

by other covers evaluated. Moderate grazing of CRP may 

contribute to reduced vegetative height, increased total canopy 

overage, and increased forb coverage, which should improve 

habitat for grassland birds over the long term. 

Klute, D.S., and Robel, R.J., 1997, Will conversion of Conservation Reserve Program (CRP) lands to pasture be detrimental for grassland birds in Kansas?: American Midland 

Naturalist, v. 137, no. 2, p. 206–212.

Report describes comparison of avian use of CRP fields 

and pasture in eastern Kansas. Pastures had significantly 

greater vegetative cover while CRP fields had more bare 

ground. Vegetation was taller in CRP fields late in summer as 

compared to heights in pasture. Total avian abundance was 

greater in pasture than CRP fields. Reproductive success and 

rates of nest parasitism did not differ between cover types but 

nests were more numerous in grazed pasture. Authors conclude if CRP is converted to pasture it would probably not be 

detrimental to grassland bird populations but this is based on 

assumption that grazing does not exceed moderate levels. 

Long-term moderate grazing tends to reduce vegetative 

height, increase basal cover of grass, decrease woody vegetation, increase vegetative heterogeneity, and increase forb 

cover. CRP fields included in study (6–7-yr-old CP2, native 

grasses) did not have these characteristics. Forb component of 

pastures (22.4 percent cover) was higher than recorded in CRP 

fields (6.4 percent). This difference was believed to be a key 

component in attraction of birds to the fields evaluated. More 

species of birds were observed in CRP fields than in pastures 

but they occurred at low abundances and more infrequently. 

Fewer avian species were observed in grazed pastures but at 

greater abundance and throughout breeding season. Authors 

conclude long-term changes in CP2 CRP fields have not been 

adequately documented and these fields are less suitable for 

grassland birds than moderately grazed pastures. This conclusion is based, however, on the abundance of only a small 

number of selected species (grasshopper sparrow [Ammodramus savannarum], dickcissel [Spiza americana], meadowlark [Sturnella neglecta], and upland sandpiper [Bartramia 

longicauda]).
Non-Game Birds 99

Knopf, F.L., 1994, Avian assemblages on altered grasslands: 

Studies in Avian Biology, v. 15, p. 247–257.

As a group, populations of endemic grassland bird species have declined more than any other group of avian species 

(including neotropical migrants) in the last quarter century. 

Unlike most forest species that winter in the neotropics, most 

birds breeding in North American grasslands winter in North 

America. Consequently problems driving declines in grassland 

species are associated almost entirely with North American 

processes. Eastern tallgrass prairie has been virtually obliterated while western shortgrass prairies continue to experience 

fragmentation. During the last 25 years, grassland species have 

shown steeper, more consistent and geographically widespread 

declines than any other behavioral or ecological guild of North 

American avian species.

Knopf, F.L., 1992, Faunal mixing, faunal integrity, and the 

biopolitical template for diversity conservation: Transactions of the North American Wildlife and Natural Resources 

Conference, 57, Charlotte, N.C., March/April 27–1, 1992, 

Proceedings: Washington, D.C., Wildlife Management 

Institute, p. 330–342.

Conservation biologists striving to protect a diversity 

of habitats and species in increasingly altered landscapes of 

North America do so primarily by protecting samples of the 

biota in natural preserves. At many locations, local species 

assemblages have been affected by addition of new species 

from contiguous or distant sites. Shifts in the composition 

of native biological diversity can lead to declines in regionally unique species. Often augmented faunas are viewed 

by the public and local Fish and Game agency personnel as 

indicative of good wildlife conservation. Future conservation of faunal integrity requires greater coordination among 

natural resource agencies. Faunal mixing presents a dilemma 

for biologists dedicated to protecting the integrity of native, 

endemic faunas. Traditional policies of natural resource agencies favor the spread of ecological-generalist species. Most 

popular game species are characteristic of early successional 

habitats and respond favorably to greater edge and diversity 

in cover composition. Enhancing species richness through 

fragmentation of landscapes is becoming less favored based 

on growing evidence that increasing the quantity of edge can 

harm composition of some wildlife communities. Ecological 

consequences of species substitutions are masked in management that focuses purely on species richness. Actions for conservation of biological diversity: minimize practices promoting site-specific diversity, emphasize between-habitat diversity 

on management units and implement a step-down (national/

regional/local) approach to conservation of biological diversity. Conservation of biological diversity must complement the 

conservation of endangered species. Despite the extinction of 

many species and a general decline in the biological diversity 

of North America, many local faunas contain more species 

today than present prior to European settlement. 

Knopf, F.L., 1988, Conservation of steppe birds in North 

America, in Goriup, P.D., ed., Ecology and conservation of 

grassland birds: Cambridge, United Kingdom, Technical 

publication no. 7, International Council for Bird Preservation, p. 27–41.

Only 9 avian species are wholly endemic to the tall and 

short grass prairies. An additional 19 species have strong 

affinities to grasslands but also occur in adjacent vegetation types. Endemic species spend the entire year within the 

grassland while remaining species tend to migrate into brush 

land and other habitats in Mexico and central America. About 

260 species of birds regularly breed in the grasslands of North 

America, however most are associated with wetlands or manaltered landscapes. Locally, bird communities within grassland 

average only three to five species during the breeding season 

with substantial seasonal and annual variation in densities. 

Conservation programs should identify needs of area-dependent stenotopic species for a locale when planning land purchases. Invasion by woody species provides habitat for birds 

more typical of eastern deciduous forests, which accelerate 

patterns of avifaunal mixing. 

Knopf, F.L., 1986, Changing landscapes and the cosmopolitanism of the eastern Colorado avifauna: Wildlife Society 

Bulletin, v. 14, p. 132–142.

Development of riparian forests on the Great Plains 

has provided corridors for movement of forest birds across 

grasslands, which have historically served as an ecological 

barrier to dispersal. Movement of eastern, woodland species 

as a direct and indirect consequence of land use and modification illustrates relevance of current conservation theory 

to decisions on local management and the need for interstate 

rationalization of management plans intended for restoration 

or preservation of grasslands. 

Knopf, F.L., and Samson, F.B., 1992, Conserving the biotic 

integrity of the Great Plains, in Johnson, S.R., and Bouzaher, A., eds., Conservation of great plains ecosystems—

Current science, future options: Kluwer Academic Press, 

p. 121–133. 

Despite relatively simplistic composition of endemic 

avifauna in the Great Pains, grassland-endemic species are 

currently showing steeper, more consistent, and geographically widespread declines than any other group of North 

American species. Of 32 grassland bird species, 10 declined 

at statistically significant rates from 1966–1991. Principle 

processes that shaped endemic plant and animal communities on the Great Plains have been drought, grazing, and fire. 
100 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

These factors favored broad expanses of monotypic vegetation 

with a minimization of ecological edges. Activities having 

universal effects on endemic diversity include fragmentation 

of grasslands, drainage of wetlands, invasion or introductions 

of alien and exotic species, and water development activities. 

Impoundments of rivers reducing natural variation in flow 

regimes and elimination of natural wildfire have had more 

severe consequences to native flora and fauna of the western 

Great Plains than has most agricultural production. Ninety 

percent of breeding bird species in northeastern Colorado did 

not breed there at the turn of the century. 

Koford, R.R., 1999, Density and fledgling success of grassland birds in Conservation Reserve Program fields in North 

Dakota and west-central Minnesota: Studies in Avian Biology, v. 19, p. 187–195.

Fields planted to CRP grassland covers were suitable breeding habitat for several species whose populations 

declined prior to implementation of the conservation program. 

The habitat furnished by CRP appeared to be as secure as 

other suitable habitats in federal WPAs within these states. 

Additional cover provided by CRP may have lowered breeding densities in all habitats with possible benefits if reproduction is density dependent. Additional habitat associated with 

the CRP also may have allowed birds to breed that otherwise 

would not have bred, such as second year birds, thereby supporting higher growth of populations.

Koford, R.R., and Best, L.B., 1996, Management of agricultural landscapes for the conservation of neotropical 

migratory birds, in F.R. Thompson, III, ed., Management 

of midwestern landscapes for the conservation of neotropical migratory birds: St. Paul, Minn, USDA Forest Service 

General Technical Report NC-781, p. 86–88.

Thirty-eight neotropical migratory birds are common in 

Midwestern agricultural landscapes. Most species depend on 

herbaceous or wooded habitats that are declining as average 

size of farms increases. Management recommendations: minimize cultivation, encourage moderate grazing, delay spring 

mowing of hay, increase acres in grassed waterways and 

roadsides, avoid nighttime mowing, encourage longer intervals 

between mowings, avoid fall mowing and annual mowing of 

grassed waterways/roadsides, retain fencelines, maintain idle 

land, and change configuration of idle land to enhance species 

richness and nesting success. Immediate effect of tillage is 

exposure of arthropods and other prey to foraging birds and 

a long-term reduction in abundance of litter-dwelling arthropods. Conventionally tilled fields have lower arthropod abundance than no-till or idle areas. Herbicides can affect birds by 

reducing availability of seeds. Insecticides reduce abundance 

and diversity of foliage-dwelling arthropods. Strip cover (for 

example, grassed waterways, terraces, fencerows roadsides 

and windbreaks/shelterbelts) usually provides habitat more 

long-term than provided by areas enrolled in crop-retirement 

programs. Strip cover in agriculturally dominated landscapes 

has decreased in recent years. Orientation of crop rows relative 

to grassed waterway influenced disturbance intensity as nest 

densities were greater when rows parallel waterways. 

Management objectives recommended include conservation of remnant prairie and savannah still in existence. 

Large-scale restoration of these habitats is often impractical 

but remnants of important cover types can be saved for education and research. Other recommendations provided include: 

increasing amount of crop residues available, maintaining 

CRP or other long-term programs, furnishing high-quality 

vegetative covers, minimizing tillage, encouraging greater 

diversification of crops, encouraging moderate grazing of 

pastures with prescription for species needs of those most 

at risk, delaying spring mowing of hay as long as possible, 

avoiding night mowing, increasing intervals between mowing, 

maintaining idle land in blocks rather than strips, increasing 

species composition of vegetation on terraces, and planting 

more diverse species mixes of vegetation. Farmers should be 

encouraged to not burn all ditches or roadside vegetation in 

the same year. Fencerows greater than 3 m (10 ft) wide should 

be encouraged. 

Kurzejeski, E. W., 1996, Vegetation structure and avian species composition in diverted farmland: Jefferson City, Mo., 

Missouri Department of Conservation Final Report Federal 

Aid Project No W-31-R-05, 75 p.

Report provides a comparison of vegetative conditions, 

avian abundance, composition and productivity on CP1 (introduced grasses/legumes), CP2 (native grasses), and row crop 

fields in northern Missouri. Total bird abundance, grassland 

bird abundance, nest density, and number of nesting species 

were all lower on cropland than recorded in CRP fields. Bird 

community using crop fields differed from CRP fields with 

short grass and open-ground feeding birds, which are predominant species found on crop fields. The conservation value of 

CRP fields for declining grassland bird species was higher for 

CP1 fields than CP2 fields. Monotypic stands of both warmseason and cool-season grasses should be avoided to increase 

the potential wildlife benefits of CRP and other idle grassland 

habitats. Management recommendations: cost sharing of 

grass plantings should be limited to multi-species seedings. 

Periodic haying and grazing may increase habitat value of 

monotypic fields and non-game bird habitat. Mowing may 

effectively decrease height and density of vegetation, however, 

litter build-up and accelerated rate of grass succession may 

negatively affect wildlife values of fields where only mowing 

(residue is not removed) is implemented. 

Leddy, K.L., Higgins, K.F., and Naugle, D.E., 1997, The 

importance of Conservation Reserve Program fields to 

breeding grassland birds at Buffalo Ridge, Minnesota: Proceedings of the South Dakota Academy of Science, v. 76, 

p. 105–111.
Non-Game Birds 101

Avian abundance and species composition were compared in CRP grasslands, pastureland, and cropland in 

southwestern Minnesota. CRP fields had higher vegetation 

measurements and supported higher densities of birds and species richness than did pasturelands and cropland. Majority of 

CRP fields evaluated were planted to smooth brome (Bromus 

inermis)/alfalfa (Medicago sativa) or to switchgrass (Panicum 

virgatum). Mean densities of birds (#/100ha, [250ac]) in CRP 

were 312.5 compared to 166.7 in pasture and 9.0 in cropland. 

Grasslands established under CRP were an important habitat 

due to the presence of sedge wren (Cistothorus platensis), 

dickcissel (Spiza americana), and clay colored sparrow (Spizella pallida) not found in other covers evaluated. In contrast, 

croplands and pasture supported only generalist species.

Little, T., and Hill, R.A., 1993, CRP having an impact: Iowa 

Conservationist, v. Sept/Oct, p. 4–9.

Description of agricultural and settlement impacts to 

wildlife habitats and an overview of CRP benefits to wildlife 

in Iowa. Converting as little as 4 percent of county from row 

crops to CRP significantly increased numbers of ring-necked 

pheasants (Phasianus colchicus) recorded on survey routes. 

Higher numbers of pheasants were attributed to greater 

overwinter survival due to the elevated quality of grassland 

cover furnished by the CRP. More than 15 nests of non-game 

birds were recorded per 40 acres (16 hectares) of CRP, which 

compared to less than one nest in same area of row crops. 

Nest success of birds in CRP was 33 percent as compared to 

20 percent in hay fields. Waterfowl nest success in CRP was 

believed to be as good, or better, than experienced in wildlife 

management areas. 

Littlefield, C.D., and Johnson, D.H., 2005, Habitat preferences of migrant and wintering northern harriers in northwestern Texas: The Southwestern Naturalist, v. 50, no. 4, 

p. 448–452.

Habitat preferences for northern harriers (Circus cyaneus) 

in four counties in the panhandle of Texas are described. The 

raptors hunted over a variety of habitats in the study areas but 

foraged mainly in CRP grasslands and vegetated playa basins. 

This area of the panhandle, as well as eastern New Mexico 

is recognized as a winter concentration area for the species. 

Within the study area land enrolled in the CRP accounted for 

16 percent of land use. The balance of land use was cropland 

(63 percent), rangeland (16 percent), and playa lakes (less 

than 2 percent). Species compositions of CRP grasslands (for 

example, native species vs. introduced species [for example, 

old world bluestem, weeping lovegrass]) are not described. 

CRP grasslands, playas, and native rangeland were used 

by harriers disproportionately more than availability. Winter wheat was used for foraging less than availability. Tilled 

stubble, cotton stubble, bare plowed fields, corn stubble, corn 

stubble planted to wheat, and plowed cotton received little 

use. Use of winter wheat increased as vegetation increased 

in height providing cover for prey species. Authors conclude 

further depletion of Ogallala aquifer may affect distribution of 

croplands in the region with potential benefits to harriers. CRP 

and playas supported 42 percent of harrier habitat use. With 

declines in irrigated cropland CRP enrollment may increase 

availability of grassland and protection of playas. If the 

dominant land-use reverts to grazing harriers may be impacted 

negatively as use of livestock grazed grasslands and playas 

have been shown to diminish pray availability. 

Lloyd, J.D., and Martin, T.E., 2005, Reproductive success of 

chestnut-collared longspurs in native and exotic grassland: 

The Condor, v. 107, p. 363–374.

Population declines of grassland birds continue to be 

apparent in prairie ecosystems that remain relatively intact 

suggesting factors in addition to habitat loss and fragmentation are involved. Changes in breeding habitat quality may 

be related to declines in populations but few studies have 

examined habitat-specific demography of grassland birds. 

Report describes investigation of reproductive success of 

chestnut-collared longspurs (Calcarius ornatus) in grasslands 

composed of native mixed-grass prairie species (species 

composition and abundance were not identified) and crested 

wheatgrass (Agropyron cristatum) monocultures in eastern 

Montana. Conservation efforts targeted toward grassland 

birds must consider not only spatial relations between covers but vegetative composition and characteristics within 

patches of habitat. 

Authors report that daily nest survival was 17 percent 

lower in crested wheatgrass plots than within native grassland. 

Lower predation rates in native prairie resulted in greater average number of young produced per nest. Nestlings in exotic 

grass also were found to gain mass more slowly, reflecting 

lower quality of the environment, leading to longer period in 

nest and greater susceptibility to predation. Fledgling mass 

in native grassland was approximately 9 percent greater than 

recorded in crested wheatgrass. There was no evidence longspurs preferred to nest in the native prairie with nest density 

similar in both habitat types. Results indicate introduction 

and spread of exotic grass have adverse fitness for this species highlighting the importance of maintaining grasslands 

comprised of native species. Land managers rarely can control 

spatial arrangement of habitats within a landscape but can 

influence changes in structure and composition of vegetation 

within patches (that is, fields). Authors conclude that changes 

in the structure and species composition of grassland vegetation can affect reproductive success of grassland birds and 

spread of exotic vegetation can have adverse fitness consequences for native wildlife. Authors believe the CRP can have 

greatest potential for endemic species of wildlife if native 

grasses are emphasized in conservation plantings. 

Lokemoen, J.T., and Beiser, J.A., 1979, Bird use and nesting 

in conventional, minimum-tillage, and organic cropland: 

Journal of Wildlife Management, v. 61, no. 3, p. 644–655.
102 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Seasonal use by birds and nesting use was evaluated in 

fallow fields, sunflower (Helianthus spp.), and wheat fields 

among conventional farms, minimum tillage farms, reduced 

tillage, and organic farms (no synthetic pesticides). Spring bird 

densities were highest in minimum-tillage, fallow fields providing food and cover. No differences in bird densities were 

found among crops or field types in fall or winter but mean 

densities of avian species in summer were highest in fallow 

fields. Fallow fields also had greater mean number of nesting 

species and highest mean densities of nests, which may have 

been due to increased amounts of plant litter cover. Mean 

number of nesting species and nest densities were higher in 

minimum tillage and organic fields. Overall hatching success 

was low for waterfowl and shorebirds and low nest success 

for passerines. Nest losses were due to predation and farming 

activities. Hatch success higher in minimum tillage fields for 

passerines and wheat fields for shorebirds. Nest densities in 

CRP were 6 times larger than that found in minimum tillage 

stubble and organic fallow and 11 times larger than densities 

in other field types and crops. 

Madden, E.M., Hansen, A.J., and Murphy, R.K., 1999, Influence of prescribed fire history on habitat and abundance of 

passerine birds in northern mixed grass prairie: Canadian 

Field-Naturalist, v. 113, no. 4, p. 627–640.

Linkages between disturbance regimes and vegetation 

response need to be more clearly defined to effectively manage 

grassland habitats and declining populations of prairie passerine birds. Avian-habitat relations are described on mixed-grass 

prairie in northwestern North Dakota in relation to history of 

prescribed fire. Post-fire succession characterized as short, 

sparse vegetation cover with few forbs and low amounts of 

litter immediately after burning to moderate amounts of forbs, 

litter, and shrubs 2–8 yr following fire. Vegetation described 

as tall, dense, and shrubby with little forbs or litter understory when fire was excluded (greater than 80 yrs). Most 

grassland birds were absent from sites where fire had been 

excluded. Species richness and abundances of Baird’s sparrow 

(Ammodramus bairdii), bobolink (Dolichonyx oryzivorus), 

grasshopper sparrow (A. savannarum), Le Conte’s sparrow 

(A. leconteii), Sprague’s pipit (Anthus spragueii), and western 

meadowlark (Sturnella neglecta) were positively related to 

application of fire. Common yellowthroat (Geothlypis trichas) 

and clay colored sparrow (Spizella pallida) were recorded at 

highest densities in unburned prairie.

Authors conclude many grassland birds in this region 

are strongly adapted to vegetation characteristics associated 

with relatively frequently burning (5–10 yr). A mosaic of 

habitats reflecting all temporal stages of succession following 

fire are recommended to provide suitable habitat for widest 

number of species. Recommended sizes and configurations for 

burned areas are not provided with authors suggesting need for 

further research. Recommendation for burning 20–30 percent 

of management area yearly is cited for Midwestern prairies. 

Authors suggest managers should furnish areas with short (2–4 

yr) moderate (5–7 yr), and long (greater than 8–10 yr) fire 

intervals to provide maximum diversity in avian species and 

habitats. The authors caution, however, management prescriptions should take into account needs of other wildlife species 

(for example, invertebrates, amphibians) that may not benefit 

from frequent application of fire.

Madden, E.M., Murphy, R.K., Hansen, A.J., and Murray, 

L., 2000, Models for guiding management of prairie bird 

habitat in northwestern North Dakota: American Midland 

Naturalist, v. 144, no. 2, p. 377–392.

It remains difficult to summarize effects of vegetation 

management on individual bird species due to differences in 

environmental conditions (moisture, soils, plant species composition). Vegetation attributes are important determinants of 

grassland bird abundance. Vegetation structure, and to a lesser 

extent, composition, can be manipulated by managers. The 

report gives specific characteristics of vegetation (shrub cover, 

herb cover, VOR) believed important for a number of prairie 

bird species. Authors conclude most public grasslands devoted 

to wildlife traditionally have been managed to promote tall, 

dense, nesting cover for game birds. Some avian species of 

importance are most associated with native bunch grasses (for 

example, little bluestem [Schizachyrium scoparium], sideoats 

grama [Bouteloua curtipendula]) rather than the broad-leaved, 

exotic grasses often planted for duck nesting cover. Vegetation 

attributes preferred by these endemic species are characteristic 

of grasslands receiving periodic defoliations such as those 

produced by fire or grazing. A mosaic of available vegetation 

types is needed to maximize avian diversity. Visual obstruction, presence of grass, forb, or shrub covers were important 

features for all specialized avian species.

McCoy, T.D., 1996, Avian abundance, composition, and reproductive success on Conservation Reserve Program fields in 

northern Missouri: Columbia, Miss., University of Missouri, 

M.S. thesis, 226 p.

Grassland bird species richness was higher on structurally 

diverse CP1 (introduced grass/legume) fields than found in 

CP2 (native grass). Vegetation in CP2 fields evaluated was tall, 

dense monocultures of switchgrass (Panicum virgatum). In 

areas where grass monocultures exist disturbances to decrease 

height and density of vegetation and increase plant diversity 

may be beneficial. Provisions for periodic haying and grazing 

may enhance habitat value for many avian species. 

McCoy, T.D., Ryan, M.R., Kurzejeski, E.W., and Burger, L.W., 

1999, Conservation Reserve Program—Source or sink 

habitat for grassland birds in Missouri: Journal of Wildlife 

Management, v. 63, no. 2, p. 530–538.

Authors conclude that further documentation of CRP 

effects on bird populations are needed to maximize benefits 
Non-Game Birds 103

of the program. The relative value of CRP can be evaluated 

by comparing reproductive habitat quality for avian species. 

However, data from CRP habitats are limited. Authors believe 

that claims that the CRP is a panacea for grassland wildlife are 

overstated, but the CRP likely has contributed to conservation 

of many species including several of special concern.

McCoy, T.D., Ryan, M.R., and Burger, L.W., and Kurzejeski, 

E.W., 2001, Grassland bird conservation—CP1 vs. CP2 

plantings in Conservation Reserve Program fields in Missouri: American Midland Naturalist, v. 145, no. 1, p. 1–17.

A comparison of the relative value of different CRP 

plantings for breeding grassland and wintering birds in CP1 

(introduced grasses/legumes) and CP2 (native grasses) fields 

in northern Missouri is provided. Differences in species 

abundance were evident between season, but overall species 

richness, abundance, and nesting success of grassland birds 

during the breeding season and total bird use in the winter did 

not differ between conservation practices. Structurally shorter, 

more diverse, cool-season grass fields were equal or better 

habitat than taller, more vertically dense switchgrass (Panicum 

virgatum)-dominated fields for grassland birds including several of high conservation concern. Authors recommend single 

species plantings of warm or cool season grasses should be 

avoided to maximize potential benefits of CRP to wildlife.

Authors concluded CP2 fields did not differ from CP1 

fields in their value as reproductive and wintering habitat for 

birds. However, CP2s fields were switchgrass monocultures. 

Greater value as habitat may be realized with establishment 

of a mix of warm-season native species. Fields planted to 

CP1 fields were orchardgrass/lespedeza (Dactylis glomerata/

Kummerowia striata), or timothy/clover (Phleum pratense/

Trifolium spp.). Analysis of mowing in late summer and early 

fall indicated CP1 fields had sufficient regrowth of cool season 

grasses, legumes, and annual weeds to provide cover and food 

for wintering birds. In comparison, cover of warm-season 

grasses was reduced for at least the following two summers 

after CP2 fields were mowed resulting in minimal structural 

and vegetational diversity until switchgrass again dominated 

fields. Authors believe landowners are not likely to intensively 

manage CRP for wildlife unless this is a condition of the contract and/or there is a monetary incentive to do so.

McMaster, D.G., and Davis, S.K., 2001, An evaluation of 

Canada’s permanent cover program—Habitat for grassland 

birds?: Journal of Field Ornithology, v. 72, no. 2, 

p. 195–210.

In the early 1990s, Agriculture Canada’s Permanent 

Cover Program (PCP) converted over 445,000 hectares 

(1,099,640 ac) of cropland to perennial vegetative cover. Permanent Cover Program sites supported higher avian species 

richness than cropland. Nine of ten commonly detected grassland bird species occurred at higher frequencies in PCP than 

cropland. Permanent Cover Program sites were characterized 

by taller, denser vegetation and less bare ground than recorded 

in cropland sites. Hayed and grazed PCP sites differed significantly in vegetative structure and avian community composition, but did not differ in species richness or evenness. Unlike 

the CRP, the PCP allows use of forage produced on program 

lands. Permanent Cover Program vegetation most commonly comprised of combinations or wheatgrass (Agropyron

spp.), brome (Bromus inermis), alfalfa (Medicago sativa), 

and crested wheatgrass (A. cristatum). Habitat maintained in 

a mosaic of successional stages would provide for the richest 

diversity of grassland avian species. 

McMaster, D.G., Devries, J.H., and Davis, S.K., 2005, Grassland birds nesting in haylands of southern Saskatchewan—

Landscape influences and conservation priorities: Journal of 

Wildlife Management, v. 69, no. 1, p. 211–221.

Authors conclude conversion of cropland to hayland provides significant benefits to grassland avian species, including 

some of conservation priority. Grassland species of conservation concern nested less frequently in hayland than recorded 

within native grassland. Because restoration of native prairie 

vegetation costs more to establish than does tame seeded 

grasses it is an option of limited availability. In contrast to 

the United States, where the CRP is generally restricted from 

annual use, grasslands established for conservation purposes 

in Canada’s PCP differ in that producers are allowed to annually hay or graze the restored, or converted lands. Evaluation 

was conducted in the Missouri Coteau region of the province 

in lands converted from crop production to hayland. Semipermanent or permanent wetlands were within, or adjacent 

to, study fields. Study fields were at least 4 yr old and hayed 

the previous year. Haylands evaluated were seeded to alfalfa 

(Medicago spp.), and a combination of grasses typically 

crested wheatgrass (Agropyron cristatum), smooth brome 

(Bromus inermis), or Russian wild rye (Elymus junceus).

Because study fields were adjacent to wetlands, waterfowl represented a significant portion of nests located. 

Estimates of relative abundance for all species were approximately twice that recorded in rotational grazing systems of 

tame and native pastures but half that of waterfowl nests found 

in idle planted nesting cover. Residual vegetation is a major 

factor determining quality of habitat for waterfowl nesting 

cover. Study results show haylands are used for nesting by 

many species of grassland birds although relatively few may 

be present at high densities. Haylands are likely to attract 

fewer waterfowl than idle vegetation since the previous year’s 

haying removes much of the residual vegetation. Nest success rates reported from this investigation are similar to those 

found in dense nesting cover and CRP (13–19 percent) and 

within range believed necessary to sustain populations (15–20 

percent). Authors conclude conservation of native grassland 

in a mosaic of heavily to lightly grazed areas likely is the best 

method to meet habitat requirements of the entire grassland bird community and conversion of cropland to hayland 
104 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

greatest advantage may be to reduce grazing pressure on 

native pasture.

Millenbah, K.F, 1993, The effects of different age classes of 

fields enrolled in the Conservation Reserve Program in 

Michigan on avian diversity, density, and productivity: East 

Lansing, Mich., Michigan State University, M.S. thesis, 

108 p.

Avian communities and vegetative characteristics were 

examined in 6 age-class fields (1–6 growing seasons) in 

central Michigan to determine relations between field age, 

vegetation characteristics, and avian communities. Younger 

CRP fields were characterized by higher amounts of forbs 

and bare ground and supported greater avian densities and 

diversities than older fields. Older fields supported greater 

height of grasses and more litter cover than did younger fields. 

Grassland birds may require a diversity of age classes of CRP 

fields in agricultural landscapes to meet habitat requirements. 

Results suggest relationship between age of field and relative 

avian abundance, diversity and productivity. Younger fields 

maintained the greater diversity and density of avian species. Older fields with greater litter and grass cover supported 

the greatest productivity. One-year-old CRP fields supported 

greatest diversity of avian species. As fields aged, diversity 

declined, but productivity increased. Both the number of 

active and successful nests was greatest in older fields. Litter 

cover serves as a physical barrier to seedlings decreasing the 

amount of light energy available for vegetative growth. On 

new fields horizontal cover is sparse. As forb and grass cover 

increased through the fourth growing season, horizontal cover 

increased. As fields became more grass-dominated and sparser 

during years 5 and 6, horizontal cover decreased.

Greater biomass and diversity of insects were available in 

younger fields. Few significant differences were found among 

field age classes, but mean insect diversities and biomass 

generally decreased as fields aged. Younger fields supported 

greater diversity. Seventy percent of surveyed landowners 

gave improvement of wildlife habitat at least some importance in enrollment into CRP. Author recommends controlled 

disturbance in years 4–6 with the goal to provide multiple successional stages for simultaneous high density, diversity, and 

productivity of avian species. 

Millenbah, K.F., Winterstein, S.R., Campa III, H., Furrow, 

L.T., and Minnis, R.B., 1996, Effects of Conservation 

Reserve Program field age on avian relative abundance, 

diversity, and productivity: Wilson Bulletin, v. 108, no. 4, 

p. 760–770.

This report is an expansion of discussion on findings 

reported in 1993 thesis by Millenbah. The authors recommend 

implementing management of CRP between years 3–6 to set 

back succession of vegetation. CRP field are a unique vegetation type in the agricultural landscape consequently little is 

known about how disturbances will ultimately influence avian 

species using these fields. Additional information is needed 

on maintenance and rejuvenation methods for planted CRP 

grasslands. Authors recommend management activities be 

accomplished in as short a time period as possible to minimize 

detrimental effects to nesting species.

Murphy, M.T., 2003, Avian population trends within the evolving agricultural landscape of eastern and central United 

States: The Auk, v. 120, no. 1, p. 20–34.

Author reports results of investigation between USFWS 

BBS and USDA statistics on changes in farmland structure 

and population trends of birds breeding in grassland and early 

successional (shrub-dominated) habitats in the central (Rocky 

mountains to Mississippi river) and eastern (Mississippi 

east) regions. Author reports changes in land use explained 

25–30 percent of variation in avian population change. 

Grassland birds exhibited stronger declines in populations 

than did shrub-habitat-associated species. Strong association of declines in grasslands birds was evident regardless of 

migratory or nesting behavior, suggesting events on breeding 

grounds have driven declines in these species. Changes in 

landscape composition accounted for more variability in population trends for grassland species than for shrub-associated 

species. Most grassland species are short-distance migrants 

overwintering in agriculturally dominated landscapes within 

North America. Author believes these species are affected by 

changes in landscape and agricultural practices both during 

breeding and non-breeding seasons. Highly individualistic 

habitat needs of species suggest a complex mosaic of habitat 

types that must be furnished within agriculturally dominated 

ecosystems if a diverse avifauna is to be maintained.

In contrast to many other studies, this investigation 

reports a negative correlation between CRP and avian populations. Five of seven negative associations were for avian 

species associated with shrub-dominated habitats and the two 

negative relations for grassland species (common nighthawk 

[Chordeiles minor], Vesper sparrow [Pooecetes gramineus]) 

regularly nest in less densely vegetated covers including row 

crops. Author attributes inability to detect positive associations between birds and CRP possibly a consequence of the 

relatively small area of land devoted to the program and its 

uneven distribution in the United States.

Negus, L.P., Davis, C.A., and Wessel, S.E., 2010, Avian 

response to mid-contract management of Conservation 

Reserve Program fields: American Midland Naturalist, v. 

164, no. 2, p. 296–310.

Many CRP grasslands lose their value as avian habitat 

as they mature or become decadent or dominated by grass 

monocultures. The objectives of this study were to investigate 

effectiveness of disking and interseeding legumes as a midcontract management practice in northeastern Nebraska CRP 
Non-Game Birds 105

fields. Vegetative response to management, grassland bird 

abundance and nest-productivity were evaluated in interseeded and disked CRP fields as well as control (unmanaged) 

fields. Study fields were 10–15 yr old and originally planted 

to smooth brome (Bromus inermis) as well as several species of legumes (Trifolium spp.). In the early years following 

planting these fields were characterized as providing excellent 

habitat for grassland birds. However, habitat quality declined 

as fields aged, became dominated by brome monocultures, 

and the legume/forb component diminished. Managed fields 

were lightly disked and interseeded with legumes. A portion of 

each field was disked in 2003 and 2004 with a total of 50–60 

percent of each field treated.

Overall avian abundance in treated fields was 4.49 bird/

transect as compared to 2.93 birds/transect in control fields. 

Avian species richness and diversity also were greater within 

treated fields as compared to untreated control fields. No 

difference in nest density or nest success was found between 

control and treated fields. Disked/interseeded portions of fields 

had higher maximum vegetation height, greater horizontal 

VOR and a higher percentage of bare ground than did control fields. Grass cover was greater within control fields than 

within treated fields. Responses of individual avian species 

(bobolink [Dolichonyx oryzivorus], dickcissel [Spiza americana], red-winged blackbird [Agelaius phoeniceus], common 

yellowthroat [Geothlypis trichas] and grasshopper sparrow 

[Ammodramus savannarum]) to the habitat management 

are discussed.

Oberheu, D., Mitchell, R., Dabbert, B., and Davis, S., 1999, 

Observations of avian nesting activity in burned and nonburned weeping lovegrass CRP: Texas Journal of Agriculture and Natural Resources, v. 12, p. 14–17.

More than 1 million acres of weeping lovegrass 

(Eragrostis curvula) has been planted in Texas as part of the 

CRP. The planting has been criticized as being of little value 

to wildlife. Although numbers of nests found were small this 

report documents nesting in weeping lovegrass by Cassin’s 

Sparrow (Aimophila cassinii) a species in decline throughout 

its range. Nests of mourning doves (Zenaida macroura) and 

common nighthawk (Chordeiles minor) also were located in 

CRP lovegrass fields. Although not the best cover for wildlife 

due to a lack of structural diversity and insufficient thermal 

cover, weeping lovegrass may be the best multiple-use cover 

for soil conservation and forage production on sandy soils in 

the southern High Plains. Because nesting seemed to be inhibited for at least two seasons following burning, the authors 

suggest application of prescribe fire should be conducted in a 

mosaic fashion to maintain diversity in vegetative cover.

Owens, R.A., and Myres, M.T., 1973, Effects of agriculture 

upon populations of native passerine birds of an Alberta 

fescue grassland: Canadian Journal of Zoology, v. 51, 

p. 697–713.

Disturbance of fescue (Festuca sp) grasslands by mowing for hay or grazing by cattle reduced or eliminated Baird’s 

sparrow (Ammodramus bairdii) and Sprague’s pipit (Anthus 

spragueii) but permitted ingress of horned lark (Eremophila 

alpestris) and chestnut-collared longspur (Calcarius ornatus). Total elimination of native grassland by cultivation for 

cereal crops eliminated all passerine species except the horned 

lark. Disturbance of peripheral areas resulting from cultivation such as field boundaries and ditches may have benefited 

species occurring in edge habitats. Vegetation physiognomy is 

probably the key factor determining distribution of grassland 

passerine species. Prairie passerines, which evolved to exploit 

original grassland environments, have been forced to make 

use of various habitats created by agriculture. Species dependent upon dense-grass situations are largely eliminated when 

grazing is heavy. Variable grazing intensities will affect habitat 

distribution differently resulting in changes in composition of 

grassland bird community. Under grazing, prescriptions aimed 

at maintaining range in good condition will probably support 

the full range of prairie passerines. Under heavier grazing, 

avian species associated with short-grass conditions will 

predominate. Some species will be present under any grazing 

prescription (meadowlarks [Sturnella spp.]). This study suggests that passerine avifauna that evolved on the Great Plains 

is adapted to survive in habitats, which are the product of 

grazing by native ungulates and periodic fires. Therefore, areas 

managed to preserve grasslands and native avifauna must 

allow these factors to operate to create similar conditions.

Patterson, M.P., and Best, L.B., 1996, Bird abundance and 

nesting success in Iowa CRP fields—The importance of 

vegetation structure and composition: American Midland 

Naturalist, v. 135, p. 153–167.

Although many bird species frequent row-crop fields, 

their abundance within them is relatively low and few species nest there. Because of predation, parasitism, and farming activities, bird reproduction in row crops may be below 

levels needed to sustain populations. Establishment of the 

CRP likely has contributed to an increase in abundance of 

many bird species in central Iowa because permanent vegetative cover replaced row-crop habitats. Authors believe CRP 

fields furnish better nesting habitat for grassland birds than do 

roadsides, grassed waterways, and other non-farmed covers 

associated with Iowa agriculture. The presence of diverse 

vegetation structure and composition, large block nature, and 

reduced agricultural activity are believed to benefit avian species. Grass species planted on CRP fields should be selected 

based on structural and composition attributes to which birds 

respond. Mowing and spraying of CRP fields for weed control 

should be deferred until after July to permit maximum nest 

success. A variety of grass species should be planted. Grass 

monocultures should be avoided. Whole field enrollments 

should be encouraged. Effects of disturbances (disking, burning, grazing and interseeding) need to be evaluated in order to 

refine conservation policies and management guidelines.
106 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Peak, R.G., Thompson III, F.R., and Shaffer, T.L., 2004, Factors affecting songbird nest survival in riparian forests in 

a midwestern agricultural landscape: Auk, v. 121, no. 3, 

p. 726–737.

Physical factors affecting nest success of songbirds investigated in riparian forest and stream buffers in northeastern 

Missouri. Spatial characteristics of habitat assessed in three 

narrow (55–95 m, [180–312 ft]) and three wide (400–530 m 

[1,312–1,739 ft]) riparian forests with adjacent grasslandshrub buffer strips and in three narrow and three wide riparian 

forests without adjacent grassland-shrub buffers. Riparian 

forests provided breeding habitat for area sensitive forest species (Acadian flycatcher [Empidonax virescens], wood thrush 

[Hyocichla mustelina], ovenbird [Seiurus aurocapillus]) and 

grassland-shrub nesting species (gray catbird [Dumetella carolinensis], Northern cardinal [Cardinalix cardinalis], and indigo 

bunting [Passerina cyanea]). Buffer strips furnished additional 

breeding habitat for grassland-shrub nesting species. When 

located in agriculturally dominated landscapes nest success 

may be marginal for these species even within wide riparian 

forests. Negative effects of predation were believed higher in 

narrow riparian buffers. However, as long as these “sink” habitats are balanced with other more productive habitat types, the 

authors suggest these types of habitats should be maintained as 

they may contribute to long-term viability for these species. 

Peterjohn, B.G., 2003, Agricultural landscapes—Can they support healthy bird populations as well as farm products?: The 

Auk, v. 120, no. 1, p. 14–19.

Intensification of agricultural production appears to 

underlie most declines in grassland-bird species numbers and 

distribution. Conservation on local scale can reverse local 

negative trends, but changes necessary to address landscapelevel patterns of population decline will require solutions that 

remain undefined. Our understanding of ecology and habitat 

requirements of many farmland species during the non-breeding season remains rudimentary limiting the ability to develop 

effective conservation strategies. Until an understanding of 

the entire annual cycle related to habitat needs is provided, the 

risk of inefficient conservation strategies remains high. Singlespecies management may not be an effective approach for the 

entire farmland bird community but may be needed for avian 

species of immediate conservation concern. Effective conservation of avian species associated with agricultural landscapes 

will require innovative solutions based on compatibility with 

current agricultural practices. Reliance on reverting to less 

intensive agricultural practices across North America is an 

unrealistic expectation. 

Some combination of variables, including grassland 

species composition, structural diversity, patch size, habitat 

fragmentation, and management activities, defines relations between grassland birds and their habitat. Each species 

responds differently. Studies at smaller spatial scales are 

needed to clarify these relationships. Simple, all-encompassing 

conservation solutions will not reverse all declines to farmland 

bird populations. Recent declines in grassland birds probably 

reflect factors other than habitat loss and include fragmentation, increased mowing and other detrimental practices 

associated with intensification of agricultural production. 

The negative relationship between population trends of avian 

species and CRP (see Murphy 2003 in Grassland Birds) is 

surprising and may reflect the fact that CRP fields constitute 

only 3.6 percent of the overall landscape and negative factors operating on remaining 96.4 percent of landscape have 

a greater influence on avian population trends. Five of seven 

negative associations reported by Murphy (2003) were for 

avian species associated with shrub-dominated habitats and 

the two negative relations for grassland species were for those 

that regularly nest in less densely vegetated covers including 

row crops. The relatively small area of land devoted to CRP 

and its uneven distribution in the U.S. probably also had an 

influence on this relationship.

Rahmig, C.J., Jensen, W.E., and With, K.A., 2009, Grassland 

bird responses to land management in the largest remaining 

tallgrass prairie: Conservation Biology, v. 23, no. 2, 

p. 420–432.

This report provides an evaluation of avian community, 

population and demographic responses to grazing, and burning 

and haying of native tallgrass prairie and grasslands restored 

under the CRP. The study area was dominated by big bluestem (Andropogon gerardii), switchgrass (Panicum virgatum), 

little bluestem (Schizachyrium scoparium), and Indiangrass 

(Sorghastrum nutans). CRP fields were planted to native 

grasses. Grazed pastures and native prairie hayfields generally 

supported a more diverse assemblage of grassland birds than 

did CRP fields, especially burned CRP. The authors conclude, 

although CRP has benefited grassland birds in agriculturally 

dominated landscapes, CRP fields may have lower habitat 

value when within a matrix of native tallgrass prairie. Planted 

to native grasses, CRP fields differed structurally from native 

prairie hayfields or grazed pasture. Unburned CRP had higher 

standing crop biomass, more litter, greater amounts of dead 

standing grass, more forb cover, and higher diversity in structure. Dickcissels (Spiza americana) were the dominant species 

recorded in CRP fields. Grasshopper sparrows (Ammodramus 

savannarum) and eastern meadowlarks (Sturnella magna) 

were found in lowest numbers in CRP. The small size of CRP 

fields (12 hectares [30 ac]) also was identified as potentially 

limiting avian use in a grassland dominated landscape. Widespread grazing and annual burning in the Flint Hills study area 

has resulted in simplification of vegetative habitat diversity. 

Diversification of management practices is recommended to 

increase habitat diversity and conservation potential for Flint 

Hills’ grassland birds.

Renfrew, R.B., Ribic, C.A., and Nack, J., 2005, Edge avoidance by nesting grassland birds—A futile strategy in a 

fragmented landscape: The Auk, v. 122, no. 2, p. 618–636.
Non-Game Birds 107

An evaluation of edge effects is described for avian 

species (Savannah sparrow [Passerculus sandwichensis], 

grasshopper sparrow [Ammodramus savannarum], bobolink 

[Dolichonyx oryzivorus] and meadowlark [Sturnella spp.]) in 

grazed pastures in Wisconsin. Authors conclude edge avoidance by grassland passerines will not necessarily reduce predation in actively grazed pastures within fragmented agricultural 

landscapes. Authors recommend larger patches with larger 

core area will likely enhance productivity of these species. 

Removal of trees and shrubby hedgerows is recommended 

when practical but this approach may be practical only when 

few wooded areas are nearby and removal increases connectivity of larger pastures or grassland covers. Covers of 

adequate height, density, and structural variability are believed 

key in conservation of grassland birds. Decreased rates of 

livestock stocking could favorably maintain vegetation height 

density making it more difficult for predators to locate nests. 

Proper management of cattle may have as much an effect on 

grassland bird populations as management of patch and landscape characteristics. 

Reynolds, R.E., Shaffer, T.L., Sauer, J.R., and Peterjohn, B.G., 

1994, Conservation Reserve Program— Benefit for grassland birds in the Northern Plains, in Transactions of the 

North American Wildlife and Natural Resources Conference, 59, Anchorage, AK., March 18–23, 1994, Proceedings: Washington, D.C., Wildlife Management Institute, 

p. 328–336.

The report concludes that CRP cover is providing benefits 

for some grassland nesting birds. Nest success for ducks in 

CRP covers estimated to be 6–18 percent higher than reported 

for planted cover in WPAs. Authors believe CRP provides 

substantial benefits for species restricted to grassland habitat 

during the breeding season. Population status of lark bunting 

(Calamospiza melanocorys) and grasshopper sparrow (Ammodramus savannarum) improved after establishment of CRP in 

North Dakota. Authors state conditions in wintering habitats, 

or along migration routes, may be influencing population 

trends of neotropical migrants that have not shown positive 

response to CRP.

Ribic, C.A., Guzy, M.J., and Sample, D.W., 2009, Grassland 

bird use of remnant prairie and Conservation Reserve 

Program fields in an agricultural landscape in Wisconsin: 

American Midland Naturalist, v. 161, no. 1, p. 110–122.

CRP grasslands provide surrogate grassland habitats previously furnished by pasture and hayfields that have declined 

across agricultural landscapes over the last 50 or more years. 

These agricultural fields became important to grassland 

obligate birds as native grasslands diminished to less than 1 

percent of their original area. Less than 0.01 percent of native 

grasslands exist in Wisconsin today. Remnant prairies, agricultural set-aside lands (for example, CRP), and idle old fields 

consequently are valuable habitat for grassland birds. While 

alfalfa (Medicago sativa) and hay fields are used by grassland 

birds, they often become ecological traps because reproductive 

success is minimal due to haying during the nesting season. 

Successful management of grassland birds requires managers 

to assess conservation strategies on a larger landscape view 

of habitat conditions than individual properties or fields. The 

objective of this study was to understand how bird species use 

different grassland habitats by determining avian densities 

in CRP and remnant prairies compared to densities found in 

pastures, alfalfa hay and contour strip crop fields. Only habitat 

use by obligate grassland birds (bobolink [Dolichonyx oryzivorus], eastern meadowlark [Sturnella magna], grasshopper 

sparrow [Ammodramus savannarum], Henslow’s sparrow [A. 

henslowii], and Savannah sparrow [Passerculus sandwichensis]) was evaluated.

Remnant prairies were associated with knobs, ridges, or 

slopes on ground too steep, rocky, or thin to plow. Virtually 

all had been grazed at some time. Most of these sites were 

surrounded by cool-season exotic grasses, most often smooth 

brome (Bromus inermis). Dominant native species included 

little bluestem (Schizachyrium scoparium), big bluestem 

(Andropogon gerardii), needle grass (Stipa spartea), Indiangrass (Sorghastrum nutans), sideoats grama (Bouteloua 

curtipendula) and panicgrass (Panicum spp.). Average heightdensity of vegetation in these sites was 18.4 cm (4.0 in). CRP 

fields included in the investigation were originally enrolled 

in the program in 1987 or 1988 and were generally 15 yr old 

at the time of the study. Cool-season grasses dominated these 

fields, primarily smooth brome. Other grasses present included 

orchardgrass (Dactylis glomerata), timothy (Phleum pratense) 

as well as a wide variety of forbs. Many of the CRP fields had 

a scattering of woody vegetation present (for example, sumac 

[Rhus spp.]). The legume component, most often alfalfa, 

included in the original plantings of these fields was mostly 

absent. Average height-density of vegetation in CRP fields was 

33.8 cm (13.3 in). 

Habitat type was more important than landscape features 

in affecting grassland bird densities in this study completed in 

a largely grass-dominated landscape. Grasshopper sparrows 

were most abundant on remnant prairie. Savannah sparrows 

were found in greatest densities in pastures and hayfields, 

habitats that characteristically have annual disturbance. 

Henslow’s sparrows were found in greatest density in CRP 

fields and rarely observed in pasture or hay fields. Bobolink 

densities were highest in hay fields followed by CRP. Meadowlark densities were greatest in CRP fields, remnant prairie and pastures. The authors conclude when managing for 

grassland birds across a single agricultural landscape with a 

large amount of grassland a continuum of habitat types will be 

necessary to benefit grassland birds as a group.

Riffell, S.D., Scognamillo, and Burger, L.W., 2008, Effects of 

the Conservation Reserve Program on northern bobwhite 

and grassland birds: Environmental Monitoring Assessment, 

v. 146, p. 309–323.
108 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Breeding Bird Survey and NRIdata are used to evaluate potential benefits of the CRP to grassland birds and 

northern bobwhite quail (Colinus virginianus). Regression 

models were developed for 15 avian species in seven ecological regions. Ecological regions were based on classification 

defined by the North American Bird Conservation Initiative. 

Obligate grassland birds included in the study were: horned 

lark (Eremophila alpestris), grasshopper sparrow (Ammodramus savannarum), dickcissel (Spiza americana), eastern 

meadowlark (Sturnella magna), and western meadowlark (S. 

neglecta). Seven facultative grassland bird also were included 

in the evaluation: mourning dove (Zenaida macroura), eastern 

kingbird (Tyrannus tyrannus), loggerhead shrike ( Lanius 

ludovicianus), common yellowthroat (Geothlypis trichas), 

lark sparrow (Chondestes grammacus), red-winged blackbird 

(Agelaius phoeniceus), and eastern bluebird (Sialia sialis). The 

brown-headed cowbird (Molothrus ater), a nest parasite, and 

the indigo bunting (Passerina cyanea), a forest edge species, 

were also included in the analysis. 

Mean abundance of birds was calculated over a 5-yr 

period (1995–1999) on routes sampled in three or more of the 

five years. The time period corresponds to the dates of best 

estimates of CRP coverage. Because 1997 was the year most 

CRP contracts (10–15 yr) would not yet have expired, 1997 

was assumed to furnish the best cumulative estimates of CRP 

distribution. Land-use data was assessed in a 1,962 km2 (758 

mi2) area around each BBS used. CRP habitat comprised an 

average of 1.6 percent of the landscapes surrounding BBS 

routes. CRP grass habitats averaged 1.3 percent and CRP 

tree dominated covers accounted for an average coverage of 

1.3 percent. 

Analysis of data showed varying responses across ecological regions. Only the eastern meadowlark was positively 

related to CRP in all regions. The CRP was a strong predictor 

of bird abundance. The CRP, especially grass-legume was 

related to higher abundance of northern bobwhite across their 

breeding range. Populations of common yellowthroat, eastern 

meadowlark and indigo bunting were associated with higher 

amounts of CRP. Analysis of relationships between CRP for 

other avian species are presented and discussed.

The authors conclude that NRI data presently furnish 

relatively coarse-resolution information on CRP. More 

thorough investigations of relations between CRP and habitat 

quality for birds, as well as other species, could be possible if 

additional NRI data themes were available. These include, but 

are not limited to, spatial arrangement of fields, age of field, 

and specific conservation practices used. An ability to assess 

landscape configuration with variables such as edge density, 

patch size, and juxtaposition of cover types would greatly 

strengthen predictive capabilities of the data set. Availability 

of information on stand age, species composition, and successional stage would also be of benefit.

Robel, R.J., Hughes, J.P., Keane, T.D., and Kemp, K.E., 2003, 

Do artificial nests reveal meaningful patterns of predation 

in Kansas grasslands?: The Southwestern Naturalist, v. 48, 

no. 3, p. 460–464.

Fates of artificial and natural bird nests were determined 

in CRP fields planted to native grasses (Indiangrass [Sorghastrum nutans], big bluestem [Andropogon gerardii], little 

bluestem [Schizachyrium scoparium], sideoats grama [Bouteloua curtipendula], switchgrass [Panicum virgatum] and 

western wheatgrass [Agropyron smithii]). Artificial nests were 

intended to simulate those of the dickcissel (Spiza americana) 

the most common avian species nesting in northeastern Kansas CRP fields. Loss of artificial nests was only 9.8 percent 

(n=562) compared to 70.1 percent of 97 natural nests monitored. Consequently, authors conclude that depredation rates 

from artificial nests might not be representative of predation 

on natural nests. Authors attribute greater rates of predation 

on natural nests to the possibility of parental activity of adult 

birds, scent associated with incubated eggs, and heat associated with developing embryos, all of which could be factors 

affecting attraction of predators. Limitations associated with 

use of artificial nests in grasslands to determine predation rates 

need to be further investigated.

Robinson, S.K., Grzybowski, J.A., Rothstein, S.I., Brittingham, M. C., Petit, L.J., and Thompson, F.R., 1993, Management implications of cowbird parasitism on neotropical 

migrant songbirds, in Finch, D.M., and Stangle, P.W., eds., 

Status and management of neotropical migratory birds: Fort 

Collins, Colo., USDA Forest Service General Technical 

Report RM-229, p. 93–102. 

Brown-headed cowbirds (Molothrus ater) benefit directly 

from human activities resulting in population increases 

potentially threatening populations of many neotropical 

migrant songbirds. Authors recommend development of 

landscape approaches to management such as consolidation 

of ownerships to preserve large tracts of land and minimize 

edge habitat. Larger tracts are preferable to smaller ones and 

compact shapes (square) are preferable to complex shapes 

with high ratios of edge to interior. Maintenance and restoration of extensive areas of contiguous grassland are recommended. Acquisition should focus on inholdings to minimize 

fragmentation. Woody fencerows, snags and corridors within 

and adjacent to prairie should be removed. 

Rodenhouse, N.L., and Best, L.B., 1983, Breeding ecology 

of vesper sparrows in corn and soybean fields: American 

Midland Naturalist, v. 110, no. 2, p. 265–275.

Avian nesting success in corn and soybean fields is low 

with losses due primarily to agricultural operations and predation. Nest predation was higher near agriculturally nonproductive areas due to an increase in density and use by predators. 

On cultivated land, nest predators use linear non-cropped areas 

as travel lanes, thus higher predation can be expected near or 

within such areas. Breeding success would be greater if the 

number of tillage operations was reduced and crop residue was 

retained on the fields. 
Non-Game Birds 109

Rodenhouse, N.L., Best, L.B., O’Connor, R.J., and Bollinger, 

E.K., 1993, Effects of temperate agriculture on neotropical 

migrant landbirds, in Finch, D.M., and Stangle, P.W., eds., 

Status and management of neotropical migratory birds: Fort 

Collins, Colo., USDA Forest Service General Technical 

Report RM-229, p. 280–295.

Ecology of neotropical migrant landbirds is reviewed for 

the purpose of developing management recommendations in 

agriculturally dominated landscapes. Migrants constitute about 

71 percent of bird species using farmland and 86 percent of 

bird species nesting there. Number and abundance of avian 

migrants using farmland are greatest in uncultivated edges 

with trees and shrubs, less in uncultivated grassed areas, and 

least in row crops. Homogeneous landscapes with larger farms 

specializing in few commodities have created ecosystems 

lacking suitable interspersion of required habitats.

 Most migrants using temperate farmland are field 

or edge species. Agriculture is implicated in decline of all 

nine neotropical migrants currently listed, or candidates, as 

threatened or endangered. The percentage of farmland in hay/

pasture or in uncultivated semi-natural habitat has decreased 

in proportion to increase in area of intensively cultivated 

row crops. Migrant richness and abundance are greater in 

wider strips of uncultivated edge vegetation. Uncultivated 

wooded areas include wooded fencerows or the edges of fields 

bordering woodland, grassed edge includes some fencerows, 

waterways, terrace berms, road edges, and most land in the 

CRP. Breeding productivity of migrants in farmland is often 

low relative to number of offspring estimated needed to balance adult and juvenile mortality. Percentage of county area in 

the CRP was positively associated with the abundance of 19 

migrant species 12 of which were field species. 

 Areas in permanent cover, even if only grasses and 

no-till cropland, often support higher arthropod abundance 

than conventionally tilled fields. Arthropod abundance is 

greater near permanent vegetated field edges and greater in 

fields surrounded by complex habitats. Weed seeds are more 

abundant near uncultivated areas because seeds disperse from 

uncultivated areas and permanent vegetation concentrates 

wind dispersed arthropods and seeds. Homogenization of 

farmland lowers diversity and abundances of plants, seeds and 

arthropods within fields ultimately affecting the quality of the 

overall landscape as foraging habitat. 

Lands in CRP covers were associated with significantly 

more migrant species than resident species. Migrants strongly 

dominate the bird communities of farmland and numerous 

major crops are positively associated with some migrant species. The presence of sheltering vegetation may be needed for 

some avian species especially edge-associated species, which 

use farmland during migration. Farmland landscape complexity has been declining in most agricultural regions due to 

increased use of large equipment requiring larger field size, 

producing/rotating fewer crops, and consolidation/increased 

average size of farms. All contribute to reduction in vegetation diversity across agriculturally dominated landscapes. The 

absence of safe nesting sites may be the factor most limiting 

reproduction and survival of migrants in cropland. 

Future of agriculture: Long-term programs such as CRP 

are needed because they allow opportunities for research into 

more effective management of habitats in agroecosystems and 

lessen environmental impacts of agricultural production.

Management recommendations: The key issue in greater 

effectiveness and acceptance of wildlife/environmental 

management by landowners is recommendations which do 

not reduce, and perhaps enhance, farm profits. Management 

recommendations must consider farmland structure as well as 

agricultural practices and be approached in an interdisciplinary manner. Recommended agricultural practices include: 

maintenance of as much crop residue as possible on fields, 

use of integrated pest management, reduction in number of 

field operations (for example, tillage, chemical, and physical 

control of weeds) that destroy nests, delay spring mowing as 

long as possible, prevention of night mowing, and spacing 

of mowing operations as widely as possible in time to permit 

maximum success of nests. Considerations for improvement in 

farmland landscape structure include: encouragement of complex vegetation structure in uncultivated edges and idle nonfarmed areas, maintenance and enhancing overall diversity in 

cover types on farmland, increase diversity of crops produced, 

and reduction in field size. Advantageous uses of CRP land 

could be greater devotion of land to strip cover within fields 

or along field edges, and preservation of small wetlands with 

encircling, broad buffers of herbaceous vegetation.

Research needs: Long-term conservation programs such 

as the CRP are needed because they provide opportunities for 

research on bird response to evolving management of agricultural ecosystems. Greater attention should be given to getting 

understandable, technical information to users and landowners. Information simply cannot be restricted to technical or 

professional journals.

Rodgers, R.D., 2005, Conservation Reserve Program successes, failures, and management needs for open-land birds, 

in Allen, A.W. and Vandever, M.W., eds., The Conservation 

Reserve Program— Planting for the future— Proceedings 

of a National Conference, Fort Collins, Colo., June 6–9, 

2004: Reston, Va., U.S. Geological Survey, Scientific Investigations Report 2005–5145, p. 129–134.

Author characterizes application of periodic management as a key factor in creation and longevity of vegetatively 

diverse CRP stands that furnish wildlife habitat of high quality. 

However, appropriate management of CRP grasslands through 

periodic disturbance has been inadequate throughout most 

of the history of the program. Absence of management (for 

example, grazing, fire) had permitted encroachment of woody 

vegetation into CRP grasslands (for example, eastern red 

cedar, Juniperus virginiana), which unchecked will ultimately 

negate habitat benefits of these grasslands for many species of 

grassland wildlife. Various conservation practices using grass 

buffers available through Continuous Conservation Reserve 
110 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Program (CCRP) offer excellent opportunities to improve 

habitat in regions dominated by agricultural production but 

have been underused in the western and southern Great Plains. 

The author furnishes the following recommendations for 

refinement in future management of the program to benefit 

grassland dependent avian species. No further planting of 

aggressive exotic grasses should be permitted. Emphasis must 

continue on provision of species diverse stands with a strong 

forb component. A greater proportion of program acres should 

be shifted to localities near existing native grassland habitats. 

Invasive trees on existing CRP grasslands must be eliminated. Impractical incidental grazing restrictions on in-field 

CCRP linear conservation practices (for example, cross wind 

strips, grassed terraces) should be discontinued. Consultation 

between USDA, state wildlife agencies, and non-government 

organizations must continue, and increase, if optimization of 

soil, water, and wildlife conservation is to be expected. 

Ryan, M.R., Burger, L.W., and Kurzejeski, E.W., 1998, The 

impact of CRP on avian wildlife—A review: Journal of 

Production Agriculture, v. 11, no. 1, p. 61–66.

The report furnishes a review of quantitative data on 

grassland bird occurrence (species richness), abundance, 

and reproductive success in CRP during breeding season in 

the central United States. Over 90 avian species have been 

documented using CRP plantings during the breeding season. 

More than 40 avian species are recorded as nesting in CRP 

covers. Grasslands in CRP supported 1.4 to 10.5 times the 

number of individual birds as did crop fields. Nest abundance 

has been found to be from 8.8 to 27 times higher in CRP fields 

than recorded in crop fields. Overall, CRP produced about 

14 times as many songbirds as did crop fields. Waterfowl 

nesting in CRP fields is believed to be comparable to covers 

specifically managed for waterfowl production (for example, 

USFWS WPAs). Numbers of ring-necked pheasants (Phasianus colchicus) are believed to be 3 to 5 times higher after 

CRP plantings were established. Nest success of pheasants in 

CRP was greater than necessary for maintenance of growth in 

populations. Although use of CRP by northern bobwhite quail 

(Colinus virginianus) is substantial, direct evidence of CRP 

contributing to growth of quail populations is lacking. Overall, 

the CRP has provided high-quality breeding habitat for many 

grassland birds, including several experiencing long-term 

declines in populations. Avian response to CRP is sufficient 

to justify efforts to maintain long-term set aside provisions in 

future federal legislation. 

Sample, D.W., and Mossman, M.J., 1993, Habitat management guidelines for grassland birds on public and private 

land in Wisconsin: Monona, Wis., State of Wisconsin 

Memorandum Bureau of Research, 13 p. 

The likely major cause of decline of grassland birds 

is loss of breeding habitat due to conversion of pasture to 

row crops and early, frequent mowing of alfalfa. Primary 

goal of habitat management for grassland birds should be to 

maximize diversity and viability of grassland bird populations 

statewide, or on a regional basis. Special attention should be 

given to identifying current or potentially large tracts suitable 

for management. 

Schmutz, J.K., 1987, The effect of agriculture on Ferruginous 

and Swainson’s hawks: Journal of Range Management, 

v. 40, no. 5, p. 438–440.

Raptors are an important component of Great Plains ecosystems. This report furnishes a summarization of effects of 

cultivation and agricultural activity on hawk density in prairie 

region of Alberta. The density of ferruginous hawks (Buteo 

regalis) declined with increasing cultivation. In contrast, 

density of Swainson’s hawks (Buteo swainsoni) was higher in 

areas of moderate cultivation (11–30 percent) than in grassland 

dominated areas (less than 10 percent cultivation). Swainson’s 

hawks appeared to tolerate higher levels of cultivation. Ferruginous hawks have affinity for land with sparse and short vegetation and avoid areas where grasses are replaced by dense, 

tall crops. In contrast, Swainson’s hawks are more adapted to 

smaller prey common in ungrazed grassy borders of ponds, 

roads, and farmsteads than in intensively grazed pastures. If 

small patches of natural or semi-natural cover containing trees 

or shrubs are strategically distributed in agricultural areas 

Swainson’s hawks are likely to remain present in reasonable 

numbers. Ferruginous hawks require grassland and will be 

common only where this land use dominates the landscape.

Smith, M.D., Barbour, P.J., Burger Jr., L.W., and Dinsmore, 

S.J., 2005, Density and diversity of overwintering birds 

in managed field borders in Mississippi: Wilson Bulletin, 

v. 117, no. 3, p. 258–269.

This paper describes potential value of field borders 

established under USDA National Conservation Buffer Initiative as habitat for wintering birds in Mississippi. Greater 

densities of several sparrow species were observed along 

transects established in association with field borders. Effects 

of borders differed by avian species and plant community 

types. Diversity, species richness, and relative conservation value were similar between bordered and non-bordered 

edges. Authors conclude that field borders are practical tools 

that can be used to address multiple environmental issues 

and enhance habitat quality for wintering bird populations in 

agricultural landscapes. 

Within many intensively farmed landscapes buffers 

(grassed waterways, contour grass strips, filter strips, riparian 

buffers, crosswind trap strips, windbreaks, and shelterbelts) 

offer the only relatively permanent, non-disturbed covers. 

Field borders may be more broadly applied as they are not 

restricted to downslope field edges providing potentially 

important wintering habitat for avian species. Authors recommend field borders be maintained in early seral stages through 

periodic disturbance (for example, disking or fire) to furnish 

greater quantities of annual plant seeds during winter. Knowledge about avian and other wildlife use of habitats in winter
Non-Game Birds 111

within agricultural landscapes is lacking and needs greater 

attention to define optimal management practices for conservation in agricultural landscapes. 

Stanley, T.R., 2010, Land use and small mammal predation 

effects on shortgrass prairie birds: Journal of Wildlife Management, v. 74, no. 8, p.1825–1843.

An investigation of the potential effects of land use on 

small mammal (for example, thirteen-lined ground squirrel 

[Spermophilius tridecemlineatus], deer mouse [Peromyscus 

maniculatus]) predation on grassland bird nests is described. 

The author states, while benefits to mid- and tallgrass prairies 

are clear, it remains unclear if CRP provides suitable nesting 

habitat for shortgrass prairie birds. Also of interest was what 

effects elevated abundance of vegetation and seed sources 

furnished by CRP, had on species richness of potential predators. Native grassland sites were dominated by buffalograss 

(Buchloë dactyloides), blue grama (Bouteloua gracilis) and 

plains pricklypear (Opuntia polyacantha ). CRP fields in the 

northeastern Colorado study area were smooth brome (Bromus inermis) and wheatgrass (Agropyron spp.). Age of fields 

was not given. Land uses on shortgrass prairie are found to 

alter small mammal communities. Small mammal densities 

and richness were found to be greater along edges and on 

CRP compared to shortgrass sites. Survival of nests (artificial 

and natural) at edge and CRP sites did not differ from native 

sites. Small mammal communities were found not to affect 

nest survival. 

Swanson, D.A., Scott, D.P., and Risley, D.L., 1999, Wildlife 

benefits of the Conservation Reserve Program in Ohio: 

Journal of Soil and Water Conservation, v. 54, no. 1, 

p. 390–394.

Habitat use by grassland-dependent species was related 

to availability of CRP. More than half of fields sampled were 

mowed during the nesting season. Twenty-one of 40 fields 

were disturbed prior to August. On average, disturbed fields 

had 51 percent of acreage mowed or burned. Disturbed fields 

had significantly lower values for VOR, percent grass canopy 

cover, and mean herbaceous height than did nondisturbed 

fields. Mean age of fields was five years (2-7). Mean field size 

20 ac (8.1 hectares). Over 80 percent of fields sampled were 

dominated by timothy (Phleum pratense), orchardgrass (Dactylis glomerata) and clover (Trifolium spp.) Forty-three breeding bird species used CRP fields. Use by eastern meadowlarks 

(Sturnella magna) and bobolinks (Dolichonyx oryzivorus) 

significantly larger in CRP fields. All species were numerically 

more abundant in CRP fields contiguous with other grassland 

habitat than recorded in isolated fields.

Swengel, S.R., and Swengel, A.B., 2001, Relative effects 

of litter and management on grassland bird abundance in 

Missouri, USA: Bird Conservation International, v. 11, 

p. 113–128.

Bird surveys were conducted in 43 tallgrass prairie sites 

in southwest Missouri from 1992–1999. Relative importance 

of management type (rotational burning, rotational haying, or 

a combination of both) and litter volume on relative abundance of avian species was evaluated in relation to abundance 

of three declining grassland songbirds, Henslow’s sparrow 

(Ammodramus henslowii), grasshopper sparrow (A. savannarum), and dickcissel (Spiza americana). Haying resulted 

in significantly higher abundance than burning for all species 

except dickcissel. Due to greater amounts of litter subsequent 

to management rotational haying should be employed more 

than burning in management of these declining birds. Midsummer haying was believed to have less impact on nest 

density and production of birds than did cool-season burning. 

Thompson, F.R., Lewis, S.J., Green, J., and Ewert, D., 1993, 

Status of neotropical migrant landbirds in the Midwest—

Identifying species of management concern, in Finch, D.M., 

and Stangle, P.W., eds., Status and management of neotropical migratory birds: Fort Collins, Colo., USDA Forest 

Service General Technical Report RM-229, p. 145–158.

Authors encourage ecosystem management to address 

needs of the many species of high management concern in 

midwestern states. Grasslands are only one of several habitats 

that deserve special management attention. Grassland species 

identified as special management concern in order of decreasing importance were; Bairds’ sparrow (Ammodramus bairdii), 

dickcissel (Spiza americana), mountain plover (Charadrius 

montanus), bobolink (Dolichonyx oryzivorus), long-billed 

curlew (Numenius americanus), grasshopper sparrow (A. 

savannarum), lark bunting (Calamospiza melanocorys), 

upland sandpiper (Bartramia longicauda), burrowing owl 

(Athene cunicularia), scissor-tailed flycatcher (Tyrannus forficatus), Swainson’s hawk (Buteo swainsoni), and lark sparrow 

(Chondestes grammacus).

Thompson, T.R., Boal, C.W., and Lucia, D., 2009, Grassland 

bird associations with introduced and native grass Conservation Reserve Program fields in the Southern High 

Plains: Western North American Naturalist, v. 69, no. 4, 

p. 481–490.

Relative abundance of grassland birds is assessed within 

CRP fields planted to native grass mixtures and two introduced 

grass monocultures (weeping lovegrass [Eragrostis curvula], 

old world bluestem [Bothriochloa ischaemum]) in the shortgrass prairie region of the western Texas panhandle. Native 

grass CRP fields were mixes of sideoats grama (Bouteloua 

curtipendula), blue grama (B. gracilis), green sprangletop 

(Leptochloa dubia), switchgrass (Panicum virgatum) and buffalograss (Buchloë dactyloides). All fields included in the evaluation were at least 3 yr old, approximately 65 hectares (160 

ac) in size, and were considered to have been successfully 

established. Native grass fields were stratified into two types 

based on the presence of buffalo grass in the seeding mix.
112 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Sixteen bird species were identified in study fields during 

the breeding season. Species richness and abundance were 

similar among cover types. During the breeding season all 

fields were dominated by one or two bird species accounting 

for approximately 80 percent of all birds observed. Grasshopper sparrows (Ammodramus savannarum), Cassin’s sparrows 

(Aimophila cassinii), and western meadowlarks (Sturnella 

neglecta) accounted for more than 90 percent of all birds 

observed. Twelve bird species were observed on study fields 

during winter. Winter species richness differed between 

introduced and native fields. Introduced fields had lower relative avian abundance than did fields planted to native grasses. 

Western meadowlarks, horned larks (Eremophila alpestris), 

and Savannah sparrow accounted for over 94 percent of winter 

observations. Greater numbers of horned larks were observed 

in the native grass fields containing buffalograss; they were 

not observed in the lovegrass fields. No differences were 

observed for Savannah sparrows or meadowlarks with both 

species being observed in all fields. However, when compared 

to other cover types, Savannah sparrows were more abundant 

in native fields without the buffalograss component.

The authors conclude no one CRP seeding type is most 

attractive to grassland passerines but the fields provide an 

important tool for conservation. Compared to monocultures of 

introduced grasses, CRP fields planted to mixtures of native 

grasses promote increased avian abundance, diversity and 

use. The authors believe the pooling of CRP grasslands only 

into broad categories of native or introduced grasses risks less 

meaningful detection of biological results when evaluating the 

use of these fields by avian species.

Veech, J.A., 2006, A comparison of landscapes occupied by 

increasing and decreasing populations of grassland birds: 

Conservation Biology, v. 20, no. 5, p. 1422–1423.

Twenty years of Breeding Bird Survey data were used to 

identify stable, increasing, and decreasing populations of 36 

grassland bird species in relation to physical features of the 

landscape adjacent to survey routes using USDA NRI data. 

Populations increasing were associated with landscapes that 

contained significantly more restored grassland and rangeland 

but less forest land and urban land than landscapes inhabited 

by decreasing populations. There was no significant difference in proportion of cropland within landscape of increasing and decreasing population although cropland composed 

greater than 30 percent of many of these landscapes. Restored 

grassland typically was a very small proportion (less than 3.5 

percent) of total land cover but was significantly more common in landscape of increasing than decreasing populations 

of grassland birds. Rangeland and CRP land held the greatest 

potential for having a positive effect on grassland birds. CRP 

was typically a low component of landscape composition 

(2.9–3.2 percent). Author concludes the amount of grassland 

habitat within a landscape can affect population trends in 

grassland birds regardless of spatial configuration of individual grassland parcels. 

Vickery, P.D., and Herkert, J.R., 2001, Recent advances in 

grassland bird research—Where do we go from here?: Auk, 

v. 118, no. 1, p. 11–15.

Although several species of grassland birds have shown 

benefits and positive response to the CRP, other species 

have shown continuing declines in populations. Unrelenting declines point to the complexities in diagnosing reasons 

behind diminishing avian populations. One or more of the 

following reasons may be the cause; CRP has not provided 

enough habitats to offset losses of grasslands, CRP fields 

may be too small, CRP grasslands are possibly population 

sinks, and/or problems affecting the species that continue 

to decline are not limited to the breeding grounds. More 

research needs to be directed toward definition of problems on 

wintering grounds.

Warner, R.E., 1992, Nest ecology of grassland passerines on 

road rights-of-way in central Illinois: Biological Conservation, v. 59, no. 1, p. 1–7.

Availability of suitable grassland cover has decreased in 

response to an increase in row crop farming. Fescue (Festuca

spp.) supported relatively few breeding birds. Where farming is diversified and habitat conditions are more favorable, 

road rights-of-ways and other linear habitats are used more 

extensively by birds. Use is influenced by habitat conditions 

in vicinity of strip and regional land use. Managed roadsides 

were important to passerine species even where hay was present because most nests in hay fields are destroyed during harvest. Management practices recommended to benefit grassland 

birds were described as: seed to brome/alfalfa (Bromus inermis/Medicago sativa) and or native grasses and forbs, delay 

mowing until after August 1, maximize strip habitat widths, 

and encourage establishment of shelterbelts and woody plants 

in some areas to enhance diversity of species attracted to 

strip vegetation.

Warren, K.A., and Anderson, J.T., 2005, Grassland songbird 

nest-site selection and response to mowing in West Virginia: 

Wildlife Society Bulletin, v. 33, no. 1, p. 285–292.

Former hayfields and pastures are becoming a more common component of the landscape in the eastern United States 

due to changing farming and land-use practices as well as 

purchase of farmland for other uses. Authors report investigation of grassland bird nest site selection and success between 

idle and mowed pastures and hayfields. Dominant vegetation 

on study fields included orchardgrass (Dactylis glomerata), 

mountain oatgrass (Danthonia compressa), sweet vernalgrass 

(Anthoxanthum odoratum), quackgrass (Elymus repens), and 

timothy (Phleum pratense). Avian nests monitored included 

bobolink (Dolichonyx oryzivorus), eastern meadowlark (Sturnella magna), red-winged blackbird (Agelaius phoeniceus), 

and savannah sparrow (Passerculus sandwichensis).
Reptiles and Amphibians 113

Authors conclude management that increases vertical 

structure and density should be promoted for grassland birds 

through mowing, grazing, and prescribed burning to set back 

grassland succession. These management techniques are 

recommended to prevent encroachment of woody vegetation 

and too excessive litter layer from developing in undisturbed 

fields. Leaving blocks of cover idle for 1–4 yr is recommended 

to maintain overall diversity in vegetation composition. 

Wentworth, K.L., Brittingham, M.C., and Wilson, A.M., 2010, 

Conservation reserve enhancement program fields— Benefits for grassland and shrub-scrub species: Journal of Soil 

and Water Conservation, v. 65, no. 1, p. 50–60.

Between 2000 and 2004, almost 74,100 acres (30,000 

hectares) of grassland were established in south-central 

Pennsylvania through the CREP. Avian surveys on 103 CREP 

fields found 32 species using these fields during the breeding 

season of which the red-winged blackbird (Agelaius phoeniceus) was the most abundant. The next most abundant species 

(song sparrow [Melospiza melodia], indigo bunting [Passerina 

cyanea], field sparrow [Spizella pusilla]) are typically associated with scrub-shrub habitats. Grassland obligate species 

(vesper sparrow [Pooecetes gramineus], savannah sparrow 

[Passerculus sandwichensis], grasshopper sparrow [Ammodramus savannarum], bobolink [Dolichonyx oryzivorus], eastern 

meadowlark [Sturnella magna]) were rare and most abundant 

in larger, cool-season dominated grass fields.

The CREP fields examined in this investigation lie within 

a forest-dominated landscape where fields tend to be small and 

irregularly shaped. Bird communities within this south-central 

Pennsylvania landscape differ from Midwest avian communities where the majority of studies on CRP avian use have been 

completed. Field size and within-field vegetation type had a 

strong influence on avian use. Grassland obligates were most 

abundant on larger fields with a lower density of vegetation. 

Avian species related with shrub-scrub dominated habitats 

were associated with smaller fields and a higher proportion of 

warm-season grasses. The authors conclude management of 

larger fields, to maintain less dense cool-season grass cover, 

and targeting smaller field adjoining woodlands may be an 

effective way to maximize the potential of CREP fields to 

provide habitat for a range of avian species in this region.

Wilson, J.D., Whittingham, M.J., and Bradbury, R.B., 2005, 

The management of crop structure—A general approach 

to reversing the impacts of agricultural intensification on 

birds?: Ibis, v. 147, p. 453–463.

Across Europe and North America intensification in 

production of agricultural products has widely been identified with declines in populations of birds associated with 

these landscapes. A major cause of declines in habitat quality 

is simplification of cover type structure and diversity across 

the landscape. Reversal in trends of simplified, homogeneous 

cover type is believed to improve nesting and foraging habitat

conditions for a wide range of avian species and may represent 

a cost-effective approach for further improvements in agroenvironmental conservation policies. Written mainly from a 

British perspective, the paper discusses effects of agricultural 

intensification of production, relations to avian habitat quality, 

and presents methods to reestablish diversity in agriculturally 

dominated landscapes.

Winter, M., Johnson, D.H., and Shaffer, J.A., 2005, Variability in vegetation effects on density and nesting success of 

grassland birds: Journal of Wildlife Management, v. 69, 

no. 1, p. 185–197.

The structure of grassland vegetation varies dramatically among years on the same sites and among regions with 

similar vegetation. Understanding of influence of variation 

in vegetation structure on bird density and nesting success is 

poorly understood because few studies have included sufficiently large temporal and spatial scale to capture variation in 

vegetation structure, avian density, or nesting success. Effects 

of vegetation structure on density and nesting success of three 

species (clay-colored sparrow [Spizella pallida], Savanna 

sparrow [Passerculus sandwichensis], and bobolink [Dolichonyx oryzivorus]) in northern tallgrass prairie are described.

Each species responded differently to vegetation variables. Because avian response varied among regions, years, 

and species, land managers need to furnish grasslands with 

differing types of vegetation structure as management guidelines based on small-scale, short-term studies may lead to 

misrepresentation of the needs of grassland avian species. 

High annual and regional variability in grassland systems 

requires studies on avian species extend over a wide geographic region and over several years. Management for several 

species requires establishment of a mosaic of management 

regimes that furnish various types of vegetation conditions 

across the landscape. 

Reptiles and Amphibians

Burrow, A.L., Kazmaier, R.T., Hellgren, E.C., and Ruthven III, 

D.C., 2001, Microhabitat selection by Texas horned lizards 

in southern Texas: Journal of Wildlife Management, v. 65, 

no. 4, p. 645–652.
114 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Horned lizards (Phrynosoma cornutum) occur throughout 

Texas, Oklahoma, and parts of Kansas, Missouri, New Mexico, and Arizona. Loss of habitat, introduction of the fire ant 

(Solenopsis invicta) and use of insecticides have contributed 

to the declining abundance of the species throughout its range. 

Open habitats resulting from relatively frequent disturbance 

are thought to be prime habitats. The species requires variety 

in habitat structure since resource needs change throughout 

the day and season. Favored habitat includes a mosaic of bare 

ground, herbaceous, and woody vegetation in close proximity. 

Donaldson, W., Price, A.H., and Morse, J., 1994, The current 

status and future prospects of the Texas horned lizard (Phrynosoma cornutum) in Texas: The Texas Journal of Science, 

v. 46, no. 2, p. 97–113.

The Texas horned lizard is a threatened species in Texas 

and a Federal category 2 candidate species. Primary reasons 

for decline of species, are habitat alteration or destruction by 

agriculture and urbanization, use of insecticides on crops and 

direct and indirect effects of the imported red fire ant (Solenopsis invicta). Agriculture seems to be the primary factor in 

absence of horned lizard populations in Texas. Best conservation measures to restore populations of horned lizard would be 

re-establishment of native vegetation communities that remain 

unplowed and untreated with agrochemicals.

Forson, D.D., and Storfer, A., 2006, Atrazine increases Ranavirus susceptibility in the tiger salamander, Ambystoma 

tigrinum: Ecological Applications, v. 16, no. 6, 

p. 2325–2332.

Pathogenic diseases and environmental contaminants are 

leading hypotheses for the decline in amphibian populations. 

Amphibians, because of their permeable skin and biphasic 

life history, are considered to be indicators of environmental 

quality. This report describes the influence of contaminants 

on susceptibility to disease in amphibians by determination of the effects of ecologically relevant doses of atrazine, 

sodium nitrate and in laboratory-bred tiger salamander to 

Ambystoma tigrinum virus (ATV). Atrazine and sodium nitrate 

significantly decreased peripheral leukocyte levels suggesting impacts on the immune system increasing susceptibility 

of larvae to ATV infection. Study results suggest ecologically 

relevant concentrations of atrazine have immunosuppressive 

effects possibly contributing to ATV epizootics. 

Gray, M.J., and Smith, L.M., 2005, Influence of land use on 

postmetamorphic body size of playa lake amphibians: Journal of Wildlife Management, v. 69, no. 2, p. 515–524.

The densities, health, and survival of amphibians may be 

affected by alteration of wetland hydroperiods due to agricultural land use around wetlands. Effects of agricultural land 

use on spadefoot toad (Spea multiplicata), plains spadefoot 

toad (S. bombifrons), Great Plains toad (Bufo cognatus), and 

barred tiger salamander (Ambystoma tigrinum) surrounding 

playa wetlands are described. For most age classes of amphibians monitored, body size was 10–148 percent greater in 

playas surrounded by grassland than found within wetlands 

surrounded by crop production. Greater body size is related 

to greater survival. Study results suggest amphibian in playas 

surrounded by cultivated land may be smaller than those found 

in wetlands not affected by agricultural land use. Although 

other factors may influence survival (for example, hydroperiod, conspecific density, predators), restoration of grassland 

covers around playas is recommended to increase survival and 

habitat quality for these species.

Gray, M.J., Smith, L.M., and Brenes, R., 2004, Effects of 

agricultural cultivation on demographics of Southern High 

Plains amphibians: Conservation Biology, v. 18, no. 5, 

p. 1368–1377.

Few data exist on effects of agriculture of wetland 

watersheds on amphibian populations. Paper describes effect 

of cultivation of playa wetlands on demographics of amphibians (New Mexico spadefoot toad [Spea multiplicata], Plains 

spadefoot toad [S. bombifrons], Great Plains toad [Bufo cognatus], Woodhouse’s toad [B. woodhousii], spotted chorus frog 

[Pseudacris clarkii], plains leopard frog [Rana blairi], and 

barred tiger salamander [Ambystoma tigrinum mavortium]) in 

the Southern High Plains of Texas.

Cropland playas had a higher abundance of amphibians than did grassland playas. No difference in mean daily 

diversity of the amphibian assemblage was detected between 

land use types. Abundance of spadefoot toads in cropland 

playas may be attributed to confinement of individuals in suitable habitat surrounded by cultivation. Geometric complexity 

and edge density were greater in cropland playas than within 

grassland playas. Roads and other habitat factors affecting 

movement and dispersal of spadefoot toads may have resulted 

in increased abundance in natal wetlands. Density of larval 

and neotenic barred tiger salamanders (a keystone predator of 

other amphibians in playas) was greater in playas surrounded 

by grassland than in cropland playas. Grassland playas 

generally have greater volume and longer hydroperiod than 

cropland playas allowing establishment of tiger salamander 

populations making other amphibian larvae more susceptible 

to predation in the wetlands more characteristic of non-agricultural conditions. 

Other factors that may influence greater numbers of 

spadefoot toads in agricultural playas are greater plant diversity and structure in cropland playas, which could increase 

food resources, and escape cover for larvae. Nitrogen influx 

from fertilizers may increase food resources for larval amphibians in cropland playas. Pesticide drift and runoff into cropland playas may reduce density of aquatic insects, which can 

compete with amphibian larvae for food resources. However, 

authors believe these factors were not ultimate reasons affecting differences between disturbed and undisturbed wetlands.
Reptiles and Amphibians 115

Authors conclude agricultural disturbance around wetlands may positively affect abundance of some amphibian 

species. Less vagile species are competitively dominant in 

absence of predation and may benefit most as a consequence 

of landscape cultivation. This does not, however, imply 

better conditions for amphibian populations. These populations may be less stable particularly if they exceed carrying 

capacity. Amphibian populations in cultivated landscapes also 

may function as ecological sinks more often than population 

sources resulting in these populations being more susceptible 

to local or metapopulation extinction than populations inhabiting more pristine habitats. 

Kolozsvary, M.B., and Swihart, R.K., 1999, Habitat fragmentation and the distribution of amphibians—Patch and landscape correlates in farmland: Canadian Journal of Zoology, 

v. 77, p. 1288–1299.

The most important negative effects of humans on 

amphibian populations are modification and destruction of 

habitat. In the midwestern United States, much of the historic 

habitat modification has resulted from massive land clearing 

and drainage of wetlands for agricultural purposes. Amphibians requiring aquatic sites for breeding and moist upland sites 

for foraging, or hibernation, may be especially susceptible to 

agricultural fragmentation of the landscapes. Species with high 

vagility and broad environmental tolerance are less affected by 

fragmentation of the landscape. In contrast, species that have 

limited mobility, require large tracts of forest cover, or have 

specific requirements for seasonal habitats are more severely 

affected by fragmentation. Authors developed model furnishing general predictions concerning how amphibian distribution 

could be affected in an agriculturally fragmented landscape 

(west-central Indiana). Species exhibited a high degree of 

nestedness in the agricultural landscape, which has probably developed since massive land clearing, and alteration of 

wetlands and hydroperiods. Amphibian species richness was 

highest for sites dominated by seasonal and semipermanent 

wetlands or sites containing a mixture of wetlands with various water regimes. The ability of a species to move through 

a cropland matrix is believed to be critical to its persistence 

in farmland. 

Langford, G.J., Borden, J.A., Major, C.S., and Nelson, D.H., 

2007, Effects of prescribed fire on the herpetofauna of a 

southern Mississippi pine savanna: Herpetological Conservation and Biology, v. 2, no. 2, p. 135–143.

Little research is available describing effects of prescribed fire on herpetofauna in the Gulf Coastal plain. The 

southeast is one of the most fire-dependent regions in the 

United States, with prescribed fire becoming an increasingly 

important tool in habitat and ecosystem management. In 

absence of fire, hardwood species become dominant in pine 

communities. Species endemic to southeastern pine forests 

(for example, Flatwood salamander [Ambystoma cinculatum], 

Oak toad [Bufo quercicus]) suffer loss of habitat resulting 

from changes in structure and vegetation diversity. The study 

was conducted in a mosaic of pine flatwoods and southern 

wiregrass (Aristida beyrichiana) savanna with open canopies 

of slash pine (Pinus elliottii) dominant. Other representative pines included slash pine (P. elliottii) and longleaf pine 

(P. palustris). Overall the authors conclude prescribed fire 

had little, if any, effect on amphibians and reptiles in the 

study area. The study suggests low intensity prescribed fire 

increased the number of individual herpetofauna in study area 

pine savannas. 

McIntyre, N.E., 2003, Effects of Conservation Reserve Program seeding regime on harvester ants (Pogonomyrmex), 

with implications for the threatened Texas horned lizard 

(Phrynosoma cornutum): The Southwestern Naturalist, 

v. 48, no. 2, p. 274–313.

Abundance of harvester ant nest sites, primary prey for 

endangered Texas horned lizard, evaluated in CRP grasslands and native prairie in Texas panhandle sites. CRP fields 

evaluated were planted to Old World bluestem (Bothriochloa 

ischaemum), weeping lovegrass (Eragrostis curvula), or mixtures of native grasses with and without buffalograss (Buchloë 

dactyloides). Native grass CRP plantings were dominated 

by sideoats grama (Bouteloua curtipendula), blue grama (B. 

gracilis), and switchgrass (Panicum virgatum). (Estimates 

of field age, comparisons of density, and other vegetation 

characteristics between seeded and native grasslands were not 

described). The fewest ant mounds were found within fields 

planted to Old World bluestem. Native (ungrazed) grassland 

had the highest density of ant mounds. However, no significant 

difference between abundance of ant mounds in native and 

exotic CRP plantings were reported. Author concludes there 

is no evidence CRP plots planted to exotic grasses are poorer 

habitat for Texas horned lizards in terms of ant abundance than 

are native plantings. 

Newbold, T.A.S., 2005, Desert horned lizard (Phrynosoma 

platyrhinos) locomotor performance—The influence of 

cheatgrass (Bromus tectorum): The Southwestern Naturalist, 

v. 50, no. 1, p. 17–23.

An investigation of the influence of vegetation structure 

on the distribution patterns of desert horned lizards and the 

effect cheatgrass has on ability of the species to move through 

its habitat. Physical structure of vegetation has non-thermal 

effects on animals. Shrub and grass densities affect the amount 

of bare substrate and can have an influence on distribution 

patterns. Negative association between lizard scat abundance 

and cheatgrass cover suggesting the lizard avoids areas with 

higher density of cheatgrass. Results demonstrate negative 

effect of cheatgrass and the potential detrimental consequences 

of cheatgrass invasion on distribution patterns of the horned 
116 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

lizard. Altered soil properties and exclusion of native plants 

are consequences of cheatgrass dominance. 

Relyea, R.A., 2005, The lethal impact of Roundup on aquatic 

and terrestrial amphibians: Ecological Applications, v. 15, 

no. 4, p. 1118–1124.

Although there is evidence pesticides may play a role in 

large-scale decline in amphibian populations few pesticides 

have been tested on these species. Author reports results of 

testing impact of Roundup overspray on leopard frogs (Rana 

pipiens), American toad (Bufo americanus), and gray tree 

frog (Hyla versicolor) tadpoles in outdoor pools. Roundup is 

a globally common herbicide widely thought to be nonlethal 

to amphibians. The herbicide is a glyphosate also sold under 

the brand names of Rodeo and Aqua Master. The herbicide 

is widely used to control weeds and often used in association 

with Roundup-ready corn and soybean production as well as 

in forestry, aquatic weed control, and residential applications. 

Roundup was the second most commonly used pesticide in 

1999 in the United States with 30–33 million kg of active 

ingredient applied on over 8 million hectares (greater than 19 

million acres).

 The most striking result of this investigation is that a 

herbicide designed to kill plants had fatal results on almost all 

tadpoles within 3 weeks and 79 percent of all juveniles within 

one day. Three weeks after application of the herbicide 96–100 

percent of larval amphibians exposed to Roundup died. 

Juvenile (post-metamorphic) anurans were exposed to direct 

overspray of the herbicide resulting in 68-86 percent mortality 

within one day. Cause of mortality appears to be from direct 

toxicity rather than reduction of algal food resources. Author 

concludes Roundup can cause extremely high rates of amphibian mortality resulting in declines in populations. 

Semlitsch, R.D., and Bodie, J.R., 2003, Biological criteria 

for buffer zones around wetlands and riparian habitats for 

amphibians and reptiles: Conservation Biology, v. 17, no. 5, 

p. 1219–1228.

Often overlooked for their value to semiaquatic species, 

terrestrial habitats surrounding wetlands are important for 

more than just protection of water quality. A close dependence 

of semiaquatic reptiles and amphibians on terrestrial cover 

types in proximity to wetlands is exhibited for critical lifehistory functions such as foraging, overwintering, or nesting. 

Criteria by which to define habitat requirements for most 

species and associated regulations to protect spatial relations 

between wetlands and terrestrial habitats are lacking. Conservation and management plans must consider both local and 

landscape dynamics, however, core habitats for local populations of species must be defined before issues of wetland and 

terrestrial connectivity can be addressed.

 Literature review by authors suggest overall core terrestrial habitat for amphibians ranged from 159 to 290 m 

(175 to 317 yd) and that of reptiles ranged from 127 to 289 

m (140 to 316 yd) from edge of aquatic sites. While wetlands 

vary in many characteristics, the authors suggest a single allencompassing value for the size of core habitats can be used 

effectively. On private lands, or areas where sustainable land 

use is the priority, a stratified system of protection zones can 

minimize impacts to wildlife. Authors propose three terrestrial 

zones adjacent to core aquatic and wetland habitats: Zone 1, 

area immediately adjacent to wetland restricted from use and 

designed to buffer the core aquatic habitat; Zone 2, core terrestrial zone that encompasses the core terrestrial habitat defined 

by semiaquatic species of priority (for example, amphibians 

159–290 m); Zone 3, beyond zone 2 serves to buffer the core 

terrestrial habitat from surrounding land use. Decisions on 

how restrictive each zone may be to land-use practices would 

depend on management goals and species of concern. Authors 

suggest buffers 15–30 m (16–33 yd) wide used to protect wetland species in many states are inadequate for amphibians and 

reptiles. A table providing summary data for movement data of 

reptiles from wetlands is furnished.

Soils

Baer, S.G., Rice, C.W., and Blair, J.M., 2000, Assessment of 

soil quality in fields with short and long term enrollment 

in the CRP: Journal of Soil and Water Conservation, v. 55, 

no. 2, p. 142–146.

Surface soil quality was examined in fields representing short and long-term enrollment in CRP. Total C and N 

amounts were similar in both types of enrollment but lower 

than recorded in native prairie. Measures of C and N, however, 

did increase in response to greater time in the CRP. Long-term 

establishment of native grasses exhibited 141 percent and 93 

percent greater microbial biomass C and N than soil recently 

enrolled in CRP. Putting land in CRP promotes soil restoration 

but 10 growing seasons (the typical enrollment period) are not 

adequate for recovery of total soil N and C pools. Soil organic 
Soils 117

C is estimated to have declined 24 to 60 percent in the Great 

Plains soils due to cultivation. Total C and N pools were not 

different between soils recently enrolled and those planted to 

CRP grasses for 10 years. The improvements in soil quality 

can decline rapidly on CRP lands if conventional tillage practices are resumed when contracts are terminated.

Burke, I.C., Lauenroth, W.K., and Coffin, D.P., 1995, Soil 

organic matter recovery in semiarid grasslands—Implications for the Conservation Reserve Program: Ecological 

Applications, v. 5, no. 3, p. 793–801.

There has been a modest amount of work completed on 

quantification of long-term recovery of soil organic matter 

and nutrient supply lost due to cultivation. Soil organic matter, 

silt content, microbial biomass, potentially mineralizable N, 

and potentially respirable C were significantly lower in soils 

of cultivated fields than in fields of native grass. Abandoned 

fields were not significantly different from native fields with 

respect to microbial biomass, potentially mineralizable N, or 

respirable C. Authors suggest 50 yr is necessary for recovery of active soil organic matter and nutrient availability but 

recovery of total soil organic matter is a much slower process. 

Ultimately establishment of perennial grasses determines the 

rate of organic matter recovery.

Losses of soil organic matter in the central grassland 

region were attributed to cultivation and cropping effects that 

increase outputs from soil and decrease residue inputs. Tillage 

increased erosion and decomposition through physical mixing, 

degradation of soil aggregates, and enhanced contact of litter 

and soil organic matter with decomposing organisms. Annual 

crop plants have lower belowground biomass production than 

native perennial grasses. Decades of continuous cultivation 

have led to losses in surface soil organic matter (0–20 cm [0–8 

in] depth) of between 20–40 percent. Historical losses of soil 

organic matter represent a significant transfer of C to the atmosphere as well as regional losses in production potential. 

Study was conducted in northeast Colorado in shortgrass 

steppe blue grama (Bouteloua gracilis). Soils tilled for a longer period of time had greater decrease in silt content. Silt is 

the soil component most susceptible to wind erosion. Silt content significantly influences rate of recovery of blue grama in 

shortgrass ecosystems. A 10-percent reduction in silt content 

may reduce grass seedling establishment rates by 90 percent. 

Long-term losses of soil organic matter from cultivated fields 

represent a significant decline in soil fertility due to decreased 

availability of nutrients. Losses of fine soil particles and total 

soil organic matter are not likely to be recovered over human 

time scales. The carbon-capture rates from recovering fields in 

semiarid regions are extremely slow.

Fuhlendorf, S.D., Zhang, H., Tunnell, T.R., Engle, D.M., 

and Cross, A.F., 2002, Effects of grazing on restoration of 

southern mixed prairie soils: Restoration Ecology, v. 10, 

no. 2, p. 401–407.

An analysis of grazing effects of cultivated lands 

reseeded to native grasses under CRP and native prairies never 

cultivated, but managed similarly, undertaken in Oklahoma. 

Vegetation monitored in study is typical of southern mixed 

prairie perennial species with dominant species varying 

depending on physical conditions and past land use. Common 

mid grasses were sideoats grama (Bouteloua curtipendula), 

purple threeawn (Aristida purpurea), and silver bluestem 

(Bothriochloa laguroides). Dominant short grasses included 

blue grama (B. gracilis) and hairy grama (B. hirsuta). Less 

common tall grasses included little bluestem (Schizachyrium 

scoparium), yellow Indiangrass (Sorghastrum nutans), and big 

bluestem (Andropogon gerardii).

Management of domestic livestock on rangelands, 

including land planted to grasses but no longer actively part 

of the CRP, can have variable effects on soil fertility, vegetation composition and structure thereby influencing the rate of 

recovery of restored grasslands. Grazing may also influence 

amounts, spatial pattern, and composition of nutrient accumulation in soil. Authors conclude that, regardless of cultivation 

history, soils and vegetation on heavily grazed sites differed 

significantly from that on moderately grazed sites. On restored 

(CRP) sites soil N and C were higher with moderate grazing 

than with heavy grazing. On native prairie sites grazing only 

minimally affected soil nutrients. Heavy grazing on former 

CRP sites reduced litter accumulation and abundance and 

increased bare ground, which led to reduction in accumulation 

of organic matter and nutrients. Results of this study suggest 

heavy grazing on native mixed prairie has little influence but 

heavy grazing on restored mixed grasslands (CRP) actually 

reduces rate of soil nutrient and organic matter accumulation. 

Authors state data support USDA policies of limited grazing 

on CRP grasslands if the objective is restoration of grassland 

ecosystems or building soil C pools. 

Gebhart, D. L., Johnson, H.B., Mayeux, H.S., and Polley, 

H.W., 1994, The CRP increases soil organic carbon: Journal 

of Soil and Water Conservation, v. 49, no. 5, p. 488–492.

Replacement of cropland to perennial grassland associated with CRP may sequester atmospheric C back into the 

soil C pool, thereby changing cultivated soils from sources to 

sinks for atmospheric carbon. Soil organic C was evaluated 

in cropland, native pasture, and 5-yr-old CRP fields in Texas, 

Kansas, and Nebraska. Across all locations, soil organic C for 

cropland, CRP, and native pasture was 59.2, 65.1, and 90.8 

metric ton C/ha (2.5 ac) in upper 300cm (118 in) of surface. 

CRP lands gained an average of 1.1 tons C/ha/yr (0.4 ton/ac/

yr). Findings illustrate that agricultural CO2 emissions might 

be effectively controlled through changes in land use and 

management systems.

Many Great Plains soils have declined in organic C content and nutrient supplying capacity since initially cultivated. 

Losses of 24–70 percent are estimated from soils cultivated 

30-43 years. Authors estimate cultivated croplands in U.S. lose 

about 2.7 million metric ton of C year (6 billion lbs/yr). An 
118 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

additional 35.4 million metric tons are released to the atmosphere yearly from agricultural fossil fuel use and manufacture 

of N fertilizers. CRP grasslands reduce atmospheric CO2 levels 

and increase soil organic C as a consequence of litter accumulation into surface soils and net primary production allocated 

to root growth. Recovery of soil organic C to pre-cultivation 

levels may take 50 or more years under perennial grasses.

Average soil organic C levels for CRP and cropland were 

significantly lower than those for native pasture indicating 

cultivation had markedly reduced pools of soil organic carbon. 

Depletion of soil organic C with initial cultivation was attributed to tillage-induced changes in plant species composition 

and inputs of C from roots to soils. Cultivation also increases 

soil temperature and microbial activity, which increase decomposition of organic matter and C content. Across all locations 

soil organic C levels in CRP were significantly greater than 

recorded in cropland to depth of 40 cm (16 in). After 5 yr of 

perennial grass cover, only 21 percent of C lost during decades 

of intensive tillage had been replaced. Carbon was 34 percent 

greater in the 0–5cm (0–2 in) depth but amount of C decreased 

with increasing depth. Greater biomass of grass roots may 

also contribute to higher C content. Authors cite other studies 

that describe mean annual C inputs to grassland soils are 90 to 

800 percent greater than inputs into cultivated soils. Authors 

speculate the 17 million hectares (42 million ac) of cropland 

enrolled in CRP may have potential to sequester about 45 

percent of the 38.1 million metric tons of C released annually 

into the atmosphere by U.S. agriculture.

Gewin, V.L., Kennedy, A.C., Veseth, R., and Miller, B.C., 

1999, Soil quality changes in eastern Washington with Conservation Reserve Program (CRP) take-out: Journal Soil and 

Water Conservation, v. 54, no. 1, p. 432–438.

Study results suggest a relative decrease of up to 10 mg 

CO2-c10 g soil in readily mineralized C (RMC) results from 

conventional tillage. Most substantial decrease in C was 

immediately following tillage treatments. RMC represent 

the amount of C readily available to microbial communities. 

Fluctuations in amount of RMC result from soil disturbance 

and amount and species composition of ground cover. Crested 

wheatgrass (Agropyron cristatum) may reduce soil quality 

compared to native grasses species as a result of lower root 

exudates and unstable organic matter. Direct seed treatments 

were most similar to original CRP condition when compared 

to conventional tillage. No decrease in RMC was found with 

direct seeding. Direct seeding maintained soil quality conditions better than conventional practices. 

Huang, X., Skidmore, E.L., and Tibke, G.L., 2002, Soil quality of two Kansas soils as influenced by the Conservation 

Reserve Program: Journal of Soil and Water Conservation, 

v. 57, no. 6, p. 344–350.

This evaluation compared soil chemical and physical properties after 10 yr of enrollment in CRP to land 

continuously cropped. Improvements in soil quality attributed 

to CRP included reduction of soil acidification, less soil compaction, and reduction of topsoil erosion. When land in CRP 

was returned to crop production with conventional tillage total 

C in surface layer and aggregate stability gradually decreased. 

Significant recovery in obtaining higher levels of soil C levels 

would require more than the standard 10-year CRP contract. 

Authors suggest appropriate land management practices are 

needed to maintain residual benefits to soil quality derived 

from CRP enrollment.

Hughes-Popp, J.S., Huszar, P.C., and Hoag, D.L., 2000, 

Reducing wind erosion damages and the Conservation Reserve Program, in Napier, T.L., Napier, S.M., and 

Tvrdon, J., eds., Soil and water conservation policies and 

programs—Successes and failures: Washington, D.C., CRC 

Press, p. 143–154.

The CRP is an extension of soil conservation policies 

begun after the 1930s dust bowl by either purchasing or 

renting highly erodible land to retire it from production and 

susceptibility to erosion. Erosion is a significant problem in 

the U.S. with more than 2 billion tons of soil lost per year on 

non-federal cropland. Forty-four percent of this loss is due to 

wind. Over 770 million tons (80 percent of all erosion in the 

western United States) is caused by wind. This represents 36 

percent of all soil erosion in the United States. 

Authors conclude the CRP has not effectively addressed 

western soil-erosion issues. Greater benefits of the CRP may 

be realized by selecting program land not on the basis of 

greatest erosion rate but on combination of erosion rates, land 

location, and land use. On-site damages of wind erosion are 

much less than off-site damages. Proximity to large population 

areas largely defines the economic impact of wind erosion. 

Low estimates of economic benefits of CRP are due to land 

far from population centers being entered into the program. 

Authors conclude in New Mexico where only 3 percent of 

the land base is in cropland the CRP has had only minor 

benefits to reduction of the overall erosion rate. Effectiveness 

of the program could be enhanced by targeting lands with 

high rates of erosion regardless of present or past use (for 

example, cropland).

Karlen, D.L., Rosek, M.J., Gardner, J.C., Allan, D.L., Alms, 

M.J., Bezdicek, D.F., Flock, M., Huggins, D.R., Miller, 

B.S., and Staben, M.L., 1999, Conservation Reserve Program effects on soil quality indicators: Journal of Soil and 

Water Conservation, v. 54, no.1, p. 439–444.

Soil-quality indicators may be useful for evaluation of 

CRP effectiveness in meeting environmental objectives. The 

study focused on how CRP affected several physical, chemical, and biological indicators of soil quality. Overall, soil 

biological indicators showed more significant differences 

than either chemical or physical indicators. Results imply 

several soil quality indicators were improved by placing 
Soils 119

highly erodible cropland into perennial grass covers. Biological indicators were affected more quickly and to greater 

extent than chemical or physical indicators of soil quality. 

These indicators could be used to assess long-term impacts 

of agricultural management practices. Discussion of applicability physical and chemical indicators is provided. Authors 

recommend if CRP lands are returned to production, no-till 

or minimum tillage practices should be used to maintain 

environmental benefits. 

McLauchlan, K.K., Hobbie, S.E., and Post, W.M., 2006, 

Conversion from agriculture to grassland builds soil organic 

matter on decadal timescales: Ecological Applications, v. 

16, no. 1, p. 143–153.

Study results show soil C accumulates linearly for at least 

the first 40 years after conversion from cropland to grassland. 

Authors conclude Midwestern U.S. agricultural lands where 

grasslands have been reestablished can store additional soil C 

for 55–75 yr after termination of crop production but will not 

continue to accumulate C more than a century after conversion to grassland. Authors believe that substantial quantities 

of C can be stabilized in surface soils within decades after 

planting to grasslands, not centuries as has been suggested by 

other studies. 

Robles, M.D., and Burke, I.C., 1997, Legume, grass, and Conservation Reserve Program effects on soil organic matter 

recovery: Ecological Applications, v. 7, no. 2, p. 345–357.

The active pool of soil organic matter can recover to 

levels indicative of undisturbed grassland on formerly cultivated fields if left undisturbed for approximately 50 yr. In the 

short term (less than 10 yr), recovery of organic matter and 

nutrient supply was highest in CRP fields containing a greater 

proportion of legumes. Net input of plant inputs and cessation of tillage generally increased pools of course particulate 

organic matter, C, and N by factors of two to four relative 

to wheat-fallow fields but had negligible effects on amounts 

of soil organic matter. Endemic levels of organic matter are 

lower in highly disturbed soils as result of cultivation because 

plant inputs are reduced and erosion and decomposition are 

elevated. Reductions of 30–50 percent total soil C and N can 

occur during cultivation with even larger reductions in organic 

matter. These losses are greatest in lands managed on wheatfallow rotations. Plant life forms and relative plant densities 

can deferentially influence recovery of organic matter in soils 

depleted during long-term cultivation having important implications for conservation management. 

After 6 yr, C and N levels are generally higher in CRP 

fields than in wheat-fallow indicating presence of perennial 

plants and lack of tillage leads to increased soil organic matter. Carbon and N levels can approach levels found in undisturbed conditions in 50 yr in abandoned fields dominated by 

perennial bunch grasses. Grasslands produce 3–5 times more 

biomass than cultivated fields mainly because belowground 

biomass is higher. Coarse particulate organic matter (POM) 

appears to be a sensitive indicator of CRP management. 

Coarse POM was nearly twice as high in CRP fields 80/20 

legume/grass than in 20/80. N-fixing species seeded in CRP 

fields played a significant role in enhancing N inputs. Nitrogen 

availability likely stimulated net primary productivity in CRP 

fields leading to increased soil organic matter. 

Recovery of potential net N mineralization under 

legumes in CRP fields was higher than under rhizomatous 

grasses and higher than under bunch grasses in native fields. 

Legumes accelerate recovery of soil heterogeneity more than 

do rhizomatous grasses. Nitrogen transfer is highest when the 

proportion of legumes is maximized. Although changes in soil 

resource and nutrient availability in CRP fields were documented they are believed to probably have minimal effects 

on future potential crop yields. Enhanced mineralizable and 

coarse organic matter pools of C and N would be quickly 

exhausted if CRP grasslands were returned to conventional 

wheat-fallow tillage. The environmental benefits derived from 

retiring land from production dissipate quickly with a return to 

conventional cultivation.

Paustian, K., Killian, K., Cipra, J., Bluhm, G., Smith, J.L., 

and Elliott, E.T., 2001, Modeling and regional assessment 

of soil carbon— A case study of the Conservation Reserve 

Program, in Soil Carbon Sequestration and the Greenhouse 

Effect: Madison, Wis., Soil Science Society of America 

Special Publication no. 57, 410 p.

Modeling suggests CRP lands are sequestering C and 

regional differences in C storage rates are controlled by differences in primary production rates and secondarily by abiotic 

and soil factors influencing decomposition. Simulated rates of 

soil organic matter accumulation under CRP ranged from less 

than 10 to more than 40 g C m(-1) yr(-1). Highest estimated 

rates are in the most humid regions. Predicted C increases 

for first 10-year period of CRP were on order of 1012 for soil 

organic matter C. Gains made in sequestered C on CRP grassland are vulnerable to loss with reversion to annual cropping.

Waisanen, P.J., and Bliss, N.B., 2002, Changes in population 

and agricultural land in conterminous United States counties, 1790 to 1997: Global Biogeochemical Cycles, v. 16, 

no. 4, p. 1137–156.

A data set of changes in population and agricultural 

land for the conterminous United States at the county level is 

provided and discussed. The data set furnishes more detail in 

spatial changes than previously available. The objective was to 

deliver data on timing of land conversion as input to models for estimation of changes in C due to alterations of land 

use, primarily conversion of native vegetation associations 

to agricultural production. However, the data have a variety 

of potential uses for physical, biological and social science 

applications. Data represent county-level information for each 
120 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

census year between 1790 and 1997 showing history of population and agricultural development. 

Conversion of forest and grasslands to agriculture has 

stimulated the release of C from soils to the atmosphere. 

Estimates of declines in soil organic C range from 20 to 40 

percent following cultivation with most of the loss occurring 

in the first 20 yr. Declines in soil C are most likely due to poor 

agricultural practices that did not maintain soil fertility or prevent erosion. Improved agricultural practices have maintained 

inputs from net primary production to allow some recovery 

of soil C on agricultural lands. Subsequent abandonment of 

cropland may enhance sequestration of C in the soil. Although 

regional variations exist, total U.S. land in farms peaked in 

1940 declining ever since. Regional trends in farmland from 

1850–1997 are presented, as are changes in non-farm grazing 

land, forestland, grassland, pasture, improved farmland, and 

harvested farmland. 

Wu, J., Nellis, M.D., Ransom, M.D., Price, K.P., and Egbert, 

S.L., 1997, Evaluating soil properties of CRP land using 

remote sensing and GIS in Finney County, Kansas: Journal 

Soil and Water Conservation, v. 52, no. 5, p. 352–358.

The report discusses integration of remote-sensing 

technologies and GIS to evaluate present CRP in terms of soil 

conservation and recommendations for future management 

and land-use decisions. Results show soil erodibility index 

(EI) of CRP land was much lower than land used for corn, 

alfalfa or grass. It was also less than county average. About 75 

percent of CRP land was in lower EI categories (less than 12) 

but about one-third of corn land had an EI greater than 30. The 

land with the highest potential for erosion was not included in 

the program. Authors conclude existing national rules governing CRP may not be appropriate for specific, local areas. 

Modification of local eligibility rules could result in more 

efficient targeting of the most environmentally sensitive land.

Zheng, F., Merrill, S.D., Huang, S., Tanaka, D.L., Darboux, 

F., Liebig, M.A., and Halvorson, A.D., 2004, Runoff, soil 

erosion, and erodibility of Conservation Reserve Program 

land under crop and hay production: Soil Science Society of 

America Journal, v. 68, p. 1332–1341.

There is concern that lands enrolled in CRP will experience increased soil erosion when returned to crop production. 

Authors report results of investigation comparing runoff, erosion, and erodibility on CRP land converted to hay production, 

crop production under conventional-till and no-till management. The study was completed in central North Dakota 6 yr 

after CRP land had been converted to hay and crop production. 

Authors conclude CRP land converted to crop production with 

a higher residue crop rotation and no-till management can possess the same low soil water erodibility as CRP land managed 

as hayed grassland. Erosion rates on no-till did not differ from 

pasture hayland. Erodibility on conventionally tilled land was

six times greater than recorded in pasture/hayland. Erodibility 

of tilled no-till was significantly higher than recorded in tilled 

pasture/hayland showing higher inherent stability of grassland 

surface soil with its perennial plant root structures. 

Surveys, Landowner Opinions, and 

Public Attitudes 

Allen, A.W., and Vandever, M.W., 2003, A national survey of 

Conservation Reserve Program (CRP) participants on environmental effects, wildlife issues, and vegetation management on program lands: Fort Collins, Colo., U.S. Department of the Interior, Geological Survey, Biological Science 

Report 2003–0001, 56 p.

A national survey of CRP contractees was completed 

to obtain information about environmental and social effects 

of the program on participants, farms, and communities. Of 

interest were observations concerning wildlife, attitudes about 

long-term management of program lands, and effectiveness 

of USDA assistance in relation to these issues. Surveys were 

delivered to 2,189 CRP participants of whom 64.5 percent 

responded. Retired farmers represented the largest category 

of respondents (52 percent). Enhanced control of soil erosion 

was the leading reported benefit of the CRP. Over 73 percent of respondents observed increased numbers of wildlife 

associated with lands enrolled in the program. The majority 

of respondents reported CRP benefits including increased 

quality of surface and groundwaters, improved air quality, 

control of drifting snow, and elevated opportunities to hunt 

or simply observe wildlife as part of daily activities. Income 

stability, improved scenic quality of farms and landscapes, and 

potential increases in property values and future incomes also 

were seen as program benefits. Negative aspects, reported by a 

smaller number of respondents, included seeing the CRP as a 

source of weeds, fire hazard, and attracting unwanted requests 

for trespass. 
Surveys, Landowner Opinions, and Public Attitudes 121

Over 75 percent of respondents believed CRP benefits 

to wildlife were important. A majority of respondents (82 

percent) believed the amount of assistance furnished by USDA 

related to planning and maintaining wildlife habitat associated 

with CRP lands was appropriate. Nearly 51 percent of respondents would accept incorporation of periodic management 

of vegetation into long-term management of CRP lands to 

maintain wildlife habitat quality. Provision of funds to address 

additional costs and changes in CRP regulations would be 

required to maximize long-term management of program 

lands. Additional, on-ground assistance related to management 

of CRP, and other agricultural lands, to maintain wildlife habitats was commonly identified as a need by survey respondents.

Andersen, C.B., and Polkinghorn, B., 1996, Geology as a 

social science—Addressing the complexity of human habits 

and values in water-quality conflicts: GSA Today, v. 6, 

p. 36–38.

An interesting, honest analysis of why scientists sometimes fail in working with communities and the public. Different values create a competing set of emphasis on the way we 

perceive information pertaining to environmental conflict. The 

result is poor communication and misunderstanding which 

is often the result of an inability of scientists to listen to the 

concerns of the community and base their recommendations 

only upon data. Often individuals or groups are effective in 

identification of what others have done incorrectly but often 

do not recognize the effects of their habits and their contribution to the problem. Resolution of most environmental 

conflicts is top down but this approach often fails when the 

community as a whole contributes to the environmental issue. 

Often, the top-down approach results in the four Rs: regulation, resentment, resistance, and refusal. Scientists must begin 

to address the social realities of environmental issues. This can 

be done by listening to the concerns of the community and to 

use these perspectives of problems as the starting point for the 

search to a solution. An understanding of how the layperson 

views the problem is necessary. Scientists are trained to think 

the scientific method is nonnegotiable and is superior to values 

that may further anger the public. Values are intrinsic to the 

community and scientists trying to tell the public how to value 

the environment based only on data is an exercise doomed to 

failure. However, science can change what the community 

values by changing the community’s perception of its relationship to the environment.

Scientists should listen and work with the community to 

develop common ground using data only as needed to address 

or answer questions. The scientist should be a conveyer of 

knowledge but the community must guide the discussion. If a 

scientist in not willing to learn how people solve problems and 

work together then they are not likely to be successful. If you 

do not possess basic communication skills beyond simple presentation of ideas they will not succeed. Solutions will come 

from basic understanding and incorporation of the human factor in decision-making. 

Anderson, W.L., and David, L.M., 1992, Results of the 

1991–1992 Illinois quail hunter survey: Chicago, Ill., 

Illinois Department of Conservation, Division of Wildlife 

Resources Administrative Report, 16 p.

An Illinois survey of 1,716 northern bobwhite quail 

(Colinus virginianus) hunters was completed with a 76 percent 

rate of response. Of the 34 percent of respondents who hunted 

on CRP, 63 percent believed habitat furnished by the program had helped quail populations. Survey results indicate 

more quail hunters hunted on CRP land than had ring-necked 

pheasant (Phasianus colchicus) hunters. Fewer quail hunters 

believed the CRP had a positive impact on quail populations 

than did pheasant hunters who saw improvements in the population of pheasants. 

Belden, N., and Russonello, J., 1996, Human values and 

natures future—American attitudes on biological diversity: 

Washington D.C., Belden and Russonello Research and 

Communications, 24 p.

This national survey indicates only 19 percent of 

the American public had heard about loss of biodiversity. 

Although eighty percent of respondents had not heard about 

loss of biodiversity upon clarification of the concept, 48 

percent of respondents thought it was important to maintain 

biodiversity. Nearly 50 percent of respondents strongly, or 

somewhat, agreed it was all right to eliminate some species in 

favor of saving jobs. The greatest concerns about environmental impacts are human health, consequences of pollution, and 

destruction of environmental components furnishing clean air 

and water. The dominant motivation expressed by respondents 

for biological diversity protection was having a healthy, pleasing environment for their existing and future family to live in.

Boody, G., Vondracek, B., Andow, D.A., Krinke, M., Westra, 

J., Zimmerman, J., and Welle, P., 2005, Multifunctional 

agriculture in the United States: Bioscience, v. 55, no. 1, 

p. 27–38.

Potential changes in farming practices are evaluated 

in two Minnesota watersheds to determine how changes in 

farm policy may affect environmental, social, and economic 

outcomes. Authors conclude environmental and economic 

benefits from farming can be attained through change in 

agricultural land management without increasing public costs. 

Benefits include improved water quality, healthier populations 

of fish, increased C sequestration, decreased greenhouse gas 

emissions, and greater farm profitability. Policies that emphasize environmental functions and products in addition to food 

production are essential. Suggestions for redirecting farm 

payments toward “green box” issues could lead to substantial 

environmental change and public benefits. 

Minnesota residents indicate they are willing to provide 

incentives for significant changes in environmental benefits 
122 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

associated with agricultural production. Members of the public 

that were surveyed indicate a desire to develop public policy, 

research, education and marketing strategies to promote 

greater diversification of food and fiber production in ways 

that lead to environmental and social benefits. Many current government programs and land grant university systems 

focus too closely on too few crops and reinforce production 

of traditional commodities. Local institutions need to change 

along with farmers. Focus groups state present commodity 

program discourages diversification in farming. U.S. farm 

policy should support agricultural diversity and nonmarket 

ecosystem services. Future programs should reward farmers 

for environmental benefits. Authors conclude that we cannot 

afford to sacrifice future agricultural productivity for the sake 

of short-term increases in commodity production. Dealing 

with worldwide food shortages will require a future agriculture 

that produces rather than consumes ecosystem benefits.

Brook, A., Zint, M., and De Young, R., 2003, Landowners’ 

responses to an endangered species act listing and implications for encouraging conservation: Conservation Biology, 

v. 17, no. 6, p. 1638–1649.

The survey provides an examination of landowner 

responses to listing of the Preble’s meadow jumping mouse 

(Zapus hudsonius preblei) under the Endangered Species Act 

(ESA). In the United States, more than 90 percent of federally 

listed species depend on non-federal land to meet a portion 

of their habitat needs. Fifty percent of these species depend 

entirely on nonfederal land. The authors conclude listing under 

ESA did not appear to improve likelihood of survival of the 

meadow jumping mouse on private land. In terms of land area 

owned, respondents who indicated they sought to harm the 

species or its habitat negated efforts of landowners who said 

they had tried to help the species. The majority (56 percent) of 

respondents to the survey had, or would not allow, a biological 

survey of their land to gather information on the species. 

Landowner conservation decisions are influenced by 

aesthetic preferences, economics, availability of trusted 

information, amount of land owned, personal values, recreational opportunities, residence, and their amount of trust in 

the government. Conservation activities are more likely to 

be accepted when they are perceived to be financially beneficial. Conflicts and mistrust between conservation interests 

and landowners is a key factor in acceptance of conservation. 

The authors conclude the previously untested assumption 

that some landowners may act to limit, or harm, rare species 

on their property is supported by their research. Effective 

acceptance conservation by landowners will depend upon an 

increasing availability of information and countering information provided by those who discourage changes in land use 

(for example, farm supply companies) or overall lack of information. Distribution of information through social networks 

appears to be a more effective approach to getting information 

to landowners over mass media or direct mailings. Distrust 

between landowners and the government is a major issue limiting acceptance of conservation policies. Landowners must be 

respected partners in conservation and working relations have 

to be built on a foundation of collaborative decision-making. 

A sense of control is especially important to acceptance of 

conservation policies by landowners. Approaches that enhance 

landowner feelings of control and diminish perceptions of 

exploitation by regulators should be pursued to gain maximum 

acceptance of governmental conservation policies.

Cable, T.T., 2002, Beliefs of Kansas agricultural producers 

about riparian areas and wildlife conservation: Human 

Dimensions of Wildlife, v. 7, p. 141–142.

Kansas agricultural producers (n = 909) were surveyed 

with a 39 percent response rate. The purpose of the survey was 

to assess beliefs about riparian lands and wildlife conservation 

on private lands. Agricultural producers have a crucial role in 

the preservation of riparian areas, but even with compensation, most appear to be ambivalent about riparian area conservation. About 40 percent of respondents had set aside land 

specifically to help wildlife but only about 20 percent would 

sign a 10-yr lease at current rental values to set aside riparian 

land for wildlife. Seventy-four percent of respondents were 

unwilling to lease land for conservation even at 125 percent 

of current rental value. Seventy percent of respondents said 

they would not lease riparian land for wildlife at any price. 

The survey showed less support for endangered species among 

agricultural producers compared to general public. Support for 

endangered species was low: 58 percent thought endangered 

animals should be protected, 43 percent favored protection of 

plants and only 16 percent favored acquisition of streamside 

land to protect fish species. About one quarter of respondents 

said they would not stop farming along a streamside to protect 

an endangered species of fish. 

Carr, S., and Tait, J., 1991, Differences in the attitudes of 

farmers and conservationists and their implications: Journal 

of Environmental Management, v. 32, p. 281–294. 

Despite being completed in the United Kingdom, results 

of two surveys reported here have direct applicability to 

issues in the United States. Farmer and conservation groups 

were queried in relation to opinions about conservation issues 

affecting agricultural production and landscapes. Authors conclude farmers’ sympathy for conservation has been overestimated in previous studies. The significance of productivity and 

efficiency in motivation of farmer decisions generally override 

concerns about conservation. Farmer opinions about what constitutes an attractive landscape and wildlife habitat quality differ from those of conservationists; therefore, attitudes toward 

conservation and stewardship by the two groups likely also 

diverge. After decades of governmental policies encouraging 

production farmers now try to maintain income under policies 

encouraging reductions in production. Strategies on the part 
Surveys, Landowner Opinions, and Public Attitudes 123

of farmers consequently tend to be short-term, exploitive, and 

extractive rather than conserving and sustainable. Although 

attitudes involving deeply held values might be resistant 

to change, beliefs can often be enhanced by providing new 

information about conservation or changing the institutional 

framework in which farmers operate. 

Cooper, E.R., 2005, The attitudes and opinions of Pennsylvania Conservation Reserve Enhancement Program (CREP) 

participants towards riparian buffers and conservation easements: University Park, Pa., Pennsylvania State University, 

M.S. thesis, 108 p.

Thesis explores attitudes and opinions of CREP participants toward establishment and preservation of riparian 

buffers. Survey was mailed to 685 CREP participants across 

20 Pennsylvania counties who had established forested riparian buffers. Many participants stated reasons to enroll in 

CREP were to practice good environmental stewardship. The 

majority of respondents (85 percent) said they were likely to 

leave buffers intact when contracts expires but are hesitant to 

commit to establishing permanent easements due to concern 

about forfeiture of property rights and allowing public access 

to their land. Financial issues and education affected willingness to establish conservation easements. Participants were 

generally satisfied with buffer rental payment but are unsure 

as to the future and hesitant to sign a contract into perpetuity. 

Landowners generally were unsure of future conditions with 

resultant hesitation about permanent loss of use of land in buffers. Education will play a major role in fostering acceptance 

of easement programs. 

Despain, W., 1995, A summary of the SWCS Wetlands 

Reserve Program survey: Journal of Soil and Water Conservation, v. 50, no. 6, p. 632–633.

A summary obtained from three landowner focus groups 

held to define attitudes toward wetlands issues, the WRP, and 

ways WRP could be improved to increase landowner participation. Results suggest most farmers believed they were well 

informed about environmental benefits of wetlands. Those 

struggling financially tended to see wetlands in terms of how 

much crop they could potentially produce if the wetlands 

were drained and farmed. Participants in focus groups seemed 

generally well informed about federal wetland programs but 

less knowledgeable about state programs. Farmers tended to 

group all government programs together but did recognize 

particular environmental organizations such as the Nature 

Conservancy and Ducks Unlimited. Recognition depended 

upon how much promotion effort was put into program communication. The programs most favored by landowners were 

voluntary. Shortcomings of the WRP enrollment process and 

administration are discussed. Respondents generally favored 

programs focused on local conditions and issues. Farmers 

wanted more specific information on how land was chosen 

for potential enrollment in the WRP. Permanent easements 

remain a concern to landowners. Shorter-term easements were 

more acceptable but not at a lower price of payment. Most 

farmers indicated they would rather receive an offer on their 

land rather than having to make a bid for enrollment. Farmers 

thought they should be compensated for income and property 

taxes that would remain due on lands enrolled in WRP. 

Diebel, P.L., Cable, T.T., and Cook, P.S., 1993, The future of 

Conservation Reserve Program land in Kansas—The landowner’s view: Manhattan, Kans., Kansas State University, 

No. 94–45-S. 56 p.

The majority of survey respondents were satisfied with 

the CRP program and ranked potential declines in soil erosion 

as an important influence in their initial enrollment. Wildlife 

habitat considerations affected decisions by 67.7 percent 

of respondents. However, 57.6 percent of respondents said 

increases in wildlife populations were undesirable. Hunting 

was most frequent form of recreation allowed on CRP land 

(76.4 percent). Market prices for commodities, forage, and 

livestock prices were key factors in landowner decisions about 

future use of CRP land. 

Duke, J.M., 2004, Participation in agricultural land preservation programs—Parcel quality and a complex policy environment: Agricultural and Resource Economics Review, v. 

33, no. 1, p. 34–49.

Information on owner and land characteristics is used to 

analyze factors affecting landowner decisions in agricultural 

preservation programs in Delaware. Farmland preservation 

programs reduce farmer risk to lawsuits and reward multifunctional benefit which may have higher social values than do 

the commodities produced from the land. Effective programs 

based on purchase of agricultural conservation easements 

must consider what issues motivate landowners to participate. 

Landowners perceive a complex policy environment suggesting factors driving participation in one program may also drive 

participation in related programs. Participation may be greatest 

in areas receiving low development pressure and by use of 

personal contact as the source of information (as compared to 

information presented in newspapers). Owners tend to make 

conservation decisions in a complex policy environment with 

preservation and commodity programs that may work against 

one another in terms of environmental quality and development. Participation in environmental programs is preferred 

by landowners in areas further from cities. In areas under the 

most development pressure owners tend to reject preservation programs due to the potentially high return that could 

be received for sale of land. Part of the reason behind this 

lack of participation may be commodity programs that offer 

alternative to preservation without requirement of long-term 

commitment. 
124 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Ervin, D.E., 1986, Constraints to practicing soil conservation—Land tenure relationships, in Lovejoy, S.B., and 

Napier, T.L., eds., Conserving soil—Insights from socioeconomic research: Ankeny, Iowa, Soil Conservation Society of America, p. 95–107.

Farmland tenancy in the United States experienced three 

major changes during the 1970s: percentage of total farmland 

owned by non-operator landlords rose, use of fixed-cash rental 

contracts increased, and landlords contributed a lesser share 

of total farm production and capital expenditure. These events 

imply increased separation of ownership from on-ground, 

daily management of farmland. The tenants only incentive 

is to invest in soil-erosion control if productivity benefits, or 

cost savings, outweigh erosion control expenses during time 

the land is rented. Landlords may under-invest in soil erosion 

control, because tenants who do not share in the costs will 

capture actual benefits. Unless tenant operators expect to rent 

land for an extended period of time, or intend to purchase the 

land, a program oriented to renters will miss the long-term 

incentives that owners have. Attempts to persuade landowners 

and tenants about conservation advantages without sound data 

may succeed in short run but will ultimately fail when real 

benefits and costs are realized. Forty percent of U.S. farmland 

is leased. 

Forshay, K.J., Morzaria-Luna, H.N., Hale, B., and Predick, K., 

2005, Landowner satisfaction with the Wetlands Reserve 

Program in Wisconsin: Environmental Management, v. 36, 

no. 2, p. 248–257.

Social and political support for wetland protection has 

increased with recognition of the ecological services that wetlands provide. The WRP establishes conservation easements 

on agricultural wetlands in exchange for financial incentives. 

Administered by NRCS, the WRP provides an increase in wetland acreage, reduction of groundwater contamination from 

agricultural sources, flood prevention, increases in groundwater recharge, and wildlife habitats. The WRP began as a 9-state 

pilot program and expanded to all states in 1995. By the end 

of 2002, 516,629 hectares (1,276,618 acres) were enrolled in 

the program. Three types of easements are offered: permanent 

easements where USDA pays 100 percent of agricultural value 

of the land and full cost for restoration; 30-year easements, 

75 percent of restoration costs paid; and cost-share where the 

operator maintains restoration for 10 yr and USDA pays 75 

percent of restoration costs.

Authors report results of a four-county 2003 investigation of 25 percent of Wisconsin WRP contracts (n=69 after 

rejection of some contracts). Restoration and easement costs, 

NRCS monitoring records, and surveys of program participants were investigated. Average size of sites included in the 

assessment was 52 hectares (128 ac). Time since restoration 

was not a significant predictor of any ecological or social variables. The most common wetland community after restoration 

was fresh meadow. On 74 percent of sites, reed canarygrass 

(Phalaris arundinacea), an invasive species was present. Cost 

for restoration was $407/ha ($162/ac). Participant survey had 

an 80 percent response rate with an overall rating of 3.6 plus 

or minus 0.2 (1–5 scale with 5 being completely satisfied). 

Environmental protection was identified by 81 percent of 

respondents as primary reason to enroll in WRP, while 71 percent identified economic incentives and 60 percent indicated 

improvement in recreational opportunities drove their decision 

to enroll. New landowners were more likely to recreate on the 

WRP land than were original owners. Concerns expressed by 

WRP participants included restriction on establishment of permanent deer stands, increase in tax rate following restoration, 

limited communication with NRCS, and lack of participation 

in restoration process.

Authors conclude monitoring data on WRP projects is 

coarse and not collected with enough consistency to quantify 

change in biodiversity or wetland function. Data was only 

effective in tracking changes in area converted from agriculture to wetland. Authors recommend a more comprehensive 

monitoring program to furnish more quantifiable data on 

ecological issues related to restoration and assessing program 

outcomes. Results indicate satisfaction with the program by 

participants and that 89 percent planned to maintain the restorations. Satisfaction was largely driven by participation in the 

restoration process and economic incentives. Results indicate 

landowners derive nonmonetary benefits from their wetlands, 

chiefly recreation. Thirty-three percent of WRP sites surveyed 

changed ownership since placed in the program.

Authors make the following management recommendations related to the WRP. Management of invasive species 

should be a priority in the WRP. Monitoring of success and 

ecological functions of restored wetlands should be more 

rigorous and systematic over a longer time period (10–20 yr). 

Wetland Reserve Program sites should receive significant tax 

relief such as a full tax exemption following establishment of 

the easement. State tax assessments have increased for conservation easements because are classified as recreational land. 

This reduces property taxes for farmers but serves as a disincentive for restoration of wetlands. Communication between 

WRP participants and NRCS needs to be increased. 

General Accounting Office, 2002, Agricultural conservation—

State advisory committees’ views on how USDA programs 

could better address environmental concerns: Washington, 

D.C., U.S. General Accounting Office, 76 p.

Sixty-two percent of respondents indicated loss of wildlife habitat on farms and ranches was a moderate or major 

concern. Over half believed loss of native species was of moderate or major concern. Almost 50 percent felt CRP was very, 

to extremely, effective in addressing state environmental and 

resource concerns. Nearly 53 percent of respondents believed 

CRP was very, or extremely, effective in protecting or improving wildlife habitat. Over 35 percent felt there was enough 

NRCS technical assistance to meet program needs while 
Surveys, Landowner Opinions, and Public Attitudes 125

58 percent believed there was less than enough assistance 

provided than needed. Fifty eight percent of respondents felt 

CRP had some very positive effects on the economy of rural 

communities while nearly 20 percent of respondents believed 

CRP had some very negative effects on local economies. Fifty 

percent of respondents believed CRP needs more emphasis on 

protecting or improving wildlife habitat. 

Habron, G.B., 2004, Adoption of conservation practices by 

agricultural landowners in three Oregon watersheds: Journal 

of Soil and Water Conservation, v. 59, no. 3, p. 109–115.

Mail survey used to identify agricultural landowner 

participation in watershed conservation projects and determine 

characteristics of participating and non-participant landowners. Because sharing management decisions with a spouse 

increases probability of adopting both upland and riparian 

ecological practices, the author recommends that conservation 

programs fully involve the entire household and not target just 

male landowners. Agencies should expend more effort in providing information about other landowner conservation experiences as landowners are often a main source of information. 

Working with other landowners reduces landowner fears about 

having conservation-agency staff on site and potential implications of sanctions or forced adoption of conservation activities. 

To be most effective landowners need a non-threatening forum 

to learn from one another. Belief in scientific experimentation 

and a tendency to tell others about conservation also influenced adoption of conservation practices. Resource agencies 

and planners should not assume all landowners have identical 

concerns or that uniform solutions to problems will always be 

the answer to resource issues

Holsman, R.H., and Peyton, R.B., 2003, Stakeholder attitudes 

toward ecosystem management in southern Michigan: Wildlife Society Bulletin, v. 31, no. 2, p. 349–361.

The move to encourage better management of natural 

resources through ecosystem management is based on the 

assumption that the public values and supports the concept. Traditional demands on resource managers to produce 

recreational and other utilitarian benefits will continue and 

affect acceptance of stakeholders in ecosystem management. 

Redistribution of benefits makes it imperative that a solid 

understanding of public preferences is used to formulate ecosystem management plans. Increases in government regulation, impacts on economic development, and potential loss in 

property rights all have substantial influence on acceptance of 

ecosystem management goals by landowners. Public perceptions are diverse and actual understanding of ecosystem 

concepts and management objectives are low. While the public 

may, in principle, support ecosystem management many 

stakeholders remain focused on, and opt for, narrow preferences like management for single species and continuation of 

economic development. Attempts to measure public support 

for ecosystem management need to plainly define attributes 

and trade-offs involved in management options. Ecosystem 

management must be based on a clear and concrete vision, 

effective communication of expected benefits and costs, and 

building of strong relationships and trust between involved 

and affected groups. 

Jensen, K., Clark, C.D., Ellis, P., English, B., Menard, J., 

Walsh, M., and de la Toree Ugarte, D., 2007, Farmer willingness to grow switchgrass for energy production: Biomass 

and Bioenergy, v. 31, p. 773–781.

A survey of farmers in Tennessee to determine willingness to grow switchgrass (Panicum virgatum) for potential 

energy markets is reported. In 2005, a survey was sent to 

19,684 Tennessee farmers with a reported income of over 

$10,000. Response rate was 23.9 percent. Of those responding 

20.8 percent previously heard of growing switchgrass as an 

energy option. Only 29.6 percent of respondents indicated an 

interest in growing switchgrass if it were profitable. Producer 

opinions about switchgrass production are presented. Study 

results suggest many farmers are still not familiar with switchgrass opportunities. The availability of technical assistance 

and poorly defined markets were factors limiting adoption of 

the practice. Land owners with off-farm income were more 

likely to convert land to switchgrass production. Control of 

soil erosion had no influence in interest in growing switchgrass but improvement of wildlife habitat quality did.

 Kurzejeski, E.W., Burger Jr., L.W., Monson, M.J., and Lenkner, R., 1992, Wildlife conservation attitudes and land use 

intentions of Conservation Reserve Program participants in 

Missouri: Wildlife Society Bulletin, v. 20, p. 253–259.

Sixty-two percent of respondents indicated wildlife 

was an important concern in their choice of farming practices. Only 9.4 percent of respondents enrolled land in 

conservation practices that furnished permanent wildlife 

habitat. Fifty-six percent of respondents indicated they were 

unaware of the availability and details about this practice. 

Increased educational efforts to promote wildlife management 

options are needed and should target both landowners and 

administering agencies.

Korsching, P.F., and Hoban, IV, T.J., 1990, Relationships 

between information sources and farmers’ conservation 

perceptions and behavior: Society and Natural Resources, 

v. 3, p. 1-10.

Traditional primary sources of information used by 

farmers to adopt new practices are, in order of importance, 

other farmers, local dealers of agricultural products, and local 

government agencies. Mass media sources were believed 

relatively unimportant. Results of this survey of 600 Iowa 

farmers indicate the top three sources of information are: farm 
126 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

magazines, other farmers, and the SCS (now USDA NRCS). 

Authors conclude the SCS was the primary source of trusted 

conservation information but mass media, particularly farm 

magazines and local papers, can be effectively used to educate 

and promote conservation issues for relatively little expense. 

Lambert, D., Sullivan, P., Claassen, R., and Foreman, L., 2006, 

Conservation-Compatible Practices and Programs—Who 

Participates?: Washington, D.C., U.S. Department of Agriculture Economic Research Service Report No. 14, 43 p.

Recent years have brought increasing emphasis on conservation programs that reward good stewardship on working 

farmland. This report examines business, operator, and household characteristics of farms that have adopted conservation 

practices with and without financial assistance from government programs. Concerns related to succession in ownership, 

desires to limit time, cost and energy spent farming, and the 

need to stabilize income can all affect decisions about farming and conservation. Not all conservation practices have 

equal environmental impact and their applicability depends on 

farmland attributes, farming practices in place, commodities 

grown, and other physical factors. Different types of farmers adopt differing conservation practices. Operators of small 

farms and operators not primarily focused on farming are 

less likely to adopt conservation practices that are management intensive than are operators whose primary occupation 

is farming. Farmers have financial incentives to maintain the 

quality of their land by limiting soil erosion, avoiding excessive use of chemicals and protecting the productivity of their 

land. However, there is little financial motivation to reduce 

off-site impacts, consequently farming remains a source of 

sedimentation and nutrients in some watersheds. Results of 

this investigation suggest farm size, commodities produced, 

and operator motivations are all associated with decisions to 

use various types of conservation practices.

Conservation practices that provide environmental 

benefits without large costs have been adopted by farms 

of all sizes, often without direct financial assistance from 

conservation programs. Operators of smaller farms, focused 

on non-farm occupations are less likely to adopt practice 

requiring extra time or expense than those of large operations 

who depend upon farming for their livelihood. Conservation 

structures such as grass waterways, riparian buffers, and planting fields, or portions of fields, to grasses come at costs for 

installation and foregone income. Younger operators, who rely 

less on off-farm income, are more likely to install conservation 

practices compatible with production. Operators who plant 

conservation cover crops as part of cropland retirement consider themselves to be retired. Larger farm operators are more 

likely to participate in working-land conservation programs 

such as the EQIP. Intensive use of land retirement programs 

(for example, CRP) is more common with retired and “lifestyle” farms. Operators who replace income from production 

with CRP payments are generally older than other farmers and 

are more reliant upon non-farm income. Those who tend to 

retire selected fields, or portions of them, in CRP tend to have 

larger farms and consider farming as their primary occupation.

Authors conclude that both working-land and landretirement programs are needed to address diverse needs of 

conservation. If farm operators do not sufficiently benefit from 

adopting conservation practices, farming-related environmental problems are less likely to be addressed. Policies other than 

direct subsidies can furnish substantial environmental benefits. 

These options include conservation compliance regulations, 

technical assistance, and research to improve farming practices. Programs based on the assumption that long-term profit 

is the driving force behind farming practices will not appeal to 

all farmers. Larger farm operators who participate in commodity programs are more likely to have adopted conservationcompatible practices than those growing non-program crops 

and livestock. A sliding scale of payments accounting for 

higher cost of conservation for smaller farm operations could 

increase adoption of conservation. Working land programs 

(for example, Conservation Security Program) are likely to 

reach more farms than land retirement programs but may 

not furnish all environmental benefits typically attributed to 

retirement programs. 

Lant, C.L., Kraft, S.E., and Gillman, K.R., 1995, The 1990 

farm bill and water quality in Corn Belt watersheds—Conserving remaining wetlands and restoring farmed wetlands: Journal of Soil and Water Conservation, v. 50, no. 2, 

p. 201–205.

Report furnished results of two surveys addressing estimated potential enrollment of farmed wetlands in the CRP and 

WRP, and farmland owner attitudes toward Swampbuster. The 

primary reason some farmers choose not to enroll in wetland 

programs is economic concern. Operators did not want to 

forgo potential production of crops on wetland acres and 51 

percent or respondents believed enrollment could leave them 

with too little flexibility to change use of land as economic 

conditions changed. Also of concern was the potential change 

in overall drainage characteristics and possible effects on 

farming operation resulting from restoration of wetlands. 

Respondents were concerned destruction of current drainage 

facilities would be difficult and maintaining wetlands would 

be too time consuming. In 1992 mean payment for Iowa WRP 

easement was $958/ac with a total of $233/ac for restoration, 

technical assistance, and settlement fees. Potential participation in wetland preservation programs increases with rising 

payment rates. Although these rental rates are high compared 

to typical CRP rental rates they are low compared to costs for 

other Federal wetland restoration programs. 

Survey results indicate that Swampbuster is an unpopular 

program with only 30 percent of respondents believing it is a 

necessary, or fair, program. Nearly 70 percent of respondents 

believed Swampbuster was an infringement on property rights. 

Over 70 percent said permitting some economic use of wetlands (pasture, hay) would make the program more acceptable. 
Surveys, Landowner Opinions, and Public Attitudes 127

Seventy five percent of respondents said wetlands enrolled 

in Swampbuster should be exempt from property taxes. The 

Swampbuster program could be made more acceptable to 

operators if wetland mapping issues are resolved, reduction 

in property taxes on farmlands subject to Swampbuster is 

accomplished, and limited, periodic, economic use of wetlands 

is allowed. In addition, if continued, Swampbuster needs consistent enforcement of regulations and constraints to prevent 

impression of favoritism and arbitrary enforcement perceived 

by some operators. 

Leistritz, F.L., Hodur, N.M., and Bangsund, D.A., 2002, 

Socioeconomic impacts of the Conservation Reserve 

Program in North Dakota: Rural America, v. 17, no. 3, 

p. 57–65.

Results of personal interviews and a survey of community leaders, CRP contract holders in 16 North Dakota counties are presented. Survey of CRP contractees based on results 

of 3,150 questionnaires sent with a 32.3 percent rate of return. 

Ninety-two community leaders received surveys with a 62 percent response rate. Negative effects of the CRP described by 

community and agricultural leaders include reduced demand 

for agricultural inputs such fuel, fertilizer, and machinery 

leading to lost income to farm supply and service sector businesses. Positive aspects of the program described by both 

CRP contractees and community leaders included increased 

control of soil erosion, improved populations of wildlife, and 

economic benefits to local communities derived from CRPassociated hunting and recreational opportunities. Recreational 

spending was perceived to be positive for local business 

including motels, cafes, gas stations, and grocery stores. In 

some areas guide services, outfitters and bed and breakfast 

operations had grown and were attributed to greater recreational opportunities stemming from establishment of the CRP. 

Contract holders said the CRP has helped stabilize revenue 

during adverse weather and volatile market conditions. 

Community leaders were concerned the CRP had contributed to farm consolidation, declining rural populations, 

and an increase in posting of land against hunting. However, 

results from CRP participants invalidate these concerns. About 

61 percent of landowners lived in the county where their CRP 

tract was located, 16 percent lived in an adjacent county, and 

only 13 percent live outside the county. Wherever they were 

living, CRP survey respondents were typically long-term 

residents. Only 11 percent had lived in county of residence 

less than 10 years. Tracts enrolled in CRP were typically small 

and represented only a fraction of the land needed to support 

an economically viable farming unit. Seventy two percent of 

respondents indicated CRP participation had reduced their 

income risk. Only 4 percent of respondents felt opportunities to supplement income with hunting fees was important. 

Eighty-nine percent of CRP respondents indicated posting of 

their land had not changed since enrollment in the program. 

Only 4 percent did not allow hunting and only 1.6 percent of 

respondents indicated they lease, or charge a fee, for hunting 

on their CRP land.

Almost 82 percent of respondents believed the CRP had 

contributed to growing populations of upland game species. 

More than 90 percent of respondents said the program had 

helped populations of big game, and about 75 percent said the 

CRP had benefited waterfowl populations. Respondents also 

said the CRP had been a benefit to hunting and trapping in 

their county. Local leaders were less likely to think the CRP 

had positive effects and enrollment criteria should focus on 

farmland characteristics rather than wildlife or environmental 

values. The authors conclude, however, North Dakota communities should develop businesses focused on capitalization of 

the enhanced recreational and subsequent economic development opportunities furnished by the CRP. 

Manfredo, M.J., Teel, T.L., and Bright, A.D., 2003, Why are 

public values toward wildlife changing?: Human Dimensions of Wildlife, v. 8, no. 4, p. 287–306.

Public values toward wildlife have changed dramatically 

over the last half of the 20th century away from traditional 

emphasis on use and management. This trend is one of the 

most influential factors affecting wildlife management as we 

enter the 21st century. The shift is associated with declining 

hunting, growth of nongovernmental organizations placing 

emphasis on nontraditional views toward wildlife, and policy 

changes through ballot initiatives. Increasing public affluence, 

higher levels of education, urbanization, and a decline in residential stability are key variables driving changes in attitudes 

toward wildlife management. Barring environmentally or 

socially catastrophic events, the authors predict continuation of the decline in utilitarian attitudes toward wildlife. The 

shift toward a largely protectionist attitude toward wildlife 

is founded within the growth of protectionist views toward 

the environment. Authors suggest environmental protection 

values will deepen and wildlife protection values will follow. 

It is important for managers and policy makers to understand 

shifting values within the public sector to guide program planning and implementation. Ultimately, success of conservation 

efforts will depend upon compatibility with cultural values. 

McCann, M.J., Nunez, J.T., and Nowack, P.J., 2006, What we 

don’t know can hurt us—Adoption of animal waste management strategies: Journal Soil and Water Conservation 

Society, v. 61, no. 1, p. 30–33.

With manure management as a focus, the authors 

describe social and research barriers to adoption of conservation practices. The discussion is applicable to farmer adoption 

of conservation practices in general. Adoption of manuremanagement strategies has been disappointing, particularly by 

smaller operators. Economic and social barriers to adoption 

are identified and described. Varying values of farmers, goals, 

previous investments are among those discussed. Given the 
128 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

variability in operators, farms, and physical characteristics 

of farm locations a one-size-fits-all policy is not appropriate. 

Barriers to adoption include profitability, cost of equipment, 

uncertainty of potential costs and benefits, and complexity of 

regulations. Solutions discussed include greater availability 

of information and well developed channels of communication. Policy focused research needs to take into account factors 

affecting adoption behavior to formulate policies that are flexible, effective, and have low costs. 

McCann, E., Sullivan, S., Erickson, D., and DeYoung, R., 

1997, Environmental awareness, economic orientation, 

and farming practices—A comparison of organic and conventional farms: Environmental Management, v. 21, no. 5, 

p. 747–758.

The farm population in the last half of the 20th century 

changed radically from a relatively homogeneous group 

of small and medium-sized family farms to larger, specialized operations. Young people continue to leave the farming 

industry as economic risks of farming continue to grow. When 

farming is no longer of interest to the next generation, family farmland almost always goes to bigger farmers with the 

machinery and capitol to make the land profitable. Although 

many of the farmers participating in this study stated love, 

respect, and an understanding of nature, they feel obligated to 

preserve the economic stability of the operation that has sustained their family and lifestyle. Based on a survey of 25 farmers in Michigan, the authors conclude organic farmers show a 

greater awareness of and concern for environmental problems 

than do conventional farmers. Although conventional farmers perceive themselves as people of the land, they frequently 

sacrifice the health of the land in the interest of continued 

farming. However, both groups of farmers express concern 

about economics and the health of the land. Both organic and 

conventional farmers are dependent on an economic structure largely beyond their control. Higher debt burdens and a 

governing economic orientation toward agriculture make large 

farms less likely to be concerned about and adopt practices of 

environmental protection. The authors conclude that governmental conservation programs have been successful in 

increasing awareness about soil erosion issues and should be 

expanded to address other environmental concerns. An understanding of farmers’ attitude and behaviors toward conservation vary but is essential for identification and implementation 

of effective conservation objectives.

McGranahan, D.A., and Beale, C.L., 2002, Understanding 

rural population loss: Rural America, v. 17, no. 4, p. 2–11.

More than 25 percent of rural counties lost population 

between 1990 and 2000. Loss rates often were greater than 5 

percent. Many of these counties were agricultural and have 

been losing population for decades. Distance away from 

metro areas, low population density, and few natural amenities 

(favorable climate, topographic diversity, and presence of surface waters) are identified as factors affecting population loss 

in these counties. Population loss was most pronounced in the 

center of the country as well as scattered areas in the Northeast 

and South. Rural life for most people is improved by access 

to doctors, schools, stores, and restaurants. The problem with 

access to services has increased as health, education and retail 

services have consolidated. Frontier counties (less than 10.1 

persons/mi2) were much more likely to lose population than 

were other more densely populated counties putting greater 

strain on services in counties least able to bear the consequences of declining population. 

People who move to or stay in rural areas generally enjoy 

a slower pace of life, less congestion, community centered 

life, and the outdoors. Areas dominated by farming tend to 

be flat, have low density of surface waters (lakes, ponds), 

and have wetter winters and hotter summers resulting in low 

rates of natural amenities that attract people. Three of four 

counties classified as frontier having below average natural 

amenities are farming dependent. Population loss in the 1990s 

was strongly related to availability of natural amenities and 

frontier status. Nearly 70 percent of frontier counties lost at 

least 5 percent of their population. Frontier counties without 

natural amenities have not attracted manufacturing with low 

labor markets and low paying jobs remaining prevalent. These 

counties also tend to have older populations with death rates 

exceeding birth rates. Industrial agricultural (large confined 

animal operation, meat packing plants), casinos and prisons 

have brought increases in populations but with low-paying, 

unskilled jobs. The authors conclude low-amenity frontier 

counties will face difficult choices. Unless these counties 

can develop a recreational industry they must deal with 

either industrial agriculture or continued declines in population comprised largely of immigrants accepting low paying, 

non-skilled jobs. 

McLeod, D.M., Miller, S.F., and Perry, G.M., 1996, North 

Central Oregon Conservation Reserve Program Survey—A 

summary of results: Corvallis, Oreg., Oregon State University Special Report 959, 46 p.

At the time that this report was written, Oregon had 

530,766 acres in CRP (1.5 percent of national total). A survey 

was administered to CRP participants in the north central and 

northeastern regions of state in six counties where the majority 

of the CRP is enrolled. The survey was sent to 670 CRP contract holders with 505 responding (75 percent response rate). 

For the entire study area (county by county results are also 

presented) 73 percent of contractees were owner operators and 

19 percent renters. Nine percent of respondents committed 100 

percent (whole farm) of their land to the CRP. Over half of the 

acreage enrolled represented less than 25 percent of the whole 

farm. Fifty-two percent of respondents indicated they were 

currently raising livestock. Primary reasons given for participation in CRP were: land of low yield/soil quality, 70 percent; 
Surveys, Landowner Opinions, and Public Attitudes 129

provision of stable income, 77 percent; leaving farming, 12 

percent; retirement, 17 percent; furnish wildlife habitat, 62 

percent; and soil protection, 84 percent. Average age of CRP 

survey respondents was 57. The typical respondent was an 

owner-operator of a 2,000-acre operation with 500 acres in the 

CRP. Upon expiration of the CRP contract, water and fencing 

costs to make land suitable for conversion to a grazing operation was estimated to be over $10,000.

Nassauer, J.I., 1989, The aesthetic benefits of agricultural land: 

Renewable Resources Journal, v. 7, p. 17–18.

Author puts forth argument that failure to address aesthetic values of farmland to operators and the public in general 

has been a shortcoming of farm legislation. Management of 

agricultural land under the CRP and other USDA programs 

could be accomplished so that it appears attractive and helps 

to convey the message of environmental quality. Both rural 

and urban public receive satisfaction from how the rural 

landscape looks, sounds, and smells. Lands can be attractive 

because they are scenic or show good stewardship. Farm Bill 

programs should protect scenic rural landscapes and create 

more attractive landscapes by making American farmland a 

more vivid demonstration of good stewardship. Accomplishing these goals may enhance participation in conservation 

programs, assist in improvement of biodiversity, help to support rural economies, and preserve open space in proximity to 

urban areas. 

Nassauer, J.I., 1995, Messy ecosystems, orderly frames: Landscape Journal, v. 14, no. 2, p. 161–170.

Ecological functions are not always recognizable to those 

not educated in a way to see or appreciate it. Ecologically 

beneficial land use and cover types may be perceived to be 

messy and uncared for. This may be a problem in convincing 

landowners to adopt conservation practices if they believe 

their neighbors see them as uncaring or sloppy managers of 

their land. The author addresses the issue that the appearance 

of indigenous ecosystems and wildlife habitats may violate 

cultural norms for the neat appearance of landscapes and how 

these obstacles can be addressed. 

People often do not know how to see ecological quality directly but only through our cultural experience. What 

is good may not look good and what looks good may not be 

good. The author states that the difference between the scientific concept of ecology and the cultural concept of nature is 

the difference between function and appearance. This difference demonstrates that applied landscape ecology is essentially a design problem. While a neat and orderly landscape is 

often seen as a sign of hard work and pride, such a landscape 

seldom enhances ecological functions. The design of ecosystems (for example, incorporation of viable conservation practices into agriculturally dominated landscapes) may depend 

upon including cues of human intention that lead to understanding the land is not neglected or awaiting development. 

The naturalness that Americans appreciate is more 

closely related to 18th century perceptions of beauty than 

ecological function. Wetlands are often modified, prairies 

planted to trees, and dead wood removed in an effort to meet 

cultural expectations. People tend to perceive landscapes that 

furnish biodiversity as messy, weedy, and unkempt. Farmers see beauty in straightness of rows, even green color, and 

neatly kept roadsides. These images represent care, pride, and 

the work ethic associated with successful farming. People who 

have “unattractive” landscapes are often seen as not caring, 

having a negative personality, or lacking resources to manage 

their land properly; ultimately they are often perceived as not 

being good neighbors. 

Mowing strips along the margins of buffers, bird nest 

boxes, bold strip patterns of conservation covers, and use of 

seed mixes heavy in native forbs, with large flowers (plants 

with small flowers are often perceived to be weeds), are identified as methods to make conservation practices more acceptable to farm operators. 

Mehmood, S., Zhang, D., and Armstrong, J, 2003, Factors 

associated with declining hunting license sales in Alabama: 

Human Dimensions of Wildlife, v. 8, no. 4, p. 243–262.

Report documents factors associated with declining hunting license sales, which include lack of time, deficiency in 

availability of public hunting areas, aging, and loss of interest. 

Former and active hunters did most hunting on private lands. 

Size of area available for hunting, abundance of game, travel 

distance, and accessibility were important factors in choosing 

hunting sites. Majority of active hunters responding to survey 

said they traveled less than 50 mi to a hunting area. Authors 

conclude once hunters quit the sport there is no policy within 

power of state wildlife agencies that can bring these persons 

back to the sport. Furthermore, agencies should increase 

efforts to retain interest of existing hunters by providing 

opportunities for hunting rather than trying to recruit new, or 

bring back former, hunters.

Miller, E.J., 1989, Wildlife management on Virginia Conservation Reserve Program land—The farmers’ view: Blacksburg, Va., Virginia Polytechnic Institute and State University, M.S. thesis, 91 p.

Seventy-two percent of survey respondents indicated 

they wanted to improve wildlife habitat on retired farmland. 

However, most respondents said they had not been informed 

about improving habitat on CRP land. Respondents identified 

USDA personnel as the primary source of habitat information 

for program participants. Only 5 percent of land was planted 

to permanent wildlife habitat. Mowing of entire CRP acreage was primary means of weed control. Leasing of CRP land 

to hunters was uncommon. Results indicate a high level of 
130 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

interest in wildlife and a need for getting more detailed information to landowners from USDA and wildlife agencies. 

Miller, E.J., and Bromley, P.T., 1989, Wildlife management on 

Conservation Reserve Program Land— The Farmer’s view, 

in Transactions of the North American Wildlife and Natural Resources Conference, 54, Washington, D.C., March 

17–22, 1989, Proceedings: Washington, D.C., Wildlife 

Management Institute, p. 377–381.

Survey results from CRP participants in Iowa and Virginia are presented. Results indicate CRP participants have a 

high level of interest in improving wildlife habitat. However, 

a lack of information and educational opportunities about 

how to specifically improve lands for wildlife appeared to be 

an important limitation. Objection to regulations and red tape 

may constrain acceptance of programs to stimulate improvement in habitat quality. Improvements in wildlife issues on 

CRP lands will require aggressive information and education 

efforts by wildlife agency staff (rather than USDA county 

staff) that can furnish precise information useful for improvement in habitat quality. 

National Environmental Education & Training Foundation, 

2001, Lessons from the Environment, Why 95 percent of 

adult Americans endorse environmental education, in Ninth 

Annual National Report Card on Environmental Attitudes, 

Knowledge and Behaviors: Washington. D.C., National 

Environmental Education & Training Foundation, 46 p.

A survey taken in 2000 confirms widespread environmental illiteracy persists within American population. However, 

there is an increasing public concern about pollution of the 

environment. Americans endorse government programs to 

protect water and air from pollution. Eighty-six percent of 

those surveyed believed government agencies should support educational programs addressing environmental issues. 

Majority of Americans believe environmental protection and 

economic development are compatible and environmental 

quality will increasingly play an important role in the nation’s 

economic future. 

Although there is a persistent and pervasive lack of 

environmental knowledge among Americans, a strong level of 

support for environmental education is apparent. The majority of the public still cannot identify leading causes of water 

pollution, air pollution, and issues related to disposal of solid 

waste. There is, however, an increasing level of public concern 

about environmental issues and Americans endorse governmental environmental protection programs. There is strong 

public support for governmental and corporate involvement 

in environmental education for adults. Americans believe a 

balance between the environment and economy is required 

for continued prosperity. Many believe environmental quality 

will be an important factor in the nation’s economic future. 

When asked to choose between environmental protection and

economic development, 71 percent of those surveyed said they 

would choose the environment. While there is general support 

for environmental quality, a lack of specific knowledge on 

environmental issues limits the public from taking effectual 

protective actions.

Newton, B.J., 2001, Environmental education and outreach—

Experiences of a federal agency: Bioscience, v. 51, no. 4, 

p. 297–299.

Conservation of natural resources is inextricably bound 

to public attitudes and opinions. Recommendations for making environmental messages and information effective: keep 

message simple, make information directly relevant to the 

individual, ask individuals to do something, develop sense of 

trust, focus outreach on events, allow for public discussion and 

input, or localize identification of issues and potential solutions as much as possible.

Pocewicz, A., Nielsen-Pincus, M., Goldberg, C.S., Johnson, 

M.H., Morgan, P., Force, J.E., Waits, L.P., and Verling, L., 

2008, Predicting land use change—Comparison of models based on landowner surveys and historical land cover 

trends: Landscape Ecology, v. 23, p. 195–210.

To make informed decisions, potential effects of policies on land use must be evaluated. A mail survey of private 

landowners was used to develop a survey-based landowner 

decision model to describe future land-use changes. The study 

was conducted in northwest Idaho. A large amount of marginal 

agricultural land in this region has been enrolled in the CRP. 

The mail survey of questions focused on land-use plans was 

sent to 442 owners of privately owned land greater than 0.8 

hectares (2.0 ac). The survey had a 54 percent rate of response.

The analysis leads the authors to conclude that nonmetropolitan growth rates will continue to grow based on 

an increasing importance of amenity-driven migration and 

economic mobility. Both forest harvesting and residential 

development on private lands were projected to grow as a 

consequence of harvest constraints on public lands. Agricultural land is projected to decrease over the next decade. The 

authors attribute loss of agricultural land mostly to enrollment 

in CRP and residential development. Analysis indicates policies designed to attract participation in the CRP would be very 

successful in the study area. The authors conclude the surveybased model is a useful approach for understanding landscapescale impacts of land management policies.

Rhoads, B.L., Urban, M., and Herricks, E.E., 1999, Interaction 

between scientists and nonscientists in community-based 

watershed management—Emergence of the concept of 

stream naturalization: Environmental Management, v. 24, 

no. 3, p. 297–308.

Environmental management in watersheds is based 

on science and engineering but must first be perceived as a 
Surveys, Landowner Opinions, and Public Attitudes 131

social process. More than ever before, approaches to environmental decision making must be based on an understanding 

and respect for social interaction and input from those most 

directly affected by programs. Local people often discount 

scientific information if they perceive the bearer of information as an outsider insensitive to the rituals and practices that 

make up their cultural identity. Scientists must develop personal relations with nonscientists based on trust and a mutual 

exchange of information and understanding. An important 

challenge for technical experts and scientists is appreciation 

for sincere, genuine understanding of the perspectives of local 

stakeholders. The biophysical environment is valued in different ways by people within the community, which ultimately 

shapes a community’s reaction to environmental issues and 

regulations. Failure to take into account local knowledge and 

values often leads to the perception of top-down intervention 

which can reinforce existing social barriers, generate mistrust, 

and strengthen the perception of the scientist as an outsider 

with little understanding of local values or concerns. 

Based on restoration of stream ecosystems in Illinois, the 

authors conclude the transformation of the fluvial environment occurred largely prior to collection of detailed environmental data and so widespread that predisturbance condition 

are largely unknown to local inhabitants. Watershed scale 

restoration is impractical because most rural communities are 

primarily concerned about maintaining high levels of production and land is too valuable for large tracts to be taken out 

of production. 

An approach described as “Naturalization” is advocated 

by the authors as an alternative to restoration for watersheds 

situated in landscapes characterized by intensive human modification. The concept is based on recognition that natural is a 

social construct that each community negotiates as an appropriate mix of human and biophysical components. The goal 

of naturalization is to establish sustainable, morphologically, 

and hydraulically varied stream systems capable of supporting biologically diverse, healthy aquatic ecosystems. The 

approach described is based on scientifically informed views 

that acknowledge importance of social and economic concerns 

yet also preserves or enhances biophysical features of the 

system. The approach accommodates a shift away from purely 

utilitarian perspectives toward a view that incorporates the 

importance of environmental sustainability. Management prescriptions must address social and economic concerns based, 

in part, that human intervention in biophysical systems is part 

of the current “natural” dynamics of modern ecosystems. 

Riddle, M, Skold, M.D., and Trock, W.L., 1994, The future 

of the Conservation Reserve Program in Colorado: Fort 

Collins, Colo., Department of Agricultural and Resource 

Economics, Colorado State University, Technical Report 

TR94–5, 41 p.

A survey of Colorado CRP contractees to ascertain expectations related to future of land use and the program. Respondents indicated that the most important reason for enrolling 

land in CRP was income brought by the program. Soil conservation also was identified an important consideration. These 

results led authors to conclude if the program expired, about 

38 percent of land would return to production. About the same 

amount of expiring CRP land would remain in grass. Because 

the lands have been in crop production, infrastructure needed 

to accommodate livestock use (for example, fencing, water) 

is generally not available on CRP grasslands. New fences and 

development of water resources would be needed to convert 

CRP grassland to grazing.

Ryan, R.L., Erickson, D.L., and De Young, R., 2003, Farmers’ 

motivations for adopting conservation practices along riparian zones in a mid-western agricultural watershed: Journal 

of Environmental Planning and Management, v. 46, no. 1, 

p. 19–37.

Report describes motivations of 268 farmers in a typical 

mid-western watershed for adopting conservation practices, 

current management practices, and future plans for management. Authors conclude farmers are motivated to practice conservation as a consequence of attachment to their land rather 

than receiving economic compensation. Farmers are more 

likely to become involved with conservation practices that 

make their farm appear well managed. Authors believe protection of riparian resources in agricultural watersheds requires 

an approach that respects farmers’ attachment to their land and 

desire to practice good stewardship. 

Conservation practices generally require a long-term 

investment with little or no short-term benefits. Understanding 

landowner motivation for adopting conservation is vital for 

success in promotion of widespread environmental protection 

and enhancement. Attachment to the land and protection of it 

for future generations are underlying motivations for farmers 

to participate in conservation activities. Emphasis on farmers’ 

concern about environmental effects on downstream neighbors may be a new approach to convince farmers to engage 

in conservation practices. The social aspects of conservation 

behavior are worth further investigation in environmental 

planning and policy research. Authors suggest adoption of 

conservation practices may be more likely when supported by 

a range of motivations (social, aesthetic, and economic) rather 

than just economic incentives. 

Aesthetic qualities of conservation practices are important but full-time farmers, in particular, did not perceive maintaining woody riparian cover as giving the appearance of good 

stewardship. Apparently, farmers are hesitant to allow acreage 

enrolled in government programs to revert to woody vegetation because the programs are generally perceived as being too 

short in duration and unpredictable. Grass-dominated cover is 

much easier to convert back to production if necessary. This 

investigation showed that no-till farming and grass buffer 

strips were the most commonly practiced management options 

in the watershed. 

Findings imply farm structure (percent of income 

derived from farming) was important in determining types of 
132 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

conservation practices adopted. Part time farmers were more 

likely to maintain woody vegetative buffers along streams. 

As farm income continues to decline in relation to off farm 

income the number of part-time farmers will grow providing 

further opportunities to diversify programs. Authors believe 

part time farmers represent an underserved portion of the 

agricultural population likely to adopt more environmentally 

beneficial practices if government programs were structured to 

take advantage of their desires and limitations.

Soil and Water Conservation Society, 2001, Seeking common 

ground for conservation: Ankeny, Iowa, Soil and Water 

Conservation Society, 58 p. 

Soil and Water Conservation Society staff interpretation 

of input provided by private interests, farmers and resource 

professionals obtained from five workshops sponsored by the 

agency to solicit input on conservation provisions for the 2002 

Farm Bill. Specific recommendations are presented describing hopes and concerns of workshop participants. The report 

concludes that weakness in the nation’s technical services 

infrastructure is the single greatest impediment to meeting the 

conservation needs of producers. The public desires improvement in environmental quality, but lack of funding for existing technical and financial assistance programs remains the 

greatest barrier to progress in conservation and environmental 

management. Most of new investment in conservation should 

be used to reach those producers who want to keep working 

the land rather that retire it from production. Report advocates 

continuation of existing conservation programs including 

the CRP. Findings imply state and local leaders need greater 

authority over the way USDA programs operate on local level. 

A farm program based on stewardship rather than commodity production will bring a needed balance to farm programs. 

Farm Bill programs should be broadly available, prevent 

conservation problems before they require treatment, achieve 

widespread enhancement to the environment, emphasize transition to production systems that enhance not just protect environment, and emphasize development of innovative practices 

that integrate conservation directly in production systems.

Recommendations ranging from more funding for existing conservation programs to creating a new overall vision 

for farm policy based on a foundation of land stewardship are 

furnished. (See report for 22 specific recommendations.) Specific to CRP, the report advocates expansion of the program, 

including lands that do not have cropping history, and integration of economic use, which may include managed haying, 

grazing, or other compatible economic use at reduced rental or 

easement payment rates. 

The authors conclude more emphasis on monitoring and 

evaluation of USDA program performance is needed to furnish 

timely, accurate information upon which to base enhancement 

of program delivery. A lack of knowledge, rather than cost, 

is identified as the primary barrier to adoption of effective 

conservation systems. Recommendations based on basic and 

applied research are needed to formulate specific guidelines 

for conservation planning, systems design, and implementation. Policy makers could improve priority setting by making 

a portion of CCC funding available to support monitoring, 

assessment, and evaluation of programs. The development of 

reliable and consistent tools to estimate environmental benefits 

of programs is needed and should be a high priority. 

Tarrant, M.A., Overdevest, C., Bright, A.D., Cordell, H.K., 

and English, D.B.K., 1997, The effects of persuasive communication strategies on rural resident attitudes toward 

ecosystem management: Society& Natural Resources, v. 10, 

p. 537–550.

The purpose of this study was to examine ways of generating more favorable attitudes on the part of rural residents 

toward environmental management. Results show although 

rural residents generally have low knowledge of environmental management, messages can be developed that significantly 

improve attitudes toward such policies. Generally, there is 

little knowledge of ecosystem concepts and management by 

rural residents. The most favorable attitudes toward ecosystem 

management were associated with messages containing strong 

arguments in favor of such a policy. Poor public knowledge 

and weakly developed opinions are, in part, based on an inadequate understanding due to the complexity of many natural 

resource issues. A lack of knowledge often equates to absence 

of support. Arguments containing aspects of high personal relevance produced the most favorable attitudes and responses on 

the part of rural residents. Managers and those who formulate 

policies need to understand their target audience. Key questions to address include whether or not the audience considers 

environmental management as highly relevant and if they hold 

general knowledge about what the concept entails. Messages 

should include not only facts about an issue but information 

that would increase relevance of the issue to the target audience. Managers should develop strong arguments for the strategy being proposed, emphasize how the issue is personally 

relevant to the audience, and furnish additional, information to 

persons already knowledgeable about the topic. 

Troy, A.R., Strong, A.M., Bosworth, S.C., Donovan, T.M., 

Buckley, N.J., and Wilson, M.L., 2005, Attitudes of Vermont dairy farmers regarding adoption of management 

practices for grassland songbirds: Wildlife Society Bulletin, 

v. 33, no. 2, p. 528–538.

A survey of 131 dairy farmers in Vermont’s Champlain 

Valley was completed to determine attitudes toward habitat 

management for grassland birds. Results show a trend toward 

earlier and more frequent harvest of hayfields with operators 

indicating they have little flexibility to alter timing of harvest. 

Forty-nine percent of respondents indicated willingness to 

adopt alternative management on at least a small portion of 

their land to benefit avian species. It is believed operators 

with smaller dairy herds were more likely to devote a greater 
Surveys, Landowner Opinions, and Public Attitudes 133

percentage of their land to alternative management prescriptions. Hayfield management is increasingly incompatible with 

reproductive cycle of grassland birds due to early June harvest, 

which is well before grassland birds can successfully fledge 

nestlings. Only small amounts of land are enrolled in USDA 

conservation programs in the northeast. Dairy farmers have 

increased intensity of hayfield harvest therefore it appears 

grassland songbirds depend upon the degree to which these 

operators have the ability and willingness to reduce management intensity on their hayfields. Authors believe study results 

have relevance to dairy farms across northern-tier dairy states 

(Wisconsin, Minnesota, Michigan, Ohio, Pennsylvania, New 

York). Authors conclude most farmers are unlikely to delay 

first cutting of hay because of the financial loss and reduced 

protein content of later cuttings. Results suggest smaller sized 

operators are more likely to alter management on a larger 

portion of their land than those with larger sized herds. Efforts 

to target large-lot landowners (non-farmers) are suggested 

as an alternative for enhancing avian reproductive habitat in 

the region. 

Valdiva, C., and Polulos, C., 2009, Factors affecting farm 

operators’ interest in incorporating riparian buffers and forest farming practices in northeast and southeast Missouri: 

Agroforestry, v. 75, p. 61–71.

Authors report the strongest positive factor in increasing 

Missouri farmers to adopt riparian buffers and forest farming is enhancing knowledge about the conservation practices. 

How farmers value the environment and future generations 

was reported as one of the strongest effects on interest in the 

practices. CRP payments had no effect on interest in enrollment. The authors conclude values and attitudes of landowners appear to be good indicators of interest in both practices. 

Older farmers were found to be less interested in the practices. For practices not perceived as commercial, or as a sole 

or important source of income, non-monetary motivations 

may be a driving force in interest and adoption of practices. In other words, environmental concerns have value in 

farmer decisions.

Vandever, M.W., and Hoag, D.L., 2006, Stakeholder opinions 

regarding management of Conservation Reserve Program 

lands to address environmental and wildlife issues: Human 

Dimensions of Wildlife, v. 11, p. 147–149.

Results of a survey completed by attendees at a national 

conference on the CRP (see Allen and Vandever in the Agricultural Conservation Policy Section of this bibliography) are 

presented. This preliminary analysis of the survey focuses 

on issues related to wildlife management and the CRP. Of 

213 official participants at the conference 124 (58 percent) 

completed the questionnaire. Of those providing responses, 

54 percent categorized themselves as employed by state or 

federal agencies, 20 percent were employed by agribusiness 

or commodity/producer groups, 16 percent represented 

conservation organizations, and 6 percent were affiliated with 

academia. Four percent categorized themselves as being in the 

“other” classification. 

In relation to management and disturbance of CRP lands, 

71 percent of respondents believed periodic disturbance of 

CRP lands would best be administered (for example, identification of priorities, frequency of disturbance, methods) at the 

state or local levels. Twenty-one percent thought these issues 

were more appropriately identified at the regional level, while 

7 percent thought the national level was most appropriate. 

Over half (53 percent) of the respondents believed wildlife 

priorities were adequately represented by the EBI used to rank 

lands being evaluated for potential inclusion in the program. 

However, 29 percent of respondents believed the EBI did not 

adequately address needs of wildlife associated with the CRP.

In relation to the 2007 Farm Bill, 52 percent of respondents wished to see continued emphasis of conservation 

priority areas and 44 percent identified monitoring of wildlife /

environmental impacts of the CRP as being a priority. Only 2 

percent of respondents believed wildlife issues were not a priority in definition of future management of CRP lands. Nearly 

two thirds (65 percent) of respondents indicated wildlife and 

management issues were of great concern and many believed 

only slight modifications of administration of the CRP were 

needed to maximize benefits. 

Vandever, M.W., Allen, A.W., and Sexton, N.R., 2002, 

Selected effects of the Conservation Reserve Program on 

program participants—A report to survey respondents: U.S. 

Geological Survey, Fort Collins Science Center, Fort Collins, Colo., Open File Report 02–476, 21 p.

The report is a brief summary of survey results to 

respondents of a nationwide survey of participants in USDA’s 

CRP. Focus of survey was program participant perceptions 

about wildlife issues and environmental effects of the CRP. 

Of interest were observations concerning wildlife, attitudes 

about long-term management of program lands, and effectiveness of USDA assistance in relation to these issues. Surveys 

were delivered to 2,189 CRP participants with a response rate 

of 64.5 percent. This report provides only brief discussion of 

management and administrative implications of respondent 

opinions. A more thorough presentation of analysis of survey results is presented in Allen and Vandever 2003 presented above.

Wagner, M.M., 2005, Watershed-scale social assessment: Journal of Soil and Water Conservation, v. 60, no. 4, p. 177–186.

Issues and potential products (for example, clean water) 

are unique to each watershed based on the geographic region, 

issues, and planning participants. Effective watershed-scale 

planning integrates place-based social information and 

physical landscape data to determine solutions for local 
134 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

communities. To be successful watershed projects need leadership from watershed residents, a fundamental requirement 

for understanding difference in goals between planners and 

residents. Implementation of watershed planning in agriculturally dominated regions requires effective communication 

and collaborative decision making between planners and 

residents. Because residents are unlikely to participate actively 

in decision making if technical data are not understood it is 

essential they be involved in the decision process from the 

beginning. Planning and land management outcomes reflect 

value systems that can be quite different between planners and 

residents. This report describes experiences and makes recommendation on watershed planning based on experiences in the 

Cedar Lake region of Iowa.

Watershed and agricultural policies are largely based 

on the assumption farmers will respond to incentive-based, 

voluntary programs. Factors that influence farmer participation include aesthetics, economic incentives, farm structure/

size and concern for the environment. Often a combination of 

social, economic, and aesthetic factors influences decisions. 

Attributes identified that influence how quickly new ideas may 

be adopted include its advantage over established practices, 

compatibility with existing values, complexity, the degree the 

practice can be implemented, and the amount to which results 

of the innovation are observable. 

White, D.D., and Hall, T.E., 2006, Public understanding of science in Pacific Northwest salmon recovery policy: Society 

and Natural Resources, v. 19, p. 305–320.

Public opinion increasingly influences governmental 

policy which has an effect on inefficiency and controversy in 

formulation of resource policies. This paper, although focused 

on salmon recovery in the Pacific Northwest, has implications for formulation of governmental policies and effectively 

addressing stakeholder inputs and concerns about the validity 

of scientific information and guidance. Factors that complicate 

formulation and implementation of natural resource policies include competing social values, divergent institutional 

priorities, and entrenched bureaucracies that limit coordinated, 

effective efforts to address issues. Many in the policy community, including Congress, advocate basing decisions on 

more and better scientific input, but there are also demands 

to increase citizens’ input more thoroughly in policymaking. Because scientists and members of the general public 

have divergent ways of relating to, and discussing, issues this 

presents problems. While many in the public have faith in 

science a growing percentage of the citizenry are suspicious of 

the motives of scientists and untrusting of scientific expertise, 

often seeing science as not being “policy neutral.” Also, some 

involved in policy formulation consciously exploit uncertainty 

and gaps in scientific knowledge to influence policymaking, 

most often as a method to stall decisions.

Authors conclude science should be demystified to 

ensure public values are not overridden. It should not be taken 

for granted more science will lead to more acceptance by 

the public. Scientists must be sensitive to how their input is 

relevant to public concerns. Authors believe citizen stakeholders often become involved in resource issues when a sense of 

injustice is perceived. Citizens are more astute about science 

and its use than often depicted and should not be treated as 

ignorant or unwilling to accept scientific evidence. 

Wimberley, R.C., Reynolds, W.N., Vander Mey, B.J., Wells, 

B.L., Ejimakor, G.D., Bailey, C., Burmeister, L.L., Harris, 

C.K., Lee, M.A., McLean, E.L., Molnar, J.J., Ohlendorf, 

G.W., Tomazic, T.J., and Wheelock, G., 2004, Food from 

our changing world—The globalization of food and how 

Americans feel about it: Raleigh, N.C., North Carolina State 

University, accessed June, 2005, at http://faculty.chass.ncsu.

edu/wimberley/Global-Food/foodglobal.pdf

Results are presented from a 2001–2002 survey by 

scientists from 11 universities of 819 U.S. adults to determine 

how globalization affects our food, communities, and quality 

of life. Fifty-seven percent of respondents worry about health 

problems stemming from American farming methods. Sixty 

eight percent say they would pay more for safe foods grown in 

America. Over 70 percent said they would pay more for food 

grown locally. Seventy percent of respondents trust farmers 

while only 11 percent trust business executives and only 20 

percent trust elected officials. Eighty-two percent trust USDA, 

while 10 percent distrust the agency. Ninety-one percent of 

respondents (following 9/11) were somewhat, or very, concerned about the safety of the American food supply. Three 

fourths of respondents were concerned about environmental 

effects of farming methods in other countries and 61 percent 

were concerned about environmental consequences in the U.S. 

industry. Ninety-four percent of respondents believe farmers 

have responsibilities to protect resources for future generations 

and 56 percent believe farmers who fail to adopt needed conservation practices should be financially penalized. Seventyone percent said they would be willing to pay more for food 

if it were produced in ways to protect the environment while 

81 percent said they would pay more for food grown on farms 

using beneficial environmental practices. Seventy-six percent 

of respondents believe government policies should focus on 

helping small, family owned farms. Only 25 percent believe 

corporate farms should get government help. Nearly 60 percent believe family farms should be supported even if it means 

higher prices for food. 

Witter, D.J., 2006, High Plains landowner survey 2006— 

Farmers, ranchers, and conservation: Mishawaka, Ind., D.J. 

Case & Associates, Playa Lakes Joint Venture, accessed 

November, 2010, at http://www.pljv.org/.

A survey of 1,800 High Plains landowners in Colorado, 

Kansas, Nebraska, New Mexico, Oklahoma, and Texas was 

completed in early 2006 with a 26 percent response rate. 

About 50 percent of the farmers and ranchers responding 
Upland Game Birds 135

had heard the term “playa.” Approximately 50 percent of 

respondents did not know playas were useful for restoration 

of groundwater recharge of the Ogallala Aquifer. Respondents 

indicated a support for more conservation measures to protect 

the Ogallala Aquifer as well as to continue the CRP. Twenty 

eight percent of respondents were highly willing and 46 percent moderately willing to plant native grass buffers around 

playas if offered economic incentives. Of those respondents 

who said they had playas on their lands, 68 percent indicated 

the wetlands had a positive effect while 25 percent saw playas 

as a negative feature of the landscape. A major benefit of playas was seen as their attraction to wildlife followed by groundwater recharge, improvement in groundwater quality, and 

availability of water for livestock. Factors identified as having 

a negative influence associated with playas was reduction of 

land available for production, flooding, and the potential negative effects of state or federal regulation associated with use 

of these lands. Landowners indicated their preferred source of 

information about conservation options was from federal and 

county agricultural sources. Non-governmental groups were 

ranked lowly as a source of potential information. 

Wright, B.A., Kaiser, R.A., and Nicholls, S., 2002, Rural landowner liability for recreational injuries—Myths, perceptions, and realities: Journal of Soil and Water Conservation, 

v. 57, no. 3, p. 183–191.

Liability for recreational injuries has been a particularly 

worrisome problem for landowners. Article describes analysis of state-level recreation-use statutes intended to protect 

landowners from legal obligations tied to injuries sustained on 

their land. Data from over 600 appellate court cases involving recreational injuries are analyzed. Authors conclude fears 

on part of landowners about liability appear to be greater than 

actual risk. State recreation-use statutes generally provide 

significant liability protection for landowners. The exceptions 

generally occur when landowners charge fees for access. In 

free access states landowners are required to make a choice 

between income generation and state provided liability protection. Resource professionals and landowners are generally not 

fully aware of the significant liability protection furnished by 

state recreation-use statutes. 

Zepeda, L., and Kim, J., 2006, Farm parents’ views on their 

children’s labor on family farms— A focus group study of 

Wisconsin dairy farmers: Agriculture and Human Values, 

v. 23, p. 109-121.

An examination of parents’ perspectives on their children’s working on family dairy farms in Wisconsin is presented. All participants in the study felt pressured as a consequence of U.S. agricultural policy to enlarge their operations 

in order to keep the farm financially viable. But focus group 

participants believed further expansion of their operation 

would overextend family labor and force the hiring of outside 

labor. This would change the operation and it would no longer be a “family farm.” Participants believed if agricultural 

programs were decoupled from production, farmers would 

not have incentives to expand operation. The study points 

to income supports, access to health care, or other options 

as alternatives to production supports. These actions were 

beveled to lessen the need for parents, particularly mothers, 

to find off-farm employment, which provides more time for 

supervision of children and reduce the need for children to 

devote so much labor to the farm operation. The investigation 

also suggests agricultural policies should target farm practices, 

safety training and alternatives to mechanization in improving 

family and social conditions on family farms.

Upland Game Birds

Northern Bobwhite Quail

Barnes, T.G., Madison, L.A., Sole, J.D., and Lacki, M.J., 

1995, An assessment of habitat quality for northern bobwhite in tall fescue-dominated fields: Wildlife Society Bulletin, v. 23, no. 2, p. 231–237.

This report presents an evaluation of tall fescue (Festuca 

arundinacea) fields as potential habitat for northern bobwhite quail (Colinus virginianus) in Kentucky. Fescue fields 

were characterized by dense vegetation, little bare ground, 

and low diversity of plant species. Tall fescue was characterized as marginal habitat for bobwhite quail due to unsuitable 

vegetation structure, poor floristic composition, and insufficient availability of food. Tall fescue is grown extensively 

for stock feed, turf, and soil-conservation purposes. Fescue 

is an excellent pasture grass and the dominant grass seeded 

in most southeastern CRP fields. Aggressive domination of 

fields planted to tall fescue may reduce plant species diversity 

resulting in lower quality of habitat for quail. Infection of 

endophytic fungus (Acremonium coenophialum), which can 

result in fescue toxicosis, reproductive disorders in mammals, 

and reduced fertility and hatching success in quail has been 

documented.
136 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Brennan, L.A., 1991, How can we reverse the northern bobwhite population decline?: Wildlife Society Bulletin, v. 19, 

no. 4, p. 544–555.

Northern bobwhite quail (Colinus virginianus) populations have declined at an alarming rate over the past 3 decades. 

Every population index for the species indicates significant 

downward trends in greater than 75 percent of the states within 

geographic range of species. The most precipitous declines 

have occurred in the southeastern region of the United States. 

Clean farming practices and forest management systems 

focused on maximizing basal area and yield of wood products 

are the most obvious causes. More intensive management of 

farmland, including an increasing size of farms and fields, has 

eliminated weedy fencerows and overall diversity in vegetative composition of agricultural landscapes. Many marginal 

farmlands in the southeast have been converted to pine plantations eliminating needed cropland and overall habitat diversity. 

Pesticides have been implicated as a possible mortality factor 

affecting bobwhite populations, however, indirect effects of 

pesticides on quail are poorly understood. Agricultural chemicals indirectly affect populations by suppressing arthropod 

populations, a fundamental and essential food resource for 

broods. Weeds provide food and feeding substrates essential 

for growth and development of chicks.

The potential for CRP to enhance habitat for quail is 

far from being realized. Required mowing for weed control 

during peak nesting season is a major problem. Conversion of 

cropland to pine plantations also has had significant impacts 

to habitat quality and availability. Periodic disturbance of 

CRP is essential to maintain annual species of vegetation and 

vegetative diversity. Strip disking is recommended as a viable 

management option to set back vegetation succession in CRP 

grasslands and early stages of pine plantations.

Brennan, L.A., 1993, Future directions for bobwhite quail and 

wildlife research in the southeastern United States, in 1993 

Tall Timbers Game Bird Seminar, Tallahassee, Fla.,1993, 

Proceedings: Tallahassee, Fla., Tall Timbers Research Station, 60 p.

An increase in arthropod abundance was recorded in 

response to burning and strip disking. Herbicide applications 

affect quail populations through disruption of the food chain 

by elimination of vegetation strata thereby limiting populations of needed insects. Widespread application of herbicides 

suppresses weed populations so well that sufficient insect 

populations are not available for hens and chicks. Suggested 

modification of herbicide application includes adoption of 

Conservation Headlands which have been documented to have 

substantially increased production of gray partridge (Perdix 

perdix) in Great Britain. Application of headland concept 

and elimination of pesticide applications in field borders has 

potential for befitting quail and other wildlife associated with 

agricultural landscapes. 

Brennan, L.A., 1993, Strategic plan for quail management and 

research in the United States— Introduction and background, in Quail III—National Quail Symposium, Kansas 

City, MO, July 1992, Proceedings: Pratt, Kans., Kansas 

Department of Wildlife and Parks, p. 160–169.

Habitat management by the private sector is apparently 

having little broad-scale impact on northern bobwhite quail 

(Colinus virginianus) populations. Leadership from professionals with creative vision for solving problems caused by 

changing land use patterns is needed. Evidence of growing 

interest in quail by the public as well as concerned landowners supports a greater management emphasis toward quail. 

Detrimental effects of existing federal agricultural policies 

include: annual spring burning, summer mowing, continued 

emphasis on planting cool-season grasses (for example, tall 

fescue [Festuca arundinacea], smooth bromegrass [Bromus 

inermis]), extensive stands of monoculture pine, and lack of 

flexibility in management are severely limiting value of CRP 

as a means to improve habitat conditions for quail. The paper 

provides detailed recommendation for modification of Federal 

agricultural policies to improve habitat quality for quail.

Burger Jr., L.W., Kurzejeski, E., Daily, T.V., and Ryan, M.R., 

1990, Structural characteristics of vegetation in Conservation Reserve Program fields in northern Missouri and their 

suitability as bobwhite habitat, in Transactions of the North 

American Wildlife and Natural Resources Conference, 55, 

Denver, Colo., March 16–21, 1990, Proceedings: Washington, D.C., Wildlife Management Institute, p. 74–83. 

Vegetation established under the CRP may provide both 

nesting and winter roosting habitat for northern bobwhite quail 

(Colinus virginianus) in northern Missouri. However, clipping, 

haying, or disking disturbed 50 percent of all fields sampled 

as part of this investigation. Thirty four percent of fields 

provided potential roosting habitat. Fields where establishment of permanent native grass (CP2) and permanent wildlife 

habitat (CP4) were planted were most likely to provide early 

season nesting habitat needed by quail. Disturbance, primarily 

for weed control was the primary factor limiting the potential 

value of CRP fields as winter roosting and nesting cover.

Burger Jr., L.W., McKenzie, D., Thackston, R., and Demaso, 

S.J., 2006, The role of farm policy in achieving large-scale 

conservation—Bobwhite and buffers: Wildlife Society Bulletin, v. 34, no. 4, p. 986–993.

Payments to farm operators under USDA conservation 

programs far outweigh the collective investment of the North 

American Wetlands Conservation Act, Endangered Species 

Act, Pittman Robertson Act, and Conservation Investment Act 

with resultant potential to alter land use and bring improvements to wildlife habitat quality on large spatial scales. Past 

effectiveness of programs has varied by program, practice, 
Upland Game Birds 137

region and wildlife species affected with effects ranging from 

positive to negative. These programs can be more effective 

if explicit goals are identified as part of large-scale conservation initiative such as the North American Waterfowl Plan and 

the Northern Bobwhite Conservation Initiative. While USDA 

conservation programs have been designed to achieve broad 

conservation objectives, available policy options often have 

not been designed to address specific wildlife goals identified 

in comprehensive, multi-agency regional and national initiatives. In the 1996 Farm Bill, wildlife was elevated to co-equal 

status with soil erosion and water quality but still wildlife 

issues do not carry equivalent weight of other objectives in 

relation to conservation compliance. An overview of how the 

Conservation Reserve Program, specifically Conservation 

Practice 33 (Habitat Buffers for Upland Birds) is being used 

to address specific goals and objectives to enhance habitat for 

these species is presented. 

The authors describe the Northern Bobwhite Conservation Initiative as a case study for refinement of USDA conservation programs to achieve specific wildlife goals. The goal 

is to restore range-wide populations to an average density 

equivalent to that which existed in 1980 which would require 

management on 32.8 million hectares (81 million ac) of farm, 

forest, and rangeland. Recommended management practices 

would change primary use on only 6–7 percent of land. The 

underlying assumption upon which this initiative is based is 

that insufficient native herbaceous grasses and forbs (primary 

covers for nesting and brood habitat) limit bobwhite populations across their range. Conservation buffers and field borders 

in uplands were identified as primary practices that could 

achieve this goal in agricultural ecosystems. Conservation 

Practice 33 was the first continuous CRP practice specifically 

designed to meet habitat and population goals under a national 

species recovery plan. It was also the first CRP practice to specifically require monitoring to determine population response. 

Habitat buffers are typically 30–120 ft wide and planted 

to native warm-season grasses, legumes, and shrubs or are 

allowed to regenerate through natural succession. Contracts 

are 10 yr in length and require periodic disturbance through 

disking, prescribed fire or application of selective herbicides. 

In the first year 29,588 hectares (73,113 ac) were enrolled in 

35 states. CP33 will likely succeed because it addresses producer economic needs, provides multiple wildlife and environmental benefits and is based on goals identified in large-scale 

conservation initiatives.

Burke, J.D., Chamberlain, M.J., and Geaghan, J.P., 2008, 

Effects of understory vegetation management on brood 

habitat for northern bobwhites: Journal of Wildlife Management, v. 72, no. 6, p. 1361–1368.

Conversion of potential habitat to pine forest and exclusion on fire from pine dominated landscapes are attributed 

to be part of the reason for long-term declines in northern 

bobwhite quail (Colinus virginianus) populations across the 

southeast. Understory vegetation response to management is 

evaluated in relation to arthropod abundance in commercially 

managed pine forest in Louisiana. Study forests were 25- to 

40-yr-old, even-aged, short-rotation loblolly pine (Pinus 

taeda) stands. Primary overstory trees were loblolly pine and 

shortleaf pine (P. echinata), red maple (Acer rubrum), water 

oak (Quercus nigra), southern red oak (Quercus flacata), and 

sweetgum (Liquidambar styraciflua). Understory vegetation 

consisted of blackberry (Rubus spp.), greenbrier (Smilax spp.), 

poison ivy (Toxicodendron radicans), sumacs (Rhus spp.), 

lespedezas (Lespedeza spp.), and beggarweeds (Desmodium

spp.). Management practices evaluated included mowing, prescribe fire only, imazapyr application in conjunction with fire, 

and control (no treatment). 

Percentage of forbs was 2 times greater in burn-herbicide 

plots relative to all other practices. Mowed plots contained the 

greater percentages of grass, whereas burn and burn-herbicide 

plots contained 10 times the amount of bare ground. Arthropod abundance and diversity were greatest in plant communities managed using prescribed fire and imazapyr. Orthoptera 

abundance was greatest in burn-herbicide plots. Quail chicks 

had the greatest foraging success in the burn-herbicide treated 

areas. Management prescriptions intended to enhance habitat 

quality for the federally endangered red-cockaded woodpecker 

(Picoides borealis) were found to benefit brood habitat quality 

for quail. To encourage more favorable vegetative conditions 

for quail brood habitat application of imazapyr in combination with a 2-yr burn rotation is recommend. The authors 

suggest more intensive management of understory vegetation 

may be necessary to achieve high-quality habitat in loblolly 

pine habitats.

Cline, G.A., 1988, Habitat relationships of bobwhite quail and 

cottontail rabbits on agricultural lands in Halifax county, 

Virginia: Blacksburg, Va., Virginia Polytechnic Institute and 

State University, M.S. thesis, 99 p.

An evaluation of a HSI model for assessment of northern bobwhite quail (Colinus virginianus) habitat is described. 

Wooded fallow fields, length of pasture/fallow, forest/forest 

edge, and total number of all edges were positively related to 

quail presence. Management recommendations are to maximize the number of different edges and number of fallow 

fields in early successional stages. Cultivation of field borders, 

corners, waterways and other idle areas should be discouraged. 

A large number of small fields, each with a fallow or brushy 

border, are better than equivalent acreage in only a few fields. 

Authors concluded that the model can correctly predict which 

habitats are preferred by bobwhite quail. 

Cox, S.A., Guthery, F.S., Lusk, J.J., Peoples, A.D., DeMaso, 

S.J., and Sams, M., 2005, Reproduction by northern bobwhites in western Oklahoma: Journal of Wildlife Management, v. 69, no. 1, p. 133–139.
138 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

A 10-yr evaluation of northern bobwhite (Colinus virginianus) reproduction suggests lower clutch size later in nesting 

season. Availability of early-season nesting cover is limiting 

and a management concern. Authors conclude high success 

of nests is possible in absence of predator suppression where 

significant high quality habitat supports abundant nests established across the landscape. Authors believe early nesting by 

the species and availability of an abundance of cover early in 

spring can support greater reproductive success. Consequently, 

management should focus on availability high quality cover in 

the early nesting season.

Doxon, E.D., and Carroll, J.P., 2008, Feeding ecology of ringnecked pheasant and northern bobwhite chicks in Conservation Reserve Program fields: Journal of Wildlife Management, v. 74, no. 2, p. 249–256.

In spite of programs like the CRP, northern bobwhite 

(Colinus virginianus) and ring-necked pheasant (Phasianus colchicus) continue to decline in some regions. These 

declines have been attributed to fewer insects in agricultural 

ecosystems, continued loss in amount and quality of habitat, and declining survival of chicks in agricultural and CRP 

fields. Four conservation practices were evaluated in relation 

to invertebrate availability: CP10 warm-season grass mix, 

improved CP10 which had less than 10 percent of the field 

interseeded with alfalfa (Medicago sativa), CP2 warm season 

grasses with a forb mix included, and CP25 warm season 

grasses with Maximilian sunflower (Helianthus maximiliani) 

purple prairie clover (Dalea purpurea), prairie coneflower 

(Ratibida columnifera) and Illinois bundleflower (Desmanthus 

illinoensis) added to the planting mix. Winter wheat was also 

sampled as part of the investigation.

Many fields, especially CP10 averaged less than 5 percent bare ground cover. Study fields with the highest percentage of bare ground (CP25 and CP2) produced some of the 

highest foraging and mobility rates for pheasant and quail 

chicks. The more open ground enabled chicks to move more 

easily and experience higher foraging rates. The amount of 

bare ground was found to have a significant impact on insect 

selection and accessibility by the chicks. The authors conclude 

brood habitat quality in CRP fields could be greatly improved 

by practices that increase bare ground cover, such as light 

disking or burning. Data suggest, at least for this region of 

Kansas, disturbance every 4 to 5 years as grass growth in 5 

to 7 year old fields had become too dense to furnish suitable 

conditions for foraging by quail and pheasant chicks. 

Greenfield, K.C., Burger Jr., L.W., Chamberlain, M.J., and 

Kurzejeski, E.W., 2002, Vegetation management practices 

on Conservation Reserve Program fields to improve northern bobwhite habitat quality: Wildlife Society Bulletin, 

v. 30, no. 2, p. 527–538.

Habitat quality for early successional and grassland 

species of wildlife may decline as CRP grasslands mature if 

they are not subjected to disturbance. Effects of strip disking 

on vegetation structure, composition, and soil erosion were 

evaluated in Missouri stands of tall fescue (Festuca arundinacea) and orchardgrass (Dactylis glomerata). Fall discing generally increased percentage of bare ground and plant 

diversity and decreased litter cover and depth. Habitat quality 

gains in fescue fields were short lived but of longer duration in 

orchardgrass fields. Vegetative response to disking diminished 

by the second growing season following treatment, especially 

in fescue. Soil losses within treated areas were estimated to 

be well within USDA tolerable limits. Authors recommend 

disking intensity on CRP fields could be increased and be 

implemented on a 2- to 3-yr rotation to maintain early succession plant communities in Midwestern and Southeastern 

CRP fields.

Greenfield, K.C., Chamberlain, M.J., Burger Jr., L.W., and 

Kurzejeski, E.W., 2003, Effects of burning and discing Conservation Reserve Program fields to improve habitat quality 

for Northern bobwhite (Colinus virginianus): American 

Midland Naturalist, v. 149, no. 2, p. 344–353.

Evaluation of burning and light disking of strips in Mississippi CRP fields planted to fescue (Festuca arundinacea). 

This report is a companion study to Missouri results described 

above in Greenfield and others, 2002. Fall disking generally 

increased percentage bare ground and plant diversity with 

corresponding declines in plant litter cover and depth. Effects 

of fall light disking diminished by the second growing season. 

Burning increased plant diversity and improved habitat quality 

for northern bobwhite quail (Colinus virginianus). Erosion 

impacts of light discing were within tolerable soil erosion 

limits therefore more intensive disking was recommended to 

extend benefits of management action.

Madison, L.A., Barnes, T.G., and Sole, J.D., 2001, Effectiveness of fire, disking, and herbicide to renovate tall fescue 

fields to northern bobwhite habitat: Wildlife Society Bulletin, v. 29, no. 2, p. 706–712.

Fields dominated by tall fescue (Festuca arundinacea) 

furnish poor habitat for northern bobwhite quail (Colinus 

virginianus) due to unsuitable vegetation structure, a lack of 

diversity in vegetation composition, and absence of suitable 

food. Tall fescue forms a dense sod and furnishes little bare 

ground, which may prevent bobwhite from efficient movement 

and foraging. The paper reports results of an examination of 

the effectiveness of controlled burning, disking, and Round-up 

to improve habitat quality for quail. Spring application of herbicide was most effective method in reduction of fescue coverage. Fescue cover was reduced for one year following disturbance by fall, spring and summer disking but became similar 

to undisturbed control plots and pre-treatment conditions by 

the second year post-treatment. Fall, spring, and summer burning did not prove to be effective in reduction of fescue.
Upland Game Birds 139

Riffell, S.K, and Burger, L.W., 2006, Estimating wildlife 

response to the Conservation Reserve Program—Bobwhite 

and grassland birds: Washington D.C., USDA Farm Service 

Agency, Department of Agriculture, Farm Service Agency, 

Acquisition Management Branch, Special Projects Section, 

Report FSA-R-28-04DC, 49 p.

A retrospective analysis of relationships among land 

use and cover type, CRP habitats, and indices of grassland 

bird populations is described. USDA NRI data and Common 

Land Unit (CLU) data were used on differing spatial scales 

to describe relations between land use, conservation practice, 

and estimates of avian populations. Conclusions drawn from 

use of NRI data indicate that CRP habitat was overwhelmingly 

associated with a higher abundance of obligate and facultative 

grasslands birds. Significant relations between CRP and grassland birds were more prevalent in ecological regions where 

the majority of the landscape was covered by forest and little 

cropland was present. Bobwhite quail (Colinus virginianus) 

were associated with both tree and grass based conservation 

practices. Common Land Unit data (from Kansas, Nebraska, 

and Missouri) indicated bobwhite were positively related to 

the density (# patches/km2) of grass dominated CRP less than 

4 yr old. Bobwhite were believed to benefit from increasing 

density of grass-dominated CRP and application of midcontract management to furnish earlier successional characteristics of vegetation composition and structure in older CRP 

fields. The authors conclude knowledge of conservation practice type, configuration, and age are key factors in determination of potential habitat quality. Simple, generic classifications 

of lands enrolled in the CRP are of limited utility in determination of program influences on quail habitat distribution and 

quality. Authors conclude their analysis consistently pointed to 

widespread positive effects of the CRP on grassland birds. 

Riffell, S., Scognamillo, D., and Burger, L.W., 2008, Effects 

of the Conservation Reserve Program on northern bobwhite 

and grassland birds: Environmental Monitoring Assessment, 

v. 146, p. 309–323.

Breeding Bird Survey and NRI data are used to evaluate potential benefits of the CRP to grassland birds and 

northern bobwhite quail (Colinus virginianus). Regression 

models were developed for 15 avian species in seven ecological regions. Ecological regions were based on classification 

defined by the North American Bird Conservation Initiative. 

Obligate grassland birds included in the study were; horned 

lark (Eremophila alpestris), grasshopper sparrow (Ammodramus savannarum), dickcissel (Spiza americana), eastern 

meadowlark (Sturnella magna), and western meadowlark (S. 

neglecta). Seven facultative grassland bird also were included 

in the evaluation; mourning dove (Zenaida macroura), eastern 

kingbird (Tyrannus tyrannus), loggerhead shrike (Lanius 

ludovicianus), common yellowthroat (Geothlypis trichas), 

lark sparrow (Chondestes grammacus), red-winged blackbird 

(Agelaius phoeniceus), and eastern bluebird (Sialia sialis). The 

brown-headed cowbird (Molothrus ater), a nest parasite, and 

the indigo bunting (Passerina cyanea), a forest edge species, 

were also included in the analysis. 

Mean abundance of birds was calculated over a 5-yr 

window (1995–1999) for routes sampled in three or more of 

the five years. The time period corresponds to the dates of 

best estimates of CRP coverage. Because 1997 was the year 

most CRP contracts (10–15 yr) would not yet have expired 

1997 was assumed to furnish the best cumulative estimates of 

CRP distribution. Land use data was assessed in a 1,962 km2 

(758 mi2) area around each BBS used. CRP habitat comprised 

an average of 1.6 percent of the landscapes surrounding BBS 

routes. CRP grass habitats averaged 1.3 percent and CRP 

tree dominated covers accounted for an average coverage of 

1.3 percent. 

Analysis of data showed varying responses across ecological regions. Only the eastern meadowlark was positively 

related to CRP in all regions. CRP was a strong predictor 

of bird abundance. The CRP, especially grass-legume, was 

related to higher abundance of northern bobwhite across their 

breeding range. Populations of common yellowthroat, eastern 

meadowlark and indigo bunting were associated with higher 

amounts of CRP. Analysis of relationships to CRP for other 

avian species are presented and discussed.

The authors conclude that NRI data presently furnish 

relatively coarse resolution information on CRP. More thorough investigations of relations between CRP and habitat 

quality for birds, as well as other species, could be possible if 

additional NRI data themes were available. These include, but 

are not limited to, spatial arrangement of fields, age of field, 

specific conservation practices used. An ability to assess landscape configuration with variables such as edge density, patch 

size and juxtaposition of cover types would greatly strengthen 

predictive capabilities of the data set. Availability of information on stand age, species composition, and successional stage 

would also be of benefit.

Roseberry, J.L., and David, L.M., 1994, The Conservation 

Reserve Program and Northern bobwhite population trends 

in Illinois, in Transactions of the Illinois State Academy of 

Science 87 (1 & 2): Edwardsville, Ill., Illinois State Academy of Science, p. 61–70. 

Authors conclude contributions of the CRP to improvements in Illinois quail habitat have been less than expected. 

Lands enrolled in CRP have positively contributed to local 

habitat quality but in some situations the CRP has had neutral 

or negative effects. Overall, CRP land composes only a small 

proportion of total habitat base in the state. CRP contributions 

to the quality of quail habitat could be improved if there is less 

mid-summer mowing, weedier early successional vegetation 

was furnished as a consequence of strip disking and burning, and less emphasis was placed on planting of cool-season 

grasses (for example, smooth bromegrass [Bromus inermis]).
140 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Stauffer, D.F., Cline, G.A., and Tonkovich, M.J., 1990, 

Evaluating potential effects of CRP on bobwhite quail in 

Piedmont Virginia, in Transactions of the North American 

Wildlife and Natural Resources Conference, 55, Denver, 

Colo., March 16–21, 1990, Proceedings: Washington, D.C., 

Wildlife Management Institute, p. 75–76.

Although authors believed that conversion of cropland to 

permanent herbaceous cover is likely to have a positive effect 

on the quality of quail habitat, the beneficial effects are liable 

to exist only while a suitable grass-forb mixture is maintained. 

If grasses such as tall fescue (Festuca arundinacea) dominate 

planting, dense sods will form and habitat benefits will be 

reduced. As croplands are converted to pine plantations, the 

quality of habitat for quail will decline as the stands mature. 

For the first 5–7 yr after conversion, plantations typically 

furnish suitable herbaceous cover. As pines mature and the 

canopy begins to close, the quality of bobwhite quail habitat 

will diminish due to declining understory vegetative cover 

needed for nesting, brood rearing, and food.

When conversion of cropland to CRP increases overall 

diversity in vegetation covers adding habitat components 

previously lacking (for example, brood cover), an increase 

in quail populations can be expected. However, when overall 

diversity is reduced, quail populations are likely to decline. 

The large amount of CRP being placed in pine plantations is 

likely to cause substantial local declines in quail populations. 

The addition of woody cover in pine plantations will lower 

overall habitat diversity in areas where woodlands already 

are a large component of the landscape. Consideration needs 

to be given to juxtaposition and interspersion of CRP with 

other cover types and land uses. A large amount of cropland 

converted to CRP may not be beneficial to quail if large fields 

are converted to grass cover. Converting many smaller fields 

rather than fewer large fields will create more diversity resulting in better quail habitat. 

Weber, W.L., Roseberry, J.L., and Woolf, A., 2002, Influence 

of the Conservation Reserve Program on landscape structure and potential upland wildlife habitat: Wildlife Society 

Bulletin, v. 30, no. 2, p. 888–898.

An evaluation and quantification of CRP effects on 

Illinois agricultural landscape composition within northern 

bobwhite quail (Colinus virginianus) range (southwestern 

and southern Illinois). Considering all land-cover types, CRP 

landscapes had smaller patches than non-CRP landscapes. 

CRP landscapes were characterized by higher patch density 

of grassland and by woodland which compared to landscapes 

without CRP. Edge density of row crop, grassland, and woodland cover types was greater within CRP landscapes in contrast to non-CRP landscapes. Farmland enrolled in CRP tended 

to be located in areas with proportionately less row crop and 

more grassland and woodland than non-CRP landscapes. 

Landscapes surrounding CRP fields were more diverse than 

non-CRP landscapes. Enrollment criteria required CRP to be 

located in areas less productive than cropland and more likely 

to have smaller patch size and greater diversity than general 

landscape. Multiple fields enrolled by landholders also might 

account for some of aggregation. Results support conclusion 

the CRP is being established in landscape that already contained grassland and woodland cover types. 

Williams, C.F., and Mjelde, J.W., 1994, Conducting a financial 

analysis of quail hunting within the Conservation Reserve 

Program: Wildlife Society Bulletin, v. 22, p. 233–241. 

The upsurge in outdoor recreation by the American public 

has strained the public land system. Public hunting lands 

remain in short supply and are receiving increasing amounts 

of demand for use. The greatest opportunities to supply quality 

hunting lies in the development of recreational opportunities 

associated with private land.

Williams, C.K., Lutz, R.S., Applegate, R.D., and Rusch, 

D.H., 2000, Habitat use and survival of northern bobwhite 

(Colinus virginianus) in cropland and rangeland ecosystems 

during the hunting season: Canadian Journal of Zoology, 

v. 78, p. 1562–1566.

Authors suggest landowners on rangeland could reduce 

natural mortality of bobwhite quail populations by taking 

advantage of state and federal programs and non-government 

organizations to increase woody cover suitable for quail. 

Woody, brushy cover is the primary escape cover for quail. 

The lack of such cover may cause higher levels of natural mortality primarily by affecting fall-winter survival. To decrease 

predation in rangeland ecosystems, authors encourage creation 

of more woody escape cover by protecting existing cover from 

development, allowing natural succession to establish cover, 

and use of USDA conservation programs to plant new cover 

where it does not presently exist. 

Williams, C.K., Guthery, F.S., Applegate, R.D., and Peterson, 

M.J., 2004, The northern bobwhite decline—Scaling our 

management for the twenty-first century: Wildlife Society 

Bulletin, v. 32, no. 3, p. 861-869.

Although the northern bobwhite (Colinus virginianus) is 

one of the most broadly researched and intensively managed 

species in North America, current and traditional management principles are incompatible with spatial scales needed 

to adequately address the nationwide, long-term decline 

(greater than 3 percent/yr from 1966–2001 in 25 of 34 states) 

of the species. Management of habitat must become focused 

on regional assessment and management (joint ventures 

between agencies, landowners) of habitat needs rather than 

fine-scale approach (edge, disked strips, food plots). Within 

regional areas, harvest management must become more 

focused and adapted to local trends in bird numbers. Bobwhite 
Upland Game Birds 141

numbers have varied with some western and northern populations increasing or stable but southeastern numbers have 

been in decline.

Changes in the agricultural industry continue to decimate 

broad-scale suitability of wildlife habitats, but approaches to 

addressing the issue remain focused on fine-scale, site-specific 

approaches to meeting wildlife needs. Because of the general 

failure of fine-scale habitat management, it has become apparent that the quantity and quality of habitat must be addressed 

on larger spatial scales (for example, multi-farm communities 

of landowners, physiographic regions). Regions with large 

amounts of suitable, useable space should be protected from 

future development while areas with potential for rehabilitation should be the primary focus of management activities. 

While management of habitat is believed to be the most critical component for recovery of bobwhite populations, harvest 

policies affect population dynamics and may need regional 

or local refinements. Fine-scale properties of habitat have 

potential to affect local population processes ultimately affecting year-to-year survival with implications for refinement of 

harvest guidelines through “risk-sensitive harvest strategies.” 

These strategies should be flexible allowing spatially variable 

levels of harvest, including no harvest, depending on local 

quality and distribution of habitat. This concept will require 

a shift away from maximizing recreational opportunities to 

maximizing biological potential.

Prairie Grouse, Sage Grouse

Boisvert, J.H., 2002, Ecology of Columbian sharp-tailed 

grouse associated with Conservation Reserve Program and 

reclaimed surface mine lands in northwestern Colorado: 

Moscow, Idaho, University of Idaho, M.S. thesis, 184 p.

Author concludes that CRP lands furnish variable benefits 

to Columbian sharp-tailed grouse (Tympanuchus phasianellus) 

in Colorado. CRP grasslands provide habitat characteristics 

preferred for lek establishment but do not furnish suitable 

nesting or brood rearing habitat. The absence of suitable nesting and brood habitat contributes to low survival and productivity. Nor did the CRP provide suitable winter habitat. To 

provide appropriate habitat, CRP fields must provide adequate 

shrub cover and residual vegetation during spring. Plant species diversity must be increased, (author recommends approximately 7 species within a 1-m radius), greater than 30 percent 

grass cover, greater than 50 cm (20 in) vertical cover, and 20 

percent forb cover during nesting and brood rearing seasons. 

Ideally, CRP fields should be near shrub-dominated native 

habitats. The CRP fields included in study were originally 

planted to non-native mixture (CP-1) primarily of smooth 

bromegrass (Bromus inermis), timothy (Phleum pratense), 

pubescent wheatgrass (Agropyron trichophorum), and alfalfa 

(Medicago sativa).

Boisvert, J.H., Hoffman, R.W., and Reese, K.P., 2005, Home 

range and seasonal movements of Columbian sharp-tailed 

grouse associated with Conservation Reserve Program and 

mine reclamation: Western North American Naturalist, 

v. 65, no. 1, p. 36–44.

Columbian sharp-tailed grouse (Tympanuchus phasianellus columbianus) use of CRP and reclaimed mine lands in 

northwest Colorado is reported. (Vegetative composition of 

CRP and reclaimed lands were not provided.) Sharp-tailed 

grouse have been documented using CRP and mine-reclamation lands for breeding, nesting, and brood-rearing. Findings 

suggest a 2.0 km (1.25 mi) radius around leks is suitable for 

assessment of breeding habitat for grouse in reclaimed mine 

lands and CRP. Home ranges of grouse associated with CRP 

(112 hectares [277 ac]) were larger than those of grouse in 

reclaimed mine lands. 

Davis, C.A., Riley, T.Z., Smith, R.A., Suminski, H.R., and 

Wisdom, M.D., 1979, Habitat evaluation of lesser prairie 

chickens in eastern Chaves County, New Mexico—Final 

report: Las Cruces, N. Mex., Department of Fish and Wildlife Science, 141 p.

Authors recommended 160-acre minimum area of 

block habitat to insure sufficient area for winter cover and 

nesting habitat for lesser prairie chickens (Tympanuchus 

pallidicinctus).

Fields, T.L., White, G.C., Gilgert, W.C., and Rodgers, R.D., 

2006, Nest and brood survival of lesser prairie-chickens in 

west central Kansas: Journal of Wildlife Management, v. 70, 

no. 4, p. 931–938.

Authors report habitat use and other sources of variation 

of survival affecting lesser prairie chicken (Tympanuchus pallidicinctus) and greater prairie chicken (T. cupido) nests and 

broods. Age of the nest and brood, timing during the season, 

age of the brooding female, and precipitation during brooding were predictors of survival. Nest survival and survival of 

chicks were identified as the most critical parameters associated with population size of prairie grouse. In Kansas, grass 

height and sagebrush density/height were described as the 

most important vegetation characteristics influencing nest success. Evidence suggests that lesser prairie chicken populations 

have remained stable or increased in western Kansas, which 

is probably related to the presence of large acreage enrolled in 

CRP. Authors recommend provision of heterogeneous habitat 

providing year round diverse opportunities for food and cover 

to counterbalance mechanisms reducing survival of nests 

and broods. Of 59 nests monitored, 69 percent were located 

in CRP fields either dominated by grasses or enhanced with 

additional seeding of forbs. Twenty-seven percent of nests 

were located in native rangeland, while 3 percent were found 

in cropland. CRP fields in the study area were planted to little 
142 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

bluestem (Schizachyrium scoparium), sideoats grama (Bouteloua curtipendula), big bluestem (Andropogon gerardii), 

switchgrass (Panicum virgatum), western wheatgrass (Pascopyrum smithii), blue grama (Bouteloua gracilis), buffalograss (Buchloë dactyloides), and Indiangrass (Sorghastrum 

nutans). Subsequent to 1997, selected CRP fields were interseeded with white sweetclover (Melilotus alba), yellow sweetclover (M. officinalis), as well as several varieties of wildflowers. The number of prairie chickens nesting in CRP indicates 

that preservation of CRP will benefit persistence of the species 

in the region. Authors conclude the brooding period may be 

the most critical parameter defining population health.

Giesen, K.M., 2000, Population status and management of 

lesser prairie-chicken in Colorado: Prairie Naturalist, v. 32, 

no. 3, p. 137–148.

There have been modest increases in population of prairie 

chickens (Tympanuchus pallidicinctus) in Colorado since the 

1960s. Continued restoration and management of degraded 

habitats and transplants of birds into suitable habitats could 

result in substantial increases in distribution and populations. 

The effects of CRP on prairie chicken populations in Colorado 

are unknown. Prairie chicken populations have not increased 

in Baca County since initiation of CRP despite fact that onethird of former cropland in the county is enrolled in program. 

There are no documented leks in CRP fields in Colorado, 

but evidence suggest that some use of CRP has occurred 

for roosting.

Jarnevich, C.S., and Laubhan, M.K., 2011, Balancing energy 

development and conservation—A method utilizing species 

distribution models: Environmental Management, v. 47, 

p. 926–936.

Authors modeled LPC (Tympanuchus pallidicinctus) 

habitat suitability using Maximum Entropy (Maxent) as a 

tool to assist energy development in Kansas. The LPC has 

experienced loss of habitat and population decreases and is 

considered an indicator of grassland conditions. Kansas is 

ranked third in potential wind energy and companies have 

established 6 wind facilities and proposed 44 more facilities. 

Avoidance from further negative impacts to wildlife (habitat 

loss and fragmentation) in areas developed for energy production are needed but agencies often do not have the resources 

to delineate distribution of wildlife or suitable habitat at 

necessary scales.

Authors identified two land use and land cover classes 

(grasslands, CRP), areas of topographic relief, and anthropogenic variables (highways, transmission lines, etc.) as inputs. 

Grasslands represented pasture, rangeland, and lands with 

greater than 50 percent cover of trees or grasslands. Normalized difference vegetation index (NDVI) was used to provide 

estimates of vegetation productivity (low values indicative of 

fallow cropland, high values indicative of lush vegetation). 

Lek locations of both LPC and GPC (T. cupido) were collected 

by Kansas Wildlife and Parks and incorporated into the model. 

Lek habitat suitability was positively correlated with 

increasing land use and land-cover classes. Average NDVI 

was the best indicator of habitat suitability across all models. 

Low NDVI values correlated with greater lek habitat suitability. Elevation was the third most important variable in all 

models except for mixed lek (LPC and GPC) models. Mixed 

leks models that included anthropogenic features showed 

distance from roads more important than standard deviation 

in elevation. Anthropogenic variables increased uncertainty 

in the models but generally had low relative contributions to 

habitat suitability. 

Maxent models do not determine causal relationships, 

and, while evidence of relationship between habitat suitability and anthropogenic variables exist and aid in siting energy 

development, the authors caution that additional testing is 

needed to confirm causal relationships.

Jensen, W.E., Robinson Jr., D.A., and Applegate, R.D., 2000, 

Distribution and population trend of lesser prairie chicken 

in Kansas: Prairie Naturalist, v. 32, no. 3, p. 169–175.

There appears to be an overall decline in lesser prairie 

chickens (Tympanuchus phasianellus) in Kansas. However, 

local variation in lek and individual count indices may be 

attributable to large blocks of grassland established under 

CRP. The lesser prairie chicken appears to occupy a large 

portion of its former range in the state but to be declining 

throughout its breeding range. The overall decline in prairie 

chicken populations in recent decades likely is due to loss, 

fragmentation, and deterioration of habitat. Fragments of 

grassland with and without extensive sand sagebrush (Artemisia filifolia) patches exist as potential breeding habitat in 

southwestern Kansas and should be maintained as a safeguard 

against a further decline of the species.

Lupis, S.G., Messimer, T.A., and Black, T., 2006, Gunnison 

sage-grouse use of Conservation Reserve Program fields 

in Utah and response to emergency grazing—A preliminary evaluation: Wildlife Society Bulletin, v. 34, no. 4, 

p. 957–952.

Use of CRP grasslands by Gunnison sage grouse (Centrocercus minimus) is reported. The study area was a mosaic 

of CRP grassland and sagebrush (Artemisia tridentata and 

A. nova). CRP fields comprised 60 percent of the study area. 

Fields grazed under emergency release, due to drought, supported crested wheatgrass (Agropyron cristatum), pubescent 

wheatgrass (Thinopyrum intermedium), alfalfa (Medicago 

spp.), and sagebrush. Most sage grouse locations were 

reported in CRP covers but the authors find no statistical 

evidence for preference of CRP cover. However, the authors 

believe CRP provides critically important habitat for sage 

grouse. CRP provided roosting cover and foraging habitat. 

CRP may furnish a greater number and diversity of critical 
Upland Game Birds 143

arthropods because of higher grass and forb cover compared 

to adjacent rangelands. Avoidance of fields by grouse during 

emergency grazing was believed to be more in response to the 

presence of cattle than in response to impacts to vegetation. 

The grazing was of short duration and high intensity. Grouse 

frequently returned to previously grazed fields. Long-term 

enrollment of CRP is critical for establishment of sagebrush to 

take place within enrolled fields. If CRP acreage is regionally 

reduced or replaced by agriculture, an immediate loss of habitat will occur. If grazing is allowed on CRP lands, or former 

lands, it should be conducted in a deferred-rotation with nonuse areas available to grouse in the spring and summer. 

Robel, R.J., Harrington, Jr., J.A., Hagen, C.A., Pitman, J.C., 

and Reker, R.R., 2005, Effect of energy development and 

human activity on the use of sand sagebrush habitat by 

lesser prairie chickens in southwestern Kansas, in Transactions North American Wildlife and Natural Resources 

Conference, 69, Spokane, Wash., March 16–20, 2004, Proceedings: Washington, D.C., Wildlife Management Institute, 

p. 251–266.

Lesser prairie chickens (Tympanuchus pallidicinctus) 

occupy xeric grasslands across much of the southern Great 

Plains dominated by sand sagebrush (Artemisia filifolia) or 

shinnery oak (Quercus havardii). In southwestern Kansas, 

populations have generally declined due to deterioration of 

sandsage habitat largely due to conversion to center-pivot irrigation for production of corn. While most of this development 

occurred in mid 1980s, populations continue to decline. Low 

nest success and survival of chicks appear to be factors contributing to decline. Authors conclude the presence of anthropogenic features (for example, buildings, roads, wellheads, 

electric transmission lines) have reduced suitability of habitat 

beyond direct loss of habitat area. Vegetative characteristics 

between used and non-used areas were identical. Avoidance 

of habitat is believed to be associated with movement and 

noise from infrastructure related to energy development and 

agriculture. Adult birds used habitat near roads, wellheads, 

buildings, and transmission lines less than areas further from 

those features. Negative impacts for buildings and transmission lines were greater than those of wellheads and roads. 

Estimates of buffers around roads and energy features where 

habitat use is affected are given. Buffered areas representing 

habitat of lower quality represents 58 percent of the sand sagebrush habitat remaining in 2001. Loss of suitable habitat for 

nesting is believed to be even greater leaving only 26 percent 

of remaining habitat available for nesting.

Rodgers, R.D., 2005, Conservation Reserve Program successes, failures, and management needs for open-land birds, 

in Allen, A.W. and Vandever, M.W., eds., The Conservation 

Reserve Program— Planting for the future—Proceedings of 

a National Conference, Fort Collins, Colo., June 6–9, 2004: 

Reston, Va., U.S. Geological Survey, Biological Resources 

Discipline, Scientific Investigations Report 2005–5145, 

p. 129–134.

The author characterizes periodic management as a key 

factor in creation and longevity of vegetatively diverse CRP 

stands to furnish habitat of high quality. However, appropriate 

management of CRP grasslands through periodic disturbance 

has been inadequate throughout most of the history of the 

program. Absence of management (for example, grazing, fire) 

has permitted encroachment of woody vegetation into CRP 

grasslands (for example, eastern red cedar, Juniperus virginiana), which unchecked will ultimately negate habitat benefits 

of these grasslands for many species of grassland wildlife. 

Various conservation practices using grass buffers available 

through CCRP offer excellent opportunities to improve habitat 

in regions dominated by agricultural production but have been 

underused in the western and southern Great Plains. 

The author furnishes the following recommendations 

for refinement in future management of the CRP to benefit 

grassland dependent avian species: (1) No further planting of 

aggressive exotic grasses should be permitted; (2) Emphasis 

must continue on provision of species diverse stands with 

a strong forb component; (3) A greater proportion of program acres should be shifted to localities near existing native 

grassland habitats; (4) Invasive trees on existing CRP grasslands must be eliminated; (5) Impractical incidental grazing 

restrictions on in-field CCRP linear conservation practices (for 

example, crosswind trap strips, grassed terraces) should be discontinued; and (6) Consultation between USDA, state wildlife 

agencies, and non-government organizations must continue, 

and increase, if optimization of soil, water, and wildlife conservation is to be expected.

Rodgers, R.D. and Hoffman, R.W., 2005, Prairie grouse population response to Conservation Reserve Program Grasslands—An overview, in Allen, A.W. and Vandever, M.W., 

eds., The Conservation Reserve Program—Planting for the 

future—Proceedings of a National Conference, Fort Collins, 

Colo., June 6–9, 2004: Reston, Va., U.S. Geological Survey, 

Biological Resources Discipline, Scientific Investigations 

Report 2005–5145, p. 120–128

Authors describe population responses of greater prairie chicken (Tympanuchus cupido), lesser prairie chicken 

(T. pallidicinctus), and sharp-tailed grouse (T. phasianellus) 

to establishment of CRP grasslands in Colorado, Illinois, 

Kansas, Minnesota, Missouri, Nebraska, North Dakota, and 

South Dakota. Generally the greatest benefits to prairie grouse 

occurred where CRP stands were established near pre-existing 

grasslands augmenting coverage and habitat diversity of the 

grassland complex. Common issues are associated with success and failure of prairie grouse populations in their response 

to the CRP. CRP grasslands 12–30 in in height appear most 

valuable to prairie grouse. Stands less than 12 in generally furnish inadequate concealment and protection from the weather. 

Grass stands greater than 30 in in height do provide thermal 

cover but such stands are often otherwise avoided. Multispecies plantings that are structurally diverse in height and 

growth are grasslands of the greatest value to these species. 
144 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Presence of a high diversity of forbs, particularly legumes, 

greatly enhances the quality of grasslands as habitat for prairie 

grouse. Native grasses furnish habitat of greater quality than 

do stands dominated by introduced species. Recommendations 

for management of individual grassland stands and landscapelevel management are presented.

Salter, G.C., Robel, R.J., and Kemp, K.E., 2005, Lesser 

prairie-chicken use of harvested corn fields during fall and 

winter in southwestern Kansas: The Prairie Naturalist, v. 37, 

no. 1, p. 1–8.

Lesser prairie chicken (Tympanuchus pallidicinctus) 

populations have declined in numbers in Kansas primarily 

due to conversion of sand sagebrush (Artemisia filifolia) to 

cropland. Fall and winter foraging by lesser prairie chickens 

is common on waste grain in harvested cornfields adjacent to 

prairie fragments. No significant relationship between numbers of bird locations and amount of waste grain in cornfields 

was found. Harvested fields with relatively low amounts of 

grain on the ground had sufficient amounts of food available. 

Authors conclude there is no need to develop supplemental 

food sources for wintering lesser prairie chicken populations 

and efforts to enhance habitat quality for this species would be 

better directed at preservation of sand sagebrush habitats. 

Schroeder, M.A. and Vander Haegen, W.M., 2006, Use of CRP 

fields by greater sage-grouse and other shrubsteppe associated wildlife in Washington: Olympia, Wash., U.S. Department of Agriculture Farm Service Agency, Washington 

Department of Fish and Wildlife, 39 p.

The CRP is the largest effort to restore grassland and 

shrubsteppe habitat in the Columbia River Basin. About 1.5 

million acres have been planted to CRP grasses in Washington. Unlike Midwestern CRP acreage established on land 

that was largely prairie prior to conversion to cropland, much 

of Washington CRP occurs on lands previously shrubsteppe 

prior to agricultural use. Declines in northwestern shrubsteppe 

habitats have coincided with declines in endemic populations 

of wildlife that include sage grouse (Centrocercus urophasianus), sage thrashers (Oreoscoptes montanus), and Brewer’s 

sparrow (Spizella breweri). Between 1992 and 1997, 89 sage 

grouse nest sites were monitored. Although more nests were 

in shrubsteppe during the study the proportion of nests in CRP 

increased (31 to 50 percent) in response to maturation of CRP 

grasses characterized by increased height and cover of perennial grass and invasion by big sagebrush (Artemisia tridentata). Nest success in both shrubsteppe and CRP was similar. 

In north central region of Washington where CRP comprised 

17 percent of occupied area by sage grouse data imply a sight 

reversal of grouse population decline. In south-central Washington, where CRP represented 2 percent of occupied area, the 

long-term decline of this grouse population continued.

Numbers of passerine birds using CRP were comparable 

to those recorded in shrubsteppe although species composition

differed. Grassland birds as a group were more abundant in 

CRP and cropland cover types. Shrubsteppe birds were more 

abundant in old CRP than in newer fields using CRP fields 

only when sagebrush was present. Older CRP fields were 

dominated by crested wheatgrass (Agropyron cristatum) while 

newer fields were dominated by the native Sandberg bluegrass 

(Poa ampla). Data suggest that mule deer (Odocoileus hemionus) and jackrabbits (Lepus spp.) are using CRP fields. Mule 

deer used newer fields and shrubsteppe to a greater degree 

than they did older CRP fields. 

Other significant findings include the conclusion shrubsteppe birds are benefiting from establishment of CRP through 

creation of suitable nesting habitat and development of a more 

contiguous non-cropland dominated landscape. CRP is of 

greatest benefit in this region when it contains sagebrush and 

is located in a previously shrubsteppe-dominated landscape. 

As sagebrush matures, CRP is gaining importance as nesting, 

brooding, and wintering habitat for sage grouse. CRP does not 

appear to be important in provision of lek sites. Authors attribute greater use of CRP by sage grouse to increasing size and 

abundance of big sagebrush in CRP fields, increasing cover of 

perennial grasses, growing success of nesting attempts in CRP, 

and possibly the recognition by sage grouse of CRP as suitable nesting habitat. The presence of CRP next to shrubsteppe 

habitat appeared to improve quality of CRP for sage grouse. 

Authors conclude sage grouse population would be severely 

impacted in Washington if the CRP were discontinued.

Silvy, N.J., and Hagen, C.A., 2004, Introduction—Management of imperiled prairie grouse species and their habitat: 

Wildlife Society Bulletin, v. 32, no. 1, p. 2–5.

This is an introductory presentation to a special coverage section of the Bulletin containing 11 papers on prairie 

grouse and their habitats. The papers are a result of a special 

symposium held at the 9th Annual Conference of The Wildlife 

Society held in Bismarck, N. Dak. in 2002. Titles of papers 

are: “Great plains ecosystems: Past, present, and future”; “The 

cause and the decline of pinnated grouse: The Texas example”; 

“Weather and prairie grouse: Dealing with effects beyond our 

control”; “Parasites and infectious diseases of prairie grouse: 

Should managers be concerned?”; “Evaluation of the lekcount index for greater sage-grouse”; “Guidelines for managing lesser prairie-chicken populations and their habitats”; 

“Private-land habitat opportunities for prairie grouse through 

federal conservation programs”; “Adaptive management of 

prairie grouse: How do we get there?”; “Assuring the future 

of prairie grouse: Dogmas, demagogues, and getting outside 

the box”; “Federal listing of prairie grouse: Lessons from the 

Attwater’s prairie-chicken”; “Summary remarks and personal 

observations of the situation by an old hunter and researcher”; 

and “Epilogue: The ghosts of prairie grouse past.”

Authors in this introductory chapter conclude that most 

non-grouse biologists are unaware of the recent decline 

in populations and habitats of these species. The public is 

even more uninformed of the plight of these species. Papers 
Upland Game Birds 145

address changes in habitat availably and quality, limiting 

factors to populations, monitoring and management of grouse 

populations, opportunities provided by federal conservation 

programs, and advantages/disadvantages of federal listing. 

A summary by R. Robel presents the recommendation that 

an aggressive plan must be implemented soon to reverse the 

downward trend in grouse if we expect to have large, viable 

populations of these species. He recommends implementation of large-scale experiments to define best-management 

practices to increase nest success and survival; flexible rangewide management plans with economic incentives to induce 

landowner participation; and aggressive large-scale (80,000+ 

ha [197,000 ac]) restoration of prairie habitats within the next 

10 yr for each species.

Sirotnak, J.M., Reese, K.P., Connelly, J., and Radford, K., 

1991, Effects of the Conservation Reserve Program (CRP) 

on wildlife in southeastern Idaho, project W-160-R-18, job 

completion report: Boise, Idaho, Idaho Department of Fish 

and Game, 45 p.

Report documents use of CRP lands by mule deer 

(Odocoileus hemionus) and upland game birds. Authors 

recommend continuation of CRP contracts to furnish wildlife benefits. Columbian sharp-tailed grouse (Tympanuchus 

phasianellus) experienced the greatest benefits of the program 

in the southeastern part of the state. The best fields for wildlife 

were described as having high levels of cover, high vegetative 

diversity, patches of native vegetation interspersed with CRP 

covers, and irregular borders providing an increased amount of 

edge habitat. The authors believed establishment of CRP may 

reduce depredation on forage crops by mule deer.

Wachob, D.G., 1997, The effects of the Conservation Reserve 

Program on wildlife in southeastern Wyoming: Laramie, 

Wyo., University of Wyoming, Ph.D. dissertation, 123 p.

This dissertation provides an evaluation of CRP effects 

on wildlife from 1993–95. It contains descriptions of vegetation and spatial characteristics of CRP influencing habitat use 

by non-game birds, small mammals, sharp-tailed grouse (Tympanuchus phasianellus), raptors, and big-game in Laramie, 

Platte, and Goshen Counties (southeastern Wyoming). Vegetation species richness, height, standard deviation of vegetation 

cover, and area were significant predictors of small-mammal 

use of CRP. All grouse nests located were in larger CRP 

patches. Hen grouse used CRP with a broad-leafed weed component and annual grasses more often than CRP without these 

features. Avian use of CRP was higher in fields with alfalfa 

than in fields without alfalfa. The CRP was determined to be 

vital reproductive habitat for sharp-tailed grouse in southeast 

Wyoming. Leks were located closer to CRP compared to 

entire study area. Landscape analysis indicated species richness increased rapidly as CRP coverage increased from 0–15 

percent. Sharp-tailed grouse were rare to absent in study area 

prior to implementation of CRP. Author recommends CRP 

should be retained at numerous patches of 200–400 hectares 

(495–988 ac).

Woodward, A.J.W., and Fuhlendorf, S.D., 2001, Influence of 

landscape composition and change on lesser prairie chicken 

(Tympanuchus pallidicinctus) populations: American Midland Naturalist, v. 145, no. 2, p. 261–274.

Declining populations of lesser prairie chickens were 

associated with landscapes characterized by greater rates of 

total landscape change (11 percent per decade) and loss of 

shrubland cover types compared with landscapes in which 

populations did not decline. Amount of cultivation was not 

associated with population trends for 13 populations monitored in Texas, New Mexico, and Oklahoma. Smaller land 

ownerships in Oklahoma increased the potential for more variable management and greater amounts of landscape change. 

Landscapes that have undergone the most rapid change over 

the past several decades also had the most intensive settlement patterns resulting in smaller land holdings. Management 

should focus on maintaining stability of land use and continuity of shrublands within 4.8 km (3 mi) of active leks.

Ring-Necked Pheasant

Applegate, R.D., Flock, B.E., Gipson, P.S., McCoy, M.W., and 

Kemp, K.E., 2002, Home ranges of ring-necked pheasants in northwestern Kansas: The Prairie Naturalist, v. 34, 

no. 1/2, p. 21–29.

Home ranges of hen ring-necked pheasants (Phasianus 

colchicus) varied from an average of 127 hectares (314 ac) 

in high-density (25 percent) CRP areas to 155 hectares (383 

ac) on low-density (8–11 percent) CRP areas. Home ranges 

for males were greater in high-density CRP areas than within 

low-density areas. During the brooding season, home range 

size on low-density CRP site was more than double that of 

home ranges on high-density areas suggesting amount of CRP 

available may have affected home range size at least during 

this season. 

Berner, A.H., 1988, Federal pheasants—Impact of federal 

agricultural programs on pheasant habitat, 1934–1985, in 

Hallett, D.L., Edwards, W.R., and Burger, G.V., eds., Pheasants—Symptoms of wildlife problems on agricultural lands, 

in Midwest Fish and Wildlife Conference, 49, Milwaukee, 

Wis., 8 December 1987, Proceedings: Minneapolis, Minn., 

p. 45–93.

Federal agricultural programs designed to assist farmers 

through cropland diversion and deficiency payment programs have significantly impacted the amount and quality of 
146 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

ring-necked pheasant (Phasianus colchicus) habitat over the 

last 50 yr. Pheasant populations have generally responded 

positively to multi-year cropland diversion programs but 

negatively to annual set-aside programs that allow poor cover 

management and require periodic disturbance of vegetative 

covers. Agricultural conservation programs requiring annual 

set-aside of land for control of commodity production (for 

example, Feed Grain Program and Wheat Production Program) resulted in habitat destruction for pheasants and other 

wildlife. Although potentially beneficial to some species, early 

destruction of cover prior to seed-head development greatly 

reduced value of set-aside lands as safe nesting and broodrearing cover. In Minnesota, data on pheasant populations 

indicate annual set aside lands have a pronounced negative 

influence on populations. Beneficial or negative effects of 

these programs are largely a function of if the cover is left 

through the nesting season and summer. The majority of 

fields enrolled in annual programs have been fallow or lightly 

seeded to small grains in early June and destroyed by July 

15. Nesting cover on set aside lands was absent, poor, or fair 

on about 80 percent of lands while good to excellent only on 

about 20 percent of evaluated fields. Hunting cover and winter 

cover were 4.4 percent fair, 7.4 percent good, and 2.8 percent 

excellent. Proper management of set-aside lands with a focus 

on maintenance of high quality vegetative cover could greatly 

benefit game and non-game populations of wildlife in agricultural ecosystems.

Berthelsen, P.S., Smith, L.M., and George, R.E., 1990, Ringnecked pheasant nesting ecology and production on CRP 

lands in the Texas southern High Plains, in Transactions 

North American Wildlife and Natural Resources Conference 

55, Denver, Colo., March 16–21, 1990, Proceedings: Washington, D.C., Wildlife Management Institute, p. 46–56.

In the Texas panhandle, high-quality nesting habitat for 

ring-necked pheasants (Phasianus colchicus), upland nesting 

waterfowl, and non-game birds has been furnished by CRP 

fields planted to blue grama/Kleingrass (Bouteloua gracilis/

Panicum coloratum), blue grama/sideoats grama (B. curtipendula), and blue grama/plains bluestem (Bothriochloa 

ischaemum). Introduction of the CRP to the panhandle region 

is projected to greatly benefit pheasants due to greater availability of cover which will enable birds to disperse from 

existing refuge covers (for example, playa lake basins). Prior 

to implementation of the CRP high quality, year-round cover 

was uncommon and isolated. One third of fields in study had 

CRP cover effectively eliminated as wildlife habitat due to 

emergency haying or weed control. 

Bogenschutz, T.R., Hubbard, D.E., and Leif, A.P., 1992, 

Corn and sorghum as a winter food source for ring-necked 

pheasants: Journal of Wildlife Management, v.59, no. 4, 

p. 776-784

Corn and sorghum furnish higher-quality winter food for 

pheasants than do natural wild foods and soybeans. Natural 

foods typically are high in fiber and low in digestible energy. 

Soybeans contain digestive inhibitors that lower the metabolically useable energy content of the diet. Female pheasants 

feeding on food plots (corn and mixed plots) had larger lipid 

reserves than females feeding on control and sorghum plots. 

Sorghum provides better winter cover due to vegetative structure. The best option, in most cases, would be to include both 

corn and sorghum in food plots. If winter cover is not limiting 

corn is a better option. If little to no winter wheat is nearby, 

food plots dominated by sorghum are preferred.

Clark, W.R., and Bogenschutz, T.R., 1999, Grassland habitat and reproductive success on ring-necked pheasants in 

northern Iowa: Journal of Field Ornithology, v. 70, no. 3, 

p. 380–392.

Study of ring-necked pheasant (Phasianus colchicus) 

reproductive success in northern Iowa finds nest success averaged 62.3 percent in undisturbed blocks of habitat such as provided by CRP and 44.8 percent in small, linear, or disturbed 

cover types. The study reaffirms importance of a diversified 

agricultural landscape with large blocks of undisturbed cover 

to maintain suitable levels of pheasant reproduction. Populations cannot increase rapidly in landscapes providing small, 

linear or disturbed habitats due to greater occurrence of nest 

failures associated with such configurations of habitat. 

Clark, W.R., Schmitz, R.A., and Bogenschutz, T.R., 1999, Site 

selection and nest success of ring-necked pheasants as a 

function of location in Iowa landscapes: Journal of Wildlife 

Management, v. 63, no. 3, p. 976–989.

Authors recommend managers should provide undisturbed grassland in blocks of greater than 15 hectares (40 ac) 

for nesting ring-necked pheasants (Phasianus colchicus). Nest 

success was highest in fields greater than 160 ac. Establishment of cover in several blocks is better than one large block 

of equivalent area. Both nest-site selection and success are 

influenced by habitat configuration within 1 home range 

radius of nest site. Specific vegetation type at nest location 

was not predictive of nest site selection or success. Authors 

conclude biologists must understand how landscape configuration is influenced by agricultural policy if they are to enhance 

wildlife populations.

Doxon, E.D., and Carroll, J.P., 2008, Feeding ecology of ringnecked pheasant and northern bobwhite chicks in Conservation Reserve Program fields: Journal of Wildlife Management, v. 74, no. 2, p. 249–256.

In spite of programs like the CRP, northern bobwhite 

(Colinus virginianus) and ring-necked pheasant (Phasianus colchicus) continue to decline in some regions. These 

declines have been attributed to fewer insects in agricultural 
Upland Game Birds 147

ecosystems, continued loss in amount and quality of habitat, and declining survival of chicks in agricultural and CRP 

fields. Four conservation practices were evaluated in relation 

to invertebrate availability: CP10 warm-season grass mix; 

improved CP10 which had less than 10 percent of the field 

interseeded with alfalfa (Medicago sativa); CP2 warm season 

grasses with a forb mix included; and CP25 warm season 

grasses with Maximilian sunflower (Helianthus maximiliani) 

purple prairie clover (Dalea purpurea), prairie coneflower 

(Ratibida columnifera) and Illinois bundleflower (Desmanthus 

illinoensis) added to the planting mix. Winter wheat was also 

sampled as part of the investigation.

Many fields, especially CP10, averaged less than 5 

percent bare ground cover. Study fields with the highest 

percentage of bare ground (CP25 and CP2) produced some of 

the highest foraging and mobility rates for pheasant and quail 

chicks. The more open ground enabled chicks to move more 

easily and experience higher foraging rates. The amount of 

bare ground was found to have a significant impact on insect 

selection and accessibility by the chicks. The authors conclude 

brood habitat quality in CRP fields could be greatly improved 

by practices that increase bare ground cover, such as light 

disking or burning. Data suggest, at least for this region of 

Kansas, disturbance every 4 to 5 yr as grass growth in 5-to 

7-yr-old fields had become too dense to furnish suitable conditions for foraging by pheasant and quail chicks. 

Eggebo, S.L., Higgens, K.F., Naugle, D.E., and Quamen, F.R., 

2003, Effects of CRP field age and cover type on ringnecked pheasants in eastern South Dakota: Wildlife Society 

Bulletin, v. 31, no. 3, p. 779–785.

An evaluation of CRP grassland species composition and 

field age related to ring-necked pheasant (Phasianus colchicus) abundance, habitat use, and productivity in the northern 

Great Plains. Fields (n=42) were stratified by species composition (CP1; cool season/introduced species, CP2; warm-season 

natives) and stand age (old: 10–13 yr, new: 1–3 yr). CP1 

fields were planted primarily to tall wheatgrass (Agropyron 

elongatum), or intermediate wheatgrass (A. intermedium) and 

smooth bromegrass (Bromus inermis). Some CP1 fields also 

contained alfalfa (Medicago sativa) and sweetclover (Melilotus officinalis). CP2 fields were dominated by switchgrass 

(Panicum virgatum), big bluestem (Andropogon gerardii), and 

Indiangrass (Sorghastrum nutans). Field age and cover-type 

effects on pheasant abundance and productivity were primarily a consequence of differences in vegetative structure among 

fields. Greater numbers of crowing pheasants were recorded in 

association with CRP cool season grasses than any other cover 

type. Higher numbers of broods were recorded in association 

with cool season than warm season CRP grasslands. Authors 

conclude cool season grass-legume mixtures should be given 

equal or higher ratings than warm-season stands of grass in 

establishment of new fields or preservation of established 

fields due to higher use by pheasants. 

Vegetation structure, as measured by VOR and litter depth, increased with age in both cool and warm season 

grassland. Vegetation height/density and litter depth increased 

more rapidly in cool season than within warm-season grasslands. Litter depth was greatest in cool-season grasslands but 

increased in all fields as they aged. Authors conclude that 

cool-season CRP grasses furnish better nesting and brood-rearing cover than do warm-season CRP grasses of comparable 

age in eastern South Dakota. Authors recommend USDA provide more flexible criteria upon which potential, or renewed, 

CRP contracts are evaluated. The authors propose because 

cool season grasses become established more quickly and are 

less expensive to establish than warm-season natives, equal 

priority should be given to planting and maintenance of coolseason grasses. However, because cool-season grasses are 

more likely to become lodged or flattened during winter and 

do not consistently furnish quality winter cover, the authors 

recommend maintenance of a mosaic of both cool and warm 

season grasses of various age classes. 

Eggebo, S.L., 2001, Ring-necked pheasant and passerine 

abundance in Conservation Reserve Program grasslands 

of differing age-classes and cover types in eastern South 

Dakota, 1998-2000: Brookings, S. Dak., South Dakota State 

University, M.S. thesis, 96 p.

Old CRP grasslands (10–13 yr old) had higher crowing 

count responses than recorded in young CRP fields (0–3 yr 

old). Cool-season grasslands (tall or intermediate wheatgrass 

[Agropyron elongatum, A. intermedium], smooth bromegrass [Bromus inermis], and legumes) had higher crowing 

count responses than did warm-season mixes (switchgrass 

[Panicum virgatum], big bluestem [Andropogon gerardii], 

Indiangrass [Sorghastrum nutans]). Non-game bird grassland 

obligates were more abundant in CRP grasslands dominated 

by cool-season grasses. Author concludes it takes at least 3 

yr for CRP fields to provide suitable habitat for ring-necked 

pheasants (Phasianus colchicus). As CRP grasslands become 

older, they may lose some qualities of dependable feeding 

cover (for example, loss of legumes) but gain value as nesting 

habitat due to greater quality of cover. Overall, the investigator concluded cool-season grassland generally furnished better 

habitat quality than did grasslands dominated by warm-season 

species. However, warm-season grasses appeared to furnish 

better winter cover. The author recommends flexibility in CRP 

planting mixes with greater priority given to providing a mix 

of grassland types in administration of the CRP. Legume component may be critical component of cool-season grass mix. 

Gabbert, A.E., Leif, A.P., Purvis, J.R., and Flake, L.D., 1999, 

Survival and habitat use by ring-necked pheasants during 

two disparate winters in South Dakota: Journal of Wildlife 

Management, v. 63, no. 2, p. 711–722.
148 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Severe winter weather can alter availability of winter 

cover and affect mortality of ring-necked pheasants (Phasianus colchicus). Pheasant habitat use and survival were 

monitored in South Dakota in the second most severe winter 

in since 1892 as well as a milder, more typical winter. Mortality due to predation exceeded mortality due to weather in both 

winters. Mortality due to weather did not differ between winters but severe weather increased vulnerability to predation. 

Authors conclude shelterbelt and food plot habitats are essential to pheasant survival during extreme weather conditions. 

When wind driven snow inundates herbaceous dominated covers and makes them unavailable for use woodland 

and food plot habitats are essential to the winter survival of 

pheasants. Authors conclude cattail- (Typha spp.) dominated 

wetlands, stands of grass greater than 25 cm tall, and food 

plots were important for pheasant survival in severe winters. 

Authors recommend managers should develop dense woody 

habitat, particularly shrubs and coniferous species near areas 

of high density pheasant populations but the potential negative effects to native flora and fauna should be taken into 

consideration when these habitat features are introduced into 

unfragmented landscapes.

Gatti, R., 1992, Nest cover for pheasants and ducks: Madison, 

Wis., Wisconsin Department of Natural Resources, Final 

Report, Study No. 127, Project W-141-R, 51 p.

Nest success is not consistently related to field size, 

shape, distance to water, cover height density, plant diversity, or cover type. Nest success was lower for nests closest 

to edges of cover types. Duck nest density was negatively 

related to plant diversity and positively related to height/

density of residual cover. Ring-necked pheasant (Phasianus 

colchicus) habitat use was higher in fields with lower diversity 

of plant species, greater structural diversity, more irregular 

in shape, and further from water. Widespread establishment 

of switchgrass (Panicum virgatum) nest cover and management of existing duck nest cover towards monotypic stands of 

switchgrass is not justified based on costs, use, or nest success. 

Authors recommend management for diversity of cover types. 

Haroldson, K.J., Kimmel, R.O., Riggs, M.R., and Berner, 

A.H., 2006, Association of ring-necked pheasant, gray partridge, and meadowlark abundance to Conservation Reserve 

Program grasslands: Journal of Wildlife Management, v. 70, 

no. 5, p. 1276–1284.

Relations between amount of land in CRP habitats in 

15 agriculturally dominated landscapes in Minnesota and a 

10-yr assessment of relative abundance of ring-necked pheasants (Phasianus colchicus), gray partridge (Perdix perdix), 

and meadowlarks (Sturnella spp.) are described. For each 10 

percent increase in areas of grass in the landscape, numbers of 

pheasants counted on survey routes increased by an average 

of 12.4 birds in spring and 32.9 birds in summer. Meadowlark 

indices increased by an average of 11.7 birds per route in summer for each 10-percent increase in grassland area. Regardless 

of the amount of grass added to the landscape, partridge numbers declined throughout the investigation. Authors conclude 

that conversion of cropland to CRP grassland is associated 

with higher population indices of pheasants and meadowlarks.

Authors recommend the effectiveness of long-term 

conservation programs should be monitored over periods of at 

least 5 yr to account for natural fluctuations in wildlife populations that occur without apparent changes in habitat quality 

or abundance. Continuation of CRP and other programs that 

restore idle grasslands in agriculturally dominated landscapes 

is recommended. These grasslands should be minimally disturbed during the primary nesting season. 

Hubbard, M.W., 1991, Habitat changes in central Iowa and 

their relationship to ring-necked pheasant populations, 

1981–1990: Ames, Iowa, Iowa State University, M.S. thesis, 

64 p.

A HSI model was evaluated by relating outputs to numbers of ring-necked pheasants (Phasianus colchicus) numbers. 

Study area encompassed 133,000 hectares. Pheasant numbers 

were negatively related to alfalfa/hay acreage and positively 

related to pasture lands. Only area in roadside and spring VOR 

was positively related to pheasant numbers. Other influences 

affected relationships between model output and estimated 

number of birds (for example, weather, population numbers). 

Pheasant populations have undergone widespread declines in 

the Northern Plains states since mid-1960s as consequence of 

habitat loss due to increased mechanization and conversion 

of non-crop acreage to croplands. The original HSI model 

appeared to lack a component to assess important sources 

of winter food for pheasants. Three variables disked corn, 

chiseled corn and disked soybeans were incorporated into the 

model in an effort to improve performance. The model source 

is not described, nor is the model presented. 

Kimmel, R.O., Berner, A.H., Welsh, R.J., Haroldson, B.S., and 

Malchow, S.B., 1992, Population responses of grey partridge (Perdix perdix), ring-necked pheasant (Phasianus colchicus) and meadowlarks (Sturnella spp.) to farm programs 

in Minnesota, in Birkan, M., ed., Proceedings of Perdix VI, 

First International Symposium on Partridges, Quails, and 

Francolins: Gibier Fauna Sauvage, v. 9, p.797–806.

Impacts of farm programs on wildlife vary depending on vegetation planted, subsequent management of the 

vegetation, and length of time cropland was removed from 

production. Spring and summer roadside counts were used to 

monitor changes in grey partridge, pheasant, and meadowlark 

population changes in 15 Minnesota study areas with varying 

amounts of land removed from production. Conservation lands 

included lands enrolled in CRP and Reinvest in Minnesota 

(RIM) program. At the time of the evaluation approximately 
Upland Game Birds 149

96 percent of CRP land in Minnesota was planted to tame 

grasses and grass-legume mixtures (CP1 and CP10). Native 

grass plantings (CP2) accounted for 4 percent of plantings. 

Grass covers planted on 80 percent of RIM lands were tame 

grasses and grass-legume mixtures. Authors estimate it would 

cost $200 million/yr for state conservation agency to establish 

the number of acres of habitat furnished by the CRP. Authors 

conclude there was not an apparent response by grey partridge 

but the abundance of pheasants and meadowlarks was positively correlated with amount of land in CRP/RIM. Wildlife 

benefits of covers provided by conservation programs vary 

according to which habitat components are furnished and how 

these components affect existing conditions. If winter cover 

and feeding areas are inadequate, the benefits of added reproductive cover furnished by CRP/RIM may be reduced. Areas 

with existing low populations of grassland birds may take a 

longer period of time for population responses to improvement 

in habitat quality to be evident.

Leif, A.P., 2003, Survival, spatial ecology and habitat use of 

male ring-necked pheasants in South Dakota: Pierre, S. 

Dak., South Dakota Department of Game, Fish and Parks 

Pittman-Robertson Completion Report 2003–08, 64 p.

Study results are based on movements and habitat use 

of radio tagged male ring-necked pheasants (Phasianus 

colchicus) monitored over a 5-yr period in eastern South 

Dakota. Lower rates of survival following severe winters were 

attributed to flattening of herbaceous cover in idle cover types 

and the drifting in and filling of wetlands with snow. Better 

habitats were associated with perennial cover that included 

grasses and forbs not mowed or grazed in the previous growing season. Use of perennial cover harvested previous growing season increased when new growth produced sufficient 

cover to provide concealment and protection from predators. 

Complexes of undisturbed herbaceous (wetlands with emergent cover or CRP plantings) and woody cover will maximize 

landscape capability to support territories of male pheasants. 

Leif, A.P., 2005, Spatial ecology and habitat selection of 

breeding male pheasants: Wildlife Society Bulletin, v. 33, 

no. 1, p. 130–141. 

Based on work completed in South Dakota, the author 

concludes susceptibility of ring-necked pheasants (Phasianus 

colchicus) to predation may decrease where shrubs border 

idle herbaceous cover types. Woody cover with high groundlevel stem density will enhance habitat suitability for breeding 

pheasants. Idle herbaceous habitats are essential to ringnecked pheasants regardless of the life-cycle requirements 

(for example, display, nesting, escape/winter cover) that this 

habitat type may fulfill. Grass species with stems that retain 

vertical structure in spring (for example, warm-season native 

grasses) offer superior protective cover compared to species 

that are prone to lodge under snow and not return upright 

when snow melts. However, cool season grasses furnish food 

and preferred nesting cover therefore both types of cover 

should be established within management units. Dense monocultures of any grass should be avoided.

Presence of low growing woody shrubs reduced size of 

breeding area required by cocks and served to reduce size of 

pheasant territories. Male pheasants with access to woody 

habitat appeared to experience lower rates of depredation. 

Managers should maximize amount of idle herbaceous cover 

on the landscape. Placement of narrow bands of shrub (2–3) 

rows along idle cover edges will furnish attractive and beneficial component of habitat. Wide shelterbelts were identified 

as crucial cover for winter survival during the most severe 

conditions. Author recommends distance between shelterbelts 

of 2.5 to 5 km (1.5 to 3 mi) and placement near idle cover 

(wetlands with emergent vegetation or CRP grasslands) and 

food sources.

Little, T., and Hill, R.A., 1993, CRP having an impact: Iowa 

Conservationist, v. Sept/Oct, p. 4–9.

This article provides a description of agricultural and 

settlement impacts to wildlife habitats in Iowa with an 

overview of CRP benefits to wildlife largely based on results 

reported from other studies. Converting as little as 4 percent 

of row crop area to CRP significantly increased numbers of 

ring-necked pheasants (Phasianus colchicus) seen on survey 

routes. Higher numbers of pheasants were attributed to greater 

overwinter survival due to the high quality of winter cover 

furnished by the CRP. More than 15 nests of non-game birds 

per 40 acres of CRP were recorded compared to less than 

one in same area of row crops. Nest success of birds in CRP 

was estimated at 33 percent as compared to 20 percent in hay 

fields. Waterfowl nest success in CRP was believed to be as 

good, or better, than that found within established wildlife 

management areas. 

Nielson, R.M., McDonald, L.L., Sullivan, J.P., Burgess, C., 

Johnson, D.S., Johnson, D.H., Bucholtz, S., Hyberg, S., 

and Howlin, S., 2008, Estimating the response of ringnecked pheasants (Phasianus colchicus) to the Conservation 

Reserve Program: The Auk, v. 125, no. 2, p. 434–444.

Associations between CRP and ring-necked pheasant 

populations were assessed using BBS data from 1987–2005 

from BBS routes in nine states. Land use and CRP habitat 

type data within a 1,000-m buffer around each survey route 

were compared to population counts. On average, a positive 

association between ring-necked pheasant counts and the 

amount of CRP herbaceous vegetation within the 1,000-m 

buffer was found. Authors conclude the analysis shows a positive association of ring-necked pheasants along BBS routes 

with larger amounts of CRP enrollment. This association was 

consistent across broad geographic regions. The statistical and 

modeling methods used for this analysis are believed a useful 
150 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

tool for further evaluation of CRP effects on other avian species and regions.

Nomsen, D.E., 2005, The Conservation Reserve Program 

Wildlife Legacy—Continuing and strengthening the U.S. 

Department of Agriculture’s most successful wildlife 

conservation program, in Allen, A.W., and Vandever, M.W., 

eds., The Conservation Reserve Program—Planting for 

the Future—Proceedings of a National Conference, Fort 

Collins, Colo., June 6–9, 2004: U.S. Geological Survey, 

Scientific Investigations Report 2005–5145, p. 53–55.

Perspectives of Pheasants Forever (PF) in relation conservation successes of the 2002 Farm Bill and the future of 

the CRP are presented as are descriptions of how PF has been 

involved in on-ground and policy refinement of conservation 

provisions affecting the CRP. Excerpts from letters from 10 

Great Plains and Midwestern (Idaho, Illinois, Iowa, Kansas, 

Minnesota, Montana, Oklahoma, South Dakota, Texas, Washington) states describing the wildlife benefits brought by the 

CRP are presented.

Riley, T.Z., 1995, Association of Conservation Reserve 

Program with ring-necked pheasant survey counts in Iowa: 

Wildlife Society Bulletin, v. 23, no. 3, p. 386–390.

Ring-necked pheasant (Phasianus colchicus) numbers 

in Iowa are believed to have increased 30 percent during first 

5 yr of CRP compared to a similar period prior to program. 

Numbers increased 34 percent in counties with greater than 

70 percent of cropland and 26 percent in counties with 50–70 

percent cropland. Increases were not detected in counties with 

less than 50 percent of their area in cropland. Although pheasant numbers were positively related to CRP area, numbers 

apparently also were influenced by percent cropland and 

cumulative snowfall. Positive association between pheasant 

survey counts and CRP land enrollment may have resulted 

from an increase in nesting and winter cover. The addition of 

idle grass-forb fields provided by the CRP may have improved 

survival of females and enhanced reproductive success by 

increasing amount and dispersion of roosting and nesting 

cover. Association of pheasant counts with percent area in 

CRP probably a function of percent cropland. Value of existing 

grass cover and that added by CRP may have been reduced by 

the persistence of snow cover.

Robertson, P.A., 1996, Does nesting cover limit abundance of 

ring-necked pheasants in North America?: Wildlife Society 

Bulletin, v. 24, no. 1, p. 98–106.

Based on a review of literature, the author concludes 

availability of attractive nesting cover is a major factor limiting ring-necked pheasant (Phasianus colchicus) density in 

North America. Although secure nesting cover can increase 

the chance of an individual hen successfully hatching a clutch, 

availability of nesting cover does not necessarily lead to longterm increases in overall density of birds. Author concludes 

that territory cover, a mixture of many habitat types, may be 

limiting in many parts of North America. Creation of habitats that support new territories could reduce spring dispersal 

and increase local breeding density. Predation, availability 

and quality of winter cover, and suitable cover for broods all 

can have important influences on quality of pheasant habitat 

and should be addressed in landscape-level development of 

pheasant habitat.

Rodgers, R. D., 1999, Why haven’t pheasant populations in 

western Kansas increased with CRP?: Wildlife Society Bulletin, v. 27, no. 3, p. 654–665.

Pheasant (Phasianus colchicus) populations in western 

Kansas declined an average of 65 percent from 1966 to1975 

and 1986 to 1995. Declines were particularly strong in the 

1980s. Over 680,000 acres of CRP were added to the regional 

landscape since 1985, but pheasant populations have not 

shown a significant increase in population numbers. Although 

summer observations show that CRP was used proportionally more than availability by pheasant broods, over-winter 

use of CRP was only 37 percent of weedy wheat stubble, a 

habitat being lost in the region. Increased use of herbicides, 

which results in less cover and lowering the quality of wheat 

stubble as habitat for pheasants represents an overwhelming 

loss of habitat for which CRP cannot compensate. Also, the 

author attributes a lack of vegetative diversity in early CRP 

plantings as further limiting their benefits to pheasants. Poor 

maintenance of stands and the large size of fields enrolled 

in the CRP is also believed to have limited benefits of the 

program to pheasants. The quality of pheasant habitat could be 

improved if perennial legume and other forbs were interseeded 

into recently burned stands and grass-legume strips were 

interspersed within intensively farmed landscapes. The lack of 

brood habitat and the failure of the CRP to improve availability of brood habitat are also attributed to the lack of response 

by pheasants. Nesting habitat, largely furnished by winter 

wheat, is not believed to be limiting in the region.

Use of weedy wheat stubble by pheasants was higher 

than use recorded in CRP grasslands. Nighttime roosting composed much of the pheasant use of CRP with only limited use 

during daytime. Native grasses typical of CRP plantings in the 

region furnish minimal food sources for pheasants as compared to waste grain and weed seeds in weedy wheat stubble. 

Excessive litter in unmanaged CRP also may restrict movement and use of these fields by pheasants. Though useful, CRP 

has not compensated for the loss in quality of habitat provided 

by weedy wheat stubble in western Kansas. But benefits of 

CRP habitats may have compensated for loss of wheat stubble 

habitats and associated impacts on pheasant populations 

preventing even further declines in populations. Greater use 

of linear conservation features (for example, grassed terraces, 

crosswind trap strips) interspersed with cropland is strongly 

advocated to enhance habitat quality for pheasants. 
Upland Game Birds 151

Schmitz, R.A., and Clark, W.R., 1999, Survival of ring-necked 

pheasant hens during spring in relation to landscape features: 

Journal of Wildlife Management, v. 63, no. 1, p. 147–154.

Density of edge between grassland and other habitats 

was predictive of the hazard rate and odds of mortality, which 

increased 2 percent for every 10 m/ha (33 ft/2.5 ac) of additional 

edge in the home range. Management to reduce vulnerability 

to predation should be targeted to areas with high measures 

of edge. Reduction in edge density by increasing field size of 

permanent cover would increase spring survival. Managers need 

to estimate how landscape changes at the township (36 mi2) 

scale if full advantages of agricultural policies and conservation 

practices are to be expected. 

Snyder, W.D., 1985, Survival of radio-marked hen ring-necked 

pheasants in Colorado: Journal of Wildlife Management, 

v. 49, no. 4, p. 1044–1050.

The lowest monthly survival of hen ring-necked pheasants (Phasianus colchicus) occurred in April. Predation was 

primarily due to predation by avian species. Great horned owls 

(Bubo virginianus), Cooper’s hawks (Accipiter cooperii), and 

prairie falcons (Falco mexicanus) were primary avian predators. 

Coyote (Canis latrans) and feral house cats (Felis silvestris) 

were the principle mammalian predators. The presence of trees 

interspersed, or in close association, with grassland covers 

contributed to high rates of avian predation. Concealment quality of early spring residual cover in grassland was important 

for survival of hens. Study area contained extensive tree and 

shrub plantings attracting both wintering pheasants and avian 

predators. Pheasants associated with grasslands containing trees 

suffered a higher rate of avian predation than their counterparts 

in habitats not containing trees. 

Taylor, M.W., Wolfe, C.W., and Baxter, W.L., 1978, Land use 

change and ring-necked pheasants in Nebraska: Wildlife 

Society Bulletin, v. 6, no. 4, p. 226–230.

Positive relationships were reported between spring 

densities of hen ring-necked pheasants (Phasianus colchicus) 

to kilometers (km) of fencerows, hectares (ac) of pasture/hay, 

and wheat and wheat stubble. Pheasant numbers were inversely 

related to area of row crops, percent of land fall-tilled, and 

amount of area irrigated. Irrigation generally involves extensive 

land leveling, or clearing, which eliminated idle areas, fencerows, old farmsteads, wetlands, and other vegetative covers 

of high value. Tillage of crop residue in fall, especially wheat 

stubble, reduced cover for wildlife. An interspersion index useful for predicting pheasant habitat quality and density of birds 

is presented.

Taylor, R.L., Maxwell, B.D., and Boik, R.J., 2006, Indirect 

effects of herbicides on bird food resources and beneficial 

arthropods: Agriculture Ecosystems & Environment, v. 116, 

p. 157–164.

This paper reports on an investigation of relations 

between agricultural herbicides, food webs, and how changes 

in the plant community affect abundance of arthropods. The 

study focuses on insects eaten by ring-necked pheasant (Phasianus colchicus) and gray partridge (Perdix perdix) chicks as 

well as arthropods that prey on insect pests and weed seeds. 

Beneficial insects were more common in diverse communities 

of vegetation than within monocultures. Study demonstrates 

that herbicides do affect abundance of beneficial insects that 

are food for avian species and predators of less desirable 

species of insects. The study confirms herbicides do reduce 

numbers and biomass of insects important to game species, 

as well as others dependent upon insects for food, by altering 

the beneficial effects of vegetation composition and diversity. 

Weedy plots contained 12 times the biomass of vegetation 

dwelling insects than did monocultures. Plots with intermediate diversity in vegetation held 8 times the biomass of insects 

than did monocultures. After spraying bromoxynil and imazamethabenz, insects in weedy plots diminished by more than 50 

percent compared to that recorded in monocultures. Authors 

advocate use of headlands (where herbicides are not used), 

interseeding, and greater use of narrow spectrum herbicides to 

lessen losses of beneficial insects in agroecosystems.

Trautman, C.G, 1982, History, ecology and management of 

the ring-necked pheasant in South Dakota: Pierre, S. Dak., 

South Dakota Department Game, Fish, and Parks, 118 p.

Winter concentrations of ring-necked pheasants (Phasianus colchicus) invariably are near weed patches, grain stubble, 

cornfields and other food sources. Distances traveled rarely 

exceed 1/4 mi. The nearness to available food is dominant 

factor in choice of winter roosting sites. Marshlands provide 

high quality winter cover. The document provides a detailed 

presentation of ring-necked pheasant history, ecology and 

management in South Dakota. 

Warner, R. E., 1994, Agricultural land use and grassland habitat in Illinois—Future shock for midwestern birds: Conservation Biology, v. 8, no. 1, p. 147–156.

During the period of most intensive agricultural production, grasslands were present only as linear edges with resultant low density and diversity of grassland nesting birds. Nest 

densities and species diversity were highest where grassland 

was nearby cover types heterogeneous and where corridors 

connected grasslands in the surrounding landscape. Nest 

destruction is high in years when both predators and nesting 

ring-necked pheasants (Phasianus colchicus) were concentrated in relatively little remaining grassy cover. The percentage of pheasant nests hatched annually from 1973 to 1981 was 

positively correlated with the amount of grassland per hen in 

spring where grassland consisted of both edge habitats (including roadsides) and fields of hay and small grain. Landscape 

characteristics associated with use of edges by nesting birds 
152 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

increased reproductive success. Nest densities and species 

diversity increased relative to the degree of spatial heterogeneity and to how well plots were connected to surrounding 

landscape by corridors. There is potential for enhancing use of 

grassy farmland edges by establishing filter strips, field borders, and improving cover in existing edges, and by locating 

hay and small grains near existing wider grassland corridors. 

It is too simplistic to conclude all linear habitats are predator 

traps. Predation rates vary with predatory-prey assemblages, 

density of birds in nesting covers, and the extent to which 

other cover and prey attract predators away from relatively 

attractive linear nesting sites. Author concludes landscapelevel phenomena affecting habitat use and predator relations 

are poorly understood at this time.

Warner, R.E. and Etter, S.L., 1985, Farm conservation measures to benefit wildlife, especially pheasant populations, 

in Transactions of North American Wildlife and Natural 

Resource Conference, 50, Washington, D.C., March 15–20, 

1985, Proceedings: Washington, D.C., Wildlife Management Institute, p. 135–141.

Three spatial factors are key variables in understanding 

interaction of agriculture and ring-necked pheasants (Phasianus colchicus), FIELD: primary site for particular biological needs; FARM: represents a unit of land management 

and describes cover types near sites of biological activity; 

REGIONAL: mosaic of cover over an extended area that 

encompasses several farms. All three scales are significant to 

occurrence, location, and outcome of specific events in the 

life of pheasants. Scales vary in importance from season to 

season depending upon weather, type of farming, and biological activity. Regional scale is important to movement during 

crop harvest, fall tillage, winter grouping and spring dispersal. 

The farm scale is more important during brood rearing and 

establishment of territories. Field-scale characteristics are 

most relevant to nest success, roosting, and predation. To be 

effective, management practices should extend over several 

contiguous townships. Management across a large spatial scale 

permits movements of birds from farm-to-farm in response to 

individual management activities and availability of habitat. 

Conservation measures must be extensive and of significantly 

long-term to benefit pheasant populations. Addressing factors 

that are critical during the reproductive season are typically 

of first priority (suitable undisturbed vegetative cover of 

sufficient area).

Warner, R.E. and Etter, S.L., 1989, Hay cutting and the survival of pheasants—A long-term perspective: Journal of 

Wildlife Management, v. 53, no. 2, p. 455–461.

Tracts of undisturbed nest cover placed near forage crops 

do not have to be extensive to benefit ring-necked pheasants (Phasianus colchicus). Grassed terraces, filterstrips, 

and other linear covers can furnish important nesting cover. 

Mortality rates of hens and nests are high when hay cutting 

coincides with late stages of incubation. Data suggests mortality of pheasants due to haying operations is increasing due to 

earlier cutting. 

Warner, R.E., David, L.M., Etter, S.L., and Joselyn, G.B., 

1992, Costs and benefits of roadside management for ringneck pheasants in Illinois: Wildlife Society Bulletin, v. 20, 

p. 279–285.

Mitigating the effects of agricultural land use on upland 

wildlife remains a significant challenge to resource agencies. 

Successful habitat programs in agriculturally dominated environments are most likely those that are relatively compatible 

with farming operations. The success of habitat initiatives is 

rarely evaluated relative to response by target species, economics, or perceptions of cooperating landholders. Roadside 

right-of-ways frequently are mowed during the growing/nesting season consequently they have little habitat value for nesting ring-necked pheasants (Phasianus colchicus). The paper 

summarizes economic costs and benefits of roadside seeding 

and maintenance in relation to improved habitat availability 

and production of pheasants.

Warner, R.E., Hubert, P., Mankin, P.C., and Gates, C.A., 2000, 

Disturbance and the survival of female ring-necked pheasants in Illinois: Journal of Wildlife Management, v. 64, 

no. 3, p. 663–672.

The paper reports results of an investigation in eastcentral Illinois in an intensively farmed landscape: 93 percent 

row crops (corn and soybeans in equal proportion). Hen ringnecked pheasants (Phasianus colchicus) exhibiting disturbance-avoidance (farm operations, hunting, weather) behavior 

were associated with extended movements and coped well 

with hazards except during nesting. Relatively long-lived birds 

made extensive use of corn and soybeans while minimizing 

use of cover traditionally considered attractive to pheasants. 

Nesting season was associated with high death rates. Primary 

nest cover in the study area was annual set-aside land planted 

to temporary cover crops (wheat, oats). Significant improvements in availability and permanence of quality cover must 

occur on numerous individual farms over larger space and 

time scales to improve survival rates and population stability 

in intensively farmed landscapes.

To further enhance benefits of the CRP, land managers 

and wildlife biologists must collaborate to identify objectives 

and maximize landscape level approaches to cover management. As enrollment criteria presently exist, opportunities 

to improve wildlife habitat are limited. Communication 

and information exchange between USDA NRCS personnel and program participants needs improvement. Administration of CRP, as well as other conservation programs, 

needs greater emphasis on landscape level planning to meet 

wildlife objectives. 
Waterfowl and Shorebirds 153

Whitmore, R., 1982, Insect biomass in agronomic crops as 

food for ring-necked pheasant chicks: Lincoln, Nebraska, 

University of Nebraska Lincoln, Ph.D. dissertation, 64 p.

Corn, soybeans, and alfalfa had significantly lower 

amounts of insect biomass than wheat, oats, sweetclover, and 

oats-sweetclover. Estimated number of chicks/ha (2.5 ac) supported by insect biomass: corn, 8; soybeans, 10; sweetclover, 

64; oats, 86; oats-sweetclover, 106.

Wooley, J.B., George, J. R., Ohde, B., and Rybarczyk, W., 

1982, Nesting evaluations of native grass pastures and 

narrow-row soybeans, in Dahlgren, R.B., Proceedings of 

Midwest Agricultural Interfaces with Fish and Wildlife 

Resources Workshop, Ames, Iowa, University of Iowa, 1–2 

June 1982: Ames, Iowa, Iowa Cooperative Research Unit, 

p. 5–6.

Native grasses have a dense growth form similar to 

other types of ring-necked pheasant (Phasianus colchicus) 

nest cover and are unlikely to be mowed or grazed until after 

most eggs hatch. Leaving the recommended 20–25 cm (8–10 

in) stubble to ensure optimum plant growth should provide 

residual cover for nesting the following spring. Pheasant-nest 

densities were high in switchgrass (Panicum virgatum) and 

little bluestem (Schizachyrium scoparium). Success was greatest in switchgrass. Mowing operations in early June destroyed 

all nests and killed 8 of 11 hens nesting in alfalfa/orchardgrass 

(Medicago sativa/Dactylis glomerata). Pheasant and passerine 

nest success was higher in switchgrass that was not grazed or 

mowed the previous summer. Greater residual cover presumably was more attractive to nesting females and resulted in 

greater numbers of successful nests. Switchgrass managed for 

nest cover should be left undisturbed. 

Waterfowl and Shorebirds

Abraham, K.F., Jefferies, R.L., and Alisauskas, R.T., 2005, 

The dynamics of landscape change and snow geese in midcontinent North America: Global Change Biology, v. 11, 

p. 841–855.

The mid-continent population of the lesser snow goose 

(Chen caerulescens caerulescens) has increased 5–7 percent 

annually since the late 1960s to 1990s due to the positive 

effect of agricultural crops (corn, rice, wheat) along flyways 

and wintering grounds. While the increased availability of 

agricultural foods has increased survival, substantial negative effects on arctic breeding grounds have resulted due to 

increased numbers of birds. Foraging by high numbers of birds 

has led to loss of coastal vegetation, adverse changes in soil 

properties, and exposed sediments which will take decades 

to recover, assuming populations are reduced through natural 

or human influences. The changes displayed by snow geese 

reflect alteration in agricultural production which potentially 

affects other wildlife associated with seasonal or year-round 

use of agricultural lands. 

Large-scale changes in agricultural practices and creation of refuges have altered patterns of land use, feeding 

habits, survival, and migratory patterns of waterfowl (Anatidae). Changes in habitat use and negative effects on arctic 

ecosystems by snow geese are described which largely are 

in response to a shift from historical winter use of salt and 

brackish marshes of the Gulf of Mexico to use of irrigated 

rice in Texas and Louisiana. The mid-continent population of 

snow geese now is dependent upon these rice fields as well 

as other agricultural crops farther north during migration and 

wintering. While land area plated to corn and wheat had not 

changed during last 50 yr, production yields have increased. 

Area devoted to rice increased from 1950 to 1975. Area in 

soybeans has risen threefold over the same period. While little 

use of soybeans is recorded for geese, this crop accounts for a 

large proportion of weeds and weed seeds on these lands may 

be consumed by the species. Waste (spilled corn) is a primary 

food source of lesser snow geese. Creation of Federal and 

State wildlife refuges coincide with major changes in agricultural practices and production, which have created landscapes 

highly favored by snow geese. Agricultural changes in land 

use have led to shift in migratory patterns on both local and 

regional scales. Availability of refuges and cropland foods 

have resulted in more frequent stopovers and reduced direct, 

non-stop migration between breeding and wintering grounds. 

Agricultural policies will continue to influence numbers 

of waterfowl as a consequence of crop production. Weed 

production associated with agricultural production is expected 

to decline in response to greater dependence on genetically 

modified, herbicide ready crops (see Krapu and others, 2004, 

below). This development can have potentially large-scale 

negative effects on waterfowl and other wildlife dependent 

upon weeds and their seeds as a food source. Increased efficiency of harvest, resulting in less waste grain, may also have 

negative consequences for wildlife in agriculturally dominated 

ecosystems. The lack of green, weedy forages; decline in 

availability of spilled/waste grains; and greater area in soybeans are believed to have negative effects on wildlife foods 

sources in agriculturally dominated landscapes.
154 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Ball, I.J., Eng, R.J., and Ball, S.K., 1995, Population density 

and productivity of ducks on large grassland tracts in northcentral Montana: Wildlife Society Bulletin, v. 23, no. 4, 

p. 767–773.

An analysis of variation in duck productivity associated with habitat size and differing effects of red fox (Vulpes 

vulpes) and coyotes (Canis latrans) is presented. Productivity 

of dabbling ducks on large grassland tracts with relatively low 

populations of predators was higher than recorded where habitat fragmentation was more extensive and high populations 

of predators were present. Authors conclude that attempts to 

improve nest success at an inappropriately small scale may be 

counterproductive if hens and predators are attracted to same 

limited area. Increasing surface water area where low rates 

of nest success prevail attracts pairs to areas where mortality exceeds recruitment. Due to foraging strategies and prey 

preferences, productivity of upland-nesting ducks can be 

expected to be higher in large grassland tracts where coyotes 

are primary predator. More fragmented habitats where red 

fox is the dominant predator will have lower productivity of 

upland nesting waterfowl due to foraging strategies and prey 

preferences by red foxes.

Clark, R.G. and Nudds, T.D., 1991, Habitat patch size and 

duck nesting success—The crucial experiments have not 

been performed: Wildlife Society Bulletin, v. 19, no. 4, 

p. 534–543.

Authors state that there is conflicting evidence concerning relations between patch size and nest success of upland 

nesting birds. Some studies show nest success increases with 

greater area and lower density of nests while others indicate 

there is no positive relationship between area and success. 

More information about relations between habitat patch size 

and composition of managed habitats to duck nesting success 

is needed. Key questions include: what kind of cover needs to 

be planted and how much; are ducks doing better in managed 

habitats than in unmanaged habitats, what is the most viable 

standard of comparison (for example, nest success, duckling survival), and are management programs cost effective? 

The review of literature presented does not clearly support 

or refute the hypothesis that duck nesting success should be 

greater in larger patches and questions the rationale of establishing relatively small (less than 300 hectares [741 ac]) areas 

of cover. The authors suggest it might be better to redirect 

efforts and limited funds to programs or management alternatives that could direct changes in agricultural policy influencing overall land use. 

Cowardin, L.M., Sargent, A.B., and Duebbert, H.F., 1983, 

Low waterfowl recruitment in the prairies— the problem, 

the reasons, and the challenge to management, in Boyd, 

H., ed., First western hemisphere waterfowl and waterbird 

symposium: Slimbridge, England, International Waterfowl 

Research Bureau, p. 16–18.

Waterfowl nest success estimates for the northern United 

States are in the range of 5–15 percent, although two studies 

in western North Dakota demonstrated success rates of 38 percent and 42 percent. Variation in success reflects differences 

in quality of habitat and predator populations. The lowest 

success rates were observed in areas of intensive agriculture. 

The highest nest success for mallards (Anas platyrhynchos) 

was in grassland and lowest in cropland. Data demonstrate a 

serious problem of low recruitment resulting from destruction of habitat and increased predation rates in remaining 

suitable habitat. Intensification of agricultural production has 

decreased both the availability of nesting cover and habitat 

available to resident prey species. The result is a concentration 

of nesting ducks and foraging predators in remaining untilled 

grassland or other non-farmed covers. Key management 

strategy is to separate nest predators from nesting waterfowl. 

Habitat preservation is essential but also requires management 

of predator populations.

Cowardin, L.M., Gilmer, D.S., and Shaiffer, C.W., 1985, Mallards and agricultural programs, in Transactions of North 

American Wildlife and Natural Resource Conference, 50, 

Washington, D.C., March 15–20, 1985, Proceedings: Washington, D.C., Wildlife Management Institute, p.132–140.

Prior to and at the time of this report, the declining quality of wildlife habitat has not been considered an issue of high 

priority by ASCS (FSA) committees charged with allocating 

funds for agricultural conservation programs. Prior to the 

1985 Farm Bill biologists from 12 midwestern states documented declines in habitat quality due to changing land use 

and agricultural practices. A summary of species-population 

data revealed estimated declines of 91 percent for ring-neck 

pheasant (Phasianus colchicus), a 72 percent decline in 

eastern cottontail (Sylvilagus floridanus) populations, and 83 

percent decline in northern bobwhite quail (Colinus virginianus) populations. Declines in these species, traditionally 

associated with diverse agricultural land use, were attributed 

to the large increase in row crop acreage. More land devoted 

to row crops has come at the cost of area in high quality nonfarmed nesting cover, small grains, pasture, and other cover 

types. More intensive use of agricultural lands has resulted in 

an overall loss of edge between different covers due to larger 

size of farms and individual fields, destruction of old farmsteads, drainage of wetlands, and fewer non-disturbed idle 

areas. Recent decades have seen a major shift from diversified 

farms to monoculture-agricultural landscapes dominated by 

operations that continue to get larger by absorbing the lands of 

surrounding less successful farmers. The report provides summary of weak points of agricultural programs (for example, 

Payment in Kind) and basic wildlife recommendations for 

1985 Farm Bill.

Cox Jr., R.R., Johnson, D.H., Johnson, M.A., Kirby, R.E., 

Nelson, J.W., and Reynolds, R.E., 2000, Waterfowl research 

priorities in the northern Great Plains: Wildlife Society Bulletin, v. 28, no. 3, p. 558–564.
Waterfowl and Shorebirds 155

A Waterfowl Working Group identified high priority 

issues for future research in Northern Great Plains. (1) Determine effects of landscape factors on demographics and recruitment of ducks in Prairie Pothole region. Studies are needed 

to quantitatively assess landscape characteristics influencing 

breeding pair density, spring summer survival, and recruitment 

rates. (2) Develop and improve estimates of important parameters used in models for management and planning. Refinement in variables describing habitat characteristics related to 

preference for various cover types and corresponding nest success rates are needed for species other than the mallard (Anas 

platyrhynchos). (3) More Evaluations of waterfowl management activities at regional scales are needed. Greater attention 

needs to be focused on large-area applications of management 

treatments corresponding to large-scale management plans 

(for example, Prairie Habitat Joint Venture, North American 

Waterfowl Management Program). (4) Direct studies on species of concern are needed. Some species have shown little 

response to increased presence of wetlands in recent years (for 

example, Northern pintail [Anas acuta], lesser scaup [Aythya 

affinis]). Studies are needed to identify factors limiting populations of these species as is evaluation of the applicability of 

bird-conservation area concept to waterfowl production. The 

assumption that core areas of excellent habitat will maintain 

viable populations of breeding birds needs to be evaluated as it 

applies to waterfowl. Population source and sink habitats and 

how they may be configured or manipulated to benefit ducks 

need further investigation.

Farmer, A.H., and Parent, A.H., 1997, Effects of the landscape 

on shorebird movements at spring migration stopovers: The 

Condor, v. 99, no. 3, p. 698–707.

The authors report associations between pectoral sandpiper (Calidris melanotos) habitats that furnish stopover sites 

are a crucial link between wintering and breeding areas for 

migratory birds. Stop-over habitats provide foods and energy 

needed for continued movements and nutritional reserves that 

may be essential for successful reproduction on the breeding 

grounds. Agricultural development has had a major impact 

on presence and quality of wetland habitats across the Great 

Plains raising concerns about maintenance of an adequate 

network of stopover wetland habitats needed by migratory 

species. The authors describe several types of stopover habitats furnishing both short-term and extended nutritional and 

habitat needs. These habitats are affected by spatial scales and 

biological organization. 

Authors report landscape pattern has a significant 

influence on bird movements independent of wetland quality potentially accounting for up to 46 percent of variance 

in movement. A highly connected landscape, in terms of 

wetland abundance and quality, allows shorebirds to exploit 

higher quality food patches while minimizing the energetic 

costs of searching. As wetlands become isolated, distances 

moved by sandpiper decline. Over-use of remaining habitats 

constrains feeding opportunities as foods become depleted. 

Individual wetlands, and food sources contained within them, 

must be distributed so individual birds can achieve relatively 

high ingestion rates at low energetic costs. Important stopover habitats are defined as having sufficient food (that is, 

wetlands) for the population of birds using the site. The food 

must be distributed at a relatively small scale to meet needs 

of individual birds. While shorebird stopover sites receiving 

the most conservation attention have been those where large 

numbers of shorebirds are observed, such sites may not furnish 

sufficient food resources to meet population needs. Conservation focused on small, closely spaced wetlands may be just as 

important to some shorebird species as are larger wetlands. 

Smaller, diverse wetlands in close proximity may furnish perpetuation of greater diversity in foods and foraging opportunities than do larger wetlands.

Fox, A.D., Madsen, J., Boyd, H., Kuijkens, E., Norriss, D.W., 

Tombre, I.M., and Stroud, D.A., 2005, Effects of agricultural change on abundance, fitness components and distribution of two arctic-nesting goose populations: Global Change 

Biology, v. 11, p. 881–893.

Although the paper focuses on two largely European arctic nesting geese (pink-footed goose [Anser brachyrhynchus] 

and Greenland white-fronted goose [A. albifrons flavirostris]) 

effects of changes in agricultural land use on avian habitat use 

and distribution are analogous to North American agricultural/

conservation issues. The increase in agricultural production 

has replaced many natural habitats but has benefited some 

avian species. Improvement in grass cultivars has enhanced 

grass quality by elevating crude protein content, increasing 

digestibility and prolonging growing seasons. Large-scale 

patterns of cultivation have created extensive areas of uniform, 

intensively managed areas of grassland and cereals. These 

changes have increased carrying capacity for true grazing 

birds. Several species of northern nesting geese have shown 

dramatic spatial redistribution and increases in population size 

in response to changes in agricultural production. In Europe 

geese have become highly dependent on the agricultural landscape as “survival habitat.” Implications of changing agricultural production and policies on these species are discussed. 

Gatti, R., 1992, Nest cover for pheasants and ducks: Madison, 

Wis., Wisconsin Department of Natural Resources, Final 

Report, Study No. 127, Project W-141-R, 51 p.

Nest success was not consistently related to field size, 

shape, distance to water, cover height density, plant diversity, 

or cover type. Nest success was, however, lower for nests closest to cover edges. Duck-nest density was negatively related 

to plant diversity and positively related to height and density 

of residual cover. Ring necked pheasant (Phasianus colchicus) 

use was higher in fields with lower diversity of plant species, greater structural diversity, more irregular in shape, and 

further from water. Widespread establishment of switchgrass 
156 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

(Panicum virgatum) nest cover and management of existing 

duck nest cover towards monotypic stands of switchgrass are 

not justified based on costs, use, or nest success. Management 

for diversity of cover types to achieve better nesting success 

is recommended. 

Horn, D.J., Phillips, M.L., Koford, R.R., Clark, W.R., Sovada, 

M.A., and Greenwood, R.J., 2005, Landscape composition, 

patch size, and distance to edges—Interactions affecting 

duck reproductive success: Ecological Applications, v. 15, 

no. 4, p. 1367–1376.

An investigation of grassland-landscape characteristics 

influencing nest success of upland nesting ducks is described. 

Study areas composed of 15–20 percent grassland and 45–55 

percent grassland in North Dakota were used to investigate 

relations between duck reproduction, field size, and distance 

to nearest field and wetland edges. Nest survival rates were 

higher in 45–55 percent grassland study area. Nest survival 

rates were highest in small and large fields and lowest in fields 

of moderate size. Study results support conclusion that both 

landscape composition and configuration affect success of 

ground-nesting birds. Authors conclude clustering of moderately sized patches of nesting habitat in agriculturally dominated landscapes have low nest success. Higher nest success 

in high-grassland study area may be due to greater probability 

of nest hatching when farther from field edges. Nest success 

was highest in small and large fields and lower in fields of 

intermediate size. Differences in success between field sizes 

were attributed to differences in predator activity. Authors 

believe predators rarely visit small patches of cover and 

predator activity in large fields reflects inability for predators 

to effectively search the entire field. Medium sized fields are 

believed to be those most thoroughly searched by predators 

(for example, red fox [Vulpes vulpes], striped skunk [Mephitis 

mephitis]) as they spend proportionally more time within fields 

in this size category. 

Hurley, T.M., Babcock, B.A., Reynolds, R.E., and Loesch, 

C.R., 1996, Waterfowl populations and the Conservation 

Reserve Program in the Prairie Pothole Region of North 

and South Dakota: Ames, Iowa, Center for Agricultural and 

Rural Development, Iowa State University, Working Paper 

96-WP 165, 30 p. 

Authors estimate that the density of waterfowl breeding pairs under current distribution of CRP land is only 12.5 

percent greater than what would have been realized had land 

been randomly enrolled in program. Authors believe initial 

enrollment rules for CRP did a relatively poor job of including the best waterfowl habitat and suggest improved targeting 

to higher quality habitat for waterfowl. These changes could 

potentially double density of breeding pairs. Further improvement in pair density may be realized if CRP lands were associated with existing Wetland/waterfowl Management Districts 

that furnished better quality habitat. It is also suggested it is 

more important to focus enrollment targeting within adjacent county regions rather than between regions. The benefits of such planning would extend to wildlife species other 

than waterfowl. 

Ignatiuk, J.B., and Duncan, D.C., 2001, Nest success of ducks 

on rotational and season-long grazing systems in Saskatchewan: Wildlife Society Bulletin, v. 29, no. 1, p. 211–217.

Rotational grazing systems intended to increase duck 

production in the Canadian prairie pothole region have had 

only limited success. A comparison of waterfowl production 

recorded in once-over rotational systems and season-long 

pastures in Saskatchewan failed to reveal differences in nest 

survival between grazing systems. Rotational systems could 

be more beneficial if they preserve or improve grassland areas, 

attract more ducks from less productive habitats, or increase 

duck survival. Strong evidence that pastures have higher nest 

success compared to most other habitat types including small 

plots of planted cover. Conversion of cropland to pasture and 

retaining existing pastures was recommended to improve 

duck production.

Kantrud, H.A., 1993, Duck nest success on Conservation 

Reserve Program land in the prairie pothole region: Journal 

of Soil and Water Conservation, v. 48, no. 3, p. 238–242.

Duck nest success was found to be higher (23.1 percent) 

on tracts of CRP than on WPAs (8.2 percent). Larger size of 

fields, greater distance from water, lower densities of nests, 

and high quality of vegetative cover on tracts of CRP were key 

factors believed to contribute to lower rates of predation and 

higher production of waterfowl. 

Krapu, G.L., Brandt, D.A., and Cox Jr., R.R., 2004, Less waste 

corn, more land in soybeans, and the switch to genetically 

modified crops—Trends with important implications for 

wildlife management: Wildlife Society Bulletin, v. 32, no. 1, 

p. 127–136.

Growing efficiency in corn harvest (greater than 99 

percent under ideal conditions) and widespread replacement 

of corn and other crops by soybeans less capable of supplying nutritional needs of wildlife represents a growing risk to 

wildlife dependent upon waste grain for energy and weeds for 

the foods and cover they provide. Nearly 25 percent of total 

cropland in the United States is used to produce soybeans. In 

2002, approximately 75 percent of soybean crop was planted 

to GM herbicide resistant types. Increased efficiency of weed 

control results in decline in amount of weeds present representing decline in foods and cover for wildlife in agricultural 

landscapes. Implications may be particularly severe on seeddependent wildlife of lower mobility and smaller home ranges 

and on migratory species with seasonally high nutritional 
Waterfowl and Shorebirds 157

needs. Prior to development of GM strains, herbicides were 

less efficient or selective resulting in some weed species 

continuing to thrive in cropland. Genetically modified crops 

appear to be on verge of greater acceptance by farm operators 

and industry broadening negative impacts on wildlife dependent upon weeds. Aggressive control of weeds in CRP fields 

and other private lands further impacts seed-eating wildlife 

when the availability of weed seeds and other high quality 

grain foods are becoming less available across agriculturally 

dominated landscapes.

Authors suggest more research is needed to determine 

impacts of weed control on CRP and other lands as well as 

studies to better document effects of GM crops on quality of 

wildlife habitat across regions. Authors believe the beneficial 

effects of the CRP in providing perennial cover for wildlife 

may be negated by more highly efficient and intensive weed 

control on lands remaining in production as well in CRP 

covers. It is suggested producers could be offered incentives 

to grow high-energy food plots, intentionally leave greater 

crop residues, and use less intensive weed-control methods to 

ensure that adequate sources of food are available for wildlife 

in areas dominated by row crop production. 

Luttschwager, K.A., 1991, Effects of two haying provisions on 

duck nesting in Conservation Reserve Program (CRP) fields 

in South Dakota: Brookings, S. Dak., South Dakota State 

University, M.S. thesis, 51 p.

This report provides an evaluation of 1988 and 1989 

release of eastern South Dakota CRP fields’ effects for emergency haying on duck-nest density and success. Nest densities in idled (non-hayed) strips and fields were significantly 

greater than recorded within hayed strips. Nest densities in 

idled and hayed blocks were similar. Nest success was lowest 

in idled strips, which apparently attracted predators as well as 

ducks. To lessen predation, the author recommends leaving a 

minimum of 25 percent of hayed fields in non-hayed cover in 

contiguous blocks rather than strips.

Luttschwager, K.A., Higgens, K.F., and Jenks, J.A., 1994, 

Effects of emergency haying on duck nesting in Conservation Reserve Program fields, South Dakota: Wildlife Society 

Bulletin, v. 22, no. 3, p. 403–408.

Authors report comparison of upland nesting duck nest 

densities and nest success among hayed, idled strips, and 

blocks of CRP grassland hayed under authorized emergency 

use. CRP haying provisions that left 10 percent of fields in 

idled (non-hayed) strips resulted in nest success of mallards 

(Anas platyrhynchos) and blue-winged (A. discors) teal below 

levels necessary to sustain their populations in areas where 

CRP fields constitute a major portion of available nesting habitat. Haying provisions requiring at least 25 percent of field be 

left standing supported sufficient reproduction to maintain or 

increase populations. The authors recommend CRP emergency 

haying be completed in blocks rather than strips. At least 25 

percent of a hayed field is recommended to be left standing, 

in a contiguous block, to maintain nesting habitat. Residual 

vegetation was attractive during the early part of the nesting 

season. Nest densities in idled strips, unharvested blocks, and 

CRP fields were 4 times greater than recorded in hayed strips 

or hayed blocks.

Reynolds, R, 1992, Evaluation of the effect of CRP on duck 

recruitment in the prairie pothole joint venture area of FWS, 

Regions 6: U.S. Fish and Wildlife Service Progress Report: 

Bismarck, N.D., 6 p.

Report documents results of 1992 pilot effort to evaluate 

waterfowl production in Montana, North Dakota, and South 

Dakota. Duck nest success was estimated to be 2 to 3 times 

higher in CRP grasslands than recorded in established WPAs. 

Reynolds, R.E., Shaffer, T.L., Loesch, C.R., and Cox Jr., R.R., 

2006, The Farm Bill and duck production in the Prairie 

Pothole Region—Increasing the benefits: Wildlife Society 

Bulletin, v. 34, no. 4, p. 963–974.

Two key provisions of the Food Security Act of 1985 

benefited waterfowl in the PPR: the CRP and Swampbuster. 

The CRP furnished attractive, secure nesting cover for upland 

ducks while Swampbuster served to protect wetlands vital to 

breeding ducks. With concerns about future availability of 

habitat brought by these programs, breeding duck population 

data and wetland habitat surveys were used to develop models 

for five species of upland-nesting ducks. Habitat quality 

assessment was completed for mallard (Anas platyrhynchos), 

gadwall (A. strepera), blue-winged teal (A. discors), northern 

shoveler (A. clypeta), and northern pintail (A. acuta). These 

models were applied to more than 2.6 million wetlands to 

evaluate where cover would be accessible to the greatest 

number of nesting hens. These data were compared to the 

distribution of current CRP contracts relative to distribution of 

upland-nesting ducks. The study area was the portion of North 

and South Dakota east of the Missouri River, known as the 

glaciated PPR and glacial Lake Agassiz plain. 

Analysis of data indicates that 75 percent of CRP contracts (as of 2005) included in the study area were accessible 

to high numbers of ducks. The authors present a method to 

prioritize extension, or reenrollment, of CRP contracts, as well 

as new lands suitable for inclusion in these programs, to maintain or increase duck populations. The approach described is 

applicable to determine the availability of habitat and to target 

desirable lands for inclusion in conservation programs in other 

regions of the country. To maintain the current potential of the 

PPR to produce ducks, the CRP and wetland-protection elements of the farm-conservation programs must be maintained. 

The authors conclude that if Swampbuster protection were 

eliminated and protected wetlands were drained, waterfowl 
158 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

production would decline by 37 percent in this region of 

the PPR.

Reynolds, R.E., Shaffer, T.L., Renner, R.W., Newton, W.E., 

and Batt, B.D., 2001, Impact of the Conservation Reserve 

Program on duck recruitment in the U.S. prairie pothole 

region: Journal of Wildlife Management, v. 65, no. 4, 

p. 765–780.

Authors conclude the CRP has furnished substantial benefits to upland nesting waterfowl during 1992–97 study period. 

Estimated nest success and recruitment rates for 5 waterfowl 

species (mallard [Anas platyrhynchos], gadwall [A. strepera], 

blue-winged teal [A. discors], northern shoveler [A. clypeata], 

and northern pintail [A. acuta]) were respectively 46 and 30 

percent higher than estimated for non-CRP covers within 

study area. Estimates of daily survival rates were positively 

related to the percent of perennial grass cover on 4 mi2 (10.4 

km2) study plots. The authors contribute significant benefits 

to populations of upland nesting ducks in the Prairie Pothole 

region to the CRP through provision of attractive, secure nesting cover. Authors estimate that 12.4 million additional ducks 

were produced in study area between1992–97 than would have 

been produced if CRP had not been implemented.

Renner, R.W., Reynolds, R.E., and Batt, B.D.J., 1995, The 

impact of haying Conservation Reserve Program lands on 

productivity of ducks nesting in the Prairie Pothole region 

of North and South Dakota in North American Wildlife and 

Natural Resources Conference, 60, Proceedings: Washington, D.C., Wildlife Management Institute, p. 221–229.

Report provides a comparison of duck nest success and 

production in hayed versus non-hayed portions of CRP fields. 

Duck production was higher on non-hayed portions of CRP 

fields. Authors suggest haying effects on litter depth and 

vegetation structure may have detrimental effects on quality 

of nesting cover through entire year following haying of CRP 

cover. The report recommends haying be allowed no more 

than once every 5 yr to maintain vegetation quality, habitat 

diversity and quality of nesting cover. 

Skagen, S.K., and Knopf, F.L., 1992, Toward conservation of 

midcontinental shorebird migrations: Conservation Biology, 

v. 7, no. 3, p. 533–541.

Successful transcontinental migrations of the highly 

diverse group of shorebirds are dependent upon dynamic 

freshwater wetlands for stopover resources essential of replenishment of fat reserves and completion of migration. Patterns 

of shorebird distribution and habitat use vary geographically 

and take advantage of uniquely different regions. Smaller species and Neotropical migrants primarily move across the Great 

Plains, whereas larger species and North American migrants 

predominantly use the intermountain west for migration. 

Transcontinental migrants disperse and use wetlands opportunistically; this highlights the need to develop a large-scale, 

coordinated regional management effort based on recognition 

of the dynamic nature of wetlands across the Great Plains. 

Smith, L.M., Haukos, D.A., and Prather, R.M., 2004, Avian 

response to vegetative pattern in playa wetlands during winter: Wildlife Society Bulletin, v. 32, no. 2, p. 474–480.

Cover to water ratios were manipulated in Texas playa 

lakes to determine avian response during winter. Cover was 

managed to yield (cover:water) 75:25, 50:50, and 25:75 ratios. 

Playa vegetation was dominated by barnyardgrass (Echinochloa crusgalli), smartweed (Polygonum spp.), and curly dock 

(Rumex crispus). Lakes were surrounded by cropland. Greatest 

bird richness and waterfowl numbers were recorded in 50:50 

cover/water ratio wetlands. Authors attribute increased edge 

and habitat diversity to greater use and numbers of avian 

species. Management of playas to furnish 50:50 ratio of 

cover to water and moist soil management is recommended 

to maximize habitat availability and wetland bird diversity 

during winter. 

Sovada, M.A., Zicus, M.C., Greenwood, R.J., Rave, D.P., 

Newton, W.E., Woodward, R.O., and Beiser, J.A., 2000, 

Relationships of habitat patch size to predator community 

and survival of duck nests: Journal of Wildlife Management, v. 64, no. 3, p. 820–831.

This report provides an evaluation of duck-nest success 

and the composition of predator community in relation to 

size of discrete patches of nesting cover in the Prairie Pothole 

region. The study focused on CRP grasslands in Minnesota, 

North Dakota, and South Dakota. Activity patterns of red 

fox (Vulpes vulpes), badger (Taxidea taxus), striped skunks 

(Mephitis mephitis), coyotes (Canis latrans), and Franklin’s 

ground squirrels (Spermophilus franklinii) were related to 

habitat patch size and daily survival rate of upland duck nests. 

Estimated annual mean daily survival rates were generally 

greater in larger habitat patches. Although authors believe 

a positive relationship between habitat patch size and nest 

success probably exists, they conclude that absolute proof 

remains elusive.

Stephens, S.E., Rotella, J.J., Lindberg, M.S., Taper, M.L., and 

Ringleman, J. K., 2005, Duck nest survival in the Missouri coteau of North Dakota–Landscape effects at multiple spatial scales: Ecological Applications, v. 15, no. 6, 

p. 2137–2149.

Over the past century the PPR landscape has been dramatically altered by agriculture. Remaining grasslands have 

become fragmented or lost to agriculture. Authors believe species composition of nest predators present in a given landscape 

may be influenced by the amount of grassland present which 
Wetlands, Aquatic Ecosystems 159

in turn may affect waterfowl nest survival rates. Design of 

successful habitat-management programs requires understanding of how predators respond to habitat features. Structure and 

configuration of landscape features may have an important 

influence on predation rates and nest success. Determination 

of what scale to measure landscape-level variables may be as 

important as is identification of individual variables. 

Study results indicate that large, intact grassland areas 

should be maintained and grasslands should be restored to 

achieve high nest survival for upland nesting ducks. Sites with 

larger, intact grasslands had high nest survival rates even in 

a year with poor overall nest survival. Intermediate levels of 

edge resulted in the lowest nest survival rates. The number of 

wetland basins was negatively related to nest survival. Authors 

suggest that long-term research is needed to better understand 

factors affecting nest survival across landscapes that include 

investigation of the relations between predators, alternate prey, 

and waterfowl nest success. 

Taft, O.W., and Haig, S.M., 2005, The value of agricultural 

wetlands as invertebrate resources for wintering shorebirds: Agriculture, Ecosystems and Environment, v. 110, 

p. 249–256.

In the Willamette valley of Oregon, significant populations of wintering shorebirds (Charadriiformes) regularly use 

hundreds of dispersed wetlands on agricultural lands. However, agricultural landscapes have received little recognition 

of the habitat and food resources they provide. Although not 

quantified, benthic invertebrates associated with these wetlands furnish critical resources necessary for survival of these 

species. Shorebirds in this region rely principally on privately 

owned agricultural wetlands. Left in agricultural production, 

wetlands in crop fields have the capacity to produce invertebrate food sources. The authors suggest, but do not describe, 

active restoration and enhancement of these wetlands and 

management of their vegetation and hydrology may increase 

invertebrate production within these wetlands. Density, biomass, and general community composition of invertebrates 

were quantified in Willamette valley sites during a dry and wet 

winter. Invertebrate densities ranged from 173 to 1,925 individuals/m2 in a wet winter to 214 to 3,484 individuals/m2 in 

the dry winter. Estimated biomass ranged from 35 to 652 mg/

m2 in the wet winter and 85 to 1,405 mg/m2 in the dry year. 

van Eerden, M.R., Zijlstra, M., van Roomen, M., and Timmerman, A., 1996, The response of Anatidae to changes 

in agricultural practice—Long-term shifts in the carrying 

capacity of wintering waterfowl: Gibier Faune Sauvage, 

v. 13, p. 681–706.

Written from a European (Netherlands) perspective, 

this report describes effects of change in agricultural production on waterfowl populations and habitat use. Both changes 

in the past and potential future changes are described with 

implications having application for North America. Herbivorous waterfowl have benefited from changes in agricultural 

production as a consequence of improved digestibility, protein, 

and longer growing seasons of grassland crop types. However, 

conversion to production of row crops and reduction in number of cattle grazing in natural areas may have negative effects 

on waterfowl along migratory routes and in wintering habitats. 

Description of the effects of historical changes in land 

use, use of fertilizer, resulting in extended growing seasons, 

expansion of cattle and dairy production, and increased availability of “waste” grains/crops are provided, as are descriptions of waterfowl response to availability of stubble fields 

and expansion of grass dominated covers. Authors report 

negative effects of increased nutrient loads on water quality causing decline in populations of macrophyte dependent 

species of waterfowl. Use of agricultural land by waterfowl 

is related to body size with larger species spending more time 

on agricultural habitats than smaller species. Spatial relations 

between natural wetland habitats, agricultural land, and species response are discussed. 

Wetlands, Aquatic Ecosystems

Allan, J.D., 2004, Landscapes and riverscapes—The influence 

of land use on stream ecosystems: Annual Review Ecology 

and Evolution Systematics, v. 35, p. 257–284.

Biological diversity and habitat quality in riverine systems is strongly influenced by landform and land use within 

the surrounding valley at multiple scales. Empirical relations between land use and stream response are difficult to 

define due to variance of anthropogenic and natural gradients, 

existence of multiple, scale-dependent mechanisms, nonlinear 

responses, and difficulties in separating present-day influences 

from those of the past. Human actions at the landscape scale 

are the principal threat to the ecological integrity of riverine 

ecosystems, affecting habitat, water quality, and associated 

biota via numerous and complex pathways. 
160 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

The author provides a comprehensive review of studies 

describing effects of agricultural practices shown to affect 

water quality, habitat value, and biological assemblages as the 

extent of agriculture increases. Higher inputs of sediments, 

nutrients, and pesticides accompany greater agricultural use 

affecting riparian and stream channel habitats. Streams in 

landscapes dominated by agriculture tend to have poor-quality 

habitat, which is reflected by declines in habitat indices and 

bank stability as well as greater deposition of sediments. 

Storm flows commonly increase in magnitude and frequency 

where land clearing, drainage ditches, subsurface drains, and 

loss of wetland area are extensive. Base flows often decline 

in agriculturally dominated basins due to reduced infiltration 

resulting in instream habitats with shallow water which is 

susceptible to greater levels of warming. 

Discussions of urban land use, management applications, and approaches to assessment of environmental impacts 

are presented. The author concludes knowledge of pathways 

and mechanisms of land use affecting stream ecosystems 

is extremely limited, particularly in relation to prescriptive 

management. The author recommends greater emphasis on 

examination of sensitive indicator species response to management practices intended to offset impacts of intensive land use 

on stream habitat quality. 

Bolen, E.G., Smith, L.M., and Schramm, H.L., Jr., 1989, Playa 

lakes—Prairie wetlands of the southern high plains: Bioscience, v. 39, no. 9, p. 615–623.

When inundated, playas form shallow lakes and wetlands 

that significantly increase plant and animal diversity in intensively cultivated landscapes. With rare exceptions, each playa 

and its watershed is a closed system. Avifauna dominates the 

vertebrate animal life associated with playas, but lagomorphs 

can reach high densities in playa habitats. Playas developed 

for agriculture have lower insect production than do unmodified basins due to reduction in fluctuation of water level. The 

value of playas as habitat lies in the diversity of vegetation 

and associated fauna. Playas receiving irrigation runoff had 

increased interspersion of vegetation and open water resulting 

in higher habitat quality. Cultivation of playas decreases their 

value as wildlife habitat. Reduction of vegetation surrounding playas can influence water quality. Establishment of pits 

within playas reduces the abundance and diversity of vegetation that requires alternating wet and dry periods. Majority of 

phytoplankton associated with aquatic vegetation is important 

for production of macroinvertebrates and forage for wintering 

waterfowl. Pits diminish value of lakes as waterfowl habitat; 

waterfowl often prefer densely vegetated sites. Losses of vegetation in littoral zones and interior islands of vegetation reduce 

nesting habitat and waterfowl production associated with these 

habitats. The loss of food production associated with modification of playas affects habitat quality for breeding, wintering, 

and migrating waterfowl and shorebirds. Loss of tall emergent 

and woody vegetation reduces roosting and nesting habitat for 

other birds. Conversely, modified playas hold water during dry 

seasons and may support greater plant biomass and diversity. 

Modified playas may provide high quality habitat particularly 

during periods of drought. However, wildlife benefits remain 

contingent on the extent of the modification and on temporal 

aspects of water-level fluctuations. 

Buck, O., Niyogi, D.K., and Townsend, C.R., 2003, Scaledependence of land use effects on water quality of streams 

in agricultural catchments: Environmental Pollution, v. 130, 

p. 287–299.

Although completed in New Zealand, this investigation 

provides an excellent summary of the influences of temporal and spatial scales on water quality and assessments and 

implies that water monitoring needs to be sensitive to scale of 

catchments under evaluation. Different processes may occur 

at different scales, and understanding cumulative contributions of land uses is vital to successful monitoring. Authors 

conclude that rigid sampling of water quality at fixed time 

intervals does not provide sufficient information. Seasonal 

changes in nutrient export and fluxes during flood events need 

to be incorporated into sampling schemes. Data on local land 

use are important in small headwater streams while total influence of land use in whole basin provides better assessment of 

water quality in larger streams. 

Conway, W.C., Smith, L.M., and Ray, J.D., 2005, Shorebird 

habitat use and nest-site selection in the playa lake region: 

Journal of Wildlife Management, v. 60, no. 1, p. 174–184.

Playa lakes provide important habitats for wintering 

waterfowl as well as for migrant and breeding shorebirds. 

Wetland-scale habitat use and nest-site selection for four 

dominant species (American avocet [Recurvirostra americana], black-necked stilt [Himantopus mexicanus], killdeer 

[Charadrius vociferus], snowy plover [C. alexandrinus]) 

nesting in playas, saline and man-created lakes, and riparian wetlands are described. Only avocets and killdeer nested 

in playas. No nests were found in created wetlands. Authors 

conclude that created wetlands cannot compensate for loss 

of playa wetlands and urge that greater conservation efforts 

be directed toward conservation of natural wetlands. Protection of playa hydroperiod should be emphasized for breeding 

shorebird conservation. Most playas have cropland-dominated 

watersheds and have lost their natural vegetative communities. 

Prairie restoration around watersheds will decrease sedimentation rates and restore playa hydrological cycles, which will 

benefit avian habitat quality and use. 

Cooper, C.M., 1993, Biological effects of agriculturally 

derived surface water pollutants on aquatic systems—A 

review: Journal of Environmental Quality, v. 22, p. 402–

408.

Agricultural contaminants are most noticeable when they 

produce immediate, toxic effects on aquatic life, but more 
Wetlands, Aquatic Ecosystems 161

subtle, sub-lethal, chronic effects may be just as damaging 

over long periods. While suspended sediment represents the 

largest volume of aquatic contaminant, pesticides, nutrients, 

and enrichment due to the input of organic materials are major 

stressors of aquatic systems affected by agriculture. The demise 

of buffers along streams accelerates effects of pollutants. Author 

believes that protection of habitat is the single most effective 

means of conserving biological diversity in aquatic systems. 

Two systems, based on input from the surrounding landscape, represent aquatic systems. Primary receivers include 

wetlands, small streams, and impoundments that receive runoff 

and contamination directly from the land. Secondary receivers include downstream rivers and larger lakes that receive 

inflow from multiple tributaries as well as limited direct runoff 

from the landscape. Ecological stressors, including physical 

and chemical inputs from agriculturally dominated landscapes, 

increase susceptibility of aquatic organisms to disease and parasites. In-stream suspended sediments and bedload, by volume, 

are the largest pollutants in the United States. Effects of sediments on benthic organisms, habitat composition, and aquatic 

productivity are discussed, as are effects of nutrients, organic 

contamination, pesticides, and metals. 

Sediment-related contamination is best prevented by 

practices that prevent erosion or trap sediments. Use of cover 

crops, conservation tillage, grassed waterways, terraces, filter 

strips, preservation and creation of riparian zones, contour farming, and water and sediment control basins are recommended 

approaches to lowering sediment input to aquatic systems. 

Many of the management practices designed to reduce sediment 

input help to lower nutrient input. Protection of aquatic systems 

must be based on a watershed management approach.

Council for Agricultural Science and Technology, 1999, Gulf 

of Mexico hypoxia—Land and sea interactions: Ames, Iowa, 

Task Force Report 134, 44 p.

Agriculture is the leading source of impairment to rivers 

and lakes that supply nutrients to marine ecosystems. Hypoxia 

(oxygen deficiency) may be the most widespread anthropogenically induced effect in estuarine and marine environments 

worldwide. No other environmental parameter of such ecological importance to coastal marine ecosystems has changed so 

drastically in such a short period of time. In 1998, the hypoxic 

zone in the Gulf of Mexico covered 12,400 km2 (4,800 mi2). 

Nitrogen export from the Mississippi River Basin has increased 

2 to 7 fold over the last century. Sedimentation of marine 

organic matter from increased nutrients is the principal cause of 

hypoxia in the Gulf. The majority of Mississippi River N originated from agricultural practices (estimated contribution 2 to 3 

lbs/ac/yr). Estimated annual contribution to Gulf of agricultural 

N is approximately 2 million tons. 

Factors that cause hypoxia are: water-column stratification, preventing mixing of waters, and decomposition of 

organic matter. The zone of hypoxia in the Gulf is now the 

largest in the western hemisphere and coincides with some of 

the nation’s most productive and important fishing waters. The 

hypoxic zone is most persistent, widespread, and severe from 

June to August. Sedimentary records document eutrophication 

and increased marine-origin organic sedimentation in bottom 

waters that are positively correlated with increasing N loads 

and oxygen stress. Coastal phytoplankton productivity has 

increased due to enriched nutrient conditions. There have been 

increasing noxious phytoplankton blooms of algae, generally less edible by zooplankton. Suggestions that hypoxia has 

increased in response to long-term increases in water flow are 

not valid. Changes are due to water quality fueled by riverine 

nutrients. Total N export from Mississippi prior to human 

settlement estimated at 0.16 kg/ha/yr. Estimates of current discharge are 5.7 kg/ha/yr. Fifty-five percent of net N is attributable to agricultural fertilizers. 

Decline in agricultural nutrient input can be accomplished by current technology and knowledge. Practices such 

as buffer strips within, and adjacent to, croplands and natural/

restored/constructed wetlands can contribute to lower N inputs 

to the river system. Alterations in seasonal application of fertilizers, soil testing to avoid over-application, and alternative 

tillage regimes to decrease sedimentation need to be adopted. 

Alteration of cropping strategies would have costs to producers and consumers, but in the long-run would yield larger 

benefits to society. 

Cowx, I.G., and Van Zyll De Jong, M., 2004, Rehabilitation 

of freshwater fisheries—Tales of the unexpected: Fisheries 

Management and Ecology, v. 11, p. 243–249.

In recent years, there have been many attempts to restore 

and rehabilitate aquatic environments to address declines in 

biodiversity and fisheries. Many of these efforts have been on 

a small scale with fragmented approaches with resulting low 

rates of success. Often fisheries are not enhanced as expected 

and improvement gained is not justified by the costs. Authors 

conclude restoration of stream habitats to pristine conditions 

is a utopian goal. In most cases river basins have undergone 

extensive changes in land use with the most dramatic effects 

stemming from deforestation and intensification of agricultural 

activities. Many rehabilitation efforts are localized addressing 

issues on only small sections of the aquatic habitat or ignore 

problems associated with adjacent land uses. Rehabilitation 

success requires a catchment perspective requiring strategic planning. It is essential post-project monitoring must be 

undertaken and results disseminated widely to enhance future 

restoration efforts.

Davie, D.K., and Lant, C.L., 1994, The effect of CRP enrollment on sediment loads in two southern Illinois streams: 

Journal of Soil and Water Conservation, v. 49, no. 4, 

p. 407–412.

Relations between CRP enrollment and changes in 

stream-sediment load were evaluated in southern Illinois. CRP
162 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

enrollment of 15.6 and 26.5 percent of all cropland in Big 

Creek and Cypress Creek watersheds resulted in estimated 24 

and 37 percent reduction in erosion. Declines in erosion due to 

land management practices do not always result in immediate 

decline in suspended sediment load. Length of time between 

management action and reduction in sediment load is affected 

by many variables, including character of sediments, changes 

in basin hydrological response, timing of flood events, and 

spatial distribution of conservation practices. Authors conclude 

CRP enrollment within the two watersheds failed to produce 

a significant decrease in suspended sediment loads. Authors

believe that reductions in suspended sediment in response to 

CRP enrollment are likely to be delayed as in and near-stream 

sediments are remobilized. In addition, few fields enrolled in 

CRP were in near-stream locations where they would be most 

effective in trapping upstream and upslope sediments.

Demissie, M., Keefer, L., Slowikowski, J., and Stevenson, 

K., 2006, Evaluating the effectiveness of the Illinois River 

Conservation Reserve Enhancement Program in reducing 

sediment delivery, in Sediment dynamics and the hydromorphology of fluvial systems: Dundee, United Kingdom, International Association of Hydrological Sciences p. 295–303.

A CREP was initiated in 1998 to address sedimentation 

and water-quality issues in the Illinois River, a tributary of the 

Mississippi. A major objective is to reduce sediment delivery 

by 20 percent by protecting and restoration of the flood plain 

corridor of the river and its tributaries. Between 1998 and 

2004, 110,854 acres have been enrolled in the program. This 

paper describes the establishment of a monitoring program 

established by the state of Illinois and collection of baseline 

data to describe effects of the program. Methods of data collection, modeling, and monitoring are described.

Dodds, W.K., Gido, K., Whiles, M.R., Fritz, K.M., and Matthews, W.J., 2004, Life on the edge—The ecology of Great 

Plains prairie streams: Bioscience, v. 54, no. 3, p. 205–216.

Great Plains streams represent an important component of 

an ever-dwindling North American supply of unpolluted freshwater resources and furnish habitat to a number of threatened 

or endangered species. Most areas of the Great Plains were 

formerly prairie but are now heavily affected by agriculture 

or urbanization resulting in pollution, hydrologic disturbance, 

and physical modification of habitats. Large areas of groundwater (for example, Ogallala-High Plains aquifer) have been 

overexploited. Climatic variation and thunderstorms result in 

highly variable runoff patterns resulting in common patterns 

of flooding and drying and the intermittent pattern of flow 

characteristic of many of these streams. Great Plains streams 

have an important role in ecosystems services: many now 

support unique and endangered biota. There is, however, little 

published research available for these streams. Many of the 

streams that were meandering through grassland ecosystems 

now are not much more than straight ditches through drainagetiled, repeatedly tilled cropland. Such streams are often heavily sedimented and contain high concentrations of nutrients. 

The future for prairie streams and historically associated fauna 

appears bleak unless conservation provisions can be applied to 

large tracts of land, especially at the watershed scale. Authors 

furnish discussions of roles of hydrologic disturbances in 

prairie streams with a focus on microbial processes, macroinvertebrates, and fish fauna. 

Forshay, K.J., Morzaria-Luna, H.N., Hale, B., and Predick, K., 

2005, Landowner satisfaction with the Wetlands Reserve 

Program in Wisconsin: Environmental Management, v. 36, 

no. 2, p. 248–257.

Social and political support for wetland protection has 

increased with recognition of the ecological services that wetlands provide. The WRP establishes conservation easements 

on agricultural wetlands in exchange for financial incentives. 

Administered by NRCS, the WRP provides an increase in wetland acreage, reduction of groundwater contamination from 

agricultural sources, flood prevention, increases in groundwater recharge, and wildlife habitats. The WRP began as a 9-state 

pilot program and was expanded to all states in 1995. By the 

end of 2002, 516,629 hectares (1,276,618 acres) were enrolled 

in the program. Three types of easements are offered: permanent easements where USDA pays 100 percent of agricultural 

value of the land and full cost for restoration; 30-yr easements, 

75 percent of restoration costs paid; and cost-share where the 

operator maintains restoration for 10 yr and USDA pays 75 

percent of restoration costs.

Authors report results of a four-county 2003 investigation of 25 percent of Wisconsin WRP contracts (n=69 after 

rejection of some contracts). Restoration and easement costs, 

NRCS monitoring records, and surveys of program participants were investigated. Average size of sites was 52 hectares (128 ac). Results include the conclusion that time since 

restoration was not a significant predictor of any ecological 

or social variables. The most common wetland community 

after restoration was fresh meadow. On 74 percent of sites 

reed canarygrass (Phalaris arundinacea), an invasive species was present. Cost for restoration was $407/ha ($162/ac). 

Participant survey had an 80 percent response rate with an 

overall rating of 3.6 plus or minus 0.2 (1–5 scale, with 5 being 

completely satisfied). Environmental protection was identified by 81 percent of respondents as primary reason to enroll 

in WRP, while 71 percent identified economic incentives and 

60 percent indicated improvement in recreational opportunities drove their decision to enroll. New landowners were more 

likely to recreate on the WRP land than were original owners. 

Concerns expressed by WRP participants included restriction 

on establishment of permanent deer stands, increase in tax rate 

following restoration, limited communication with NRCS, and 

lack of participation in restoration process.

Authors conclude that monitoring data on WRP projects is coarse and not collected with enough consistency to 
Wetlands, Aquatic Ecosystems 163

quantify changes in biodiversity or wetland function. Existing 

monitoring was only successful in tracking changes in area 

converted from agriculture to wetland. Authors recommend 

that a more comprehensive monitoring program should be 

established to furnish more quantifiable data on ecological 

issues related to restoration and assessing program outcomes. 

Results indicate satisfaction with the program by participants 

and that 89 percent planned to maintain the restorations. Satisfaction was largely driven by participation in the restoration 

process and economic incentives. Results indicate landowners 

derive nonmonetary benefits from their wetlands, chiefly recreation. Thirty-three percent of WRP sites surveyed changed 

ownership since placed in the program.

Authors make the following WRP management recommendations. Management of invasive species should be a 

priority in the WRP. Monitoring of success and ecological 

functions of restored wetlands should be more rigorous and 

systematic over a longer time period (10–20 yr). WRP sites 

should receive significant tax relief, such as a full tax exemption, following establishment of the easement. State level tax 

assessments increase for conservation easements classifying 

them as recreational land. This reduces property taxes for 

farmers but serve as a disincentive for restoration or wetlands. 

Communication between WRP participants and NRCS needs 

to be increased. 

General Accounting Office, 2004, Watershed management—

Better coordination of data collection efforts needed to 

support key decisions: Washington D.C., U.S. General 

Accounting Office, GAO-04-382, 145 p.

GAO concludes that almost all federal and state agencies 

contacted believe coordination of water quality data is poor. 

Reasons for poor coordination include differing objectives for 

collection of data, inconsistencies in data collection protocols, 

unawareness of other agencies and their data collection efforts, 

and overall low priority given to collection of data. GAO recommends designation of a lead organization to coordinate data 

collection. Those agencies responsible for gathering of water 

quality data concur that overall shortage of data was a more 

serious problem than is lack of coordination about knowledge 

of what information is available. 

Genito, D., Gburek, W.J., and Sharpley, A.N., 2002, Response 

of stream macroinvertebrates to agricultural land cover in 

a small watershed: Journal of Freshwater Ecology, v. 17, 

no. 1, p. 109–119.

An evaluation of aquatic macroinvertebrate community 

structure in watersheds affected by agriculture is reported. 

Macroinvertebrate samples were collected on first- to thirdorder streams in central Pennsylvania. Taxonomic richness 

of macroinvertebrates (mayflies [Ephemeroptera], caddisflies 

[Trichoptera]) was lower in streams draining watersheds 

with a high percentage of agricultural land. Habitat quality 

decreased as percentage of agricultural land cover increased. 

Authors conclude that a high percentage of agricultural land 

in a watershed reduced the number of sensitive macroinvertebrate taxa resulting in a community that reflects altered 

habitat quality.

Common macroinvertebrate community responses to 

agriculturally derived pollution include decreases in overall 

species diversity, loss of sensitive taxa, and increased abundance of tolerant taxa. Macroinvertebrate communities varied 

in structure and function in relation to the amount of upstream 

land in agriculture and site-specific habitat quality. Sites 

with less agricultural activity upstream had higher total taxa 

richness. Habitat quality for sampled species decreased when 

agricultural land use reached approximately 40 percent of 

the watershed. 

Gilley, J.E., Patton, B.D., Nyren, P.E., Simanton, J.R., 1996, 

Grazing and haying effects on runoff and erosion from a 

former Conservation Reserve Program site: Applied Engineering in Agriculture v. 12, no. 6, p. 681–684.

Comparisons of runoff and erosion are made from a 

former CRP field with treatments including undisturbed CRP, 

twice-over rotational grazing, season-long grazing, haying, 

and burning. The experimental field was formerly in CRP and 

planted to 40 percent intermediate wheatgrass (Agropyron 

intermedium), 50 percent smooth brome (Bromus inermis) and 

10 percent alfalfa (Medicago sativa). Runoff and erosion were 

based on simulated rainfall. No significant difference was 

found between season-long grazing and burned treatments. 

Similar amounts of erosion were recorded from twice over 

rotational grazing, season-long grazing, and hayed treatments. 

Use of CRP for grazing or haying resulted in a significant 

increase in runoff when compared to leaving the site in undisturbed CRP cover. Grazing and haying operations resulted in 

significantly reduced infiltration rates for surface waters. The 

authors determine, however, that grazing and haying of this 

CRP site would not result in “excessive” erosion if adequate 

canopy and soil surface cover were maintained.

Harding, J.S., Benfield, E.F., Bolstad, P.V., Helfman, G.S., 

and Jones III, E.B.D, 1998, Stream biodiversity—The ghost 

of land use past: Proceedings of the National Academy of 

Sciences of the United States of America, v. 95, p. 14843–

14847.

The study focuses on an investigation of relations 

between land use and invertebrate and fish diversity in 

streams. Findings lead authors to conclude that past land use, 

particularly agriculture, may result in long-term modification 

to and reductions in aquatic diversity, regardless of revegetation in riparian zones. Preservation of only fragments in a 

watershed may not be sufficient to recover, or maintain, natural diversity. Although recovery of physical habitat is often 

possible, the degree to which biological communities can 
164 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

recover from long-term disturbance is relatively unknown. By 

emphasizing the restoration of riparian zones, land managers 

assume stream conditions can be mitigated by attention only 

to land adjacent to the stream. Findings indicate that largescale and long-term agricultural disturbances in a watershed 

limit recovery of stream diversity for many decades. Current 

stream-restoration philosophy and policy supports the assumption that recovery of stream fauna can occur relatively rapidly 

after short-term natural and human disturbances are addressed 

by restoring vegetation. Authors conclude that recovery may 

take decades. These findings challenge assumptions about both 

maintenance and future recovery of biodiversity in disturbed 

stream ecosystems. High or sustained impacts (that is, agriculture) profoundly alter biotic communities and effects of such 

disturbance persist across decades. 

Heimlich, R.E., Wiebe, K.D., Classen, R., Gadsby, D., and 

House, R.M., 1998, Wetlands and agriculture—Private 

interests and public benefits: Washington, D.C., USDA 

Economic Research Service Agricultural Economic Report 

No. 765, 94 p.

This report furnishes an analysis of wetland-policy questions in the context of private landowner and public interests. 

Although society values wetlands, private landowners usually 

cannot benefit from them economically unless they are converted to other than natural use (for example, agriculture or 

development). New incentive programs encourage landowners 

to make socially acceptable use of wetlands. Federal and State 

conservation programs are partly responsible for the decrease 

in wetland conversion over the past 25 yr but falling commodity prices also contributed to reduction in wetland conversion. 

The share of wetlands converted to agricultural uses declined 

from more than 80 percent in 1954–74 to 20 percent from 

1982 to 1992. Elimination of current wetland preservation 

programs would likely increase wetland conversion rates. 

Preservation and improvement in quality of remaining wetlands is an important goal because fully functioning wetlands 

provide environmental services highly valued by society. 

Wetland issues will remain important in agricultural conservation policy requiring continued research to support refinement 

of policy issues and program administration.

Hodne, C.J., 2005, Concentrating on clean water—The challenge of concentrated animal feeding operations: Mount 

Vernon, Iowa, The Iowa Policy Project, accessed online 

June 06, 2011, at http://www.iowapolicyproject.org.

Agricultural industrialization has resulted in large numbers of animals in confinement on a minimal amount of land 

with external sources of grain used as feed. These operations 

are commonly referred to as concentrated animal feeding operations (CAFOs). Large amounts of CAFO-generated manure 

are not readily usable and can exceed needed nutrient levels 

when applied to surrounding lands. CAFOs are disconnected 

from crop production and an integrated land base. Areas of 

high levels of CAFO production experience substantial risks 

of water pollution. Large-scale, vertically integrated CAFOs 

have taken over livestock production with all aspects of 

production, processing, and distribution coordinated through 

common ownership and management. Although often seen as 

a way to save small family farms, over time farmers’ entrepreneurial, management, and marketing autonomy is diminished with operators often becoming contract farmers to large 

corporations. CAFOs annually produce approximately 575 

billion pounds of manure. The main components of CAFO 

manure potentially affecting water quality are N, P, potassium, 

ammonia, bacteria, feed additives, antibiotics, hormones, salts, 

trace elements, organic matter, and solids. Contamination can 

stem from lagoon spills, discharges, seepage, discharge of pollutants to air, and deposition to water and soil. Shallow, private 

wells used in rural areas are especially vulnerable to contamination by CAFOs.

The author concludes that some policy makers, development planners, and rural residents assume that rural residents 

need to sacrifice healthy environments for the benefits of local 

economic growth from CAFOs. Many studies suggest this is 

an illusory trade-off and rural quality of life is often lost without the promised gain in economic benefits. Large CAFOs are 

being given advantage over diversified, family farm operations 

through government subsidized inexpensive grain, tax exemptions, poor environmental regulatory enforcement, and weak 

control over CAFO siting. 

The author makes the following recommendations. A 

sustainable livestock-production industry requires research, 

producer education, equitable producer consumer relations, 

and effective environmental regulation. Improvements can be 

made through enhanced economic health of livestock producers with moderately sized, diversified operations. There are 

rising demands for political and social response from domestic 

and global consumers for safer, healthier meats; restoration 

and protection of water quality; soil health; and improvements 

in the general environment. Iowans should have the option to 

reverse policies that favor unsustainable practices in livestock 

production. Greater local control over regulatory processes 

and siting would likely increase local water quality

Knopf, F.L., and Scott, M.L., 1992, Altered flows and created 

landscapes in the Platte River Headwaters, 1840–1990, in 

Sweeney, J.M., ed., Management of dynamic ecosystems: 

West Lafayette, Ind., North Central Section, The Wildlife 

Society, p.70–74.

Impoundments have altered Platte River flow dynamics, 

which has affected annual runoff peaks and severe reductions 

in total discharge. Deciduous gallery forest associated with 

the river provides local habitats for more wildlife species than 

currently occur elsewhere, or historically, in the headwaters. 

Stabilization of hydrodynamics regimes in headwater streams 

has drastically altered the characteristic fluvial processes that 

shaped these ecosystems. Unique characteristics of riparian 

ecosystems are the pulsed flow resulting from spring runoff 
Wetlands, Aquatic Ecosystems 165

and linear connectively across elevational gradients in the 

basin. Annual floods tend to maintain wide, shallow, and 

active river channels with high sediment loads. Changes in 

hydrology can be attributed to removal of beaver (Castor 

canadensis), water development/diversion for agriculture, 

municipal, and industrial use. Woody vegetation on pristine 

rivers occurred as widely scattered stands of cottonwood 

(Populus spp.) and willows (Salix spp.). Hydrologic conditions 

controlled the patterns of establishment and growth of woody 

riparian species. Crop irrigation recharge to the river raised 

local water tables and a perennial, lower-flow regime. The 

ecological consequences of more permanent, but low, summer 

flows have been the driving ecological force in Platte Rivers 

and have enabled dramatic movements of faunal assemblages 

at local and regional levels. Connectivity provided by the 

riparian corridor established as a consequence of altered flow 

regimes has allowed western expansion of species such as 

white-tailed deer (Odocoileus hemionus), fox squirrel (Sciurus 

niger), and numerous small mammals and avian species to 

move westward from eastern ecosystems. 

Knutson, M.G., Richardson, W.B., Reineke, D.M., Gray, B.R., 

Parmelee, J.R., and Weick, S.E., 2004, Agricultural ponds 

support amphibian populations: Ecological Applications, 

v. 14, no. 3. p. 669–684.

This report describes an assessment of small, constructed 

ponds in southeastern Minnesota which were studied to 

determine their value as breeding sites for amphibians. Small 

agricultural ponds furnished habitat for at least 10 species of 

amphibians. Species richness and reproductive success were 

more closely associated with pond characteristic than those 

of the surrounding landscape. Ponds surrounded by cropland 

had similar species richness and reproductive success to ponds 

surrounded by non-grazed pasture. Ponds used by livestock 

showed a trend toward lower reproductive success due to 

higher levels of P and higher turbidity. Authors conclude that 

properly managed small ponds may help sustain amphibian 

populations where natural wetland habitat is rare. Authors 

recommend limiting access by livestock, reduction of N 

inputs by establishing grass-dominated buffers, and avoiding 

introduction of fish to favor establishment and inhabitation 

by amphibians. 

Lant, C.L., Kraft, S.E., and Gillman, K.R., 1995, The 1990 

farm bill and water quality in Corn Belt watersheds— Conserving remaining wetlands and restoring farmed wetlands: Journal of Soil and Water Conservation, v. 50, no. 2, 

p. 201–205.

This report furnishes results of two surveys addressing 

estimated potential enrollment of farmed wetlands in the CRP 

and WRP and farmland-owner attitudes toward Swampbuster. 

The primary reason some farmers choose not to enroll in 

wetland programs is economic concern as operators did not 

want to forgo potential production of crops on wetland acres. 

Fifty-one percent of respondents believed enrollment in the 

wetland programs could leave them with too little flexibility to change use of land as economic conditions changed. 

Also of concern was the potential change in overall drainage characteristics and possible effects on farming operation 

resulting from restoration of wetlands. Respondents were 

concerned destruction of current drainage facilities would be 

difficult and maintaining wetlands would be too time consuming. In 1992, mean payment for Iowa WRP easement was 

$958/ac with $233/ac for restoration, technical assistance, 

and settlement fees. Potential participation in wetlandpreservation programs increases with rising payment rates. 

Although these rental rates are high compared to typical CRP 

rental rates, they are low compared to costs for other Federal 

wetland-restoration programs. 

Survey results indicate that Swampbuster is unpopular, 

with only 30 percent of respondents believing it is a necessary 

or fair program. Nearly 70 percent of respondents believed 

Swampbuster was an infringement on property rights. Over 70 

percent said permitting some economic use of wetlands (pasture, hay) would make the program more acceptable while, 

75 percent said wetlands enrolled in Swampbuster should be 

exempt from property taxes. The Swampbuster program could 

be made more acceptable to operators if wetland-mapping 

issues are resolved; property taxes on farmlands subject to 

Swampbuster are reduced; and limited, periodic, economic 

use of wetlands is permitted. In addition, if continued, 

Swampbuster needs consistent enforcement of regulations and 

constraints to prevent impression of favoritism and arbitrary 

enforcement perceived by some operators. 

Lowe, W.H. and Likens, G.E., 2005, Moving headwater 

streams to the head of the class: BioScience, v. 55, no. 3, 

p. 196–197.

Conservative estimates indicate headwater streams 

account for more than 70 percent of stream-channel length 

in the United States. However, because of their typical small 

size, these streams are often not addressed in natural-resources 

management. The effects of land use on headwater streams 

affects many valued ecosystem services including clean water, 

recreation, nutrient removal, and biodiversity. Growing evidence that the overall health of freshwater systems depends on 

functions and quality of environmental conditions in headwater streams. Headwater streams are characterized by strong 

and vital interactions with the systems that surround them. 

The high sensitivity of ecological processes and natural communities in headwater streams to atmospheric and terrestrial 

disturbances lead to low thresholds of impact. There is growing evidence that in-stream processes play a significant role in 

modifying N input-output balance of headwater watersheds. 

Luo, H., Smith, L.M., Allen, L.B., and Haukos, D.A., 1997, 

Effects of sedimentation on playa wetland volume: Ecological Applications, v. 7, no. 1, p. 247–252.
166 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Playas within a surrounding cultivated watershed contained more sediments than those within rangeland watershed. 

On average, playas in cultivated watersheds lost all of their 

original volume whereas playas within rangeland dominated 

watershed had lost only about one third of volume. Sedimentation was found to be greater in medium-texture soil than 

within fine-texture soils. Authors recommend continuation of 

the CRP and management to address sedimentation be focused 

on coarser areas of soils and permanent vegetative cover (buffers planted to perennial native grasses) be established around 

playa wetlands to reduce further loss in volume and changes 

in hydroperiod. Research is needed to determine the optimum 

size of buffers. Removal of sediments from playas may be 

feasible to restore playas deemed of critical value to wildlife.

Marshall, D.W., Fayram, A.H., Panuska, J.C., Baumann, J., 

and Hennessy, J., 2008, Positive effects of agricultural landuse changes on coldwater fish communities in southwest 

Wisconsin streams: North American Journal of Fisheries 

Management, v. 28, no. 3, p. 944–953.

An investigation of relations between CRP enrollment and effects on fish community structure in coldwater 

streams in southwestern Wisconsin is described. An index of 

biotic integrity (IBI) for coldwater fish and species richness 

in streams in areas of relatively high CRP enrollment (21.3 

percent of land area) and comparatively low CRP enrollment 

(12.3 percent of land area) were compared. All streams were 

sampled prior to implementation of the CRP in the 1970s. 

Streams were resampled in the same locations in 2000 and 

2005 after CRP lands were established.

Fish-community health is often negatively correlated 

with intensive agricultural land use. In Wisconsin, high runoff 

associated with intensive farming and steep topography has 

degraded streams that historically supported salmonids and 

smallmouth bass (Micropterus dolomieu). Rare non-game 

fish populations have also become imperiled. High concentration of P (attributed to agricultural land-use) results in oxygen depletion stemming from excessive primary production 

in aquatic ecosystems. The goals of this investigation were 

to determine whether biotic integrity, species diversity, and 

estimated P loading in streams differed prior to and after adoption of CRP land practices. Significant acreage was regionally 

enrolled in the CREP, one result of which was riparian buffer 

zones were enlarged to 305 m (333 yd) from stream channels. 

The authors found that coldwater fish IBI score increased 

and the mean number of fish species per stream decreased over 

time in the high-CRP area relative to the low-CRP area. Mean 

IBI score in low-CRP streams was 7.2 before CRP implementation and 16.1 after the CRP was established. Within the 

high-CRP area, mean IBI score increased from 21.7 (poor 

environmental habitat range) to 56.8 (good environmental habitat range) following CRP establishment. The mean number 

of species declined over time in streams within the high-CRP 

area. Predicted P loading rate declined in both areas over time 

as agricultural production intensity diminished with greater 

area devoted to conservation practices. The decline in P 

loading was greater within the high-CRP area than within the 

low-CRP area. Greater responses in the fish community were 

recorded in the high-CRP area as stenothermal, cool water 

species (mottled sculpin [Cottus bairdii], brown trout [Salmo 

trutta]) became dominant. In the low-CRP area, eurythermal 

species, tolerant of a wider range in water temperatures, dominated both pre- and post-CRP implementation. These species 

(johnny darters [Etheostoma nigrum], central stonerollers 

[Campostoma anomalum], and fantail darters [E. flabellare]) 

declined in abundance within both study areas. The continued 

dominance of eurythermal fish species in the low-CRP streams 

presumably reflected continued effects of P and sediments.

Within the high-CRP area, stream improvements occurred 

at the watershed scale with fish communities favoring stenothermal species that serve as indicators of more desirable trout 

streams. This response did not occur within streams in the 

low-CRP area. The authors concluded the more favorable shift 

to stenothermal species was attributable to CRP borne from 

beneficial water and environmental changes at the watershed 

scale. The improvement in water/habitat quality improved 

even as instream and riparian habitats in this area continued to 

degrade from excessive woody shading. Too much growth by 

boxelders (Acer negundo) inhibited grass and other vegetative 

growth along streambanks, important habitat for brown trout. 

The authors conclude by noting that productive farms 

remain in operation in the high-CRP area. Most farms historically were in dairy production but many now blend production 

of row crops, hay, beef cattle, sheep, CRP, and woodlands. 

This analysis stands as convincing evidence that the current 

balance of agricultural production and CRP are beneficial 

to stream ecosystems bringing desirable changes in aquatic 

habitat quality.

Marty, J.T., 2005, Effects of cattle grazing on diversity in 

ephemeral wetlands: Conservation Biology, v. 19, no. 5, 

p. 1626–1632.

Conservation of rare habitats depends not only on 

avoiding development but on implementation of appropriate 

management regimes. In regions lacking native wild grazers, cattle may produce the type of disturbance that helps to 

maintain diverse communities. Assessment of grazing effects 

was completed on 72 vernal pools in the Central Valley of 

California. After 3 yr of treatment, ungrazed pools had 88 

percent higher cover of exotic annual grasses and 47 percent 

lower relative cover of native species. Species richness of 

native plants declined by 25 percent and aquatic invertebrate 

richness was 28 percent lower in ungrazed wetlands compared 

to wetlands with continuously grazed treatment. The absence 

of grazing reduced the vernal pool inundation period by 50 

to 80 percent. Primary cause of decrease in hydroperiod may 

be due to increased evapotranspiration rates resulting from 

greater abundance of vegetation in absence of grazing. Decline 

in invertebrate taxa richness was attributed to altered hydrology. Author concludes the debate over grazing needs to move 
Wetlands, Aquatic Ecosystems 167

beyond simple conclusions that it is either good or bad. Effects 

of the grazing needs to be properly evaluated through experimental studies of practical management alternatives.

McCauley, L.A., and Jenkins, D.G., 2005, GIS-based estimates of former and current depressional wetlands in an 

agricultural landscape: Ecological Applications, v. 15, no. 4, 

p. 1199–1208.

Wetland drainage of agriculturally dominated landscapes 

has been extensive and well documented. Current and future 

efforts to restore wetlands would benefit from information 

describing historical (that is, pre-settlement) wetland distribution. Shallow, small, depressional wetlands accounted 

for the majority of wetlands lost; consequently, they should 

be a priority in restoration. Authors describe several models 

using hydric soils as input but analyzed by Digital Raster 

Graphic, Digital Elevational models, or Digital Orthophotography Quarter Quadrangles. Model output varied, but for the 

study area (Champaign County, Ill.), estimates of wetlands 

lost ranged from 1,077–4,090 depressional wetlands; this 

represents a 78 to 92 percent loss of wetlands in the county. 

Authors conclude wetland losses hold substantial potential 

to negatively affect species that evolved with a more diverse, 

numerous wetland complex. Restoration efforts should 

give priority to wetlands in proximity to other wetlands and 

seek to restore wetland complexes consistent with former 

wetland distributions. 

Mitsch, W.J., Day, J.W., Jr., Gilliam, J.W., Groffman, P.F., 

Hey, D.L., Randall, G.W., and Wang, N., 1999, Reducing 

nutrient loads, especially nitrate-nitrogen, to surface water, 

groundwater, and the Gulf of Mexico—Topic 5 Report 

for the Integrated Assessment of Hypoxia in the Gulf of 

Mexico: Silver Spring, Md., NOAA Coastal Ocean Program, Decision Analysis Series No. 19, 111 p. 

Over-enrichment by nutrients is one of the major stresses 

on coastal ecosystems. A large area (13,000 to 20,000 km2 

[5,020 to 7,722 mi2]) of the Gulf of Mexico suffers from a 

seasonally depleted oxygen level (less than 2 mg/l) due to 

nutrient-induced eutrophication. Most aquatic species cannot 

survive at such low levels of oxygen. This hypoxia zone forms 

in the middle of the most important commercial and recreational fisheries region in the conterminous United States.

The goal of the report is to identify and evaluate 

approaches for solving the Gulf of Mexico hypoxia problem. 

Methods for controlling nutrient input, particularly nitratenitrogen, into waterways are reviewed. Among recommendations made are several on-farm practices that include reduction of N fertilizer application, optimum timing of fertilizer 

application, and use of alternative crops. The report recommends efforts be increased to restore, or create, 24 million 

acres (3.4 percent of Mississippi River basin) of riparian zones 

and wetlands which may reduce N inputs by 40 percent. Also 

recommended is restoration of flood prone lands in the Upper 

Mississippi River Basin to natural wetland vegetation and 

functions. Additional recommendations are provided. A comprehensive evaluation and monitoring of practices to reduce N 

inputs are presented.

Mitsch, W.J. and Gosselink, J.G., 2000, The value of wetlands—Importance of scale and landscape setting: Ecological Economics, v. 35, no. 1, p. 25–33.

Wetlands have value because their functions are useful to 

humans. The reason wetlands are often legally protected has to 

do with their values to society, not with intangible ecological 

processes that occur in wetlands. Wetland value increases with 

increased use and greater scarcity. Wetlands function best in 

landscapes as spatially distributed systems. Wetland values are 

defined by where wetlands are found in the landscape allowing 

hydrologic and biological fluxes to operate with other systems. 

Authors suggest that 3–7 percent of temperate-zone watersheds should be in wetlands to provide desirable flood control 

and water-quality values.

Wetlands are multiple-value systems that perform many 

processes. Optimization of one function generally comes at 

expense of other functions. The most valuable product of 

wetland is public amenities. Once wetlands are lost, restoration of their functions and values is often impossible. At the 

ecosystem scale, wetlands provide environmental services 

because they are most effective when abiotic and biotic parts 

of the ecosystem are synchronized. The term “value” depends 

on human perceptions. In the absence of human population, or 

in situations where population is so dense as to make wetlands 

nonfunctional, wetland value is low to zero. Marginal value of 

wetlands increases with human development only to a point as 

wetland functions begin to be lost. Wetland value appears to 

be maximized when distributed across the landscape and balanced with natural services and human enterprises. 

Moore, A.A., and Palmer, M.A., 2005, Invertebrate biodiversity in agricultural and urban headwater streams—Implications for conservation and management: Ecological Applications, v. 15, no. 4, p. 1169–1177.

Urbanization of agricultural land is the dominant pattern 

of land use in developed countries leading to agricultural land 

preservation programs and riparian restoration and protection. Ecological benefits of such efforts are poorly understood 

and have yet to be fully explained. This paper describes an 

investigation of stream macroinvertebrate community structure along a gradient of agriculture to urban development in 

headwater streams with varying amounts of intact riparian 

buffers in four watersheds near Washington D.C. Without 

direct analysis between farming practices and macroinvertebrate, diversity results lead to the conclusion that conservation 

practices implemented on agricultural lands have had positive 

environmental impacts.
168 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Macroinvertebrate richness was strongly related to land 

use with the highest diversity associated with streams in 

agriculturally dominated landscapes. Agricultural headwater 

streams were not only more diverse than urban headwaters but 

levels of macroinvertebrate diversity were high compared to 

other studies published for agriculturally dominated landscapes. Authors believe that higher richness values may be 

due to widespread use of “Best Management Practices” (for 

example, no-till farming, contour farming, grassed waterways, 

establishment of buffers) in the region that may alleviate 

stressors caused by cultivation. Authors suggest these practices 

help protect headwater streams from sediment and chemical 

inputs to aquatic systems and recommend further research to 

better understand how specific farming practices influence 

stream ecosystems. 

Mushet, D.M., Euliss Jr., N.H., and Shaffer, T.L., 2002, Floristic quality assessment of one natural and three restored 

wetland complexes in North Dakota, USA: Wetlands, v. 22, 

no. 1, p. 126–138.

Although it has received little rigorous evaluation, 

floristic quality assessment is a potentially important method 

for conservation efforts. Relying upon coefficients assigned 

to each plant species in a region’s flora, the authors conclude 

coefficients assigned subjectively by expert botanists furnish 

adequate information to perform accurate floristic quality 

assessments. This method is based on a system where each 

native plant species is assigned a coefficient of 0 to 10, where 

0 represents species that tolerate almost any disturbance and 

can be found in almost any habitat. Species with a value of 

10 have very low tolerance to disturbance and high fidelity to 

habitat integrity. Species falling between the two extremes are 

assigned appropriate coefficients based on professional judgment of botanists familiar with the area. This method was used 

to assess the quality of plant communities on one natural and 

three restored wetland complexes in North Dakota. Authors 

conclude that the floristic quality method provides means to 

identify high-quality wetlands based on vegetation present. 

The method provides a means to evaluate restoration efforts, 

compare plant communities among different sites, monitor 

change over time, and evaluate response of plant communities 

to management. 

Rabalais, N.N., Turner, R.E., Dortch, Q., Justic, D., Bierman 

Jr., V.J., and Wiseman Jr., W.J., 2002, Nutrient-enhanced 

productivity in the northern Gulf of Mexico—Past, present, 

and future: Hydrobiologia, v. 475-476, no. 1, p. 39–63.

Nutrient over-enrichment is having pervasive effects on 

coastal ecosystems around the world. The largest zone of oxygen-deplete coastal waters in the entire western Atlantic Ocean 

is in the northern Gulf of Mexico on the Louisiana/Texas continental shelf influenced by the Mississippi discharge. Nutrient 

concentration and loading have changed in the last half of the 

20th century with average annual nitrate concentration doubling. Estimated affected area in 1993–2001 was 20,700 km2

(8,000 mi2). With increase in world population, concentration 

of populations in coastal areas, agricultural expansion in major 

river basins and increased energy consumption eutrophication 

has become a major environmental problem in coastal waters 

throughout the world. The seasonally hypoxic zone associated with the Mississippi River is among the largest in world’s 

coastal oceans. 

Authors conclude that nutrient loading and hypoxic zone 

can be diminished, but response time would be years. Beneficial changes in marine ecosystem may also have a response 

time of years. Nutrient management activities and landscape 

alterations that reduce flux of dissolved N from the Mississippi 

watershed are necessary for a reduction in N load entering 

Gulf of Mexico. Nitrogen-reduction goals have been successful in Chesapeake Bay, Long Island Sound, and other regions 

of the world and can be realized in Gulf of Mexico with societal and political will.

Rankin, E.T., and Armitage, B.J., 2004, Protection, restoration, and aquatic life potential in Nature Conservancy areas 

in the agricultural Midwest—French Creek (New York), St. 

Joseph River and Fish Creek (Indiana, Michigan and Ohio), 

and the Mackinaw River (Illinois)—A report prepared for 

the Nature Conservancy, Indiana Chapter: Columbus, Oh., 

Midwest Biodiversity Institute, not paginated.

Report documents results of three watershed studies 

to determine efficacy of various management practices and 

increase awareness of the importance of watershed management to improve water quality in agricultural watersheds. 

Knowledge of stressors and limiting factors at watershed 

and regional scales can help to interpret success or failure of 

management at smaller scales. Analysis indicates ranges of 

biological response to nutrient changes resulting from application of best management practices (BMPs) likely are small in 

short term at local scale. Data at watershed scale illustrate that 

biological changes that influence populations of sensitive species are related to cumulative impacts. Local projects may not 

be failures if biological responses are not strong, but should be 

considered incremental responses to larger scale cumulative 

impacts at watershed scale.

Instream habitat quality is critical for maintenance of 

the biotic integrity of stream ecosystems. A framework for 

successful management of watershed should include application of BMPs in uplands, riparian, and in-channel habitats. 

It is important to consider watershed and regional conditions 

before implementing BMPs at local level. Pre-management 

conditions must be known and post-management monitoring 

over extended periods of time is essential for refinement and 

documentation program benefits. Evaluations in watersheds 

with good water and instream habitat quality are needed to 

serve as examples and benchmarks for guiding restoration in 

impaired watersheds.
Wetlands, Aquatic Ecosystems 169

This investigation shows that with proper effort, agricultural BMPs can be implemented and changes in biological 

and chemical patterns can be detected. Habitat restoration in 

streams is an emerging science that needs more complete integration of geomorphic and ecological principles. Many methods of restoration, large to small, are considered experimental 

due to lack of information derived from long-term monitoring. 

Focus of restoration should be on headwater (smaller) streams 

because they are more manageable and represent the predominant interface between aquatic and upland systems. Multiple 

approaches are required to protect and restore high quality 

watersheds. Headwater streams offer the greatest potential for 

restoration and where BMPs would be most effective especially for nutrient and sediment control. Headwater streams 

may themselves be relatively low in biodiversity but serve 

to control ecological functions that strongly influence downstream biodiversity.

Richards, R.P, and Grabow, G.L., 2003, Detecting reductions 

in sediment loads associated with Ohio’s Conservation 

Reserve Enhancement Program: Journal of the American 

Water Resources Association, v. 39, no. 5, p. 1261–1268.

The purpose of this study was to determine if minimum 

detectable change analysis could determine the amount of 

change in concentrations of water quality constituents needed 

to be considered statistically significant in Lake Erie CREP. 

Authors conclude minimum detectable changes for sediment 

loads were around 6 percent. Changes in load smaller than 

10 percent are unlikely to be detectable except when intense 

sampling over a relatively long period of time (greater than 

a decade) before and after implementation of conservation 

practices is completed. 

Shields, F.D., Jr., Langendoen, E.J., and Doyle, M.W., 2006, 

Adapting existing models to examine effects of agricultural 

conservation programs on stream habitat quality: Journal 

of the American Water Resources Association, v. 42, no. 1, 

p. 25–33.

Although conservation funding for agriculture increased 

about 80 percent in the 2002 Farm Bill, environmental benefits 

of these programs remain largely unquantified. Authors believe 

watershed models used in current evaluations (for example, 

CEAP) which are focused on water quantity and quality are 

insufficient to assess changes in the quality of aquatic habitats. 

Current models are hydrologic simulation models which have 

minimal habitat simulation capability and even more limited 

links to ecological condition. This is due to the fact that habitat 

has rarely been considered in design of these models. Impairment to habitat quality in many watersheds are physical degradation of habitat not water quality issues. Existing models 

used for CEAP emphasize simulation only.

Threats to stream corridors and aquatic habitats in 

agricultural landscapes are severe. The major hazard in many 

watersheds is degradation of the physical habitat. Sedimentation and habitat degradation accounted for 53 percent of 

impaired river and stream miles in the 2000 National Water 

Quality Inventory. Declines in stream habitat quality threaten 

85 percent of the 2,500 plant and animal species listed as 

imperiled, while only 25 percent are threatened by pollution.

This paper describes specific components that should be 

added to permit assessments of stream-habitat quality as part 

of efforts to evaluate effectiveness of farm conservation programs. At a minimum, six additional variables are suggested 

for use in examination of ecological impacts: land use, streamflow, water temperature, streambed material type, large woody 

debris, and hydrologic conditions at base flow. Discussions of 

the implications of each of these variables to quality of aquatic 

habitats are presented. All of these variables are influenced by 

presence, location, and quality of riparian buffers. Incorporation of the above variables may substantially contribute to 

more effective evaluation of conservation programs. Authors 

conclude more detailed analysis of capabilities of existing 

models to simulate effects of land retirement, conservation 

buffers, and management of stream habitats is needed but 

existing models do provide a wealth of information. The 

authors advocate additional research to refine combination of 

simulated or measured habitat quality parameters into methods 

for assessment of stream habitat quality. Adaptations to methods currently used in the CEAP are presented.

Smith, L.M., and Haukos, D.A., 2002, Floral diversity in 

relation to playa wetland area and watershed disturbance: 

Conservation Biology, v. 16, no. 4, p. 964–974.

Within the intensively cultivated Southern Great Plains 

are 25,000 to 30,000 playa wetlands. Report describes results 

of plant-community composition in 224 playas and relations to wetland area and watershed characteristics. Playas 

in cropland-dominated watersheds had more exotic species, 

higher diversity, and fewer perennial species than playas 

within grassland-dominated watersheds. Cultivated watersheds 

contributed to playas dominated by annual and exotic vegetation species. Playas often function as island refuges in a region 

dominated by agriculture. Consequently, their preservation is 

important to maintenance of biodiversity for the entire shortgrass plains ecoregion where playas account for only 2 percent 

of landscape area. Most playas (greater than 75 percent) 

exist within cultivated watersheds. Cultivation contributes to 

increased sedimentation of basins, alteration of hydroperiod, 

and an increase in presence of exotic species as a consequence 

of greater input of nutrients. Protection of the native shortgrass 

prairie surrounding playas is fundamental to maintaining playa 

wetland ecosystem functions. Restoration of playas should 

focus first on upland watershed then on removal of sediment 

to restore a more natural hydroperiod.

Smith, L.M., Haukos, D.A., and Prather, R.M., 2004, Avian 

response to vegetative pattern in playa wetlands during winter: Wildlife Society Bulletin, v. 32, no. 2, p. 474–480.
170 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

Cover to water ratios were manipulated in Texas playa 

lakes to determine avian response during winter. Cover was 

managed to yield (cover:water) 75:25, 50:50, and 25:75 ratios. 

Playa vegetation is dominated by barnyard grass (Echinochloa crusgalli), smartweed (Polygonum spp.), and curly dock 

(Rumex crispus). Lakes were surrounded by cropland. Greatest 

bird richness and waterfowl numbers were recorded in 50:50 

cover/water ratio wetlands. Authors attribute increased edge 

and habitat diversity to greater use and numbers of avian species. Management of playas to furnish 50:50 ratio of cover to 

water and moist soil management is recommended to maximize wetland bird diversity during winter. 

Vaché, K.B., Miller, J.M., and Santelmann, M.V., 2002, Water 

quality modeling of alternative agricultural scenarios in the 

U.S. corn belt: Journal of the American Water Resources 

Association, v. 38, no. 3, p. 773–787.

Report documents results of changes in land use and 

management on water quality in two Iowa watersheds using 

the simulation model Soil Water Assessment Tool. The objective was to evaluate effects of agriculture on water quality at 

the watershed scale and provide quantitative estimates of how 

landscape and management changes may affect water quality. 

Despite an increase in understanding of physical processes and 

sources of agriculturally derived nonpoint source pollution and 

application of BMPs, aquatic systems associated with agriculturally dominated regions continue to receive high loadings 

of agricultural pollutants. Significant changes in water quality 

improvement, on order of 50-percent reduction in loading 

reduction, will require development of integrated watershed 

plans including innovative land use and management practices. Because these changes in management of agricultural 

landscapes will be economically costly, public support will 

be required.

Results imply that restoration of water quality through 

reduction in nutrient export will require major reconsideration 

of conservation approaches. Scenarios that included widespread reduction of N application (10 to 33 percent reduction) 

along with implementation of other BMPs can result in diminished reduction of N export by 50 percent or more. Conversion to no-till cultivation and residue management across 

large areas is an effective approach to reduction in N export. 

Decreased production of row crops and wider riparian buffers 

may reduce N export by up to 65 percent.

Wang, L., Lyons, J., Kanehl, P., and Gatti, R., 1997, Influences 

of watershed land use on habitat quality and biotic integrity 

in Wisconsin streams: Fisheries, v. 22, no. 6, p. 6–12.

Report documents analysis of relations between watershed land use, habitat quality, and biotic integrity for 134 sites 

in 103 streams throughout Wisconsin. Habitat quality and 

biotic integrity scores were positively correlated with amount 

of forested land and negatively correlated with amount of 

agricultural land in entire watershed and in 100 m wide buffer 

along streams. Correlations were generally stronger for entire 

watersheds than buffers. Decline in habitat quality and integrity scores were apparent in agricultural watersheds only when 

agricultural land exceeded 50 percent. High rates of urban land 

use were strongly associated with poor biotic integrity and 

poor aquatic habitat quality. Levels of urbanization in watershed beyond 10–20 percent consistently had low values. 

Generally, land use within the 100-m buffers was similar 

to the amount of land use for the entire watershed. For urban 

land, use values in the buffer were almost identical with values 

for the entire watershed. The amount of agricultural land 

upstream tended to be inversely related to habitat quality and 

biotic integrity. Watershed agricultural land use was negatively 

correlated with the biotic integrity score. When agricultural 

land use exceeded 50 percent, the integrity and habitat scores 

decreased. Results demonstrate strong effects of upstream 

land uses on stream ecosystems. Agricultural land use often 

increases runoff; destabilizes flow, temperature, and channel 

morphology; as well as reducing the supply of coarse organic 

materials. Urban-land uses expand areas of impermeable land 

surface with substantially increased watershed runoff. With 

increased runoff, the equilibrium between watershed and 

stream channel breaks down, causing major change in stream 

morphology, bank erosion and, degradation in water and 

habitat quality.

Authors conclude watershed land-use patterns were 

generally a better predictor of habitat quality and biotic 

integrity than were riparian land-use patterns. Watershed 

landforms and distribution of land use within a watershed may 

be as important as the amount of land used is in influencing 

stream ecosystems. 

Yates, A.G., Bailey, R.C., and Schwindt, J.A., 2006, No-till 

improves stream ecosystem quality: Journal of Soil and 

Water Conservation, v. 61, no. 1, p. 14–19.

Authors report increased use of no-till cropping systems 

has a positive effect on quality of stream habitats in agroecosystems. Measures of stream habitat and water quality in 32 

small sub-watersheds show increased use of no-till resulted in 

improvement in habitat and water quality and benthic macroinvertebrate communities. As a consequence of environmental 

and economic benefits, no-till cropping has become common 

across North America over the past two decades. In addition to being the best management practice for maintaining 

soil productivity, the practice(s) are often recommended as a 

method for limiting sediments entering surface waters. This 

investigation examines a gradient of tillage systems with the 

objective of determining relations between tillage methods and 

three measures of stream ecosystem quality (water, habitat, 

and benthic macroinvertebrates). Improvement in stream 

quality was attributed to reduced amounts of fine sediments in 

streams as proportion of cropland under no-till increased. Notill systems did indicate a tendency to lead to higher levels of
Wetlands, Aquatic Ecosystems 171

nitrates in stream water than reported for conventional tillage. 

Authors conclude increasing no-till is an effective mitigation 

tool where sediment and sediment-associated stressors are of 

primary concern.

Zimmerman, J.K.H., Vondracek, B., and Westra, J., 2003, 

Agricultural land use effects on sediment loading and fish 

assemblages in two Minnesota (USA) watersheds: Environmental Management, v. 32, no. 1, p. 93–105.

Agricultural practices have affected stream ecosystems 

by increasing sediment and nutrient loads; raising stream 

temperature; and altering channel morphology, hydrological 

regime, and composition and abundance of riparian vegetation. In the midwestern United States, row-crop agriculture is 

the leading source of water pollution resulting in 70 percent of 

streams being classified as “impaired.” Changes in structure 

and function of stream as a consequence of land use often 

result in reduced diversity of fish, less complex size/age structure of fish populations, higher relative abundance of herbivorous/detritivorous fish, and greater variability in abundance of 

fish. Simplification of aquatic habitat diversity, such as loss 

of deep pools or decreased complexity of stream substrates, 

is the root cause of changes in composition of fish population 

diversity and structure. Fish assemblages can also be affected 

by sublethal and lethal effects of suspended sediment resulting 

in greater abundance of species more tolerant to silt introduced 

into the aquatic system. Warm water fish species are more sensitive to suspended sediment levels than are salmonid species. 

These are the species most often associated with intensively 

farmed agricultural landscapes.

This report discusses findings from field-scale estimates 

of sediment loss and fish life-history data analysis using 

simulation models to investigate changes in lands use in two 

Minnesota watersheds. The purpose of the data analysis was 

to estimate potential changes in fish assemblages as land use 

shifts away from conventional row-crop agriculture to include 

a greater proportion of conservation tillage, riparian buffers, 

permanent cover crops, and grass. Land-use changes led to 

reductions in sediment loading of up to 84 percent in one 

watershed and 49 percent in the other. Reduction in sediment 

loading may be directly related to reduction in runoff by about 

35 percent. A 98-percent reduction in lethal concentrations of 

suspended sediment was estimated in Wells Creek as a consequence of greater use of conservation tillage, riparian buffers, 

and permanent vegetation cover. 

Buffers and Filter Strips

Atwill, E.R., Tate, K.W., Pereira, M.D.G.C., Bartolome, J., 

and Nader, G., 2006, Efficacy of natural grassland buffers 

for removal of Cryptosporidium parvum in rangeland runoff: Journal of Food Production, v. 69, no. 1, p. 177–184.

Authors report results of an investigation to determine 

effectiveness of grass buffers to reduce the input of animal 

(cattle) waste carrying Cryptosporidium parvum into surface 

waters. Cryptosporidium parvum is a zoonotic protozoal 

parasite of heightened public health concern due to its ability 

to enter surface waters used for municipal and recreational 

purposes. Authors conclude grass buffers retain C. parvum

oocysts from cattle manure from entering surface waters 

potentially contaminating drinking and irrigation water supplies. Results suggest strategically placed buffers can be a 

beneficial management practice that will minimize risk of 

waterborne contamination of surface water supplies.

Daniels, R.B. and Gillam, J.W., 1996, Sediment and chemical load reduction by grass and riparian filters: Soil Science 

Society of America Journal, v. 60, no. 1, p. 246–251.

Authors report results from an investigation of the 

amount of nutrients and sediment removed by natural and 

planted filter strips in North Carolina Piedmont. Effectiveness 

of vegetated filter strips varies with watershed erosiveness and 

storm intensity but across a wide range of rainfall filter strips 

reduce sediment load 60–90 percent. Runoff nutrient loads are 

reduced less than sediment load. Ephemeral riparian channels need a continuous vegetative cover to be effective filters, 

which is generally not possible under a closed-tree canopy. 

Forested buffers were effective sediment sinks during dry 

season but were ineffective during large storm events because 

of little ground vegetation and resistance to flow. Total sediment decrease through grass and riparian filters was about 80 

percent. High volume flows commonly overwhelmed both 

grass and riparian filters next to cultivated fields. 

Das, C., Capehart, W.J., Mott, H.V., Zimmerman, P.R., and 

Schumacher, T.E., 2004, Assessing regional impacts of 

Conservation Reserve Program-type grass buffer strips on 

sediment load reduction from cultivated lands: Journal of 

Soil and Water Conservation, v. 59, no. 4, p. 134–142.

Paper describes a method to determine regional estimates 

of CRP area needed to achieve a given percentage reduction 

of agricultural sediment yield into surface waters. Simulations 

using Universal Soil Loss Equation (USLE) and Water Erosion Prediction Project (WEPP) model provide estimates of 

grass buffer strip areas required to achieve targeted reductions 

of sediment yield

Dillaha, T.A. III, Sherrard, J.H., and Lee, D., 1989, Long-term 

effectiveness of vegetative filter strips: Water, Environment 

and Technology, v. 1, p. 418–421.

Report furnishes a summary of filterstrip effectiveness. Taller weeds shaded desirable grasses and reduced 

filterstrip effectiveness. Mowing, herbicides, and reseeding 

or combinations of the three could improve effectiveness 
172 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

of this conservation practice. Grazing by cattle generally 

decreases the quality of vegetation cover and effectiveness of 

filter strips.

Dodds, W.K. and Oakes, R.M., 2006, Controls on nutrients 

across a prairie stream watershed—Land use and riparian 

cover effects: Environmental Management, v. 37, no. 5, 

p. 634–646.

This paper presents a discussion on understanding the 

scale at which land use influences nutrient loading to define 

management recommendations and policies to improve water 

quality. Relations between land use and stream nutrients in 

a first-order intermittent stream in a prairie watershed (Kansas) are discussed. Total N, nitrate, and P concentrations 

were greater in lower portions of the watershed mirroring 

increased density of row crop agriculture. Land use in the 

entire watershed had a large influence on downstream water 

quality; this suggests that nutrient criteria may not be met by 

addressing land-use issues associated only with permanently 

flowing streams.

Intermittent streams in grassland-dominated ecosystems 

and relations to water quality are at present poorly known. 

Areas formerly in grassland but now dominated by row-crop 

agriculture contribute substantially to eutrophication problems 

in the Gulf of Mexico. Nutrient concentrations were found to 

closely reflect increasing level of agricultural intensity from 

headwaters to lower reaches. Authors recommend protected 

riparian zones, including intermittent streams, may help to 

lessen land- use impacts in the midwestern United States. 

Ducros, C.M. and Joyce, C.B., 2003, Field-based evaluation 

tool for riparian buffer zones in agricultural catchments: 

Environmental Assessment, v. 32, no. 2, p. 252–267.

Report presents and describes a method to evaluate characteristics and effectiveness of riparian buffers in agricultural 

landscapes. Based on criteria developed from literature and 

peer review, a method of scoring perceived effectiveness of 

buffer zones is provided. The method could be useful for guiding the establishment of riparian buffers and monitoring their 

effectiveness in furnishing environmental enhancement and 

improvements in habitat quality. The method is based on physical, hydrological, and vegetative criteria that can be easily 

collected in the field. Although the authors suggest the method 

needs further refinement and testing, they believe the procedure is a rapid, relatively simple, and inexpensive method for 

assessment of the quality and effectiveness of riparian buffers 

in agricultural ecosystems.

Henningsen, J.C., and Best, L.B., 2005, Grassland bird use of 

riparian filter strips in southeast Iowa: Journal of Wildlife 

Management, v. 69, no. 1, p. 198–210.

This report documents results of investigation of breeding grassland bird use of 33, 3-4 year-old CRP filter strips. 

Relative abundances of birds and nests were similar between 

cool-season and warm-season grass plantings. The most abundant avian species recorded were red-winged blackbird (Agelaius phoeniceus), dickcissel (Spiza americana), song sparrow 

(Melospiza melodia), and common yellowthroat (Geothlypis 

trichas). Nest success was generally low in all treatments 

evaluated, with predation being the major cause of nest failure. 

Several differences between vegetation characteristics in 

filter strips planted to cool-season (mixtures of brome [Bromus inermis], orchardgrass [Dactylis glomerata] and timothy 

[Phleum pratense]) and warm-season (switchgrass [Panicum 

virgatum]) were recorded. Generally, warm-season planting 

had more vertically dense live vegetation, taller residual vegetation, and greater plant-species richness (forbs). Grass cover 

was greater on cool-season filter strips. Cool season grass and 

legume plantings are more horizontally dense and more resistant to encroachment from weedy plants. Proximity to woody 

vegetation influenced bird species richness, abundance, and 

nest abundance. Species richness was higher in non-wooded 

sites as grassland. Bird species tend to be less abundant, or 

less likely to nest, near wooded edges. Nest-success estimates 

were generally low in all treatments (planting mixture, edge 

type) and were lower than nest success reported for blockshaped CRP fields in Iowa. Authors conclude that the presence of woody vegetation adjacent to filter strips has negative 

effects on use by grassland birds, but if enhancement of the 

overall avian community is a goal, establishment of filter strips 

adjacent to wooded riparian corridors is a reasonable management option. Greater filter strip width potentially can increase 

use by birds infrequently recorded in existing filter strips. 

Johnson, L.B., Breneman, D.H., and Richards, C., 2003, Macroinvertebrate community structure and function associated 

with large wood in low gradient streams: River Research 

and Applications, v. 19, no. 3, p. 199–218.

An assessment of the role of large woody debris and 

macroinvertebrate communities in central Michigan and 

southeastern Minnesota agricultural regions is described in 

this report. Although wood was not abundant in these streams 

and small in size, wood is an important habitat in these aquatic 

systems. Eighty-six and 95 percent (in Michigan and Minnesota, respectively) of total taxa encountered were found in 

association with wood. Presence of wood increased average 

taxa richness by 15 and 10 taxa in Michigan and Minnesota, 

respectively. Wood in stream systems increases flow heterogeneity by retarding flow and creating plunge pools, changing 

channel depth and form, and increasing retention of organic/

inorganic matter. Woody material also contributes to shelter 

for fish species, perching/foraging habitat for higher species of wildlife, and provides food for invertebrates. Despite 

low abundance of large woody material in streams within 

developed landscape, the material provides important habitat. 

Management practices in agriculturally dominated landscapes 

remove wood and other structures that obstruct flow. These 

features, however, provide important habitat and contribute to 
Wetlands, Aquatic Ecosystems 173

diversity in stream ecosystems often lacking in agriculturally 

dominated regions. Authors suggest that stream clearing practices that result in reduction of diversity in stream and bank 

structure should be moderated.

Lee, K.H., Isenhart, T.M., Schultz, R.C., and Mickelson, S.K., 

1999, Nutrient and sediment removal by switchgrass and 

cool-season grass filter strips in central Iowa, USA: Agroforestry Systems, v. 44, no. 2-3, p. 121–132.

In the short-term, switchgrass (Panicum virgatum) and 

cool-season grass filter strips (smooth bromegrass [Bromus 

inermis], timothy [Phleum pratense], fescue [Festuca arundinacea]) removed about the same amount of sediment. 

Long-term effectiveness of cool-season grass-filter strips 

may be limited, however, due to sediment accumulation in 

this typically low-stature, less-resilient vegetation. Switchgrass may offer higher long-term effectiveness because it 

produces large amount of litter, has stiff stems, strong root 

systems, and a growth pattern more uniform and erect than 

cool-season grasses.

Lovell, S.T., and Sullivan, W.C., 2006, Environmental benefits 

of conservation buffers in the United States—Evidence, 

promise, and open questions: Agriculture, Ecosystems and 

Environment, v. 12, no. 4, p. 249–260.

Conservation buffers can have large environmental benefits by reducing erosion, improving water quality, 

enhancing biodiversity, and providing habitats for wildlife. 

However, buffers have yet to be fully accepted by landowners and those who forge agricultural policies in the United 

States. The authors furnish a review of why buffers have not 

been accepted as a viable conservation practice, environmental 

benefits of buffers, and the importance of the correct design of 

buffers in agroecosystems. Many questions related to design 

and management of buffers remain unanswered. The recommendations provided include modification of policies to better 

reflect landowner desires, assessment of buffers at watershed 

scales, and designing buffers based on aesthetic preferences 

and regional variation.

The underlying goal of buffers of all types is to enhance 

environmental quality by impacting ecological health on and 

beyond the farm by reducing soil loss due to wind and water 

erosion. Properly maintained, buffers have been shown to 

remove up to 97 percent of soil sediment prior to runoff entering surface waters. Removal of N has been shown to range 

between 40 to 94 percent with 50-percent removal more likely. 

Buffers have been shown to furnish environmental benefits at 

specific sites, but much remains to be known about effects at 

larger spatial scales. Questions about buffer effectiveness as 

a consequence of their spatial placement, effectiveness and 

movement corridors for wildlife, and influence on biodiversity 

at watershed scales are yet to be answered. Long-term management of buffers may be critical to their ultimate success 

in addressing environmental issues. Regional differences in 

buffer design and functions need to be addressed. Social and 

economic constraints affecting landowner acceptance of these 

conservation options must be addressed as well.

Economic, social, and environmental benefits of buffers are diverse, but farmers are often driven by short-term 

economic considerations rather than long-term benefits. Costs 

incurred by landowners have an important impact on the willingness of landowners to change land-use patterns. Although 

economic incentives may be substantial, many operators are 

hesitant to participate in governmental programs because 

they do not want to forgo control of their land, work with the 

federal government, or are concerned about loss of future 

economic income. 

An issue affecting effectiveness of governmental programs, including buffer initiatives, is a lack of coordination 

between and within agencies. Goals are often unclear or, to 

farmers, appear to be inappropriate. The lack of information 

on long-term management of buffers also appears to have an 

effect on the adoption of these practices. Design and aesthetic 

characteristics of landscape buffers have received too little 

attention. Findings suggest that conservation buffers should 

be designed so they convey a sense of stewardship and visible 

signs of care to receive greatest acceptance by farmers. 

Authors conclude that, by working at watershed scale, 

buffer systems could be made more efficient and interconnected, thereby providing greater environmental and social 

benefits. They also believe greater attention needs to be 

directed toward correct species composition of vegetation 

used, appropriate management activities, education, and 

aesthetic qualities of buffers. Recommendations made to those 

who direct formulation of policy include greater emphasis on 

the role of visual quality of buffers to increase public support 

and consideration of the best approaches to receive the greatest 

economic benefits to society (for example, purchase vs. easement). Conventional approaches to agricultural policy need to 

be challenged to create a more sustainable agricultural system. 

Lynch, L., and Brown, C., 2000, Landowner decision making 

about riparian buffers: Journal of Agricultural and Applied 

Economics, v. 32, no. 3, p. 585–596.

Understanding farmer decision making with regards to 

property and conservation practices is crucial to implementation of effective conservation programs. Determination of 

conditions that influence farmer decisions when most benefits 

accrue to society (for example, establishment of riparian buffers) and not to the landowner is important in setting program 

incentives and policies. Authors conclude that non-agricultural 

opportunity costs affect decisions and will be required if 

environmentally sensitive but high-value land is desired for 

enrollment additional incentives. Up-front costs for adoption 

were important determinants in land-owner decisions. Farmers 

were more sensitive to the relative cost-share rates to establish 

conservation practices than to relative incentive rates. Authors 

conclude increasing cost-share rates may be more effective in 
174 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

increasing enrollment, or participation in specific conservation practices, than would be increasing rental rates. Up-front 

signing bonuses encourage more participation than does an 

increase in annual rental payments. Land values, rental rates, 

and crop prices affect farmer decisions about participation. 

In areas with high land values or low rental rates additional 

incentives such as higher annual incentive rates or signing 

bonuses may be needed to achieve enrollment goals. 

Lyons, J., Trimble, S.T., and Paine, L.K., 2000, Grass versus 

trees—Managing riparian areas to benefit streams of central 

North America: Journal of American Water Resources Association, v. 36, no. 4, p. 919–930.

Authors provide a review and comparisons of advantages 

and disadvantages of wooded and grass/herbaceous dominated riparian buffers. Comparisons are presented on effects 

of grassed riparian areas on bank stability, erosion, channel morphology, cover for aquatic species, hydrology, water 

temperature, organic matter inputs, primary production, and 

macroinvertebrates. Grass-dominated riparian cover may be 

more effective in reducing bank erosion and trapping suspended sediments than are riparian areas dominated by woody 

species. Maintenance of grassy riparian vegetation usually 

requires management, as succession tends to ultimately favor 

woody vegetation. 

Mankin, P.C., Kammin, L.A., Hoffman, C.L., Hubert, P.D., 

Teisberg, J.E., and Warner, R.E., 2005, Management of conservation buffers for upland wildlife in Illinois: Springfield, 

Ill., Illinois Department of Natural Resources, Federal Aid 

in Wildlife Restoration Act Project P-R W-144-R., 72 p.

As of July 2005, 514,877 acres (208,370 hectares) of 

filter strips had been established in the Midwest, 29 percent 

(149,314 ac) of which were established in Illinois. This document reports findings on an investigation of Illinois filter strips 

established under the CRP describing habitat characteristics 

and use by birds and mammals. Authors find that CRP plantings in the eastern Corn Belt have been minimal and the relatively small amount of CRP has tended to be in covers other 

than large blocks (that is, whole fields). Grassland birds experiencing the greatest declines in this region were not found to 

be nesting in filter strips in central Illinois. Authors speculate 

the filter strips were too narrow to attract these species. 

The authors report that most filter strips evaluated were 

successfully established at first planting, but approximately 

20 percent in 2001 and 2003 were not designed adequately 

for filtering sediments. Unapproved uses of filter strips 

were documented that included use as driving lanes, farmequipment storage, food plots, junk storage, deposit of dredge 

spoils, and as a shooting range. By 2003, filter strips included 

in the evaluation began to decline in quality as a consequence 

of unapproved uses and poor management (primarily mowing during the nesting season) and invasion by undesirable 

vegetation. The authors believe that with no provision for 

follow-up consultation or compliance checks the habitat quality of filter strips will continue to decline. Limited technical 

assistance, including landowner education, will be required 

over many years to optimize habitat quality. 

Avian use of filter strips was evaluated in fall, winter, and 

spring/summer. In winter, the number of birds observed did 

not differ based upon type of grass (cool vs. warm season), 

but more birds were observed where grass filter strips contained, or were adjacent to, a tree line. Nesting studies were 

sampled on representatives filter strips (n = 62) where 743 

nests were found. Overall, nest success was extremely low. Of 

521 nests found in herbaceous cover, 82 percent were depredated. Brown-headed cowbirds (Molothrus ater) parasitized 5 

percent of nests. 

Biomass (relative abundance) of small mammals in 

conservation buffers was low and species richness was high. 

Small mammals were more abundant in warm-season grass 

filter strips than within those planted to cool-season grasses. 

Authors conclude widespread adoption of conservation tillage 

and filter strips has benefited mammal species in agriculturally 

dominated ecosystems and fields where these conservation 

practices are used may host source populations that spread into 

more intensively farmed fields or less optimal habitats. 

Although filter strips are likely sinks for nesting birds, 

they do furnish birds, mammals, and reptiles with cover and 

forage that would not exist in crop fields. Vegetation structure 

and plant-species composition seem to have more influence 

over nest-site selection than does the type of grass (cool vs. 

warm season). Filter strip plantings should be multi-species 

rather than monocultures. Forbs should be encouraged. The 

mandate to control weeds should be balanced with recognition 

that some of these “weed” species (for example, cow parsnip 

[Heracleum lanatum] and Canada thistle [Cirsium arvense]) 

are desirable components of habitat for some species of wildlife. Mowing of filter strips should be restricted to occur only 

after the breeding season. Driving on filter strips and using filter strips as turn-arounds should be prohibited. Authors believe 

there is no evidence to suggest removal of treelines and woody 

vegetation would increase use of filter strips by grassland birds 

in Illinois. It is likely that too narrow a width is the factor limiting use of filter strips by grassland bird species of priority in 

this region. A width of 100 ft (30 m) for filter strips is recommended. Finally, authors recommend a focus on establishing 

blocks of grassland habitat, as filter strips alone cannot stem 

the decline in grassland birds in this region. Filter strips will 

have their greatest value to wildlife when used in association with blocks of grassland cover that include pastures, hay 

fields, and CRP planted to grass in whole field enrollments. 

Mayer, P.M., Reynolds Jr., S.K., Canfield, T.J., and 

McCutchen, M.D., 2006, Riparian buffer width, vegetative 

cover, and N removal effectiveness—A review of current 

science and regulations: Cincinnati, Ohio, U.S. Environmental Protection Agency, EPA/600/R-05/118, 27 p.
Wetlands, Aquatic Ecosystems 175

A synthesis of existing literature on effectiveness of 

riparian buffers to improve water quality by removal of N 

from surface and groundwaters is provided. The authors 

conclude there remains no consensus for what constitutes 

optimal riparian buffer design or width to achieve maximum 

effectiveness in removal of N from surface and groundwaters. 

The report attempts to identify generalizations and trends 

described in published literature for improving decisions 

about establishing, maintaining and restoring riparian buffers. 

Nitrogen removal effectiveness varied widely among buffers 

studied. Subsurface removal of N did not appear to be related 

to buffer width. Surface-water removal was partly related 

to buffer width but generally inefficient in removing only a 

small amount of total nitrogen. In some cases, narrow buffers 

actually contributed greater amounts of N into riparian zones. 

Buffers of various vegetation compositions were equally effective at removing N in the subsurface but not in surface flow. 

Soil types, watershed hydrology, and subsurface biogeochemistry may be more important in defining N concentration. The 

authors found state and federal guidelines for buffer width 

varied widely but were generally consistent with published 

literature recommending buffers 7 to 100 m (8 to 110 yd) 

in width. Proper placement and protection of buffers from 

soil compaction, loss of vegetation, and stream incision are 

critical to the effectiveness of buffers. Buffers around stream 

headwaters will likely be most effective at maintaining overall 

quality of watersheds and will be most effective when used 

in conjunction with control of point and nonpoint sources of 

N inputs. Riparian buffers are often used to achieve multiple 

environmental goals which in some cases may require greater 

width, specific types of vegetation, and incorporation of other 

special considerations and designs. 

Mersie, W., Seybold, C.A., McNamee, C., and Lawson, M.A., 

2003, Abating endosulfan from runoff using vegetative 

filter strips—The importance of plant species and flow rate: 

Agriculture, Ecosystems and Environment, v. 97, no. 1-3, 

p. 215–223.

Endosulfan, a chlorinated cyclodiene insecticide, is used 

extensively on cropland, particularly on east and west coast 

vegetable crops, to control insects. The presence of endosulfan 

in surface water is of concern due to adverse impact on human 

and aquatic life. The pesticide is known to cause metabolic 

and reproductive disorders in fish and grass shrimp (Palaemonetes pugio), which is a key component of the food chain in 

estuarine marsh ecosystems. Data on performance of vegetative filter strips in reduction of pollutant loads reaching surface 

waters is scant, as is information related to the effectiveness of 

different species of grass used in filter strips. Study compares 

performance of switchgrass (Panicum virgatum) and tall fescue (Festuca arundinacea) in removal of dissolved endosulfan. Performance of the two species varied with flow rate. At 

slow flow, tall fescue was more effective than switchgrass in 

removal of endosulfan. At relatively fast flow, there was no 

difference between the two grasses. Efficiency of grass filter 

strips in removing endosulfan declined as flow rate increased 

but both grasses were more effective than bare ground in abating endosulfan from a fast flowing runoff. 

Osborne, L.L., and Kovacic, D.A., 1993, Riparian vegetated 

buffer strips in water quality restoration and stream management: Freshwater Biology, v. 29, p. 243–258.

Authors furnish a review on effectiveness and limitations 

of vegetated buffer strips for improving water quality. Riparian zones link aquatic systems with terrestrial catchment and 

have an influence on physical and chemical substance input 

to stream ecosystems. In small to mid-size streams, forested 

riparian zones can moderate temperatures, reduce sediment 

input, stabilize stream banks, and provide organic inputs. 

Forested and grass buffers reduced nitrate concentrations 

in shallow groundwater by up to 90 percent. On an annual 

basis, forested buffers were more effective in reducing nitrate 

concentrations than were grassed buffers but were less effective in retaining dissolved phosphorus. Vegetated buffer strips 

were not as effective in areas where fields are drained by tiles. 

Alternative practices, such as discharging tiles into constructed 

wetlands, may be a more effective means of controlling nonpoint source inputs in these situations.

Both forested and grass buffers will require periodic 

maintenance to sustain maximum performance. Failure to 

maintain shallow sheet flow and promote infiltration will 

reduce effectiveness of buffers to trap sediments. Vegetation in intermediate successional conditions is believed to be 

optimum for sediment capture. Vegetative composition can 

have an influence on buffer strips effectiveness but selection of appropriate species will be dependent upon specific water quality issue to be addressed. Authors conclude 

grass buffer strips are generally more socially acceptable in 

agricultural areas. 

Peak, R.G., Thompson III, F.R., and Shaffer, T.L., 2004, Factors affecting songbird nest survival in riparian forests in 

a midwestern agricultural landscape: Auk, v. 121, no. 3, 

p. 726–737.

This report provides a discussion of physical factors 

affecting nest success of songbirds investigated in riparian 

forest and stream buffers in northeastern Missouri. Spatial 

characteristics of habitat assessed in three narrow (55–95 m 

[60–104 yd]) and three wide (400–530 m [438–580 yd]) riparian forests with adjacent grassland-shrub buffer strips and in 

three narrow and three wide riparian forests without adjacent 

grassland-shrub buffers. Riparian forests provided breeding 

habitat for area-sensitive forest species (Acadian flycatcher 

[Empidonax virescens], wood thrush [Hyocichla mustelina], 

ovenbird [Seiurus aurocapillus]) and grassland-shrub nesting 

species (gray catbird [Dumetella carolinensis], Northern cardinal [Cardinalix cardinalis], and indigo bunting [Passerina 

cyanea]). Buffer strips furnished additional breeding habitat 
176 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

for grassland-shrub nesting species. When located in agriculturally dominated landscapes, nest success may be marginal 

for these species even within wide riparian forests. Negative 

effects of predation were believed higher in narrow riparian 

buffers. However, as long as these “sink” habitats are balanced 

with other more productive habitat types, the authors suggest 

these types of habitats should be maintained as they may contribute, in some years, to long-term viability for these species. 

Richards, C., Johnson, L.B., and Host, G.E., 1996, Landscapescale influences on stream habitats and biota: Canadian 

Journal of Fisheries and Aquatic Science, v. 53, no. S1, 

p. 295–311.

Authors describe results of investigation between influences of geologic versus human-induced (anthropogenic) 

effects on stream ecosystems and macroinvertebrate assemblages in 45 central-Michigan river catchments. Row-crop 

agriculture and the presence of wetlands were the most important land-use variables influencing amounts of woody debris. 

Stream buffers were more important than whole catchment 

data for predicting sediment-related habitat related variables. 

Authors believe catchment-wide geology and land use may be 

more important than stream buffers for maintaining and restoring stream ecosystems. The proportion of permanent vegetation in a catchment was vital for mediating land-use impacts 

on stream habitats. Row-crop agriculture is a major determinant of stream condition. The presence of wetlands influences 

surface water flow and hydrology affecting morphological 

development of stream channels. Substrate characteristics and 

bank erosion were strongly related to factors influenced by 

stream buffers. Authors conclude influence of landscape cover 

throughout the drainage basin may be as important as is riparian vegetation in understanding stream ecosystems. 

Stauffer, J.C., Goldstein, R.M., and Newman, R.M., 2000, 

Relationship of wooded riparian zones and runoff potential 

to fish community composition in agricultural systems: 

Canadian Journal of Fisheries and Aquatic Science, v. 57, 

p. 307–316.

An analysis of fish-community composition to riparian cover and runoff potential in 20 Minnesota River Basins 

streams highly affected (greater than 50 percent area) by 

agriculture is discussed. Streams with wooded riparian zones 

had higher biological integrity, species richness, diversity, 

and percentage of benthic organisms than did streams with 

open riparian zones. Streams with low runoff potential had 

higher biological integrity scores and species richness than 

streams with high runoff potential. Amount of riparian cover 

influenced fish community composition more than did runoff 

potential. Authors conclude that, in the Minnesota River 

Basin, the local riparian zone condition has more influence 

on fish-community composition than the broad-scale watershed runoff potential. Streams without wooded riparian zones 

usually lacked instream woody debris and sufficient habitat for 

a diverse fauna of fish. Authors conclude that, in intensively 

farmed areas, protection and restoration of riparian vegetation 

may greatly benefit fish communities. 

Semlitsch, R.D., and Bodie, J.R., 2003, Biological criteria 

for buffer zones around wetlands and riparian habitats for 

amphibians and reptiles: Conservation Biology, v. 17, no. 5, 

p. 1219–1228.

Often overlooked for their value to semiaquatic species, 

terrestrial habitats surrounding wetlands are important for 

more than the protection of water quality. A close dependence 

of semiaquatic reptiles and amphibians on terrestrial cover 

types in proximity to wetlands is exhibited for critical life-history functions such as foraging, overwintering, or nesting. Criteria by which to define habitat requirements for most species 

and associated regulations to protect spatial relations between 

wetlands and terrestrial habitats are lacking. Conservation and 

management plans must consider both local and landscape 

dynamics; however, core habitats for local populations of species must be defined before issues of wetland and terrestrial 

connectivity can be addressed. Authors suggest that overall 

core terrestrial habitat for amphibians ranged from 159–290 

m (175–317 yd) and that of reptiles ranged from 127–289 m 

(139–316 yd) from the edge of aquatic sites.

While wetlands vary in many characteristics, the authors 

suggest that a single, all-encompassing value for the size of 

core habitats can be used effectively. On private lands, or areas 

where sustainable land use is the priority, a stratified system of 

protection zones can minimize impacts of wildlife and desired 

land uses. Authors propose three terrestrial zones adjacent to 

core aquatic and wetland habitats: Zone 1: area immediately 

adjacent to wetland restricted from use and designed to buffer the core aquatic habitat; Zone 2: core terrestrial zone that 

encompasses the core terrestrial habitat defined by semiaquatic 

species of priority (for example, amphibians 159–290 m 

[175–317 yd]); and Zone 3, beyond zone 2 serves to buffer the 

core terrestrial habitat from surrounding land use. Decisions 

on how restrictive each zone may be to land-use practices 

would depend on management goals and species of concern. 

Authors suggest buffers 15–30 m (16–33 yd) wide used to protect wetland species in many states are inadequate for effectively protecting habitat for amphibians and reptiles. A table 

providing summary data for movement data of reptiles from 

wetlands is furnished in the report. 

Teels, B.M., Rewa, C.A., and Myers, J., 2006, Aquatic condition response to riparian buffer establishment: Wildlife 

Society Bulletin, v. 34, no. 4, p. 927–935.

Authors describe the assessment of changes in condition 

of aquatic resources resulting from establishment of riparian 

buffers established under the CREP in northern Virginia. A fish 

IBI and Stream Visual Assessment Protocol (SVAP) are used 
Woodland Management 177

to determine changes in aquatic condition. Improvements in 

stream condition were recorded at some sites within one year 

of buffer establishment. While not all sites evaluated indicated 

positive trends mean SVAP and IBI scores for buffered sites 

increased while results on control sites showed no change or 

were downward. Authors conclude buffers alone cannot be 

expected to protect streams. Riparian restoration should be 

planned in concert with other conservation practices applied at 

the watershed scale to optimize effectiveness of buffers. 

Buffer establishment improved stream bank cover, 

decreased sedimentation, decreased manure/nutrient inputs, 

and improved appearance of water. Positive results from 

restoration were most evident at the most degraded sites, 

leading to the conclusion that unless upstream influences are 

overwhelming, the greatest response to establishment of buffers can be expected at sites with a high level of degradation. 

Smaller than average drainage areas (less than 58.8 km2 [22 

mi2]) also may be expected to exhibit the greatest observable 

response. The authors conclude implementation of a single 

practice (such as buffers) should not be expected to protect 

streams and their biota from all adverse impacts that occur at 

the landscape scale. They also caution that ecological response 

cannot always be expected to occur rapidly and some functions may take years to respond (for example, growth of trees 

to sufficient height to affect aquatic habitat variables).

Valdivia, C., and Poulos, C., 2009, Factors affecting farm 

operators’ interest in incorporating riparian buffers and forest farming practices in northeast and southeast Missouri: 

Agroforestry, v. 75, no. 1, p. 61–71.

Authors report that the strongest positive factor in 

increasing Missouri farmers to adopt riparian buffers and 

forest farming is enhancing knowledge about the conservation practices. How farmers value the environment and future 

generations was reported as one of the strongest effects on 

interest in the practices. CRP payments had no effect on interest in enrollment. The authors conclude values and attitudes 

of landowners appear to be good indicators of interest in both 

practices. Older farmers were found to be less interested in 

the practices. For practices not perceived as commercial, 

or as a sole or important source of income, non-monetary 

motivations may be a driving force in interest and adoption of 

practices. In other words, environmental concerns have value 

in farmer decisions.

Wenger, S., 1999, A review of the scientific literature on 

riparian buffer width, extent, and vegetation: Athens, Ga., 

University of Georgia, Office of Public Service & Outreach, 

Institute of Ecology, 59 p.

The author provides a document to establish a defensible 

basis for determination of riparian buffer size and vegetation 

composition based on his review of more than 140 relevant 

documents and publications. Although buffers as narrow 

as 4.6m (15 ft) have been shown to be effective in trapping 

sediment and reducing channel erosion, long-term studies 

suggest much wider buffers are more effective and needed. 

An absolute minimum width of 9 m (30 ft) is suggested. To be 

most effective buffers must extend along all streams including 

intermittent and ephemeral channels. Buffer widths in relation 

to phosphorous and nitrate control are discussed as are recommendations for enhancement of aquatic terrestrial habitat quality. The report focuses mainly on southeastern ecosystems and 

restoration of wooded vegetation in buffers.

Woodland Management

Allen, A.W., 1995, Agroforestry and wildlife—Alternatives 

and opportunities, in Rietveld, W.J., Proceedings of agroforestry, sustainable agriculture symposium, 7–10 August, 

1994: Fort Collins, Colo., U.S. Forest Service General Technical Report RM-GTR-261, p.67-73.

This report provides a discussion of integration of agroforestry practices into existing farming operations to benefit 

wildlife. Presentation of spatial design considerations of 

tree-dominated cover types within agricultural ecosystems to 

benefit selected species of wildlife. A discussion of potential 

negative effects of tree/shrub-dominated covers to endemic 

avian grassland species is presented.

Allen, A.W., Bernal, Y.K., and Moulton, R.J., 1996, Pine plantations and wildlife in the southeastern United States—An 

assessment of impacts and opportunities: Washington, D.C., 

U.S. Department of the Interior National Biological Service, 

Information and Technology Report 3, 32 p.

This report documents growing dependence on southeastern forest products and the major role private lands will 

play in provision of timber resources in future decades. 

However, the priorities of owners of non-industrial, private, 

Photo credit: Loblolly stand managed for pine savanna, Reggie E. 

Thackston, Georgia Department of Natural Resources, Wildlife 

Resources
178 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

forests (NIPF) suggest nontimber-related financial investment, recreation, and aesthetic considerations will increasingly 

define acceptable management goals. Wildlife is a principal 

factor affecting management on a growing number of privately owned forestlands. Within the next 50 yr, the area of 

even-aged pine plantations, including CRP, on southeastern 

NIPF lands is projected to exceed 20 million acres (809,356 

hectares). Silvicultural prescriptions applied influence wildlife 

habitat quality within, as well as across, stand boundaries and 

may potentially influence habitat distribution on a landscape 

scale. Various alternatives in physical design, location, and 

management of pine plantations are presented to mitigate 

negative effects of large-scale dependence of even-aged forest 

management on wildlife habitat.

Bassett-Touchell, C.A., and Stouffer, P.C., 2006, Habitat 

selection by Swainson’s warblers breeding in loblolly pine 

plantations in southeastern Louisiana: Journal of Wildlife 

Management, v. 70, no. 4, p. 1013–1019.

Swainson’s warblers (Limnothlypis swainsonii) are typically associated with bottomland hardwood forests but also 

breed in even-age plantations of pine. Authors report investigation of Swainson’s warbler use of loblolly pine (Pinus 

taeda) plantations of various age classes and management 

histories in southern Louisiana to determine stand structure 

preferences of the species. The warblers were found in pine 

stands that had well-developed canopy closure, abundant 

understory vegetation and sparse ground cover. Swainson’s 

warblers were recorded as using 7- to 24-yr-old, unthinned, 

even-aged loblolly pine stands as breeding habitat. Authors 

conclude that even-aged, thinned stands are not used as breeding habitat by this species. A mosaic of even-aged stands 

within a landscape is recommended to furnish habitats for 

avian species requiring early and mid-successional habitats. 

Use of pine plantations by Swainson’s warblers is believed to 

begin when stands reach 7 yr of age. Use will continue only if 

the stands remain unthinned.

Cable, T.T., 1991, Windbreaks, wildlife, and hunters, in 

Rodiek, J.E., and Bolen, E.G., eds., Wildlife and habitats 

in managed landscapes: Washington, D.C., Island Press, 

p. 35–55.

Even though their value is widely recognized, windbreaks 

continue to be lost due to removal for farming. Windbreaks 

deteriorate in condition and quality as they become decadent. 

As trees and shrubs die over time, less protective cover is 

furnished. Hedgerows in five midwestern states are being lost 

at a rate of 0.6 to 3.1 percent/yr. The degree of importance 

of windbreaks varies according to needs of specific wildlife species; however, they are important to resident species 

as well as migrants. Less than 3 percent of Great Plains is 

forested. Although woodland habitats are scarce, woodland 

birds account for 46 percent of avifauna in western Kansas. 

Functions of windbreaks as wildlife habitat include reproductive, escape, and protective cover. Windbreaks are particularly important to many wildlife species during severe winter 

weather. Shelterbelt presence may result in higher rates of 

predation on ground nesting birds in vicinity of wooded cover. 

Shelterbelts provide additional sources of food (both seed and 

insects). The number of species and individuals completely or 

partially insectivorous increased as the size of the windbreak 

increased. Windbreaks serve as wooded islands in agricultural landscape that can serve as travel corridors and dispersal 

habitat between riparian habitats and other wooded covers. 

The value of shelterbelts to wildlife is typically a function of 

size, number of rows, plant diversity, and height. In general, 

windbreaks furnish greater benefits to wildlife if located in, or 

adjacent to, grain fields rather than grazed pasture. 

Carmichael Jr., D.B., 1997, The Conservation Reserve Program and wildlife habitat in the southeastern United States: 

Wildlife Society Bulletin, v. 25, no. 4, p. 773–775.

Author presents a discussion focused on the lack of 

significant wildlife benefits of CRP in southeastern states compared to those benefits realized in Midwest and Great Plains 

states. A discussion of limitations and negative effects of pine 

plantations and tall fescue (Festuca arundinacea) as CRP covers in southern states is presented. Pine plantations ultimately 

represent loss of early successional and agricultural habitats. 

Fescue forms dense sod impenetrable by smaller animals. Both 

practices have provided only limited benefits to wildlife. The 

report provides a summary of recommendations to improve 

new CRP and argues for FSA and wildlife professionals to 

commit to improvement in regional conservation policies.

Frey, G.E., Mercer, D.E., Cubbage, F.W., and Abt, R.C., 2010, 

Economic potential of agroforestry and forestry in the 

Lower Mississippi Alluvial Valley with incentive programs 

and carbon payments: Southern Journal of Applied Forestry, 

v. 34, no. 4, p. 176–185.

Conversion of bottomland hardwood forests in the 

Lower Mississippi Alluvial Valley (LMAV), the historical 

floodplain of the Mississippi river below the confluence of 

the Ohio River, to agricultural production has brought loss of 

ecosystem services. Conversion of these lands to agriculture 

and other uses has reduced the original bottomland hardwood 

forest ecosystem to only 25 percent of its original extent. What 

remains suffers from fragmentation, altered hydrology, excessive sedimentation, water pollution, invasive exotic plants, 

and indiscriminant harvest of timber. Consequently there has 

been significant reduction in wildlife habitat, flood mitigation, 

groundwater recharge, nutrient uptake, sediment deposition, 

and C sequestration. Some of these services could be enhanced 

through establishment of forested conservation buffers on agricultural land through enrollment-conservation programs that 

include the CRP and WRP. Forestry and agroforestry on these 
Woodland Management 179

sensitive lands may assist other efforts to restore bottomland 

hardwood forests in the LMAV. Adoption of these programs 

by landowners depends on sufficient financial returns at least 

equal to what could be produced by agricultural crops. This 

study investigates private profitability of agroforestry, production forestry, and annual cropping to evaluate the economic 

incentives for landowners to adopt agroforestry systems in 

the LMAV. Analysis was based on expert panels (Delphi 

technique), government databases, and input from regional 

agricultural and forestry institutions.

The authors find that, without governmental incentive 

payments, agroforestry and forestry conservation practices 

are unlikely to be adopted by landowners over much of the 

LMAV. Only pine silvopasture, production of cottonwood 

(Populus deltoides), sawtimber, and cottonwood alley cropping were competitive with potential income from agriculture 

and then only on the most marginal lands. The WRP and CRP 

Conservation Practice 22 (riparian buffers) were found to be 

economically competitive only in limited areas, with both 

generally falling below agriculture in profitability. Interest by 

landowners in adopting forestry/agroforestry may increase if 

markets for C sequestration and biomass production become 

practical. However, recent increases in commodity prices 

make adoption of forestry practices even less appealing to 

agricultural producers. The authors conclude that more direct 

payments from governmental programs and conservation 

organizations will be required for landowners to convert agricultural lands to uses that restore depleted ecosystem services 

in the LMAV. 

Hoefer, P.J., Fechner, G.H., and McDonald, S.E., 1990, Trees 

are the answer— 42nd Annual Meeting, Forestry Committee, GPAC—June 1990, Colorado Springs, Colorado: 

Colorado Springs, Colo., Great Plains Agricultural Council 

Publication 132, 112 p.

The central theme of federal agricultural policy has been 

control of variability in agricultural production and prices. 

During first 150 years of American history, federal policy successfully promoted expansion of United States farmland. Current policy is shifting focus to supply management by placing 

restrictions on resource use rather than just land use. The 

greatest need for education and research rests with integrating conservation practices with cropping systems. The 1980s 

may be viewed as a transitional decade for agricultural policy 

shifting focus from production control to production management. The environmental impacts of alternative agricultural 

production-control policies have been considered during the 

development and implementation of legislation. Since the 

1930s, agricultural policies have sought to modify farmers’ 

allocation of resources almost exclusively through use of positive and negative incentives. The peak of U.S. farmland acreage occurred in the early 1950s when acreage devoted to crops 

peaked at nearly 395 million acres. Total production of basic 

commodities has grown rapidly since the 50s as technology 

brought increases in productivity. Federal policies designed 

to boost agricultural output through research and extension 

continues to achieve this goal. 

Jones, P.D., Mixon, M.R., Demarais, S., 2009, Habitat quality 

following mid-rotation treatment in Conservation Reserve 

Program Pines: Journal of Wildlife Management, v. 73, 

no. 7, p. 1166–1173.

Mid-rotation pine plantations often have a hardwood 

midstory that limits development of early succession habitats important to white-tailed deer (Odocoileus virginianus), 

northern bobwhite quail (Colinus virginianus), as well as other 

grass-dependent species. Imazapyr herbicide and prescribed 

burning were applied to 13–22-yr-old loblolly pine (Pinus 

taeda) plantations in southeastern Mississippi to determine 

effects on creation of earlier succession habitat supporting 

greater abundance of grasses and forbs. Each plantation had 

been thinned once between years 12 and 16. Dominant woody 

competitors were sweetgum (Liquidambar styraciflula) and 

Chinese privet (Ligustrum sinense). All fields were enrolled 

in CRP or the Forestry Incentives Program. Herbicides were 

applied October–December, and prescribed burns were completed January–March. 

Application of herbicides and prescribed fire created a 

two-layered forest structure potentially benefiting wildlife 

species associated with pine-grassland communities. The herbicide/fire treatment resulted in a more open understory with 

greater coverage of debris and herbaceous plants than recorded 

in non-treated plots. Autumn and winter food plant coverage 

for quail was not different between treatments but accessibility 

was improved in treated plots. Nesting cover was improved 

in treated plots. Increased coverage of forbs furnished a more 

diverse forage base for deer. The authors suggest mid-rotation 

pine plantations enrolled in cost-share programs should 

be treated with selective application of herbicide followed 

by periodic prescribed fire and thinning to maintain early 

succession conditions. 

Londo, A.J., Traugott, T.A., Dicke, S.G., and Roberts, S.D., 

2002, How to determine when your Conservation Reserve 

Program (CRP) pine plantation is ready to thin, in Proceedings of the Eleventh Biennial Southern Silvicultural 

Research Conference, 11, Knoxville, Tenn., 20–22 March 

2001: Asheville, N.C., USDA Forest Service General Technical Report SRS-48, p. 159–162.

In Mississippi alone, 308,000 acres of pine plantations 

have been established under the CRP. Over 1.2 million acres 

have been established under the program overall. At the time 

of this report, the authors suggest many plantations in Mississippi will be ready for initial thinning. Timing and frequency 

of first thinnings should be determined by site quality and 

landowner objectives. The authors conclude, however, that 

initial thinning of pine plantations is often considered to 

be as income source for landowners and not a method for 
180 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

improvement of the stand. The authors present criteria upon 

which to base pine-management decisions that include: stand 

density, natural pruning height, average diameter of trees, 

height of dominants and codominants in stand, and basal area 

growth rate. Recommendations are made from a silvicultural 

perspective to determine optimum time for first thinning of 

loblolly pine (Pinus taeda) plantations.

Mixon, R.M., Demarais, S., Jones, P.D., and Rude, B.J., 2008, 

Deer forage response to herbicide and fire in mid-rotation 

pine plantations: Journal of Wildlife Management, v. 73, 

no. 5, p. 663–668.

Mid-rotation pine plantations enrolled in cost-share programs (for example, CRP) often have a substantial hardwood 

mid-story that limits desirable understory growth for whitetailed deer (Odocoileus virgininaus). Application of imazapyr 

herbicide and prescribed fire effects on understory composition in 13–22-yr-old loblolly pine (Pinus taeda) plantations in 

Mississippi is reported. Evaluation was undertaken 1 and 2 yr 

post-treatment. Deer foraging habitat was improved by greater 

growth of nutritious forbs following treatment. Results support 

the use of selective herbicide and prescribed fire to improve 

deer foraging habitat in pine plantations enrolled in conservation cost-share programs. In addition to improvements in deer 

habitat, enhancement of habitat for avian species of conservation concern was also noted. It has been shown that control of 

woody understory vegetation in pine plantations substantially 

improves pine growth making the management financially 

viable over the long-term.

Nuttle, T., and Burger, L.W., 1996, Response of breeding bird 

communities to restoration of hardwood bottomlands, in 

Annual Southeastern Association Fish and Wildlife Agencies, 50, Hot Springs, Ark., October 5–9, 1996, Proceedings: Tallahassee, Fla., Southeastern Association Fish and 

Wildlife Agencies, p. 228–236.

Bird-community response in relation to restoration of 

bottomland hardwoods is reported. Stands sampled included 

hardwood plantations that ranged from 0–4, 7–15, and 21–27 

yr old and natural sawtimber (greater than 50 yrs old) stands. 

Oaks commonly planted in plantations sampled included cherrybark (Quercus pagoda), Nuttall (Q. nuttallii), and water (Q. 

nigra) and willow oaks (Q. phellos). Mean number of avian 

species increased with stand age. Plantations in the 21–22 

and 7–15 age classes supported a substantial portion of the 

potential forest avian community but lacked area-sensitive 

and selected late-successional species. Young plantations 

provided temporary habitat for regionally declining grassland 

bird species.

Authors suggest that management prescriptions for hardwood plantations that mimic natural succession (such as planting of multiple hardwood species and thinning) may enhance 

restoration efforts. Because oaks are slow growing, inclusion 

of faster-growing species in addition to oaks may enhance 

structural diversity of plantations at a quicker rate benefiting 

avian species. Thinning of hardwood plantations 20–25 yr 

after establishment was recommended to allow development 

of ground and midstory vegetation to enhance structural and 

habitat diversity.

O’Leary, C.H., and Nyberg, D.W., 2000, Treelines between 

fields reduce the density of grassland birds: Natural Areas 

Journal, v. 20, no. 3, p. 243–249.

Fragmentation of grassland by fencerows could be a 

factor contributing to decline of grassland birds. Avian species 

sensitive to area of available habitat may be especially affected 

by introduction of wooded covers into grassland habitats. Recommendations to maintain habitat quality for grassland birds 

are furnished that include: reduce woody vegetation within 

fields, replace woody vegetation separating fields with grass, 

and connect fields to furnish larger interior area.

Okwudili, O.O., and Wheelock, G.C., 1999, Assessing the 

retention potential of Conservation Reserve Program 

practices in Alabama: Southern Journal of Applied Forestry, 

v. 23, no. 2, p. 83–87.

CRP participants were surveyed to determine potential 

utilization of CRP acres if contracts expired without opportunities to re-enroll in the program. Survey results imply that 90 

percent of lands planted to CRP trees would be retained after 

contract expiration, thus providing continuing environmental benefits. However, 60 percent of lands planted to grasses 

would be converted back to row-crop production. Authors 

suggest that, to maintain soil loss benefits and reduction in 

excess production, tree planting should be encouraged on new 

enrollments in CRP. 

Pienaar, L.V., and Shiver, B.D., 1993, Early results from an 

old-field loblolly pine spacing study in the Georgia Piedmont with competition control: Southern Journal of Applied 

Forestry, v. 17, no. 4, p. 193–196.

Information is presented in this report on yield potential 

of improved loblolly pine (Pinus taeda) on marginal cropland 

with control of herbaceous competition. Early growth rates 

of seedlings exceeded those recorded in plantations without 

vegetation control. After 8 yr, average tree height, average 

diameter at breast height, and basal area/acres were more 

than twice the average growth rate in plantations without 

herbicide treatment. 

Pierce II, R.A., Farrand, D.T., and Kurtz, W.B., 2001, Projecting the bird community response resulting from the 

adoption of shelterbelt agroforestry practices in eastern 

Nebraska: Agroforestry Systems, v. 53, p. 333–350.
Woodland Management 181

The purpose of this investigation was to develop a 

methodology for the evaluation of changes in wildlife habitat 

occurring as a consequence of conservation practices at the 

farm level. More specifically, the objective was to project 

changes occurring within avian communities as a consequence of establishing shelterbelts at the farm landscape 

level. The Habitat Analysis and Modeling System (HAMS) 

was used to project composition and spatial patterns resulting 

from the establishment of shelterbelts with resultant impacts 

on associated avian communities. Policies promoting shelterbelts create edge habitats which ultimately favor avian species 

associated with forest edge. Avian species associated with 

grassland habitats would potentially be negatively affected.

The authors note that little research has been completed 

to assess wildlife habitat changes resulting from adoption 

of agricultural policies promoting agroforestry. Appraisal of 

wildlife habitats within agroecosystems requires an ability to 

accurately forecast consequences of land-use changes. The 

ability to conduct such research has been enhanced with technological advances in remote sensing, geographical information systems, and methods to quantify spatial attributes of the 

landscape. Because agricultural policies affect species across 

broad scales it is important to assess interrelationships of 

land management on large regional scales when developing 

agricultural conservation policies.

Rutledge, B.T., and Conner, L.M., 2002, Potential effects of 

groundcover restoration on breeding bird communities in 

longleaf pine stands: Wildlife Society Bulletin, v. 30, no. 2, 

p. 354–360.

An investigation of how disturbed vs. undisturbed 

ground cover in Georgia longleaf pine (Pinus palustris) forest 

may have on distribution and abundance of ground nesting 

birds is reported. Investigation was in area of longleaf pine 

forest where historical agricultural use resulted in disturbed 

ground cover. Undisturbed sites were dominated by native 

vegetation, chiefly wiregrass (Aristida beyrichiana). Prescribed fire has been applied to these sites on a 2-yr rotation. 

Undisturbed sites were used as a surrogate for nonexistent 

restored longleaf pine stands.

Although differences in abundance of some species were 

recorded, the authors conclude that avian species richness and 

diversity within disturbed and native groundcovers were very 

similar. Discussion of avian species’ relations with both cover 

types is presented. The authors suggest that breeding birds 

may be more influenced by the presence of an herbaceous 

understory than by restoration of specifically native vegetation species. Over the long term, it is believed breeding bird 

communities will be relatively similar regardless of if native 

ground cover is established in the restoration of longleaf pine 

stands. However, from a management perspective, native 

groundcover restoration will enhance the ability to apply prescribed fire as a tool in stand development and maintenance. 

Sladek, B., Burger, L., and Munn, I., 2008, Avian community response to mid-rotation herbicide release and prescribed burning in Conservation Reserve Program plantations: Southern Journal of Applied Forestry, v. 32, no. 3, 

p. 111–119.

Due to widespread changes in land use and control of 

wildfire, early successional plant communities are declining in the forest-dominated Southeast. In this region, shrubdependent birds associated with early successional habitats 

have experienced a 0.99 percent decline per year from 1966 to 

2004. Approximately 1.6 million acres of CRP pine plantations have been established across the southeast. Given this 

vast area, the potential to manage these habitats to benefit 

species of management concern is significant. The 2002 Farm 

Bill permits mid-contract management on CRP plantations that 

include: thinning, prescribed burning, disking, and use of herbicides. If managed with appropriate disturbance regimes, pine 

plantations established under the CRP have potential to furnish 

habitat for declining pine/grassland and shrub-successional 

bird species. Both prescribed fire and herbicides are used to 

reduce hardwood midstory trees and encourage enhanced 

growth of grasses, forbs, and other seed-bearing plants characteristic of more open, early successional habitats. Reduction of 

midstory vegetation in wooded environments typically results 

in a change in the avian community from dominance of forestinterior species to those more associated with grassland and 

early successional habitats.

This report focuses on the effects of the herbicide Imazapyr and prescribed burning on avian-community characteristics and pine growth in thinned, midrotation loblolly pine 

(Pinus taeda) CRP plantations in the Upper and Lower physiographic regions of Mississippi. The pine plantations included 

in the study were 15-18 yr old and recently thinned. Dominant understory vegetation in study sites were Chinese privet 

(Ligustrum sinense) and sweetgum (Liquidamber styraciflua). 

Treated sites were applied with 0.2 kg (7 oz) imazapyr and a 

nonionic surfactant in 75.7 l (19.8 gal) of total spray solution per hectare (2.5 ac). Prescribed burns were applied in 

January–February.

One year following treatment, understory hardwood 

and woody shrub basal area was reduced by 69 percent. Two 

years following treatment, percent midstory hardwood canopy 

differed significantly between treated and control (untreated) 

plots. Mean growth increments (mean diameter, total height, 

and basal area) of pine trees did not differ between treated 

and control sites. In both years following treatment, early 

successional and shrub-associated avian species richness was 

significantly greater within treated plots than in control plots. 

Of four early successional/shrub associated species (common 

yellowthroat [Geothlypis trichas], indigo bunting [Passerina 

cyanea], downy woodpecker [Picoides pubesens], summer 

tanager [Piranga rubra]), all were more abundant in treated 

plots. Because control plots favored habitat for several forestinterior species of management concern (hooded warbler 

[Wilsonia citrine], Kentucky warbler [Oporonis formosus], and 
182 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

white-eyed vireo [Vireo griseus]), the authors recommend 

that forest management maintain a mosaic of hardwood 

midstory control rather than broad-scale application of midstory thinning in CRP pine plantations. Detailed discussion 

of avian species and community level response to habitat 

management are presented in the report. 

Twedt, D.J., Somershoe, S.G., Hazler, K.R., and Cooper, 

R.J., 2010, Landscape and vegetation effects on avian 

reproduction on bottomland forest restorations: Journal of 

Wildlife Management, v. 74, no. 3, p. 423–436.

Restoration of forests has taken place on over 200,000 

hectares (494,220 acres) of agricultural land in the Mississippi Alluvial Valley. Decisions on where to restore bottomland forests ultimately depend on landowner objectives. 

Ecologists have advocated planting a diverse mix of densely 

spaced, fast-growing tree species for forest-restoration 

projects in this region. Planted in areas adjacent to existing forest land, this procedure has benefited area-sensitive 

forest-dependent birds. The effectiveness of this policy was 

assessed on 36 bottomland sites. Restoration sites evaluated 

ranged from 2–15 yr old. The majority of sites (25) were on 

private land and enrolled in the WRP. Most sites had been 

planted to water oak (Quercus nigra), willow oak (Q. phellos), Nuttall’s oak (Q. nuttallii), green ash (Fraxinus pennsylvanica), sweet pecan (Carya illinoinensis), and bald cypress 

(Taxodium distichum). 

Avian densities and breeding-bird abundance were 

influenced by landscape composition and vegetation structure on restoration sites. Detailed avian habitat relationships 

found for grassland, shrub-scrub, and slow and fast growing 

tree-associated species are presented. Bottomland restoration sites planted to slow-growing species retain grassland 

like habitat conditions for up to 10 yr following planting. 

Such sites, with shorter and sparser tree cover, attracted 

bird species characteristic of grassland habitats. Due to low 

reproductive success, these sites were determined to be 

population sinks for these species. Restoration sites with 

taller trees and higher stem densities were found to support 

species characteristic of shrub-scrub and forested habitats. 

Compared to sites in agriculturally dominated landscapes, 

restoration plantings adjacent to existing forest experienced 

increased invasion rates of woody plants supporting greater 

bird densities and nest success. To maximize avian benefits, 

the authors’ recommend restoration efforts are within largely 

forested landscape of at least 8,000 hectares (19,760 acres). 

Planting recommendations for bottomland sites should be 

at least 1,000 stems/ha (400 stems/acres). Forty to seventy 

percent of these trees should be a mixture of light-seeded, 

soft-mast bearing, fast-growing tree species.

Twedt, D.J., Wilson, R.R., Henne-Kerr, J.L., and Grosshuesch, D.A., 2002, Avian response to bottomland hardwood reforestation—The first 10 years: Restoration Ecology, v. 10, no. 4, p. 645–655.

Bottomland hardwood forests were established on 

agricultural cropland in Mississippi and Louisiana with 

either oak (Quercus spp.) or eastern cottonwood (Populus 

deltoides) planted. Avian colonization was evaluated at years 

2 and 10 subsequent to planting. Rapid growth of cottonwood resulted in forest structure supporting greater species 

richness of breeding birds and greater avian density than 

recorded on oak-dominated sites. Fourteen species of shrubscrub species and early successional forest birds were characteristic of cottonwood sites 5 to 9 yr after planting. Authors 

recommend reforestation for avian conservation should 

include a high proportion of fast-growing species (such 

as cottonwood) to allow for earlier colonization by avian 

species during the period when slower-growing hardwoods 

are gaining height and structural diversity. Cottonwood is 

relatively short lived with other hardwood species replacing 

it in dominance over time

Van Lear, D.H., Carroll, W.D., Kapeluck, P.R., and Johnson, 

R., 2005, History and restoration of the longleaf pinegrassland ecosystem—Implications for species at risk: 

Forest Ecology and Management, v. 211, p. 150–165.

At the time of European discovery, the longleaf pinegrassland (Pinus palustris-Poaceae) ecosystem is believed 

to have occupied over 30 million hectares (greater than 

12.1million acres) which was sustained by frequent low- to 

moderate-intensity surface fires preventing lands from reaching eventual succession to domination by mixed hardwood 

forests. The ecosystem has experienced loss to only about 

1.2 million hectares (485,000 ac) due to disruption of natural 

fire regimes, land conversion, urbanization, as well as other 

factors. Due to habitat loss and fragmentation of remaining 

stands, many species dependent upon this ecosystem are 

rare or in decline. Key factors affecting restoration include 

understanding the historical condition of the longleaf ecosystem, initiation and expansion of an appropriate fire regime, 

management of herbaceous diversity, continued research, 

and encouragement of multi-ownership to conservation 

approaches and responsibilities. 
Relevant Books and Publications 183

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2005–5145

The Conservation Reserve Program– 

Planting for the Future:

Proceedings of a National Conference, 

Fort Collins, Colorado, June 6–9, 2004

Relevant Books and Publications

Agricultural and Conservation Policy

Albrecht, D.E., and Murdock, S.H., 1990, The sociology of 

U.S. agriculture—An ecological perspective: Ames, Iowa, 

Iowa State University Press, 249 p.

Allen, A.W. and Vandever, M.W., eds., 2005, The Conservation Reserve Program—Planting for the Future—Proceedings of a National Conference, Fort Collins, Colo., June 

6–9, 2004: U.S. Geological Survey, Scientific Investigations 

Report 2005–5145, 248 p.

Aillery, M.P., Bertels, P., Cooper, J.C., Moore, M.R., Vogel, 

S.J., and Weinberg, M., 1996, Salmon recovery in the 

Pacific Northwest—Agricultural and other economic 

effects: Washington, D.C., USDA Economic Research 

Service, Natural Resources and Environment Division, 

Agricultural Economic Report No. 727, 72 p.

 Anderson, M., and Magleby, R., 1997, Agricultural resources 

and environmental indicators, 1996–97: Washington, D.C., 

USDA Economic Research Service, Agricultural Handbook 

No. 712, 347 p.

Blatz, C.V., 1991, Ethics and agriculture—An anthology on 

current issues in world context: Moscow, Idaho, University 

of Idaho Press, 674 p.

Browne, W.P., Skees, J.R., Swanson, L.E., Thompson, P.B., 

and Unnevehr, L.J., 1992, Sacred cows and hot potatoes—

Agrarian myths in agricultural policy: Boulder, Colo., 

Westview Press, 150 p.

Brouwer, F., and Crabtree, B., 1999, Environmental indicators 

and agricultural policy: New York, N.Y., CABI Publishing, 

305 p.

Council for Agricultural Science and Technology, 1990, 

Ecological impact of federal conservation and cropland 

reduction programs: Ames, Iowa, Council for Agricultural 

Science and Technology, Report No. 11, 28 p. 

Center for National Policy, 1991, U.S. Agriculture— Myth, 

Reality and National Policy: Washington, D.C., Center for 

National Policy, 76 p.

Claassen, R., Hansen, L., Peters, M., Breneman, V., Weinberg, 

M., Cattaneo, A., Feather, P., Gadsby, D., Hellerstein, D., 

Hopkins, J., Johnson, P., Morehart, M., and Smith, M., 

2001, Agri-environmental policy at the crossroads—Guideposts on a changing landscape: Washington, D.C., USDA 

Economic Research Service, Agricultural Economic Report 

No. 794, 66 p.

Claassen, R., Breneman, V., Bucholtz, S., Cattaneo, A., 

Johansson, R., and Morehart, M., 2004, Environmental 

compliance in U.S. agricultural policy—Past performance 

and future potential: Washington, D.C., USDA Economic 

Research Service, Agricultural Economic Report No. 832, 

50 p.

Cochrane, W.W., 1993, The development of American agriculture—A historical analysis: Minneapolis, Minn., University 

of Minnesota Press, 500 p.

Cochrane, W.W., 2003, The curse of American agricultural 

abundance—A sustainable solution: Lincoln, Neb., University of Nebraska Press, 154 p.

Cochrane, W.W., and Runge, C.F., 1992, Reforming farm 

policy—Toward a national agenda: Ames, Iowa, Iowa State 

University Press, 279 p.

Ervin, D., Algozin, K., Carey, M., Doering, O., Frerichs, S., 

Heimlich, R., Hrubovcak, J., Konyar, K., McCormick, I., 

Osborn, T., Ribaudo, M., and Shoemaker, R., 1991, Conservation and environmental issues in agriculture—An 

economic evaluation of policy options: Washington, D.C., 

USDA Economic Research Service, Staff Report No 9134, 

62 p.

Ervin, D.E, and Smith, K.R., 1996, What it takes to “Get 

to Yes” for whole farm planning policy: Greenbelt, Md., 

Henry A. Wallace Institute for Alternative Agriculture, 

Policy Studies Report No. 5, 42 p.

Feather, P., Hellerstein, D., and Hansen, L., 1999, Economic 

valuation of environmental benefits and the targeting of 

conservation programs—The case of the CRP: Washington, D.C., USDA Economic Research Service, Agricultural 

Economic Report No. 778, 56 p.

Freyfogle, E.T., 2003, The land we share—Private property 

and the common good: Washington D.C., Island Press, 

336 p.
184 Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography

General Accounting Office, 1995, Conservation Reserve 

Program—Alternatives are available for managing environmentally sensitive cropland—Report to the Committee on 

Agriculture, Nutrition, and Forestry, U.S. Senate: Washington, D.C., GAO/RCED-95-42, 68 p.

General Accounting Office, 2003, Agricultural Conservation— 

SDA needs to better ensure protection of highly erodible 

croplands and wetlands—Report to the ranking Democratic 

member, Committee on Agriculture, Nutrition, and Forestry, 

U.S. Senate: Washington D.C., GAO-03-418, 106 p.

Gardner, B.L., 2002, American agriculture in the twentieth 

century—How it Flourished and What It Cost: Cambridge, 

Mass., Harvard University Press, 388 p.

Gerard, P.W., 1995, Agricultural practices, farm policy, and the 

conservation of biological diversity: Washington D.C., U.S. 

Department of the Interior, National Biological Service, 

Biological Science Report 4, 28 p.

Hallberg, M.C., 2001, Economic trends in U.S. agriculture and 

food systems since World War II: Ames, Iowa, Iowa State 

University Press, 179 p.

Haufler, J.B., ed., 2005, Fish and wildlife benefits of Farm Bill 

conservation programs—2000–2005 update: Bethesda, Md., 

The Wildlife Society Technical Review 05-2, 205 p.

Heard, L.P., Allen, A.W., Best, L.B., Brady, S.J., Burger, W., 

Esser, A.J., Hackett, E., Johnson, D.H., Pederson, R.L., 

Reynolds, R.E., Rewa, C., Ryan, M.R., Molleur, R.T., and 

Buck , P., 2000, A comprehensive review of Farm Bill 

contributions to wildlife conservation, 1985–2000: Madison, Miss., USDA Natural Resources Conservation Service, 

Wildlife Habitat Management Institute, Technical Report 

USDA/NRCS/WHMI-2000, 208 p.

Heimlich, R.E., Wiebe, K.D., Classen, R., Gadsby, D., and 

House, R.M., 1998, Wetlands and agriculture—Private 

interests and public benefits: Washington, D.C., USDA 

Economic Research Service Agricultural Economic Report 

No. 765, 94 p.

Hughes, J.S., Hoag, D.L., and Nipp, T.E., 1995, The Conservation Reserve—A survey of research and interest groups: 

Ames, Iowa, Council for Agricultural Science and Technology, 44 p.

Jack, Z.M., 2005, Black earth and ivory tower—New American essays from farm to classroom: Columbia, S.C., University of South Carolina Press, 312 p.

Kuntson, R.D., Penn, J.B., and Boehm, W.T., 1990, Agricultural and food policy: Englewood Cliffs, N.J., Prentice Hall, 

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Allen and Vandever—Conservation Reserve Program Contributions to Wildlife Issues—An Annotated Bibliography—Scientific Investigations Report 2012–5066