U.S. Department of the Interior

U.S. Geological Survey

Professional Paper 1745

Ecosystem Services Derived from Wetland Conservation 

Practices in the United States Prairie Pothole Region with 

an Emphasis on the U.S. Department of Agriculture 

Conservation Reserve and Wetlands Reserve Programs
Ecosystem Services Derived from Wetland 

Conservation Practices in the United 

States Prairie Pothole Region with an 

Emphasis on the U.S. Department of 

Agriculture Conservation Reserve and 

Wetlands Reserve Programs

Edited by Robert A. Gleason, Murray K. Laubhan, and Ned H. Euliss, Jr.

Chapter A

Background and Approach to Quantification of Ecosystem Services

By Robert A. Gleason and Murray K. Laubhan

Chapter B

Plant Community Quality and Richness

By Murray K. Laubhan and Robert A. Gleason

Chapter C

Carbon Sequestration

By Robert A. Gleason, Brian A. Tangen, and Murray K. Laubhan

Chapter D

Floodwater Storage

By Robert A. Gleason and Brian A. Tangen

Chapter E

Reduction of Sedimentation and Nutrient Loading

By Brian A. Tangen and Robert A. Gleason

Chapter F

Proposed Approach to Assess Potential Wildlife Habitat Suitability 

on Program Lands

By Murray K. Laubhan, Kevin E. Kermes, and Robert A. Gleason

Professional Paper 1745

U.S. Department of the Interior

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

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2008

For product and ordering information:

World Wide Web: http://www.usgs.gov/pubprod

Telephone: 1-888-ASK-USGS

For more information on the USGS–the Federal source for science about the Earth, its natural and living resources, 

natural hazards, and the environment:

World Wide Web: http://www.usgs.gov

Telephone: 1-888-ASK-USGS

Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the 

U.S. Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.

Suggested citation:

Gleason, R.A., Laubhan, M.K., and Euliss, N.H., Jr., eds., 2008, Ecosystem services derived from wetland conservation 

practices in the United States Prairie Pothole Region with an emphasis on the U.S. Department of Agriculture Conservation Reserve and Wetlands Reserve Programs: U.S. Geological Professional Paper 1745, 58 p.

Library of Congress Cataloging-in-Publication Data

Gleason, Robert A.

Ecosystem services derived from wetland conservation practices in the United States Prairie Pothole Region with an 

emphasis on the U.S. Department of Agriculture Conservation Reserve and Wetlands Reserve Programs / edited 

by Robert A. Gleason, Murray K. Laubhan, and Ned H. Euliss, Jr.

p. cm. –(U.S. Geological Survey professional paper ; 1745)

Includes bibliographic references.

ISBN 978-1-4113-2017-8 (alk. paper)

1. Wetlands Reserve Program (U.S.) 2. Conservation Reserve Program (U.S.) 3. Ecosystem management--Prairie 

Pothole Region. 4. Restoration ecology--Prairie Pothole Region. 5. Wetland conservation--Prairie Pothole Region. 

I. Gleason, Robert A. II. Laubhan, Murray (Murray K.) III. Euliss, Ned H. IV. Geological Survey (U.S.) V. Series: 

Professional paper (Geological Survey (U.S.)) ; no. 1745.

QH76.E339 2008

639.9--dc22

2008003460
iii

Acknowledgments

Funding for this project was provided by U.S. Department of Agriculture (Farm Service Agency 

(FSA) and Natural Resources Conservation Service (NRCS)) and U.S. Geological Survey programs, including the Climate Change and Integrated Science Programs. For their assistance 

and cooperation, we thank personnel from U.S. Fish and Wildlife Service (Regions 3 and 6), 

NRCS, and FSA field offices; the Minnesota Department of Natural Resources; the South Dakota 

Department of Game, Fish and Parks; the Iowa Department of Natural Resources; and the many 

landowners in Iowa, Minnesota, Montana, North Dakota, and South Dakota, who granted 

access to private lands. We wish to thank the following people for review of this report: Art 

Allen, Norman Bliss, Barry Botnen, Colleen Charles, Edward DeKeyser, Diane Eckles, Qinfeng 

Guo, Daniel Hubbard, Skip Hyberg, Gregg Knutsen, Christine Negra, James Ringelman, Susan 

Skagen, Edward Steadman, and Bruce Wylie. Additionally, we thank Deb Buhl and Wesley 

Newton for statistical assistance, Raymond Finocchiaro for managing fieldwork, and Justin 

Askim, Bethany Baibak, Jesse Beckers, Nancy Fritz Cressey, Charlie Dahl, Jessica Elam, Chris 

Flannagan, Michaela Koenig, Greg Meyer, Greg Olson, Jason Riopel, Nichole Sayers, Jennie 

Skancke, Jeremy Todoroff, and Shane Trautner for conducting fieldwork.
iv

Contents

Acknowledgments........................................................................................................................................iii

Executive Summary—Ecosystem Services Derived From Wetland Conservation Practices in 

the United States Prairie Pothole Region with an Emphasis on the U.S. Department of 

Agriculture Conservation Reserve and Wetlands Reserve Programs ....................................1

Principal Findings..................................................................................................................................1

Plant Community Quality and Richness ...................................................................................1

Carbon Sequestration .................................................................................................................1

Floodwater Storage.....................................................................................................................2

Reduction of Sedimentation and Nutrient Loading................................................................2

Potential Wildlife Habitat Suitability.........................................................................................2

Chapter A: Background and Approach to Quantification of Ecosystem Services .............................3

Introduction............................................................................................................................................3

Background............................................................................................................................................4

Methods.........................................................................................................................................6

Report Format.............................................................................................................................12

References...........................................................................................................................................12

Chapter B: Plant Community Quality and Richness ...............................................................................15

Synopsis ...............................................................................................................................................15

Methods................................................................................................................................................15

Results. ..................................................................................................................................................16

Floristic Quality Index................................................................................................................17

Species Richness ......................................................................................................................17

Discussion............................................................................................................................................18

References...........................................................................................................................................22

Chapter C: Carbon Sequestration .............................................................................................................23

Synopsis ...............................................................................................................................................23

Methods................................................................................................................................................24

Data Collection...........................................................................................................................24

Data Analyses.............................................................................................................................24

Results. ..................................................................................................................................................24

Soil Organic Carbon ..................................................................................................................24

Vegetation Organic Carbon......................................................................................................25

Discussion............................................................................................................................................25

References...........................................................................................................................................30

Chapter D: Floodwater Storage.................................................................................................................31

Synopsis ...............................................................................................................................................31

Methods................................................................................................................................................31

Topographic Surveys.................................................................................................................31

Model Development ..................................................................................................................31

Estimating Water Storage, Upland Zones of Catchments, and Interception Areas.......32

Results. ..................................................................................................................................................32

Discussion............................................................................................................................................32

References...........................................................................................................................................34
v

Chapter E: Reduction of Sedimentation and Nutrient Loading ............................................................38

Synopsis ...............................................................................................................................................38

Methods................................................................................................................................................38

Results. ..................................................................................................................................................39

Discussion............................................................................................................................................40

References...........................................................................................................................................43

Chapter F: Proposed Approach to Assess Potential Wildlife Habitat Suitability on 

Program Lands................................................................................................................................45

Synopsis ...............................................................................................................................................45

Methods................................................................................................................................................46

Results. ..................................................................................................................................................48

Discussion............................................................................................................................................52

References...........................................................................................................................................56

Figures

A–1—A–5. Maps showing:

A–1. Conservation Effects Assessment Project (CEAP) Wetland Regional 

Assessment Areas...............................................................................................................4

A–2. Land use in the Prairie Pothole Region of the United States .......................................5

A–3. Extent of the Prairie Pothole Region in the United States, and locations of 

wetlands sampled by the U.S. Geological Survey during 1997 and 2004 in 

portions of Iowa, Minnesota, Montana, North Dakota, and South Dakota................7

A–4. Major Land Resource Areas defined by the U.S. Department of Agriculture 

in the Prairie Pothole Region of the United States.........................................................8

A–5. Location of sample points in the Prairie Pothole Region of the United States 

in portions of Iowa, Minnesota, Montana, North Dakota, and South Dakota ...........9

A–6. Plan and profile view of catchment zones .............................................................................11

A–7. Diagram showing wetland functions and ecological services expected to change 

along a condition gradient ranging from highly altered wetlands to relatively 

unaltered wetlands.....................................................................................................................13

B–1—F–2. Graphs showing:

B–1. Differences in floristic quality, native species richness, and nonnative 

species richness among catchment types....................................................................19

B–2. Differences in floristic quality, native species richness, and nonnative 

species richness between the upland and wetland zones within a 

catchment type ..................................................................................................................19

B–3. Floristic quality among land-use treatments in the upland and wetland 

zones of surveyed catchments in the glaciated plains and Missouri coteau 

physiographic regions ......................................................................................................20

B–4. Native species richness among land-use treatments in the upland and 

wetland zones of surveyed catchments in the glaciated plains and 

Missouri coteau physiographic regions ........................................................................20

B–5. Mean nonnative species richness among land-use treatments in the 

upland and wetland zones of surveyed catchments ...................................................21
vi

C–1. Soil organic carbon in the surface soil among land-use treatments 

in the upland and wetland zones of surveyed catchments in the 

glaciated plains and Missouri coteau physiographic regions...................................26

C–2. Soil organic carbon at soil depths between 15 and 30 cm among 

land-use treatments in the upland and wetland zones ...............................................26

C–3. Relationship of soil organic carbon content in the 0–15 cm soil depth to 

age of restored catchments by catchment zone and physiographic region...........27

C–4. Relationship of soil organic carbon content of restored catchments to 

restoration age and the Palmer Drought Severity Index ............................................29

D–1. Models developed to predict upland zone areas and wetland volumes 

for the primary physiographic regions of the Prairie Pothole Region ......................34

F–1. Land-use treatments prior to and following implementation of the 

Conservation Reserve Program in a single township in the glaciated 

plains of the Prairie Pothole Region...............................................................................53

F–2. Median, interquartile range, and 10–90 quantile range of vegetation 

obstruction measurements for nine land-use treatment/catchment type 

combinations in the vicinity of the Prairie Pothole Region township .......................55

Tables

A–1. Total area and estimated wetland area on lands enrolled in the Conservation 

Reserve and Wetlands Reserve Programs in the Prairie Pothole Region ..........................6

A–2. Numbers of wetlands sampled during 1997 in the Prairie Pothole Region 

by physiographic region, catchment type, and land-use treatment..................................10

A–3. Numbers of wetlands sampled during 2004 in the Prairie Pothole Region by 

physiographic region, catchment type, and land-use treatment .......................................10

A–4. Soil, vegetation, and morphological variables collected in catchments surveyed 

in 1997 and 2004 that are indicators of structure and function and that can be 

used to estimate various ecosystem variables .....................................................................12

A–5. Natural Resources Conservation Service and Farm Service Agency practices 

and standards commonly applied to Conservation Reserve Program and 

Wetlands Reserve Program lands in the Prairie Pothole Region.......................................13

B–1. Distribution of 263 wetland catchments based on land-use treatment, 

catchment type, and physiographic region that were evaluated in the 

Prairie Pothole Region ...............................................................................................................17

B–2. Number and percent of native and nonnative plant species recorded in 

263 catchments in the glaciated plains and Missouri coteau physiographic 

regions, 2004................................................................................................................................18

C–1. Net carbon gain stored in plant biomass when cultivated cropland is planted 

to perennial cover as part of the Conservation Reserve Program and Wetlands 

Reserve Program in the Prairie Pothole Region....................................................................28

D–1. Models developed to estimate wetland volume and upland zone area by 

physiographic region in the Prairie Pothole Region.............................................................33

D–2. Estimated area and maximum water storage volumes of wetlands enrolled in 

U.S. Department of Agriculture conservation programs in the Prairie Pothole 

Region...........................................................................................................................................35
vii

D–3. Estimated wetland zone areas, upland zone areas, and catchment areas of 

wetlands enrolled in U.S. Department of Agriculture conservation programs 

in the Prairie Pothole Region ....................................................................................................35

E–1. Revised Universal Soil Loss Equation factor values used to estimate average 

annual soil losses for cultivated croplands and conservation program lands ................39

E–2. Mean soil-loss values calculated by using the Revised Universal Soil Loss 

Equation........................................................................................................................................40

E–3. Potential reduction in total soil loss when cultivated croplands are 

converted to perennial cover as part of the U.S. Department of Agriculture 

Conservation Reserve and Wetlands Reserve Programs in the Prairie Pothole 

Region...........................................................................................................................................41

E–4. Estimated potential reduction in nitrogen and phosphorous loss when 

cultivated cropland is converted to perennial cover as part of the U.S. 

Department of Agriculture Conservation Reserve and Wetlands Reserve 

Programs in the Prairie Pothole Region..................................................................................46

F–1. Change in the number of suitable grassland patches for five grasslanddependent bird species in a Prairie Pothole Region township...........................................46

F–2. Range of visual obstruction measurements in the upland zone of 54 catchments 

sampled in the vicinity of the example township in the glaciated plains, and the 

range of visual obstruction estimates at nest sites of nine bird species reported 

in the literature............................................................................................................................47

F–3. Bird species recorded by observation from vantage points and one walking 

survey conducted prior to measuring vegetation and abiotic variables in 

263 catchments in the Prairie Pothole Region in 2004..........................................................49

F–4. Conservation status of avian species selected for evaluation...........................................52

F–5. Change in number of polygons and area of land-use classes prior to and 

following implementation of the Conservation Reserve Program in a single 

township in the glaciated plains of the Prairie Pothole Region..........................................54
viii

Conversion Factors

Inch/Pound to SI

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

acre 4,047 square meter (m2)

acre 0.4047 hectare (ha)

square foot (ft2) 0.09290 square meter (m2)

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2) 

Volume

cubic foot (ft3) 0.02832 cubic meter (m3) 

acre-foot (acre-ft) 1,233 cubic meter (m3)

acre-foot (acre-ft) 0.123 hectare meter (ha-m) 

acre-foot per acre (acre-ft∙acre-1) 0.3048 hectare meter per hectare (ha-m∙ha-1)

Mass

pound (lb) 454 gram (g)

pound (lb) 0.4536 kilogram (kg)

ton, short (2,000 lb) 0.9072 megagram (Mg)

ton per acre (ton∙acre-1) 2.24 megagram per hectare (Mg∙ha-1)

SI to Inch/Pound

Multiply By To obtain

Length

centimeter (cm) 0.3937 inch (in.)

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

Area

square meter (m2) 0.0002471 acre 

hectare (ha) 2.471 acre

square meter (m2) 10.76 square foot (ft2) 

hectare (ha) 0.003861 square mile (mi2) 

square kilometer (km2) 0.3861 square mile (mi2)

Volume

cubic meter (m3) 35.31 cubic foot (ft3)

cubic meter (m3) 0.0008107 acre-foot (acre-ft) 

hectare meter (ha-m) 8.107 acre-foot (acre-ft) 

hectare meter per hectare (ha-m∙ha-1) 3.281 acre-foot per acre (acre-ft∙acre-1)

Mass

gram (g) 0.0022 pound (lb)

kilogram (kg) 2.205 pound (lb)

megagram (Mg) 1.102 ton, short (2,000 lb)

megagram per hectare (Mg∙ha-1) 0.446 ton per acre (ton∙acre-1)
ix

List of Abbreviations

CEAP Conservation Effects Assessment Project

CRP Conservation Reserve Program

DOI United States Department of the Interior

FQI Floristic Quality Index

FSA Farm Service Agency

MLRA Major Land Resource Area

NLCD National Land Cover Data

NRCS Natural Resources Conservation Service

NRI National Resources Inventory

NWI National Wetlands Inventory

RUSLE Revised Universal Soil Loss Equation

SOC Soil Organic Carbon

USDA United States Department of Agriculture

USFWS United States Fish and Wildlife Service

USGS United States Geological Survey

VOC Vegetation Organic Carbon

WRP Wetlands Reserve Program
Executive Summary–Ecosystem Services Derived From 

Wetland Conservation Practices in the United States 

Prairie Pothole Region with an Emphasis on the U.S. 

Department of Agriculture Conservation Reserve and 

Wetlands Reserve Programs

Edited by Robert A. Gleason, Murray K. Laubhan, and Ned H. Euliss, Jr.

Implementation of the U.S. Department of Agriculture 

(USDA) Conservation Reserve Program (CRP) and Wetlands 

Reserve Program (WRP) has resulted in the restoration of 

approximately 2,200,000 ha (5,436,200 acres) of wetland 

and grassland habitats in the Prairie Pothole Region. These 

restored habitats are known to provide various ecosystem 

services; however, little work has been conducted to quantify 

and verify benefits on program lands (lands enrolled in the 

CRP and WRP) in agriculturally dominated landscapes of the 

Prairie Pothole Region. To address this need, the U.S. Geological Survey (USGS), in collaboration with the USDA Farm 

Service Agency and Natural Resources Conservation Service, 

initiated a study to develop and apply approaches to quantify 

changes in ecosystem services resulting from wetland restoration activities funded by the USDA. To accomplish this goal, 

the USGS conducted a comprehensive, stratified survey of 

204 catchments (wetland and surrounding uplands contributing runoff to the wetland) in 1997 and 270 catchments in 2004 

to gather data necessary for estimating various ecosystem 

services. In 1997 and 2004, the surveys included catchments 

with seasonal and semipermanent wetlands that were restored 

as part of USDA conservation programs, as well as nonprogram catchments in native prairie. Additionally, in 2004 data 

collection was expanded to include temporary wetlands for 

all treatments and nonprogram cropped catchments for all 

wetland classes: temporary, seasonal, and semipermanent. 

A key element in the sample design is that catchments span 

an alteration gradient ranging from highly altered, such as 

cropland, to minimally altered, such as native prairie. Therefore, we evaluated restoration programs by comparing changes 

in program (restored) catchments to nonprogram (cropland 

and native prairie) catchments. Information collected during 

both surveys included easily measured soil, vegetation, and 

morphological variables that were used to estimate the following ecosystem services: plant community quality and richness, 

carbon sequestration, floodwater storage, sediment and nutrient reduction, and potential wildlife habitat suitability. In this 

report, we evaluate the extent that these ecosystem services 

changed in restored wetlands relative to cropland and native 

prairie baselines. In most cases, our results indicate restoration 

activities funded by the USDA have positively influenced ecosystem services in comparison to a cropped wetland baseline; 

however, most benefits were only considered at a site-specific 

scale, and better quantification of off-site benefits associated 

with conservation programs will require detailed spatial data 

on all land areas enrolled in conservation programs.

Principal Findings

Plant Community Quality and Richness

Restoration practices improved upland floristic quality 

and native species richness relative to cropped catchments, but 

upland floristic quality and native species richness of restored 

catchments did not approach the full site potential as defined 

by native prairie catchments. In general, restoration activities also improved wetland floristic quality and native species 

richness relative to cropped wetland baselines; however, the 

magnitude and significance of change varied depending on 

physiographic region and response variable evaluated. Causal 

factors for these relationships were not examined, but they 

may be related to the frequency and extensiveness of cropping 

that can vary by catchment type (temporary, seasonal, semipermanent). Ultimately, determining the adequacy of restoration techniques solely on the basis of floristic quality and 

richness is ill advised because plant community composition 

can change rapidly in response to natural variation in abiotic 

factors and processes as well as in response to human-induced 

restoration and management activities.

Carbon Sequestration

Catchments with a history of cultivation, including those that have been restored and those with cropland, 

had less soil organic carbon (SOC) in the upper soil profile (0–15 cm [0–6 in]) than did native prairie catchments. 
Differences in SOC between native catchments and those 

with a cultivation history varied from 12 to 26 percent 

depending on physiographic region and catchment zone. 

On the basis of the average difference in SOC (15 Mg∙ha-1

[6.7 tons∙acre-1]) between restored and native prairie catchments, we estimate that restored catchments on program lands 

(444,574 ha [1,098,542 acres]) have the potential to sequester 

6,662,355 Mg (7,341,915 tons) of SOC, assuming that all such 

lands can assimilate carbon to the extent measured for native 

prairie. We did not detect a significant increase in SOC stocks 

in restored catchments relative to cropland baselines, nor were 

we able to demonstrate a relationship between carbon content 

and time since restoration. Explanations for our inability to 

detect changes in restored catchment SOC stocks are discussed. On the basis of published SOC sequestration rates, we 

estimate that catchments on program lands could sequester 

222,287 Mg∙yr-1 (244,960 tons∙yr-1) of SOC and, since enrollment, may have sequestered 2,712,714 Mg (2,989,411 tons) 

of SOC. In addition, 715,094 Mg (788,034 tons) of organic 

carbon may be stored in the plant biomass on program lands.

Floodwater Storage

We estimate that wetland catchments on program lands 

in the Prairie Pothole Region could intercept precipitation 

across approximately 444,574 ha (1,098,542 acres) and store 

approximately 56,513 ha-m (458,151 acre-ft) of water if 

wetlands filled to maximum capacity. This amount equates to 

an average storage volume of 0.34 ha-m∙ha-1 (1.1 acre-ft∙acre-1) 

of wetland. Our water storage estimates are likely conservative 

because the data we used tend to underestimate area of wetlands on program lands. Further, our estimates of maximum 

wetland water storage do not account for dynamic hydrologic 

processes that attenuate the rate at which wetlands fill and 

overflow. For example, establishment of perennial cover in 

upland catchments reduces water received by wetlands by 

enhancing evapotranspiration and soil water holding capacity 

and infiltration. Consequently, the potential flood storage service provided by wetlands is greater than the maximum water 

storage value reported in this study. Regardless, these estimates suggest that wetlands on program lands have significant 

potential to intercept and store precipitation that otherwise 

might contribute to “downstream” flooding; however, we 

could not quantify the potential floodwater storage services 

because detailed spatial data on the location of program lands 

and wetland resources in relation to contributing and noncontributing areas within watersheds currently are not available. 

Availability of such data will facilitate application of models 

to better quantify dynamic floodwater-storage benefits at both 

site-specific and watershed scales.

Reduction of Sedimentation and Nutrient 

Loading

Conversion of cultivated cropland to herbaceous perennial cover as part of the CRP and WRP reduced total soil loss 

from uplands (276,021 ha [682,048 acres]) by an estimated 

average of 1,760,666 Mg∙yr-1 (1,940,254 tons∙yr-1). For this 

area, we estimate that nitrogen and phosphorus losses would 

be reduced by 5,102 Mg∙yr-1 (5,622 tons∙yr-1) and 68 Mg∙yr-1

(75 tons∙yr-1), respectively. Assuming that reduction in 

annual losses remains static, we estimate a cumulative soil 

loss reduction of 21,156,125 Mg (23,314,050 tons) and a 

cumulative reduction in nitrogen and phosphorus losses of 

60,772 Mg (66,971 tons) and 798 Mg (879 tons), respectively, 

since restoration. A primary benefit of reduced soil erosion 

is that wetland depressions do not become filled and thereby 

maintain the topographic relief that is critical to sustaining all 

ecosystem services derived from wetlands. Reduction of soil 

erosion will almost certainly reduce the delivery of sediments 

to sensitive offsite ecosystems such as lakes, streams, and 

rivers; however, we did not evaluate the effects of this process 

with this study.

Potential Wildlife Habitat Suitability

We examined the effects of CRP enrollment on potential 

habitat suitability by comparing nesting area and vegetation obstruction measures in CRP tracts to published habitat 

requirements of 10 bird species in a single North Dakota 

township (93.2 km2 [36.0 mi2]). Effects of conservation 

programs included an increase in number of grassland areas 

that exceeded published nesting area requirements for the five 

area-sensitive grassland bird species that we evaluated and for 

which information was available. Published information on 

upland vegetation obstruction measurements at nesting sites 

was available for nine of the species evaluated. Comparisons 

of this information with vegetation obstruction data collected 

near the township indicate that restored seasonal catchments 

may provide suitable nesting habitat for all nine species. In 

contrast, restored temporary and restored semipermanent 

catchments may provide nesting habitat for seven and eight of 

the nine species, respectively. Our results suggest that restored 

catchments, regardless of wetland type, provide at least 

some necessary resources for a diversity of bird species that 

cropland catchments do not. The justification for this type of 

approach is discussed, as are the underlying assumptions and 

data requirements needed to apply the approach.

2 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Chapter A: Background and Approach to Quantification of Ecosystem Services

By Robert A. Gleason and Murray K. Laubhan

Introduction

Conservation programs administered by the U.S. Department of Agriculture (USDA) have significantly influenced 

landscape conditions in the Prairie Pothole Region of the 

United States. Approximately 2,200,000 ha (5,436,200 acres) 

in the Prairie Pothole Region are enrolled in either the Conservation Reserve Program (CRP) or Wetlands Reserve Program 

(WRP). The ecosystem services provided by lands in these 

programs are diverse, ranging from improvements in local and 

broad-scale environmental conditions, such as air and water 

quality, and reduction of hazard risks, such as floodwater storage, to an improved ability to conserve the Nation’s biological 

resources and provide increased recreational opportunities 

(Knutsen and Euliss, 2001; Allen and Vandever, 2003). Collectively, these services provide benefits valued by a broad 

spectrum of American society; however, the failure to quantify the full range of benefits provided by these programs has 

led to increasing scrutiny regarding their actual value. For 

example, the President’s Budget and Performance Integration 

Initiative requires that Federal programs demonstrate effectiveness, accurately account for the expenditure of program dollars, and document results achieved. Consequently, developing 

approaches that meet these new accountability guidelines is 

critical to ensuring the continued funding of Federal conservation programs. This is particularly relevant for both the CRP 

and WRP, which have not yet achieved a rating of “effective” 

according to the Program Assessment Rating Tool administered by the Office of Management and Budget.

In response to this need, the USDA Farm Service Agency 

(FSA) and the USDA Natural Resources Conservation Service 

(NRCS) pooled resources with the U.S. Department of the 

Interior (DOI) U.S. Geological Survey (USGS) to conduct a 

study to quantify the environmental effects of USDA and DOI 

wetland conservation practices in the Prairie Pothole Region. 

This collaborative venture was advantageous because the 

needs of each agency were valuable to the other agencies. A 

primary interest of the USDA was to quantify the environmental effects of conservation practices implemented by private 

landowners enrolled in USDA conservation programs, especially the CRP administered by the FSA and the WRP administered by the NRCS. Similarly, the DOI was interested in 

quantifying the effects of conservation practices implemented 

on private lands through the Partners for Fish and Wildlife 

Program (PFWP) administered by the U.S. Fish and Wildlife 

Service (USFWS). The PFWP is a primary mechanism for 

delivering voluntary on-the-ground habitat improvements on 

private lands for the benefit of trust species. In administering 

the PFWP program, the USFWS often works closely with the 

NRCS and the FSA to help deliver many Farm Bill conservation programs. This work also benefits the USGS mission 

of conducting research to provide science-based information for better management of the Nation’s natural resources, 

especially natural resources managed on public lands by the 

USFWS and other agencies within the DOI.

This study also addresses the Wetlands Component (other 

components include cropland, grazing land, and wildlife) 

of the USDA’s Conservation Effects Assessment Project 

(CEAP) National Assessment. The CEAP is a multiagency, 

national effort to develop science-based approaches to quantify and periodically report the status of ecosystem services 

derived from conservation practices implemented through 

Farm Bill programs. Conservation practices to be assessed 

through CEAP include, but are not limited to, conservation 

buffers, erosion control, wetlands conservation and restoration, wildlife habitat establishment, grazing, tillage, irrigation 

water, nutrient reduction, and pest control (Natural Resources 

Conservation Service, 2005). The CEAP Wetlands Component 

was initiated in 2004 and consists of 10 regional assessments 

conducted in agricultural landscapes (fig. A–1). The USDA 

selected the Prairie Pothole Region for the first assessment 

because a 1997 regional survey conducted by the USGS 

Northern Prairie Wildlife Research Center provided the only 

known regional database and study design that conformed to 

the conceptual framework of the CEAP Wetlands Component, 

including sampling USDA program wetlands along an alteration gradient to quantify ecosystem services. From a programmatic perspective, the Prairie Pothole Region also was ideal 

because conservation of depressional prairie pothole wetlands 

is achieved primarily on the basis of wetland compliance 

provisions (the “swampbuster” provision) of the 1985 Farm 

Bill, and a significant number and area of wetlands have been 

restored as part of the CRP and the WRP. In addition, Prairie 

Pothole Region wetlands are nationally and internationally 

critical habitats for avian species of economic and ecological 

importance, and restored prairie potholes have the potential to 

sequester significant amounts of atmospheric carbon (CO2-C) 

in soils, thus providing a greenhouse gas reduction service 

(Gleason and others, 2005; Euliss and others, 2006). Finally, 

the combined financial resources of the USDA and USGS provided an unprecedented opportunity to collaborate on quantifying wetland ecosystem services at a regional scale.

The goal of this report is to provide information describing the development and application of approaches used to 

estimate changes in five ecosystem services that result from 

implementation of conservation programs in the Prairie Pothole Region: restoration of native plant communities, atmospheric carbon sequestration, floodwater storage, reduction 

of sediment and nutrient inputs, and wildlife habitat enhancement. The focus is on prairie potholes, but plant community 

composition, soils, and topography of lands surrounding 

potholes also were evaluated because upland conditions 

Chapter A: Background and Approach to Quantification of Ecosystem Services 3
Figure A–1. Conservation Effects Assessment Project (CEAP) Wetland Regional Assessment Areas 

(http://www.nrcs.usda.gov/technical/NRI/ceap/wetlands.html).

are integral to understanding wetland processes and resulting benefits. The information contained in this report is of a 

general nature and is based on a combination of data collected 

and analyzed as part of this study and the authors’ collective 

knowledge of Prairie Pothole Region wetland ecosystems. 

Analyses of physical, chemical, and biological data are ongoing to develop and refine models to translate ecosystem structure and function into measures of ecosystem services; hence, 

this study is a work in progress. Although additional work 

is necessary to objectively evaluate and quantify ecosystem 

services derived from restoration programs, preliminary information in this report is intended to focus future discussions 

regarding approaches used to assess environmental benefits 

derived from restoration programs at a national scale.

Background

The Prairie Pothole Region of the Northern Great Plains 

covers about 900,000 km2 (347,490 mi2) and extends from the 

north-central United States to south-central Canada (Gleason 

and others, 2005). Historically, the Prairie Pothole Region was 

composed primarily of short-, mixed-, and tall-grass prairie 

interspersed with isolated wetlands and river systems that 

had tremendous natural resource value; however, the Prairie 

Pothole Region also is valuable for agricultural production, 

and activities associated with agriculture have a tremendous 

impact on native habitats. Drainage to enhance agricultural 

production has been the primary factor resulting in wetland 

loss (Dahl, 1990; Dahl and Johnson, 1991). From the 1780s to 

4 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Figure A–2. Land use in the Prairie Pothole Region of the United States.

the 1980s, wetland loss was approximately 89 percent in Iowa, 

42 percent in Minnesota, 27 percent in Montana, 49 percent in 

North Dakota, and 35 percent in South Dakota (Dahl, 1990). 

Remaining wetlands continue to be directly and indirectly 

impacted by numerous agricultural practices that can cause 

accelerated sedimentation rates (Martin and Hartman, 1987; 

Gleason and Euliss, 1998; Gleason and others, 2003), addition 

of agricultural chemicals and nutrients (Grue and others, 1989; 

Neely and Baker, 1989), unnatural variance in water-level 

fluctuations (Euliss and Mushet, 1996), and altered vegetative 

communities (Kantrud and Newton, 1996; Mushet and others, 

2002). Uplands in the Prairie Pothole Region have experienced 

similar loss and degradation. Since 1830, declines of native 

prairie exceed those reported for any other ecosystem in North 

America (Samson and Knopf, 1994). In the Prairie Pothole 

Region, tillage associated with agriculture has resulted in the 

loss of native prairie and has fragmented remaining grassland 

tracts (fig. A–2). Remaining tracts of native prairie also have 

been degraded by invasion of nonnative species, which is due 

to fire suppression, changes in herbivory, and introduction of 

Eurasian species (Johnson and others, 1994).

Restoration of wetland and grassland habitats on private 

lands in the Prairie Pothole Region has been an important 

activity of the DOI and the USDA. The most notable Federal 

restoration programs in the Prairie Pothole Region include the 

CRP and WRP. A 2005 USDA database indicates that there 

are approximately 2,166,049 ha (5,352,307 acres) of CRP and 

33,427 ha (82,598 acres) of WRP lands enrolled in the Prairie 

Pothole Region (table A–1). Sites restored generally are areas 

that were previously altered to facilitate production of agricultural crops. Thus, the most common wetland restoration 

techniques include eliminating unnatural drains to restore 

hydrology and planting vegetation to restore adjacent uplands.

A fundamental premise used to justify funding Federal 

conservation programs is the benefit to both program participants and society. For instance, participating landowners 

receive monetary incentives to alter management practices, 

which in turn improves various ecological services desired by 

Chapter A: Background and Approach to Quantification of Ecosystem Services 5
Table A–1. Total area and estimated wetland area on lands enrolled in the Conservation Reserve and Wetlands Reserve Programs 

in the Prairie Pothole Region.

[CRP, Conservation Reserve Program; WRP, Wetlands Reserve Program; SE, standard error; --, no data]

State

WRP1 CRP1 CRP and WRP

Total area, 

in hectares 

(acres)

Wetland area,

in hectares ± SE

(acres ± SE)

Total area, 

in hectares 

(acres)

Wetland area,

in hectares ± SE

(acres ± SE)

Total area, 

in hectares 

(acres)

Wetland area,

in hectares ± SE

(acres ± SE)

Iowa 11,376

(28,110)

5,076 ± 256

(12,543 ± 633)

53,183

(131,415)

24,172 ± 1,201

(59,729 ± 2,968)

64,559

(159,525)

29,248 ± 1,457

(72,272 ± 3,600)

Minnesota 8,633

(21,332)

3,168 ± 403

(7,828 ± 996)

167,349

(413,519)

51,848 ± 8,629

(128,116 ± 21,332)

175,982

(434,852)

55,016 ± 9,032

(135,945 ± 22,318)

Montana -- -- 411,127

(1,015,895)

2,996 ± 1,690

(7,403 ± 4,176)

411,127

(1,015,895)

2,996 ± 1,690

(7,403 ± 4,176)

North Dakota 3,239

(8,004)

199 ± 40

(492 ± 99)

1,099,218

(2,716,168)

61,669 ± 12,558

(152,384 ± 31,031)

1,102,457

(2,724,171)

61,868 ± 12,598

(152,876 ± 31,130)

South Dakota 10,179

(25,152)

539 ± 111

(1,332 ± 274)

435,172

(1,075,310)

18,887 ± 4,442

(46,670 ± 10,976)

445,351

(1,100,462)

19,426 ± 4,553

(48,002 ± 11,250)

Total 33,427

(82,598)

8,982 ± 810

(22,195 ± 2,002)

2,166,049

(5,352,307)

159,572 ± 28,520

(394,302 ± 70,473)

2,199,476

(5,434,905)

168,554 ± 29,330

(416,497 ± 72,474)

1

 Total area based on the 2005 U.S. Department of Agriculture (USDA) Natural Resources Conservation Service national WRP database and on the 2005 

USDA Farm Service Agency national CRP database. Wetland areas in each program were estimated by multiplying total area by the average percentage of 

wetland area on cropland that was estimated by using the 1997 National Resources Inventory (U.S. Department of Agriculture, 2000).

the American public (National Academy of Sciences, 2004). 

The most frequently mentioned ecological services include 

enhancing fish and wildlife habitat, improving water quality, reducing sedimentation and nutrient loading, increasing 

floodwater retention, recharging ground-water supplies, 

conserving biological diversity, sequestering carbon, and 

increasing opportunities for recreation (Knutsen and Euliss, 

2001); however, efforts to quantify changes in these ecological 

services resulting from Federal programs have been minimal. 

Consequently, developing approaches to quantify the efficacy 

of conservation programs is especially important, particularly 

because both the CRP and the WRP are scheduled for program assessment in the near future. The goal of the Prairie 

Pothole Region Regional Assessment was to address this need 

by exploring the development and application of approaches 

that facilitate estimation of ecological services resulting from 

restoration activities funded by USDA conservation programs.

Methods

Our study was conducted in the United States portion 

of the Prairie Pothole Region, which encompasses more 

than 300,000 km2 (115,830 mi2) and includes portions of 

Iowa, Minnesota, Montana, North Dakota, and South Dakota 

(fig. A–3). Major physiographic regions in the Prairie Pothole 

Region are of glacial origin and include the Missouri coteau, 

prairie coteau, and glaciated plains (also known as drift 

prairie) (fig. A–3). Boundaries of these physiographic regions 

correspond relatively well with the following nine Major 

Land Resource Areas (MLRAs) defined by the USDA (U.S. 

Department of Agriculture, 1981): 53A, 53B, 53C, 55C, 102B, 

55A, 55B, 102A, and 103 (fig. A–4). The Missouri and prairie 

coteaus were formed by stagnant and dead-ice moraines that 

created a rugged area of closely spaced hills and depressions 

(Bluemle, 2000). In contrast, the glaciated plains region was 

formed primarily as a result of ground-moraine processes that 

created a gently rolling landscape. Climate of the region varies 

along a northwest-to-southeast gradient, with precipitation and 

temperature increasing toward the southeast (Visher, 1966). 

Collectively, these factors influence agricultural production 

in the Prairie Pothole Region, including spatial and temporal 

extent of wetland drainage and cropping practices (Galatowitsch and van der Valk, 1994). On the basis of 2005 USDA 

data, 2,199,476 ha (5,434,905 acres) of land in the Prairie 

Pothole Region is enrolled in the CRP and WRP (table A–1). 

Detailed spatial data, such as location and area, of all wetland resources on CRP and WRP lands were not available at 

the time of this report; however, we estimated lands enrolled 

in these programs encompassed approximately 168,554 ha 

(416,497 acres) of wetlands (table A–1).

We designed a comprehensive survey of 204 wetlands 

in 1997 and of 270 catchments (wetland and surrounding 

uplands contributing runoff to the wetland) in 2004 (fig. A–3) 

to gather data necessary for estimating the following ecosystem services: plant community composition, carbon sequestration, floodwater storage, sediment and nutrient reduction, 

and wildlife habitat. During 1997, a systematic sampling 

design stratified by physiographic region was used to select 

6 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Figure A–3. Extent of the Prairie Pothole Region in the United States, and locations of wetlands sampled by the U.S. Geological 

Survey (USGS) during 1997 and 2004 in portions of Iowa, Minnesota, Montana, North Dakota, and South Dakota.

a representative spatial sample of catchments along the 

northwest-to-southeast climate and land-use gradients in the 

Prairie Pothole Region. Along the natural orientation of each 

physiographic region, we systematically identified 9 sample 

points in the Missouri coteau, 3 in the prairie coteau, and 12 

in the glaciated plains (fig. A–5). Allocation of sample points 

was proportional to the linear length of each physiographic 

region. Near each sample point, we located and obtained 

permission to survey seasonal and semipermanent wetlands 

(Class III and IV wetlands) (Stewart and Kantrud, 1971) subjected to each of the following land-use treatments:

1. Partially restored drained wetlands: wetlands that had 

been drained but whose upland zones of catchments were 

planted to perennial cover as part of USDA or similar 

restoration programs. The hydrology was altered since the 

drains were not plugged, and because of active drainage 

prior to partial restoration, these wetlands were farmed 

more frequently than nondrained wetlands.

2. Hydrologically restored wetlands in two age classes 

(restored less than 5 years and more than 5 years): 

previously drained wetlands that had been restored by 

plugging drains and planting upland zones of catchments 

to perennial cover as part of USDA or similar restoration 

programs. Because of active drainage prior to restoration, 

these wetlands were farmed more frequently than nondrained wetlands.

3. Nondrained restored wetlands: wetlands that had not 

been drained but whose upland zones of catchments were 

restored by planting perennial cover as part of USDA or 

similar restoration programs. Prior to restoration, these 

nondrained wetlands were farmed less frequently than 

actively drained wetlands.

4. Native prairie wetlands: wetlands that had not been 

drained and whose upland zones of catchments are composed of native prairie vegetation. There was no history of 

cultivation in the wetland or upland zones of catchments.

Chapter A: Background and Approach to Quantification of Ecosystem Services 7
Figure A–4. Major Land Resource Areas defined by the U.S. Department of Agriculture in the Prairie Pothole Region of the United 

States. Symbols represent locations of wetlands sampled by the U.S. Geological Survey (USGS) during 1997 and 2004.

Ideally, the 1997 survey should have resulted in selection of 240 wetlands, but not all land-use treatment and 

wetland type combinations occurred near each sampling 

point; therefore, the sampling effort resulted in selection of 

only 204 wetlands (fig. A–3 and table A–2). For the 2004 

survey, a subsample of points used during the 1997 survey 

was used, and data collection was expanded to include entire 

catchments and a broader spectrum of wetland types. These 

design changes were implemented to enable comparisons of 

ecological services provided by restored catchments relative 

to both cropland and native prairie catchments. Of the original 

21 sample points selected during 1997 in the Missouri coteau 

(n = 9) and glaciated plains (n = 12), 5 points in the Missouri 

coteau (MC01, MC03, MC05, MC07, MC09) and 5 points in 

the glaciated plains (GP01, GP03, GP05, GP09, GP11) were 

selected for sampling in 2004 (fig. A–5). Near each sampling point we attempted to locate a temporary, seasonal, and 

semipermanent depressional wetland subjected to each of the 

following land-use treatments:

1. Hydrologically restored wetlands in three age classes 

(restored less than 5 years, 5–10 years, and more than 

10 years): previously drained wetlands that had been 

restored by plugging drains and planting upland zones of 

catchments to perennial cover as part of USDA or similar 

restoration programs. Because of active drainage prior to 

restoration, these wetlands were farmed more frequently 

than nondrained wetlands.

2. Nondrained restored wetlands in three age classes 

(restored less than 5 years, 5–10 years, and more than 

10 years): wetlands that had not been drained but whose 

upland zones of catchments were restored by planting 

perennial cover as part of USDA or similar restoration 

programs. Prior to restoration, these nondrained wetlands 

were farmed less frequently than actively drained wetlands.

3. Drained cropland wetlands: wetlands that had been 

drained and whose upland zones of catchments were 

8 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Figure A–5. Location of sample points in the Prairie Pothole Region of the United States in portions of Iowa, Minnesota, Montana, 

North Dakota, and South Dakota. All glaciated plains (GP01–GP12), Missouri coteau (MC01–MC09), and prairie coteau (PC01–PC03) 

points were used during the 1997 survey, whereas a subsample (circled points) of points was used during the 2004 survey.

predominantly cropland. Because of active drainage, 

wetlands were farmed more frequently than nondrained 

wetlands.

4. Nondrained cropland wetlands: wetlands that had not 

been drained and whose upland zones of catchments were 

predominantly cropland. Wetlands were farmed, but with 

less frequency than actively drained wetlands.

5. Native prairie wetlands: wetlands that had not been 

drained and whose upland zones of catchments were composed of native prairie. There was no history of cultivation 

in the wetland or upland zones of catchments.

The 2004 sampling effort resulted in selection of 

270 catchments, of which 52 had been sampled during the 

1997 survey (fig. A–3 and table A–3). The 2004 survey differed from the 1997 survey by including upland areas that 

surround wetlands, adding temporary and cropped wetland 

catchments as land-use categories, eliminating partially 

restored wetlands as a land-use category, and separating 

nondrained restored wetlands into categories on the basis of 

restoration age.

Data within each catchment were collected along four 

transects originating in the center of the wetland and extending outward in cardinal directions to the catchment boundary. 

Along each transect, we identified wetland catchment subzones (wet-meadow, shallow-marsh, and deep-marsh) (Stewart 

and Kantrud, 1971) and upland catchment subzones (toeslope, mid-slope, and shoulder-slope) that bisected the transect 

(fig. A–6). Soil and vegetation data were collected at the 

midpoint of each subzone. A topographic survey of the entire 

catchment was completed, and the spatial locations of samples 

were recorded by using the Global Positioning System. Additional details on data collection methods are described in chapters B–F. During the 1997 survey, only wetland subzones were 

surveyed, whereas both upland and wetland subzones were 

Chapter A: Background and Approach to Quantification of Ecosystem Services 9
Table A–2. Numbers of wetlands sampled during 1997 in the Prairie Pothole Region by physiographic region, catchment type, and 

land-use treatment.

Catchment type

Restored lands

Native prairie

Hydrologic restoration

Nondrained

restoration

Partially restored

drained

Years restored

<5 years >5 years

Glaciated plains

Seasonal 11 11 12 12 12

Semipermanent 4 10 9 9 10

Missouri coteau

Seasonal 5 12 9 7 9

Semipermanent 4 8 8 3 9

Prairie coteau

Seasonal 3 3 3 3 3

Semipermanent 3 3 3 3 3

Table A–3. Numbers of wetlands sampled during 2004 in the Prairie Pothole Region by physiographic region, catchment type, and 

land-use treatment.

[Numbers in parentheses represent wetlands that were also sampled during the 1997 survey]

Catchment type

Restored lands1

Croplands

Native prairie

Hydrologic restoration Nondrained restoration

Years restored Years restored

1–5 5–10 >10 1–5 5–10 >10 Drained

Nondrained

Glaciated plains

Temporary 6 1 0 5 7 8 4 6 5

Seasonal 9 4 (2) 7 (6) 4 2 7 (2) 5 6 5 (3)

Semipermanent 5 5 (3) 7 (5) 4 4 (1) 5 (1) 3 6 5 (3)

Missouri coteau

Temporary 5 4 7 4 3 8 5 5 5

Seasonal 4 8 (2) 6 (4) 6 6 8 (5) 7 6 5 (4)

Semipermanent 3 1 5 (3) 3 3 5 (4) 3 5 5 (4)

1

 Of the restored wetlands, 130 were located on lands enrolled in U.S. Department of Agriculture Conservation Reserve Program or Wetlands Reserve 

Program, and 49 wetlands occurred on sites restored through other, non-USDA programs.

surveyed in 2004. Further, all catchments surveyed contained 

the three upland subzones, but the number of wetland subzones varied depending on the class of wetland occupying the 

catchment. Typically, temporary catchments only supported 

a wet-meadow subzone, seasonal catchments supported a 

wet-meadow and shallow-marsh subzone, and semipermanent 

catchments supported a wet-meadow, shallow-marsh, and 

deep-marsh subzone.

Information collected during both surveys included 

measurements of soil, vegetation, and morphological variables 

that are indicators of structure and function and that are useful 

in estimating various ecosystem services (table A–4). A key 

element in the sample design is that land-use treatments span 

an alteration gradient ranging from highly altered (cropland 

catchments) to minimally altered (native prairie catchments). 

Therefore, a “reference-based” approach (Smith and others, 

1995; Brinson and Rheinhardt, 1996) can be applied to assess 

how program wetlands (restored catchments) have changed 

relative to nonprogram wetlands (cropland and native prairie 

catchments) along the alteration gradient (fig. A–7). Restored 

10 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Figure A–6. Plan and profile view of catchment zones. The upland zone is the area contributing surface runoff 

to the wetland zone and is composed of three subzones based on landscape position: shoulder-slope, mid-slope, 

and toe-slope. All subzones are present in an upland zone regardless of catchment type (temporary, seasonal, 

semipermanent). The wetland zone is delineated on the basis of the location of hydrophytes and is composed of 

one to three subzones depending on catchment type: temporary catchments have a wet-meadow zone, seasonal 

catchments have wet-meadow and shallow-marsh zones, and semipermanent catchments have wet-meadow, 

shallow-marsh, and deep-marsh zones. Size and location of wetland zones fluctuate within and among years 

depending on hydrologic condition (wet/dry periods). The interception area is equivalent to the entire catchment 

area (both upland and wetland zones).

Overflow/spill

elevation

Shoulder-slope

Mid-slope

Toe-slope

Upland catchment

zone

Upland subzones

Deep-marsh

Shallow-marsh

Wet-meadow

Wetland catchment

zone

Wetland subzones

Shoulder-slope

Mid-slope

Toe-slope

Shallow-marsh

Deep-marsh

Wet-meadow

Overflow/spill

elevation

Catchment

Upland catchment

zone

Wetland catchment

zone

Overflow/spill

elevation

Shoulder-slope

Mid-slope

Toe-slope

Upland catchment

zone

Upland subzones

Deep-marsh

Shallow-marsh

Wet-meadow

Wetland catchment

zone

Wetland subzones

Shoulder-slope

Mid-slope

Toe-slope

Shallow-marsh

Deep-marsh

Wet-meadow

Overflow/spill

elevation

Catchment

Upland catchment

zone

Wetland catchment

zone

Chapter A: Background and Approach to Quantification of Ecosystem Services 11
Table A–4. Soil, vegetation, and morphological variables 

collected in catchments surveyed in 1997 and 2004 that are 

indicators of structure and function and that can be used to 

estimate various ecosystem services.

[C, carbon; P, phosphorus; N, nitrogen]

Variable Measure

Soils Nutrients (C, P, N)

pH

Electric conductance

Bulk density

Texture

Soil horizon description

Redox characteristics

Soil consistency

Vegetation Composition

Cover estimates

Litter depth

Biomass

Visual obstruction

Width of zones

Morphology Area

Overflow/spill elevation

Relief

Volume

wetlands included in our sample are representative of wetlands restored on CRP and WRP lands. Although the CRP is 

administered by the FSA, the NRCS establishes technical land 

eligibility determinations, provides conservation planning, 

and is involved with practice implementation. Consequently, 

a similar suite of NRCS practice standards are used on both 

CRP and WRP lands to restore wetlands and adjacent upland 

ecosystems. Table A–5 provides the most commonly applied 

NRCS practice standards in the Prairie Pothole Region. A key 

element of the phrase “adjacent upland ecosystems” is that 

the upland zone surrounding a restored wetland is planted 

to perennial cover by using various conservation practices 

(table A–5). Consequently, for many of the ecosystem functions and services considered in this report, it is not appropriate to delineate spatial boundaries between the wetland and the 

adjacent upland ecosystem (National Academy of Sciences, 

2004). Likewise, attempting to quantify ecosystems services 

for each “program practice” applied would not be possible or 

appropriate since wetland functions and processes are intimately linked to the surrounding upland ecosystem.

Report Format

The objective of this report is to present preliminary 

findings on existing ecosystem services provided by Prairie 

Pothole Region wetland catchments subjected to different 

land-use treatments. Chapter A (this section) describes the 

impetus for the report and provides general information on 

the study area, overall study design, and sampling approach 

used during the 1997 and 2004 surveys. Chapters B–F contain 

information on individual ecosystem services as follows: plant 

community quality and richness (chap. B), carbon sequestration (chap. C), floodwater storage (chap. D), reduction of sedimentation and nutrient loading (chap. E), and wildlife habitat 

(chap. F). Each chapter includes a synopsis and methods, 

results, discussion, and references cited sections. The methods 

section in each chapter identifies which survey data (1997, 

2004) were used and how data were collected and analyzed 

to quantify the ecosystem service. To reduce redundancy of 

methods among chapters, information regarding sampling 

design and terminology used in the report is presented only in 

chapter A.

References

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: Denver, Colo., U.S. Government 

Printing Office, Biological Science Report, USGS/BRD/

BSR–2003–0001, 51 p.

Bluemle, J.P., 2000, The face of North Dakota—the geologic 

story (3d ed.): Bismarck, North Dakota Geological Survey 

Educational Series 26.

Brinson, M.M., and Rheinhardt, R., 1996, The role of reference wetlands in functional assessment and mitigation: 

Ecological Applications, v. 6, p. 69–76.

Dahl, T.E., 1990, Wetland losses in the United States 1780s to 

1980s: Washington, D.C., U.S. Department of the Interior, 

Fish and Wildlife Service.

Dahl, T.E., and Johnson, C.E., 1991, Status and trends of 

wetlands in the coterminous United States, mid-1970s to 

mid-1980s: Washington, D.C., U.S. Department of the 

Interior, Fish and Wildlife Service.

Euliss, N.H., Jr., Gleason, R.A., Olness, A., McDougal, R.L., 

Murkin, H.R., Robarts, R.D., Bourbonniere, R.A., and 

Warner, B.G., 2006, North American prairie wetlands are 

important nonforested land-based carbon storage sites: 

Science of the Total Environment, v. 361, p. 179–188.

Euliss, N.H., Jr., and Mushet, D.M., 1996, Water-level 

fluctuation in wetlands as a function of landscape condition 

in the prairie pothole region: Wetlands, v. 16, p. 587–593.

12 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Figure A–7. Wetland functions and ecological services expected to change along a condition 

gradient ranging from highly altered wetlands to relatively unaltered wetlands.

Reduction of soil

erosion and

sedimentation

Carbon

sequestration

Floodwater

storage

Relatively

unaltered

Condition

gradient

Highly

altered

Condition

gradient

Nutrients

Pesticides

Water quality

Habitat

Invasive species

Biodiversity

Condition

gradient

Highly

altered

Condition

gradient

Element cycling and transformation

Trophic structure support

Organic matter production and cycling

Surface-water storage

Support of plant community dynamics

Functions

Ground-water recharge

Table A–5. Natural Resources Conservation Service and Farm Service Agency practices and standards commonly applied to 

Conservation Reserve Program and Wetlands Reserve Program lands in the Prairie Pothole Region.

[FSA, Farm Service Agency; CRP, Conservation Reserve Program; NRCS, Natural Resources Conservation Service; CP, conservation practice]

NRCS practice standards

(code-practice: purpose)

FSA CRP conservation practices

CP1-Establishment 

of permanent 

introduced grasses 

and legumes

CP2-Establishment 

of permanent 

native grasses

CP23-Wetland 

restoration

327-Conservation Cover: To reduce soil erosion and sedimentation, 

improve water quality, and enhance wildlife habitat.

X X

644-Wetland Wildlife Habitat Management: To maintain, develop, 

or improve habitat for waterfowl, furbearers, or other wetland 

associated flora and fauna.

X X X

657-Wetland Restoration: To restore hydric soil, hydrologic conditions, hydrophytic plant communities, and wetland functions that 

occurred on disturbed wetland sites prior to modification to the 

extent practicable.

X

659-Wetland Enhancement: To modify the hydrologic condition, 

hydrophytic plant communities, and/or other biological habitat 

components of wetlands to favor specific wetland functions or 

values.

X

587-Structure for Water Control: To control the stage, discharge, 

distribution, delivery, or direction of water flow.

X

Chapter A: Background and Approach to Quantification of Ecosystem Services 13
Galatowitsch, S.M., and van der Valk, A.G., 1994, Restoring 

prairie wetlands—an ecological approach: Ames, Iowa State 

University Press.

Gleason, R.A., and Euliss, N.H., Jr., 1998, Sedimentation of 

prairie wetlands: Great Plains Research, v. 8, p. 97–112.

Gleason, R.A., Euliss, N.H., Jr., Hubbard, D.E., and Duffy, 

W.G., 2003, Effects of sediment load on emergence of 

aquatic invertebrates and plants from wetland soil egg and 

seed banks: Wetlands, v. 23, p. 26–34.

Gleason, R.A., Euliss, N.H., Jr., McDougal, R.L., and Kermes, 

K.E., 2005, Potential of restored prairie wetlands in the 

glaciated North American prairie to sequester atmospheric 

carbon: Grand Forks, N. Dak., Energy and Environmental 

Research Center, Plains CO2 Reduction Partnership topical 

report August 2005.

Grue, C.E., Tome, M.W., Messmer, T.A., Henry, D.B., Swanson, G.A., and DeWeese, L.R., 1989, Agricultural chemicals 

and prairie pothole wetlands—meeting the needs of the 

resource and the farmer U.S. perspective: Transactions of 

the North American Wildlife and Natural Resources Conference, v. 54, p. 43–58.

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.

Kantrud, H.A., and Newton, W.E., 1996, A test of vegetationrelated indicators of wetland quality in the prairie pothole 

region: Journal of Aquatic Ecosystem Health, v. 5, 

p. 177–191.

Knutsen, G.A., and Euliss, N.H., Jr., 2001, Wetland restoration 

in the prairie pothole region of North America—a literature 

review: U.S. Geological Survey, Biological Resources 

Division, Biological Science Report, USGS/BRD/BSR 

2001–0006.

Martin, D.B., and Hartman, W.A., 1987, The effect of cultivation on sediment and deposition in prairie pothole wetlands: 

Water, Air, and Soil Pollution, v. 34, p. 45–53.

Mushet, D.M., Euliss, N.H., Jr., and Shaffer, T.L., 2002, 

Floristic quality assessment of one natural and three 

restored wetland complexes in North Dakota, USA: 

Wetlands, v. 22, p. 126–138.

National Academy of Sciences, 2004, Valuing ecosystem 

services—toward better environmental decision-making: 

Washington, D.C., The National Academies Press.

Natural Resources Conservation Service, 2005, Conservation 

Effects Assessment Project (CEAP), background-scope: 

U.S. Department of Agriculture CEAP Web site, accessed 

August 10, 2006, at http://www.nrcs.usda.gov/technical/

NRI/ceap/about.html

Neely, R.K., and Baker, J.L., 1989, Nitrogen and phosphorus 

dynamics and the fate of agricultural runoff, in van der 

Valk, A., ed., Northern prairie wetlands: Ames, Iowa State 

University Press, p. 92–131.

Samson, F.B., and Knopf, F.L., 1994, Prairie conservation in 

North America: Bioscience, v. 44, p. 418–421.

Smith, R.D., Ammann, A., Bartoldus, C., and Brinson, M., 

1995, An approach for assessing wetland functions using 

hydrogeomorphic classification, reference wetlands, and 

functional indices: Vicksburg, Miss., U.S. Army Corps 

of Engineers, Waterways Experiment Station, Technical 

Report WRP–DE–9.

Stewart, R.E., and Kantrud, H.A., 1971, Classification of natural ponds and lakes in the glaciated prairie region: Washington, D.C., U.S. Department of the Interior, Fish and Wildlife 

Service, Resource Publication 92.

U.S. Department of Agriculture, 1981, Land resource regions 

and major land resource areas of the United States. Agricultural Handbook No. 296: Washington, D.C., U.S. Department of Agriculture Soil Conservation Service, 156 p.

U.S. Department of Agriculture, 2000, Summary report—1997 

national resources inventory (revised December 2000): 

Washington, D.C., Natural Resources Conservation Service.

Visher, S.S., 1966, Climatic atlas of the United States: Cambridge, Mass., Harvard University Press.

14 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Chapter B: Plant Community Quality and Richness

By Murray K. Laubhan and Robert A. Gleason

Synopsis

One of the most observable effects following restoration activities is the rapid development of plant communities. 

Plants are the foundation of natural ecosystems because they 

capture solar energy through photosynthesis and store it as 

chemical energy in plant biomass that can be transferred to 

other trophic levels in the ecosystem. For example, photosynthetic energy is converted to animal biomass when plant 

material is ingested by primary consumers, such as herbivores, 

and atmospheric carbon captured through photosynthesis and 

stored in aboveground and belowground biomass results in 

carbon sequestration benefits (see chap. C). Decomposition 

of root systems facilitates development of soil organic matter 

that improves soil fertility, structure, aggregation, and waterholding capacity, whereas aboveground plant cover reduces 

the velocity and amount of surface water runoff, soil erosion, 

and sedimentation of wetland basins (see chaps. D and E). 

Plant community composition also determines the diversity 

of foods and cover types available for wildlife (see chap. F). 

Hence, a diversity of vegetation is the underpinning of most 

ecological services derived from restoration programs.

The objective of this chapter is to evaluate the impacts 

of conservation programs on vegetation composition. We 

compared floristic quality and species richness of temporary, 

seasonal, and semipermanent catchments in cropped, restored, 

and native prairie treatments in the glaciated plains and Missouri coteau physiographic regions of the Prairie Pothole 

Region of the United States. We selected floristic quality and 

richness because these measures not only characterize plant 

community composition but also directly and indirectly influence numerous other ecological services. Cropped treatments 

included catchments that were actively farmed, whereas native 

prairie treatments included catchments with no prior history 

of disturbance related to crop production. Restored treatments 

included wetlands that had been restored by plugging drains 

(if present) to restore hydrology and planting uplands surrounding wetlands to perennial cover.

In general, floristic quality of the upland and wetland 

zones of restored catchments was significantly greater than 

that of the cropland baseline but lower than that of native 

prairie catchments in both the glaciated plains and Missouri 

coteau. The only exception to this trend was similar floristic 

quality in the wetland zones of restored and native prairie 

catchments in the glaciated plains. Catchment type also 

influenced floristic quality independent of treatment. Factors contributing to observed differences among treatments 

were not investigated; however, planting native vegetation 

rather than agricultural crops and differences in the number of 

nonnative species influenced upland floristic quality. Further, 

direct and indirect changes in hydrology from hydrologic and 

nonhydrologic restorations and establishment of native species 

with different coefficients of conservatism influenced wetlands 

floristic quality. Although the restoration strategies evaluated 

in this study improved floristic quality as compared to cropland baselines, full recovery to native conditions likely will 

require additional time and/or manipulations to reduce nonnative species and stimulate recruitment of additional native 

grasses and forbs from the seed bank.

Methods

The floristic quality index (FQI) method and species 

richness of native and nonnative species were used to assess 

the impact of land-use treatment on plant community quality 

and composition. The FQI method is based on the concept that 

plants respond rapidly to both improvement and degradation 

of systems (Northern Great Plains Floristic Quality Assessment Panel, 2001; Ervin and others, 2005) because individual 

species display varying degrees of fidelity to specific habitats and differ in the ability to tolerate disturbance (Swink 

and Wilhelm, 1979, 1994). Each native species in a region is 

assigned a score (coefficient of conservatism [C]) of 0–10, 

with species exhibiting low tolerance to disturbance and high 

fidelity to a specific habitat receiving higher scores. Therefore, 

FQI provides a standardized approach that enables comparisons among different sites and different habitat management 

and restoration efforts (Northern Great Plains Floristic Quality 

Assessment Panel, 2001). The equation used to calculate FQI 

is as follows:

FQI = × C N ,

where

C

C

N = ∑ , and

N = number of native plants.

This formula does not incorporate nonnative species—

these species evolved disjunct from the native regional flora 

and cannot be used in natural area assessments (Swink and 

Wilhelm, 1979, 1994)—however, excluding nonnative species 

may result in overestimation of ecological integrity because 

the presence of even one exotic species may have significant 

impacts on wetland health (Ervin and others, 2005). This concept is particularly relevant because we evaluated catchments 

across a broad disturbance gradient that included highly disturbed environments, such as drained cropland, that potentially 

could support numerous nonnative species and, in some cases, 

no native species. Therefore, we used the following modified 

Chapter B: Plant Community Quality and Richness 15
FQI equation that incorporates total species richness and the 

proportional richness of native to nonnative species:

FQI = × ∑C

S

N

S ,

where

S = total number of all species encountered.

This equation originally was proposed for use with 

wetness coefficients rather than C values (Ervin and others, 

2005), but we retained the use of C values assigned to species 

in North and South Dakota and adjacent grasslands (Northern 

Great Plains Floristic Quality Assessment Panel, 2001).

We used only 2004 survey data in this analysis because 

upland vegetation was not collected during the 1997 survey 

(fig. A–3). Vegetation data was collected on four transects that 

radiated from the center of the wetland and extended in cardinal directions to the catchment boundary. Along each transect, we located a 1-m2

 (10.8-ft2) quadrat at the midpoint of 

each catchment subzone (fig. A–6). Within each quadrat, we 

recorded all plant species, vegetation cover of each taxon by 

ocular estimation (Daubenmire, 1959), and litter depth (cm). 

Portions of a quadrat devoid of vegetation were categorized as 

either bare or open water. Of 270 catchments surveyed in 2004 

(table A–3 and fig. A–3), 263 catchments were included in 

the analysis (table B–1) (7 catchments were excluded because 

they were restored prior to implementation of the CRP and 

WRP). We calculated FQI separately for upland and wetland 

zones of each catchment by combining data from the three 

highest (shoulder-slope, mid-slope, toe-slope) and three lowest (wet-meadow, shallow-marsh, deep-marsh) topographic 

zones, respectively (fig. A–6). All catchments contained the 

three upland zones, but the number of wetland zones varied 

depending on wetland class within the catchment. In general, 

one wetland zone (wet-meadow) occurred in temporary catchments, two zones (wet-meadow and shallow-marsh) occurred 

in seasonal catchments, and three zones (wet-meadow, 

shallow-marsh, and deep-marsh) occurred in semipermanent 

catchments.

Although the equation used to calculate FQI incorporates 

nonnative species, a separate analysis of species richness was 

conducted to compare native and nonnative taxa among landuse treatments in each catchment type. This information provides additional insight into plant community composition and 

interpretation of the FQI (Kantrud and Newton, 1996). Each 

plant species was classified as native or nonnative on the basis 

of information published by the Northern Great Plains Floristic Quality Assessment Panel (2001) to maintain consistency 

between the two analyses. Each catchment was divided into 

an upland zone and wetland zone as described in the previous 

paragraph, and the mean richness of native and nonnative taxa 

was calculated separately for each zone.

Analysis of variance (ANOVA) was used to assess the 

influence of land-use treatment on FQI and species richness. Sample points used as focal areas to originally select 

catchments were included as a blocking factor (fig. A–5). The 

model for both FQI and species richness included physiographic region (Missouri coteau, glaciated plains), catchment 

type (temporary, seasonal, semipermanent), catchment zone 

(upland, wetland), land-use treatment (drained and nondrained 

cropland, nondrained and hydrologically restored, and native 

prairie), and all possible interactions as independent variables. 

For significant main effects and interaction terms, we tested 

for differences among the following categories: (1) cropped 

(drained and nondrained cropped categories), (2) restored 

(hydrologically restored and nondrained restored categories 

of all ages), and (3) native (native prairie category). The two 

cropped treatments were combined because differences were 

primarily temporal: both drained and nondrained cropland 

catchments were tilled and planted in drier years. Thus, the 

only difference was the frequency and extent of cropping in 

the wetland zone of these catchments (for example, drained 

wetland zones are farmed more frequently than are nondrained). Although intensity and frequency of cropping can 

have important impacts on vegetation community quality and 

composition, records of past activities were not of sufficient 

detail to reliably separate catchments on the basis of temporal 

patterns of agriculture. Similarly, most hydrologically restored 

and all nondrained restored catchments were planted to perennial cover. In addition, neither restoration strategy involved 

planting wetland vegetation. Given similar planting regimens 

and the large variation in antecedent conditions of hydrologically restored wetlands (see chap. C), we decided to combine 

the restored treatments because assessing the overall value 

of restoration activities relative to cropland and native prairie 

sites was of most interest. We used univariate ANOVA and 

contrast statements with inferences that applied only to the 

observed levels of the random effects to test for differences 

in FQI and species richness among the cropped, restored, 

and native prairie treatments. All analyses were conducted 

by using PROC MIXED of SAS version 8.2 (SAS Institute, 

Inc., 1999) and considered a P ≤ 0.05 as the level of statistical 

significance for all tests.

Results

According to the Northern Great Plains Floristic Quality Assessment Panel (2001), there are 1,584 plant taxa in the 

Dakotas and surrounding grasslands. We documented 349 

(22.0 percent) of these species in catchments surveyed, including 231 (66.2 percent) forbs, 67 (19.2 percent) grasses, 24 

(6.9 percent) sedges, 16 (4.6 percent) shrubs, and 5 (1.4 percent) trees (table B–2). The majority of species (n = 248; 

71.1 percent) were perennials, followed by annuals (n = 87; 

24.9 percent) and biennials (n = 14; 4.0 percent). Seasonal 

catchments supported 209 species compared to 200 and 

158 species in semipermanent and temporary catchments, 

respectively.

Native plant species made up 76.8 percent (n = 268) of 

all plants identified in catchments compared to 23.2 percent 

16 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Table B–1. Distribution of 263 wetland catchments based on land-use treatment, catchment type, and 

physiographic region (glaciated plains, Missouri coteau) that were evaluated in the Prairie Pothole Region.

Land-use 

treatment

Catchment type

Semipermanent Seasonal Temporary

Glaciated 

plains

Missouri 

coteau

Glaciated 

plains

Missouri 

coteau

Glaciated 

plains

Missouri 

coteau

Cropland 9 8 11 13 10 10

Restored 28 20 30 38 25 31

Native prairie 5 5 5 5 5 5

(n = 81) nonnative species. Native species composition was 

dominated by forb (n = 178; 66.4 percent) and grass (n = 41; 

15.3 percent) species, followed by sedge (n = 24; 8.9 percent), shrub (n = 15; 5.6 percent), and tree (n = 5; 1.9 percent) 

species (table B–2). Forb (n = 53) and grass (n = 26) species 

accounted for 65.4 percent and 32.1 percent of nonnative 

plants, respectively, with the remaining 2.5 percent of nonnative species being accounted for by one shrub and one tree 

species.

Floristic Quality Index

Regardless of treatment, floristic quality differed among 

catchment types (F2,100 = 5.85, P < 0.004) with semipermanent 

catchments exhibiting greater quality than temporary catchments (F1,100 = 11.70, P < 0.0009) (fig. B–1). In contrast, the 

floristic quality of seasonal catchments was intermediate and 

similar to that of both semipermanent (F1,100 = 3.59, P < 0.06) 

and temporary catchments (F1,100 = 2.83, P < 0.10). The interaction of catchment type and zone also influenced floristic 

quality (F2,108 = 3.91, P < 0.02); however, further analysis 

indicated that the only difference was lower floristic quality 

in the upland compared to the wetland zone in semipermanent 

catchments (F1,108 = 5.07, P < 0.026) (fig. B–2). Floristic quality did not vary by physiographic region (F1,8 = 2.43, 

P < 0.16) or zone (F1,8 = 0.09, P < 0.76), but it was affected 

by treatment (F4,100 = 60.18, P < 0.0001) and the interaction of 

treatment with physiographic region and zone (F4,108 = 3.07, 

P < 0.02) (fig. B–3). The upland zone FQI of restored catchments was greater relative to the cropland baseline (glaciated plains, F1,108 = 14.65, P = 0.0002; Missouri coteau, 

F1,108 = 14.20, P < 0.0003), but it was lower relative to native 

prairie reference catchments in both physiographic regions 

(glaciated plains, F1,108 = 42.08, P < 0.0001; Missouri coteau, 

F1,108 = 282.12, P < 0.0001) (fig. B–3). In the Missouri coteau, 

the wetland zone FQI exhibited trends similar to the upland 

zone FQI with restored catchments having a greater FQI than 

cropped catchments (F1,108 = 13.59, P < 0.0004) but a lower 

FQI than native prairie catchments (F1,108 = 14.39, P < 0.0002). 

In the glaciated plains, the wetland zone FQI of restored 

catchments also was greater than that of cropped catchments 

(F1,108 = 8.73, P < 0.0001), but there was no difference between 

restored and native prairie catchments (F1,108 = 0.44, P < 0.51).

Species Richness

Native species richness differed among catchment types 

(F2,100 = 16.86, P < 0.0001) and zones within catchment types 

(F2,108 = 8.37, P < 0.0004), regardless of treatment. Semipermanent catchments supported a greater native richness 

than did seasonal catchments (F1,100 = 7.11, P < 0.009), and 

seasonal catchments were richer in native species than were 

temporary catchments (F1,100 = 11.57, P < 0.001) (fig. B–1). In 

semipermanent catchments, native richness was greater in the 

wetland zone than in the upland zone (F1,108 = 4.99, P < 0.028), 

whereas in temporary catchments the upland zone supported 

more native species than the wetland zone (F1,108 = 12.16, 

P < 0.0007) (fig. B–2). In seasonal wetlands, the richness of 

native species in the upland and wetland zones was similar 

(F1,108 = 0.05, P < 0.82).

Physiographic region (F1,8 = 9.22, P = 0.02), treatment 

(F4,100 = 25.97, P < 0.0001), and the interaction of physiographic region, zone, and treatment (F4,108 = 2.68, P < 0.04) 

also influenced native species richness. Upland native species 

richness of restored catchments in both the glaciated plains 

and Missouri coteau was greater than that of cropped catchments (glaciated plains, F1,108 = 8.41, P = 0.005; Missouri 

coteau, F1,108 = 18.32, P < 0.0001), but it was lower than that 

of native prairie catchments (glaciated plains, F1,108 = 20.68, 

P <0.0001; Missouri coteau, F1,108 = 118.97, P < 0.0001) 

(fig. B–4). In contrast, the richness of native wetland plants 

in restored catchments was similar to that of both cropped 

(F1,108 = 1.98, P < 0.16) and native prairie (F1,108 = 0.01, 

P < 0.92) catchments in the glaciated plains, whereas in 

the Missouri coteau the richness of native wetland plants 

in restored catchments was similar to that of native prairie 

catchments (F1,108 = 1.10, P < 0.30) and greater than that of 

cropped catchments (F1,108 = 7.22, P = 0.008).

Chapter B: Plant Community Quality and Richness 17
Table B–2. Number and percent of native and nonnative plant species recorded in 263 catchments in the 

glaciated plains and Missouri coteau physiographic regions, 2004.

Physiognomy

Native Nonnative Total

Number Percent Number Percent Number Percent

Cryptogam 4 1.5 0 0.0 4 1.1

Forb

Annual 44 16.4 22 27.2 66 18.9

Biennial 9 3.4 5 6.2 14 4.0

Perennial 125 46.6 26 32.1 151 43.3

Grass

Annual 3 1.1 15 18.5 18 5.2

Perennial 38 14.2 11 13.6 49 14.0

Sedge

Annual 3 1.1 0 0.0 3 0.9

Perennial 21 7.8 0 0.0 21 6.0

Shrub 15 5.6 1 1.2 16 4.6

Tree 5 1.9 0 0.0 5 1.4

Vine 1 0.4 1 1.2 2 0.6

Total 268 100.0 81 100.0 349 100.0

Nonnative species richness was greater in the Missouri coteau (x = 5.22 ± 0.22) than in the glaciated plains 

(x = 3.99 ± 0.22) regardless of treatment (F1,8 = 15.46, 

P = 0.004). Differences in nonnative richness also occurred 

among catchment types (F2,100 = 6.68, P = 0.002) and zones 

within catchment type (F2,108 = 4.69, P = 0.01) in the absence 

of treatment. The nonnative richness of semipermanent and 

seasonal catchments was similar (F1,100 = 1.75, P < 0.19), but 

both semipermanent (F1,100 = 12.73, P = 0.0006) and seasonal 

(F1,100 = 5.99, P = 0.02) catchments exhibited greater nonnative 

richness than did temporary catchments (fig. B–1). In contrast, 

the upland zone had a richer nonnative plant community than 

did the wetland zone in all three catchment types (semipermanent, F1,108 = 13.08, P = 0.0005; seasonal, F1,108 = 13.61, 

P = 0.0004; temporary, F1,108 = 53.82, P < 0.0001) (fig. B–2). 

Treatment (F4,100 = 6.38, P = 0.0001) and the interaction of 

treatment and zone (F4,108 = 5.66, P = 0.0004) also influenced 

nonnative richness. In the upland zone, restored catchments 

had a richer nonnative plant community than both cropped 

(F1,108 = 39.42, P < 0.0001) and native prairie (F1,108 = 11.55, 

P = 0.001) catchments. In the wetland zone, non-native plant 

richness in restored catchments was similar to both cropped 

(F1,108 = 2.35, P = 0.13) and native prairie (F1,108 = 0.61, 

P = 0.44) (fig. B–5) treatments.

Discussion

Our study was conducted to evaluate changes in floristic 

quality and plant species composition resulting from Federal 

restoration programs. The best approach for accomplishing 

this goal is to assess the outcomes of restoration activities in 

relation to current and future potential landscape scenarios. In 

the Prairie Pothole Region, agricultural activities largely are 

responsible for the loss and degradation of both terrestrial and 

aquatic vegetation communities. In addition, agriculture is, 

and likely will remain, the predominant land use in this region 

(Samson and Knopf, 1994). Thus, we selected cropped catchments as our baseline reference for use in assessing improvements on the landscape. At the other extreme, determining if 

restoration programs are performing at their greatest potential 

requires comparison to some desired condition. We selected 

native prairie catchments as the upper benchmark because they 

are floristically rich and represent the potential upper bound of 

what could be accomplished with regard to natural vegetation 

restoration in the Prairie Pothole Region; however, the use of 

native vegetation conditions as a benchmark does not necessarily equate with the goals of Federal restoration programs, 

which are diverse and tend to vary depending on specific 

conservation practices and programs considered.

18 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
0

2

4

6

8

10

Semipermanent 

Seasonal

Temporary

A

AB

B

A

B

C

A

A

B

MEAN (p STANDARD ERROR)

FLORISTIC QUALITY

INDEX

NATIVE SPECIES

RICHNESS

NONNATIVE SPECIES

RICHNESS

0

2

4

6

8

10

Upland zone

Wetland zone

FLORISTIC QUALITY

INDEX

NATIVE SPECIES

RICHNESS

NONNATIVE SPECIES

RICHNESS

A

B

AA A

A

A

B

AA

A

B

A

B

A A

B

B

SEMIPERMANENT

SEASONAL

TEMPORARY

SEMIPERMANENT

SEASONAL

TEMPORARY

SEMIPERMANENT

SEASONAL

TEMPORARY

MEAN (p STANDARD ERROR)

Figure B–1. Differences in floristic quality, native species 

richness, and nonnative species richness among catchment 

types (semipermanent, seasonal, temporary). Bars with letters in 

common within a group are not significantly different (P > 0.05).

Figure B–2. Differences in floristic quality, native species richness, and 

nonnative species richness between the upland and wetland zones within a 

catchment type (semipermanent, seasonal, temporary). Bars with letters in 

common within a catchment type and group are not significantly different 

(P > 0.05).

Within this construct, the average upland zone FQI of 

restored catchments we evaluated was higher than that of 

cropped catchments but lower than that of native prairie catchments. This trend occurred regardless of catchment type in 

both the glaciated plains and Missouri coteau. The observed 

differences between treatments likely were due to a combination of factors, but we suspect that a shift in the type and 

number of species planted and differences in nonnative species 

richness were among the most important. Agricultural species 

are not assigned a C value because they are not native to the 

Prairie Pothole Region, whereas some native species planted 

as part of conservation programs have moderate C values. 

For example, the C values for big bluestem (Andropogon 

gerardii) and little bluestem (Andropogon scoparius) are 5 

and 6, respectively. Further, agricultural species are favored 

in cropped catchments owing to cultivation and chemical 

application, which are designed to eliminate all other species, 

whereas the intensity and frequency of disturbance are much 

less on restored lands. Collectively, these changes act to immediately improve FQI of restored upland zones.

Only about four to eight native grass species are typically 

seeded as part of restoration activities, whereas native prairie 

upland zones typically support a more diverse flora. Consequently, planting a limited number of native species cannot 

increase the floristic quality of restored catchments to levels 

Chapter B: Plant Community Quality and Richness 19

comparable to native prairie conditions. Another 

factor that may have lowered upland floristic quality in restored catchments relative to native prairie 

catchments was the presence of more nonnative 

species. Many terrestrial nonnatives are annual 

forbs and grasses (Northern Great Plains Floristic 

Quality Assessment Panel, 2001), many of which 

are adapted for germination on disturbed soils. 

Thus, restored upland zones in our study may be 

more vulnerable, at least initially, to invasion by 

nonnative species because the process of restoring 

agricultural lands often includes a period when 

soils are disturbed and plant cover is minimal. In 

contrast, native prairie uplands in our study had 

no previous history of large-scale soil disturbance 

from farming; thus, the temporal frequency and 

spatial extent of exposed, disturbed soils has been 

lower. These results indicate further increases in 

FQI will require establishment of additional native 

species, many of which exhibit high site fidelity 

and are intolerant of disturbance.

In the Missouri coteau, wetland floristic 

quality exhibited the same general trend as upland 

floristic quality, with the FQI of restored treatments being intermediate between cropped and 

native prairie treatments. In the glaciated plains, 

wetland floristic quality of restored treatments also 

was greater compared to cropped treatments, but 

it was similar to native prairie treatments. Unlike 

upland restoration, wetland restoration techniques 

evaluated in this study did not include planting 
0

5

10

15

20

Cropland

Restored

Native prairie

A

A A

A

A A

B

B

B

B

C

C

GLACIATED PLAINS MISSOURI COTEAU

UPLAND ZONE

WETLAND ZONE

UPLAND ZONE

WETLAND ZONE

MEAN (p STANDARD ERROR) NATIVE SPECIES RICHNESS

Figure B–3. Floristic quality among land-use treatments (cropland, restored, 

native prairie) in the upland and wetland zones of surveyed catchments in the 

glaciated plains and Missouri coteau physiographic regions. Bars with letters in 

common within a catchment zone and physiographic region are not significantly 

different (P > 0.05).

Figure B–4. Native species richness among land-use treatments (cropland, 

restored, native prairie) in the upland and wetland zones of surveyed catchments in 

the glaciated plains and Missouri coteau physiographic regions. Bars with letters 

in common within a catchment zone and physiographic region are not significantly 

different (P > 0.05).

0

2

4

6

8

10

12

14

16

Cropland

Restored

Native prairie

GLACIATED PLAINS MISSOURI COTEAU

A

B

C

A

B

A

B

C

A

B

C

B

UPLAND ZONE

WETLAND ZONE

UPLAND ZONE

WETLAND ZONE

MEAN (p STANDARD ERROR) FLORISTIC QUALITY INDEX

vegetation. Therefore, differences in wetland 

floristic quality likely were associated with 

changes in land-use treatments relative to 

natural wetland processes and extant seed 

banks. Although many abiotic factors are 

important in determining floristic quality of wetland zones, hydrologic cycles are 

among the most important. The frequency, 

timing, and duration of flooding directly 

and indirectly influence the primary factors (moisture, temperature, chemistry, and 

oxygen concentration of the soil) controlling seed germination (Stewart and Kantrud, 

1971; Simpson and others, 1989; Cronk and 

Fennessy, 2001). In native prairie catchments, 

dynamic hydrologic cycles result in constantly changing environmental conditions 

that facilitate germination of diverse plant 

species; hence, floristic quality can change 

intra-annually and inter-annually. In cropped 

catchments, however, hydrologic cycles are 

often curtailed and less variable because 

modern techniques enable many wetlands to 

be drained completely and planted to nonnative crops even in wet years. Reduced hydroperiod variability, coupled with planting 

crops in all or a portion of the wetland, likely 

contributed to the low floristic quality we 

observed in wetland zones of cropped catchments. Conversely, improvements in wetland 

floristic quality likely occurred following 

either hydrologic restoration or elimination 

of agriculture in the surrounding lands, such 

as nondrained restored catchments, because 

both strategies return hydroperiods to a more 

natural state. Although we did not examine 

causal factors, hydrologic restoration strategies would eliminate or reduce discharge of 

water from ditches; and planting the surrounding catchment to perennial cover can 

reduce sedimentation rates (see chap. E), 

lower inputs of agrichemicals and nutrients 

from surrounding uplands, and attenuate 

unnatural surface water input to the basin 

(Neely and Baker, 1989; Euliss and Mushet, 

1996; Gleason and Euliss, 1998; chap. D, this 

report). Our results suggest that the extent 

to which these restoration techniques are 

successful depends on physiographic region. 

Greater Cvalues and similar species richness in native prairie treatments compared 

to restored treatments indicate that greater 

C values are related more to the uniqueness 

of the plant communities in native prairie 

treatments than to the number of species per 

catchment (fig. B–3).

20 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
UPLAND ZONE WETLAND ZONE

0

5

10

15

20

Cropland

Restored

Native prairie

A

B

A

A A A

MEAN (p STANDARD ERROR) NONNATIVE SPECIES RICHNESS

Figure B–5. Mean nonnative species richness among landuse treatments (cropland, restored, native prairie) in the upland 

and wetland zones of surveyed catchments. Bars with letters in 

common within a catchment zone are not significantly different 

(P > 0.05).

The lack of interaction between treatment and catchment type suggests that the restoration approaches evaluated 

in this study are viable regardless of the wetland class that 

occurs within a catchment; however, our analysis suggests 

that differences in floristic quality and composition occurred 

among catchment types because the extent of plant community 

recovery following restoration may vary by wetland class. 

Semipermanent catchments exhibited greater floristic quality, 

native richness, and nonnative richness than did temporary 

catchments. In contrast, the floristic quality of seasonal catchments was similar to that of both semipermanent and temporary catchments, native species richness was intermediate 

between that of semipermanent and temporary catchments, 

and nonnative species richness was similar to that of semipermanent catchments. Causal factors were not examined as 

part of this study; however, one possible explanation for these 

differences may be related to abiotic factors (soils, hydrology, 

topography) that influence the frequency or extent of cropping in catchments supporting different wetland types. Both 

duration of drainage and cultivation have been demonstrated 

to reduce species richness and abundance of wetland seed 

banks that play a critical role in reestablishment of wetland 

vegetation (Erlandson, 1987; Wienhold and van der Valk, 

1989). Catchments supporting temporary wetlands typically 

can be cropped more frequently and extensively because these 

wetlands are shallow, typically express surface water only 

several weeks annually, and can be rapidly drained in most 

years. In contrast, many semipermanent wetlands are difficult 

to drain completely because they contain large volumes of 

water, are connected to groundwater, and often occupy lower 

topographic position of catchments. Therefore, cropping may 

change the area of wetland vegetation, but complete tillage 

of semipermanent catchments is rare, and wetland floristic 

quality may not be as severely altered because refugia for 

native plants exist in most years. This conclusion is supported 

to some extent by differences between the wetland and upland 

zones of each catchment type. Floristic quality and native 

species richness were greater in the wetland zone than in the 

upland zone of semipermanent catchments, whereas this trend 

was reversed for temporary catchments, although the difference in floristic quality was not significant. The upland and 

wetland zones of catchments supporting seasonal wetlands, 

which have hydroperiods intermediate of semipermanent and 

temporary wetlands, were similar in floristic quality and native 

species richness.

In summary, our study indicates that the approaches 

being used to restore catchments in the Prairie Pothole Region 

are effective in improving floristic quality and native species 

richness. In general, restoration activities improved floristic 

quality of both the upland and wetland zones relative to the 

baseline reference of cropped catchments, but floristic quality 

did not approach full site potential as defined by native prairie 

catchments, with the exception of restored wetland catchments 

in the glaciated plains. The magnitude and significance of 

change varied depending on wetland class that occupied the 

catchment (catchment type), physiographic region, and catchment zone. Causal factors for these relationships were not 

examined, but differences among catchment types occurred 

independent of treatment effects and may be related to the 

frequency and extensiveness of cropping that can occur in 

catchments with different wetland classes. In addition, differences in the floristic quality of upland zones between cropped 

and restored treatments likely result from conversion of planting agricultural crops to planting a limited mixture of native 

species, whereas the difference between the restored and 

native prairie treatment may be due to a combination of higher 

native species richness and the presence of more species with 

high site fidelity in the native prairie treatment. Differences in 

wetland floristic quality among treatments likely were related 

to hydroperiod and the time since cessation of agricultural 

planting. The low floristic quality of cropped wetlands likely 

resulted from a combination of shortened hydroperiods and the 

planting of agricultural crops. In contrast, the improved floristic quality of restored treatments can be partially explained 

by the absence of cropping in the wetland and either the direct 

restoration of hydrology by plugging ditches or, in the case of 

nondrained wetlands, indirect restoration of hydroperiods by 

planting uplands to perennial cover. These activities resulted 

in wetland floristic quality improvements that were similar 

to native prairie conditions in the glaciated plains, but they 

achieved only 50 percent of the native prairie wetland floristic 

quality in the Missouri coteau.

Although our results indicate that restoration activities 

improved floristic quality, current strategies may be limited 

Chapter B: Plant Community Quality and Richness 21
in attaining the level of floristic quality and native species 

richness of native prairie catchments. The primary impediment appears to be the ability to facilitate establishment of 

plant species with high site fidelity in both the upland and 

wetland zones. Many of these species tend to have specific 

germination requirements or occupy precise niches. Therefore, further improvement in floristic quality and native 

species richness may require refinement of existing restoration 

techniques to more fully restore critical ecosystem processes, 

such as hydrology, fire, and grazing; implementing intensive 

management actions for several years following restoration; 

or a combination of both activities. Ultimately, determining 

the adequacy of restoration techniques solely on the basis of 

floristic quality and richness is ill advised because plant community composition can change rapidly in response to natural 

variation in abiotic factors and processes as well as in response 

to human-induced restoration and management activities.

References

Cronk, J.K., and Fennessy, M.S., 2001, Wetland plants—

biology and ecology: New York, Lewis Publishers.

Daubenmire, R.F., 1959, Plants and environment—a text book 

of plant autecology (2d ed.): New York, John Wiley & Sons, 

Inc.

Erlandson, C.S., 1987, The potential role of seed banks in the 

restoration of drained prairie wetlands: Ames, Iowa State 

University, master’s thesis.

Ervin, G.N., Herman, B., and Bried, J., 2005, Evaluation of 

wetland floristic quality indices as indicators of ecological integrity in north Mississippi wetlands: Mississippi 

State University, Water Resources Research Institute, 

technical completion report, U.S. Geological Survey grant 

no. 01HQGR0088.

Euliss, N.H., Jr., and Mushet, D.M., 1996, Water-level fluctuation in wetlands as a function of landscape condition in the 

prairie pothole region: Wetlands, v. 16, p. 587–593.

Gleason, R.A., and Euliss, N.H., Jr., 1998, Sedimentation of 

prairie wetlands: Great Plains Research, v. 8, p. 97–112.

Kantrud, H.A., and Newton, W.E., 1996, A test of vegetationrelated indicators of wetland quality in the prairie pothole 

region: Journal of Aquatic Ecosystem Health, v. 5, 

p. 177–191.

Neely, R.K., and Baker, J.L., 1989, Nitrogen and phosphorus 

dynamics and the fate of agricultural runoff, in van der 

Valk, A., ed., Northern prairie wetlands: Ames, Iowa State 

University Press, p. 92–131.

Northern Great Plains Floristic Quality Assessment Panel, 

2001, Coefficients of conservatism for the vascular flora 

of the Dakotas and adjacent grasslands: U.S. Geological 

Survey, Biological Resources Division, Information and 

Technology Report USGS/BRD/ITR–2001–0001.

Samson, F.B., and Knopf, F.L., 1994, Prairie conservation in 

North America: Bioscience, v. 44, p. 418–421.

SAS Institute, Inc., 1999, SAS/STAT user’s guide: Cary, N.C., 

SAS Institute, Inc., Online Doc Version 8.

Simpson, R.L., Leck, M.A., and Parker, V.T., 1989, Seed 

banks—general concepts and methodological issues, in

Leck, M.A., Parker, V.T., and Simpson, R.L., eds., Ecology of soil seed banks: San Diego, Calif., Academic Press, 

p. 3–21.

Stewart, R.E., and Kantrud, H.A., 1971, Classification of natural ponds and lakes in the glaciated prairie region: Washington, D.C., U.S. Department of the Interior, Fish and Wildlife 

Service, Resource Publication 92.

Swink, F.A., and Wilhelm, G.S., 1979, Plants of the Chicago 

region (3d ed.): Lisle, Ill., Morton Arboretum.

Swink, F.A., and Wilhelm, G.S., 1994, Plants of the Chicago 

region (4th ed.): Indianapolis, Indiana Academy of 

Sciences.

Wienhold, C.E., and van der Valk, A.G., 1989, The impact of 

duration of drainage on the seed banks of northern prairie 

wetlands: Canadian Journal of Botany, v. 67, p. 1878–1884.

22 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Chapter C: Carbon Sequestration

By Robert A. Gleason, Brian A. Tangen, and Murray K. Laubhan

Synopsis

In response to concerns over global climate change, 

many countries are developing strategies to reduce emission of 

greenhouse gases such as carbon dioxide (CO2), nitrous oxide 

(N2O), and methane (CH4). One such strategy is to sequester 

atmospheric carbon by implementing conservation practices 

on agricultural lands to enhance soil organic carbon (SOC) 

sinks (Lal and others, 1998). Policies promoting wetland 

conservation and restoration, such as the U.S. Department of 

Agriculture (USDA) Conservation Reserve Program (CRP) 

and Wetlands Reserve Program (WRP), have led to the restoration of approximately 2.2 million ha (5.4 million acres) of 

wetland and grassland habitats in the Prairie Pothole Region 

of the United States. Restoration of grassland and wetland 

habitats (including wetland catchments) via the CRP or WRP 

is most often recognized for improving soil and water quality, 

reducing soil erosion, enhancing flood storage, and creating 

wildlife habitat (Knutsen and Euliss, 2001); however, these 

restorations also have had an influence on carbon sequestration and greenhouse gas emissions in the United States. 

Research suggests that wetlands and grasslands in the Prairie 

Pothole Region historically were sinks of atmospheric carbon, 

but cultivation, the current principal land use, shifted their 

function to net sources of atmospheric carbon (Follett and 

others, 2001; Euliss and others, 2006). Studies have shown 

that shifting land use from cultivation to a more natural state 

often results in replenishment of SOC stocks and the capture 

and storage of atmospheric carbon. A recent inventory of 

greenhouse gas emissions and sinks for the United States (U.S. 

Environmental Protection Agency, 2003) identified restored 

wetlands and grasslands on lands enrolled in the CRP and 

WRP as carbon sinks.

Our objective was to evaluate the impact of conservation 

programs on carbon sequestration in the soils and vegetation communities of restored wetland catchments on program 

lands. During 2004, a survey of 270 catchments in the Prairie 

Pothole Region was conducted to evaluate how SOC and 

vegetation organic carbon (VOC) stocks of restored catchments on program lands vary in relation to cropland and 

native prairie catchment baselines. Our results demonstrated 

that catchments with a cultivation history, including those 

that have been restored and those with cropland, had 12 to 

26 percent less SOC in the soil surface (0–15 cm [0–6 in]) 

than native prairie catchments, depending on physiographic 

region (Missouri coteau, glaciated plains) and catchment 

zone (upland, wetland). These results are consistent with the 

published literature indicating that cultivation reduces native 

prairie carbon stocks. On the basis of the average difference in SOC (15 Mg∙ha-1 [6.7 tons∙acre-1]) between restored 

and native prairie catchments, we estimated that catchments 

(444,574 ha [1,098,542 acres]) on program lands in the Prairie 

Pothole Region have a total of 6,662,355 Mg (7,341,915 tons) 

less SOC than an equivalent area of native prairie catchments. This estimate of total SOC loss represents the potential 

amount of SOC that could be replenished by the capture and 

storage of atmospheric carbon (sequestration) on catchments located on program lands. We were not able to detect 

a significant increase in SOC stocks in restored catchments 

relative to cropland baselines, nor were we able to detect a 

relationship between the time since restoration and carbon 

content. Consequently, we were unable to calculate a SOC 

sequestration rate for restored catchments that we could use 

to estimate the amount of SOC sequestered on program lands; 

however, on the basis of a published SOC sequestration rate 

of 0.5 Mg∙ha-1∙yr-1 (0.2 tons∙acre-1∙yr-1) for CRP lands (Follett and others, 2001), catchments on program lands possibly sequester 222,287 Mg∙yr-1 (244,960 tons∙yr-1) of SOC. 

Considering the cumulative annual carbon sequestration since 

lands have been enrolled in these conservation programs, 

we estimated a total SOC sequestration of 2,712,714 Mg 

(2,989,411 tons) for catchment areas on program lands in the 

Prairie Pothole Region. Further, on the basis of our survey, 

an additional 715,094 Mg (788,034 tons) of VOC could be 

stored in the plant biomass in catchment areas. Explanations 

for our inability to detect changes in restored catchment SOC 

stocks are discussed and include difficulties inherent to pairedsampling designs and the influence of climatic variations that 

alter SOC sequestration processes and baselines.

Sequestration of atmospheric carbon in soils and plants 

following restoration was not an intended outcome when the 

CRP and WRP were originally implemented. Hence, this 

benefit is considered an additional ecological service that may 

contribute to offsetting greenhouse gas emissions. In addition 

to sequestering carbon, restored catchments also may result in 

reduction of other greenhouse gas emissions, such as N2O and 

CH4, according to studies conducted outside the Prairie Pothole Region that have demonstrated that nutrient enrichment 

from agricultural runoff can enhance emissions of greenhouse 

gases (Merbach and others, 2002). Consequently, converting 

cultivated cropland to permanent grassland within restored 

catchments should reduce nutrient enrichment in restored wetlands (see chap. E) and lower emission of N2

O, and possibly 

CH4, relative to a cropland baseline.

Chapter C: Carbon Sequestration 23
Methods

Data Collection

During 2004, we collected SOC and VOC samples 

from 270 wetland catchments in the Prairie Pothole Region 

(fig. A–3 and table A–3). This sample included catchments 

containing temporary, seasonal, and semipermanent wetlands 

in hydrologically restored and nondrained restored catchments on program lands; drained and non-drained catchments 

on croplands; and native prairie catchments (table A–3). We 

collected samples along four transects that radiated from the 

center of the wetland and extended in cardinal directions to the 

catchment boundary. Along each transect we collected SOC 

samples to a depth of 30 cm (12 in) in each catchment subzone 

(shoulder-slope, mid-slope, toe-slope, wet-meadow, shallowmarsh, and deep-marsh) (fig. A–6). Previous work (Euliss 

and others, 2006) demonstrated that most differences in SOC 

between farmed and non-farmed wetlands occur within the 

upper 15 cm (6 in); however, we sampled to a depth of 30 cm 

(12 in) to ensure compatibility with current and future carbon 

sink and source inventories for the United States (for example, 

U.S. Environmental Protection Agency, 2003). A separate 

soil sample from each subzone was collected for determination of bulk density (total mass per unit volume) to facilitate 

conversion of nutrient concentrations to mass per unit area. 

The four SOC samples from each subzone were composited 

by 0–15 cm (0–6 in) and 15–30 cm (6–12 in) depth increments 

for determination of physical (particle size) and chemical 

(extractable phosphorus [P], total and inorganic carbon [C], 

total and extractable nitrate [NO3

-

], and ammonium [NH4

+

]) 

attributes by using standard methods (Page and others, 1982; 

Klute, 1986). In contrast to SOC samples, VOC samples were 

collected from subzones on only one of the four transects by 

clipping all aboveground biomass (live and dead) within a 

0.25-m2 (2.7-ft2) quadrat. For VOC samples, we determined 

total dry mass, total carbon, total nitrogen, and total phosphorus by following standard methods (Page and others, 1982; 

Klute, 1986).

Data Analyses

We calculated SOC and VOC content separately for 

upland and wetland zones in each of the 270 catchments 

surveyed during 2004. Upland zone estimates included carbon 

estimates collected from three upland subzones (toe-slope, 

mid-slope, and shoulder-slope) that occurred in every catchment. In contrast, wetland zone estimates consisted of a 

combination of three subzones that varied by catchment type 

(temporary, seasonal, semipermanent) (fig. A–6); in general, 

one subzone (wet-meadow) occurred in temporary catchments, 

two subzones (wet-meadow and shallow-marsh) occurred 

in seasonal catchments, and three subzones (wet-meadow, 

shallow-marsh, and deep-marsh) occurred in semipermanent 

catchments.

We used analysis of variance (ANOVA) to test for differences in SOC and VOC among land-use treatments. Sample 

points used as focal areas from which to select catchments 

across the climate and land-use gradient of the Prairie Pothole 

Region were included as a blocking factor (fig. A–5), and our 

model included physiographic region (Missouri coteau and 

glaciated plains), catchment type (temporary, seasonal, semipermanent), catchment zone (upland and wetland), land-use 

treatment (drained and nondrained cropland, hydrologically 

and nondrained restored, and native prairie), and all possible 

interactions as independent variables. For significant main 

effects and interaction terms, we constructed specific ANOVA 

tests by developing contrast statements with inferences that 

applied only to the observed levels of random effects to test 

for differences in carbon among main effects. We constructed 

treatment-weighted contrasts to test for differences among the 

following categories: (1) cropland (drained and nondrained 

cropland categories), (2) restored (hydrologically and nondrained restored categories of all ages), and (3) native (native 

prairie category). We selected 263 of the 270 catchments 

sampled (table A–3), of which 128 and 135 occurred in the 

glaciated plains and Missouri coteau, respectively (7 wetlands 

were excluded from the analysis because they were restored 

prior to implementation of the CRP and WRP). We used 

PROC MIXED of SAS version 8.2 (SAS Institute, Inc., 1999) 

to conduct all analyses and considered P ≤ 0.05 as the level 

of statistical significance for all tests. We used simple linear 

regression (PROC REG; SAS Institute, Inc., 1999) to examine 

the relationship of SOC to restoration age (in years).

Results

Soil Organic Carbon

Soil organic carbon in the surface 15 cm (6 in) was 

affected by treatment (F4,100 = 18.48, P < 0.0001) and the 

interaction of treatment with physiographic region and 

catchment zone (F4,108 = 2.82, P = 0.0285) (fig. C–1). Most 

comparisons of SOC among treatments within physiographic 

regions indicated that SOC in both the upland and wetland 

zones was significantly higher in native prairie catchments 

than in restored and cropland catchments (fig. C–1). The 

one exception to this trend occurred in the glaciated plains, 

where SOC in the wetland zone of cropland catchments was 

not significantly lower than that of native prairie catchments 

(F1,108 = 2.94, P = 0.0891) (fig. C–1). In the Missouri coteau, 

SOC in both the upland and wetland zones of restored catchments was lower than that of cropland catchments. In contrast, 

SOC in the upland and wetland zones of restored catchments 

in the glaciated plains was similar to that of cropland catchment zones (fig. C–1).

Soil organic carbon at the 15–30-cm depth (6–12-in) was 

affected by the interaction of treatment with physiographic 

region and catchment type (F8,100 = 2.48, P = 0.0170). In the 

Missouri coteau, SOC below 15 cm (6 in) was greater in native 

24 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
prairie semipermanent catchments (x = 53.14 ± 4.52 Mg∙ha-1

[23.70 ± 2.02 tons∙acre-1]) than in restored catchments 

(x = 37.26 ± 3.49 Mg∙ha-1 [16.62 ± 1.56 tons∙acre-1]; 

F1,100 = 21.58, P < 0.0001) and cropland catchments 

(x = 41.52 ± 4.16 Mg∙ha-1 [18.52 ± 1.86 tons∙acre-1]; 

F1,100 = 7.47, P = 0.0074). All other comparisons among treatments within physiographic regions and catchment types were 

not significantly different. Soil organic carbon below 15 cm 

(6 in) also was affected by the interaction of treatment and 

catchment zone (F4,108 = 2.56, P = 0.0426) (fig. C–2). Carbon 

below 15 cm (6 in) in the upland zone of restored catchments 

was lower than that in native prairie catchments (F1,108 = 5.20, 

P = 0.0246) but was similar to that in cropland catchments 

(F1,108 = 0.25, P = 0.6170), whereas SOC in the wetland zone 

of restored catchments was lower than that in cropland catchments (F1,108 = 4.25, P = 0.0417) but similar to that in native 

prairie catchments (F1,108 = 0.09, P = 0.7613). Soil organic 

carbon in both the upland and wetland zones of cropland 

catchments was similar (F1,108 = 2.95-3.26, P = 0.0738-0.0889) 

to that in native prairie catchments (fig. C–2). Regression 

analyses indicated that SOC in restored wetlands did not significantly (P > 0.05) vary with restoration age (fig. C–3).

Vegetation Organic Carbon

Amounts of VOC in standing crops varied significantly among treatments (F4,99 = 56.67, P < 0.0001), with 

greater VOC in restored catchments (x = 1.85 ± 0.08 Mg∙ha-1

[0.83 ± 0.04 tons∙acre-1]) compared to native prairie catchments (x = 1.47 ± 0.14 Mg∙ha-1 [0.66 ± 0.06 tons∙acre-1]; 

F1,99 = 7.52, P = 0.0073) and cropland catchments 

(x = 0.24 ± 0.011 Mg∙ha-1 [0.11 ± 0.005 tons∙acre-1]; 

F1,99 = 225.8, P < 0.0001). Native prairie catchments had 

significantly greater (F1,99 = 60.79, P < 0.0001) VOC stores 

than did cropland. Based on differences in average VOC 

stores among restored and cropland catchments, we estimated 

that restoration of catchments (444,574 ha [1,098,542 acres]) 

on program lands has resulted in a net VOC storage gain of 

715,094 ± 60,412 Mg (788,034 ± 66,574 tons) (table C–1).

Discussion

We conducted a regional assessment of SOC stocks in the 

Prairie Pothole Region to evaluate how carbon in restored wetlands varied in relation to cropland and native prairie catchment baselines. Our results indicate that SOC stocks in the 

surface soil (0–15 cm [0–6 in]) of wetland and upland zones in 

both physiographic regions was significantly lower in restored 

catchments than in native prairie catchments (fig. C–1). In 

nearly all cases cropland catchments also had significantly 

lower SOC stocks than native prairie catchments; however, for 

one comparison in the glaciated plains, SOC in the wetland 

zone of cropland catchments (x = 52.88 ± 3.29 Mg∙ha-1

[23.58 ± 1.47 tons∙acre-1]) was not significantly (F1,108 = 2.94, 

P = 0.0891) lower than that in native prairie catchments 

(x = 58.78 ± 3.77 Mg∙ha-1 [26.22 ± 1.68 tons∙acre-1]). 

Collectively, our results suggest that catchments with a cultivation history have lost SOC relative to a native prairie baseline. 

Overall, previously farmed catchments in the glaciated plains 

had 12 and 26 percent less SOC in the upland and wetland 

zones, respectively, than did native prairie catchments. Similarly, previously farmed catchments in the Missouri coteau had 

20 and 26 percent less SOC in the upland and wetland zones, 

respectively, than did native prairie catchments. Our findings 

are consistent with other studies demonstrating that conversion 

of native prairie to cultivated agricultural land often reduces 

carbon stocks by 20 to 50 percent or more (Mann, 1986; 

Anderson, 1995; Cihacek and Ulmer, 1995).

Presumably, the lowered SOC in previously farmed 

wetlands represents carbon losses from oxidation by cultivated 

agriculture. On average, restored catchments had 15 Mg∙ha-1

(6.69 tons∙acre-1) less SOC in the upper 15 cm (6 in) than 

did native prairie catchments. On the basis of this estimate, 

the 444,574 ha (1,098,542 acres) of catchments on program 

lands in the Prairie Pothole Region would have a total of 

6,662,355 Mg (7,341,915 tons) less SOC than would an 

equivalent area of native prairie catchments.

The above estimate of total SOC loss represents the 

potential amount of SOC that could be replenished through 

carbon sequestration on program lands, but it does not address 

the rate of SOC replenishment. When grasses and forbs are 

reestablished in the upland zone of croplands, SOC stocks 

generally increase as a result of carbon sequestration by 

plants. Though estimates are highly variable, studies have 

demonstrated that conversion of cropland to grassland on CRP 

lands results in carbon sequestration rates of approximately 

0.5–1.0 Mg∙ha-1∙yr-1 (0.22–0.45 tons∙acre-1∙yr-1; for example, 

Follett and others, 2001). A commonly applied approach to 

estimate carbon sequestration rates is to compare SOC stocks 

on restored lands to cropped sites that are as similar as possible with respect to edaphic and climatic factors. In our study 

we used a similar approach to estimate carbon sequestration 

rates; however, we were unable to detect a significant increase 

in SOC of restored catchments relative to a cropland baseline. 

Rather, we found that carbon stocks were significantly higher 

in cropland than in restored catchments in the Missouri coteau, 

whereas carbon stocks were statistically similar between 

restored and cropland catchments in the glaciated plains 

(fig. C–1). Further, we were unable to detect a linear increase 

in carbon with restoration age (fig. C–3). Therefore, we were 

unable to estimate carbon sequestration rates by using a 

paired-sampling design for restored and cropland catchments, 

nor were we able to estimate rates by using a relationship 

between carbon stocks and restoration age. In contrast, a previous study in the Prairie Pothole Region did show a positive 

relationship between wetland zone SOC and restoration age 

for semipermanent catchments but not for seasonal catchments 

(Euliss and others, 2006). Upland zones were not examined by 

Euliss and others (2006).

The rate at which SOC stocks change is likely a function 

of climate, cropping history, type of plants seeded, landscape 

Chapter C: Carbon Sequestration 25
GLACIATED PLAINS

0

20

40

60

80

100

Cropland

Restored

Native prairie

A AB

B

A A

B

B

A

A

B

C

C

UPLAND WETLAND

MISSOURI COTEAU

UPLAND WETLAND

SOIL ORGANIC CARBON (MEGAGRAMS PER HECTARE

IN THE 0–15-CENTIMETER DEPTH)

CATCHMENT ZONE

0

10

20

30

40

50

60

Cropland

Restored

Native prairie

AB A

B

A AB

B

UPLAND WETLAND

SOIL ORGANIC CARBON (MEGAGRAMS PER HECTARE

IN THE 15–30-CENTIMETER DEPTH)

Figure C–1. Soil organic carbon in the surface soil (0–15 cm 

[0–6 in]) among land-use treatments (cropland, restored, native 

prairie) in the upland and wetland zones of surveyed catchments 

in the glaciated plains and Missouri coteau physiographic 

regions. Bars with letters in common within a catchment zone and 

physiographic region are not significantly different (P > 0.05).

Figure C–2. Soil organic carbon at soil depths between 

15 and 30 cm (6 and 12 in) among land-use treatments 

(cropland, restored, native prairie) in the upland and 

wetland zones. Bars with letters in common within a 

catchment zone are not significantly different (P > 0.05).

position, hydrology, soil characteristics, and time. Ideally, 

all of these factors are considered when pairing restored 

catchments to cropped catchments. In reality, however, the 

pairing of restored catchments to cropland catchments is 

extremely difficult because a given catchment often is not 

uniform with respect to abiotic features. For example, most 

catchments in our study included two to three soil mapping 

units. Further, the position of catchments in the landscape 

influences surface-water and ground-water hydrology which 

in turn are affected by inter-annual and intra-annual climatic 

conditions. Such variation in hydrology influences plant communities that develop following restoration. Even when soil 

factors and catchment types (temporary, seasonal, and semipermanent) are relatively well matched, restored and cropland 

catchments often have very different cropping histories, such 

as tillage practices, crop type, and crop rotations, that greatly 

influence SOC stocks. Collectively, the difficulties associated with paired-sampling designs likely contributed to wide 

variation in SOC values and our inability to detect measurable 

increases in SOC on restored lands. Other studies that have 

used paired-sampling designs also have observed variable 

SOC sequestration rates, including SOC estimates for cropland sites that exceed those for restored grassland sites on CRP 

lands (for example, Follett and others, 2001).

Conducting studies to estimate carbon sequestration 

rates of restored catchments may require long-term monitoring, including SOC measurements before and after restoration, rather than paired-sampling designs. Future studies also 

should consider how carbon sequestration rates and SOC 

baselines vary in relation to climatic variation. We believe that 

some of the observed variation in SOC estimates within and 

between different restoration age classes (fig. C–3) may be 

related more to climatic conditions before, during, and after a 

site is restored rather than to restoration age. For example, wet 

and dry cycles in the Prairie Pothole Region greatly influence 

the intensity and frequency that catchments are cultivated and 

the cycling of vegetation within wetland catchments. Farmable wetlands often are cultivated during dry periods, which 

contribute to oxidation and loss of SOC. In contrast, these 

wetlands are not cultivated during wet periods, which results 

in increased carbon sequestration by the plant communities 

that typically develop. Hence, wet and dry conditions prior to 

restoration may explain why some recently restored wetlands 

had higher carbon stocks than did wetlands restored for longer 

periods (fig. C–3). This potential climatic effect might also 

explain some of the variation in SOC within restoration age 

class and why cropland catchments had similar or higher SOC 

than did some restored wetlands (fig. C–1).

Once wetlands are restored, wet and dry cycles also are 

expected to greatly influence carbon sequestration rates and 

processes (belowground primary production and sedimentation). In general, wetland vegetation communities exhibit the 

following four phases in response to water-level fluctuations 

during wet and dry cycles: dry marsh, regenerating marsh, 

degenerating marsh, and lake marsh (van der Valk and Davis, 

1978). The first two phases, dry marsh and regenerating 

26 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
0

10

20

30

40

50

60

70

80

0

10

20

30

40

50

60

70

80

Glaciated plains

Upland zone

RESTORATION AGE, IN YEARS RESTORATION AGE, IN YEARS

SOIL ORGANIC CARBON (MEGAGRAMS PER HECTARE pSTANDARD ERROR) 

IN THE 0–15-CENTIMETER DEPTH

0 2 4 6 8 10 12 14 16 18 20 0 2 4 6 8 10 12 14 16 18 20

Glaciated plains

Wetland zone

Missouri Coteau

Upland zone

Missouri Coteau

Wetland zone

Figure C–3. Relationship of soil organic carbon content in the 0–15 cm (0–6 in) soil depth to age of 

restored catchments by catchment zone (upland and wetland) and physiographic region (glaciated 

plains and Missouri coteau).

marsh, generally occur during dry to moderately wet conditions, respectively. During these phases, production of belowground biomass by emergent vegetation typically develops 

rapidly and likely is the primary process that contributes 

to development of soil organic matter and sequestration of 

carbon. The latter two phases (degenerating marsh and lake 

marsh) occur during prolonged wet periods, and high water 

levels typically result in the death of emergent vegetation 

and development of floating aquatic plants that contribute to 

carbon sequestration. During the degenerating marsh and lake 

phases, death of emergent plants and floating aquatic vegetation results in the sedimentary accumulation of organic matter. 

Burial of this organic matter through sedimentary processes 

in prairie wetlands has been estimated to be approximately 

0.83 Mg∙ha-1∙yr-1 (0.37 tons∙acre-1∙yr-1) (Euliss and others, 

2006). On the basis of this information, two assumptions about 

SOC can be made regarding variability in carbon sequestration processes relative to wetland phases: (1) the greatest 

contribution to SOC would occur during the dry marsh and 

regenerating marsh phases, when primary production of 

belowground biomass is highest, and (2) direct contributions 

to SOC would be expected to be lower during the degenerating marsh and lake phases, when rooted emergent plants are 

replaced by floating aquatic vegetation communities, whereas 

sedimentary carbon sequestration may be higher. Given this 

construct, restoration age would influence the rate of carbon 

sequestration less than would the dominant phases expressed 

by a restored wetland.

Our study included sites that had been restored over a 

19-year period (1986–2004), a timespan that included one 

of the most extreme dry and wet cycles recorded during the 

last 100 years in the Prairie Pothole Region. This cycle likely 

influenced SOC baselines and carbon-sequestration rates 

and processes in catchments. Considering the importance 

of climatic variation on vegetation community phases and 

carbon sequestration processes and baselines, we examined 

how climatic conditions varied from 1986 to 2004 in relation to restoration age and SOC of restored wetlands. We 

Chapter C: Carbon Sequestration 27
Table C–1. Net carbon gain stored in plant biomass (vegetation organic carbon [VOC]) when cultivated cropland is planted to 

perennial cover as part of the Conservation Reserve Program (CRP) and Wetlands Reserve Program (WRP) in the Prairie Pothole 

Region. Net gain is the difference between CRP/WRP and cropland estimates.

[CRP, Conservation Reserve Program; WRP, Wetland Reserve Program; ha, hectare; Mg, megagram; SE, standard error]

State Program

Area, ha 

(acre)

CRP/WRP Cropland Net gain

Mg carbon ± SE 

(tons ± SE)

Mg carbon ± SE 

(tons ± SE)

Mg carbon ± SE 

(tons ± SE)

Iowa CRP 53,182

(131,413)

98,387 ± 4,255

(108,422 ± 4,689)

12,764 ± 5,850

(14,066 ± 6,447)

85,623 ± 7,234

(94,357 ± 7,972)

WRP 11,184

(27,636)

20,690 ± 895

(22,800 ± 986)

2,684 ± 1,230

(2,958 ± 1,355)

18,006 ± 1,521

(19,843 ± 1,676)

Minnesota CRP 134,873

(333,271)

249,291 ± 10,780

(274,719 ± 11,880)

32,340 ± 14,823

(35,639 ± 16,335)

216,951 ± 18,328

(239,080 ± 20,197)

WRP 7,934

(19,605)

14,672 ± 634

(16,169 ± 699)

1,903 ± 872

(2,097 ± 961)

12,769 ± 1,079

(14,071 ± 1,189)

Montana CRP 8,869

(21,915)

16,408 ± 710

(18,082 ± 782)

2,129 ± 976

(2,346 ± 1,076)

14,279 ± 1 ,206

(15,735 ± 1,329)

North Dakota CRP 171,767

(424,436)

317,231 ± 13,718

(349,589 ± 15,117)

41,154 ± 18,862

(45,352 ± 20,786)

276,077 ± 23,323

(304,237 ± 25,702)

WRP 553

(1,366)

1,021 ± 44

(1,125 ± 48)

132 ± 61

(145 ± 67)

889 ± 75

(980 ± 83)

South Dakota CRP 54,685

(135,127)

101,167 ± 4,375

(111,486 ± 4,821)

13,124 ± 6,015

(14,463 ± 6,629)

88,043 ± 7,438

(97,023 ± 8,197)

WRP 1,527

(3,773)

2,823 ± 122

(3,111 ± 134)

366 ± 168

(403 ± 185)

2,457 ± 208

(2,708 ± 229)

Total CRP 423,376

(1,046,162)

782,484 ± 33,838

(862,297 ± 37,289)

101,511 ± 46,526

( 111,865 ± 51,272)

680,973 ± 57,529

(750,432 ± 63,397)

Total WRP 21,198

(52,380)

39,206 ± 1,695

(43,205 ± 1,868)

5,085 ± 2,331

(5,604 ± 2,569)

34,121 ± 2,883

(37,601 ± 3,177)

Total Prairie Pothole Region 444,574

(1,098,542)

821,690 ± 35,533

(905,502 ± 39,157)

106,596 ± 48,857

(117,469 ± 53,840)

715,094 ± 60,412

(788,034 ± 66,574)

plotted the Palmer Drought Severity Index (PDSI) with SOC 

of restored wetlands and their restoration age (fig. C–4). The 

PDSI is a measure of dryness, with zero indicative of normal 

conditions, positive numbers indicative of wet conditions, and 

negative numbers indicative of drought conditions. Variation 

in the PDSI over the past 19 years indicates two pronounced 

climate phases. The first phase (1986–96) included a period of 

extreme drought (1986–92) followed by an extreme wet period 

(1993–96). The second phase (1997–2004) showed a transition 

from extreme wetness to less moist conditions (fig. C–4). The 

relationship between the SOC content of restored wetlands to 

climatic variation as indicated by the PDSI cannot be quantified with the available data; however, the extreme variation 

in climatic conditions does provide a platform from which to 

discuss how cropland and restored SOC baselines may have 

varied over the past 19 years. As indicated earlier, we have 

frequently observed that many farmable catchments are only 

cultivated during dry periods. In contrast, with the exception of well-drained wetlands, catchments are infrequently 

cultivated during pronounced wet periods (for example, 

1993–2001) (fig. C–4) and robust emergent vegetation often 

develops. Essentially, during wet periods, farmable catchments 

may sequester carbon at rates similar to those of restored 

catchments. Given this scenario, we would expect a restored 

wetland to have SOC stocks similar to those of a cropland 

wetland that, because of wet conditions, had not been cultivated and was flooded like a restored wetland. Consequently, 

the amount of SOC in cropland catchments likely oscillates 

over wet and dry cycles that influence intensity and frequency 

of cultivation activities. The prevalence of above normal 

moisture conditions over the past decade likely resulted in 

cropland catchments having higher SOC stocks than would 

have occurred during dryer periods. Likewise, SOC baselines 

in recently restored catchments would vary depending on 

the intensity and frequency of cultivation activities prior to 

restoration. It has only been in the last few years that farmers 

have been able to reclaim and cultivate farmable catchments. 

Reclaiming these catchments usually results in tillage that 

28 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Glaciated plains

Upland zone

0

10

20

30

40

50

60

70

80

-6

-4

-2

0

2

4

6

-6

-4

-2

0

2

4

6

-6

-4

-2

0

2

4

6

-6

-4

-2

0

2

4

6

YEAR YEAR

2003

1995

1

1987

989

1991

1

1997

1993

999

2001

2003

1995

1

1987

989

1991

1

1997

1993

999

2001

2003

1995

1

1987

989

1991

1

1997

1993

999

2001

2003

1995

1

1987

989

1991

1

1997

1993

999

2001

0

10

20

30

40

50

60

70

80

0

10

20

30

40

50

60

70

80

90

0

10

20

30

40

50

60

70

80

RESTORATION AGE, IN YEARS

0 2 4 6 8 10 12 14 16 18 20

RESTORATION AGE, IN YEARS

0 2 4 6 8 10 12 14 16 18 20

0 2 4 6 8 10 12 14 16 18 20 0 2 4 6 8 10 12 14 16 18 20

Carbon

EXPLANATION

PDSI

SOIL ORGANIC CARBON (

MEGAGRAMS PER HECTARE) IN THE SURFACE 15-CM DEPTH

SOIL ORGANIC CARBON (

MEGAGRAMS PER HECTARE) IN THE SURFACE 15-CM DEPTH

PALMER DROUGHT SEVERITY INDEX (PDSI) (ANNUAL AVERAGE)PALMER DROUGHT SEVERITY INDEX (PDSI) (ANNUAL AVERAGE)

Glaciated plains

Wetland zone

Missouri coteau

Upland zone

Missouri coteau

Wetland zone

Figure C–4. Relationship of soil organic carbon content of restored catchments to restoration age and the Palmer Drought Severity 

Index (PDSI) (bold lines represent a smoothing function).

incorporates any robust emergent vegetation that developed 

into the soil. Incorporation of this vegetative biomass would 

increase SOC and may explain why wetland zones of cropland catchments had higher SOC than did restored catchments 

(figs. C–1 and C–2); however, with continued dry conditions 

that would facilitate repeated cultivation, we expect that much 

of the SOC from incorporation of emergent vegetation would 

ultimately be oxidized and lost to the atmosphere.

The previous examples depict how SOC baselines can 

oscillate in response to climatic conditions. Understanding 

how SOC varies in relation to climate is critical to allow meaningful comparisons of SOC of restored catchments to cropland 

catchments or to compare SOC within and between restoration 

ages. The question still remains, however, “How much carbon 

has been sequestered on program lands?” We were unable to 

estimate a SOC sequestration rate for restored catchments that 

we could use to estimate how much SOC has been sequestered 

on the 444,574 ha (1,098,542 acres) of restored catchments 

on program lands in the Prairie Pothole Region. Published 

literature, however, indicates that conversion of cropland to 

grassland on CRP lands results in carbon sequestration rates 

of 0.5–1 Mg∙ha-1∙yr-1 (0.22–0.45 tons∙acre-1∙yr-1) (for example, Follett and others, 2001), and Euliss and others (2006) 

estimated that restored wetland catchments have potential to 

sequester up to 3 Mg∙ha-1∙yr-1 (1.34 tons∙acre-1∙yr-1). Using 

the most conservative of the published sequestration rates 

(0.5 Mg∙ha-1∙yr-1 [0.22 tons∙acre-1∙yr-1]), we estimated that 

222,287 Mg∙yr-1 (244,960 tons∙yr-1) could be sequestered 

on program lands. When considering the cumulative annual 

carbon sequestration since lands have been enrolled in conservation programs, we estimated a total SOC sequestration of 

2,712,714 Mg (2,989,411 tons).

In addition to replenishment of SOC stocks, the vegetative community that rapidly develops in restored catchments 

represents an additional pool of sequestered carbon. We estimated that an additional 715,094 Mg (788,034 tons) of VOC 

Chapter C: Carbon Sequestration 29
could be stored on program lands (table C–1), which equates 

to approximately 1.6 Mg∙ha-1 (0.71 tons∙acre-1) of restored 

catchment. On the basis of these projections, it appears that 

substantial atmospheric carbon can be stored in the emergent 

vegetation of restored wetlands. Though carbon stored in vegetation often is viewed as being susceptible to loss from disturbances, such as fire, vegetative communities often quickly 

reestablish. Given the resilient nature of plant communities, 

carbon storage in vegetation is an almost immediate and rather 

constant form of carbon storage.

In summary, SOC sequestration is considered an ancillary benefit of USDA conservation programs because climate 

change mitigation was not an intended outcome when the 

CRP and WRP were originally implemented. Hence, it is 

considered an additional ecological service that may contribute to offsetting greenhouse gas emissions. As demonstrated 

by our work, more research is necessary to quantify rates of 

atmospheric carbon sequestration and its storage in the soil 

and vegetation on program lands. In addition to sequestering 

carbon, conservation programs also may influence emission 

of other greenhouse gases such as N2O and CH4. Though there 

is little information on N2O and CH4 emissions from prairie 

wetlands, studies outside the Prairie Pothole Region have demonstrated that nutrient enrichment from agricultural runoff can 

influence emission of these greenhouse gases (Merbach and 

others, 2002). Consequently, converting cultivated cropland to 

perennial grassland within restored catchments should reduce 

nutrient enrichment in restored wetlands (see chap. E) and 

could lower emission of N2O and CH4 relative to a cropland 

baseline. Any reduction in emissions of CH4 and N2O that 

results from restorations relative to a cropland baseline would 

represent an additional greenhouse gas reduction benefit.

References

Anderson, D.W., 1995, Decomposition of organic matter 

and carbon emissions from soils, in Lal, R., Kimble, J.M., 

Levine, E., and Stewart, B.A., eds., Soils and global change: 

Boca Raton, Fla., CRC Press, p. 165–175.

Cihacek, L.J., and Ulmer, M.G., 1995, Estimated soil organic 

carbon losses from long-term crop-fallow in the northern 

Great Plains of the USA, in Lal, R., Kimble, J.M., Levine, 

E., and Stewart, B.A., Soil management and greenhouse 

effect: Boca Raton, Fla., CRC Press, p. 85–92.

Euliss, N.H., Jr., Gleason, R.A., Olness, A., McDougal, R.L., 

Murkin, H.R., Robarts, R.D., Bourbonniere, R.A., and 

Warner, B.G., 2006, North American prairie wetlands are 

important nonforested land-based carbon storage sites: 

Science of the Total Environment, v. 361, p. 179–188.

Follett, R.F., Pruessner, E.G., Samson-Liebig, S.E., Kimble, 

J.M., and Waltman, S.W., 2001, Carbon sequestration under 

the Conservation Reserve Program in the historic grassland 

soils of the United States of America, in Lal, R., ed., Carbon 

sequestration and greenhouse effect: Soil Science Society of 

America, Special Publication No. 57, p. 27–40.

Klute, A., ed., 1986, Methods of soil analysis, part 

1—Physical and mineralogical methods (2d ed.): Madison, 

Wis., Soil Science Society of America.

Knutsen, G.A., and Euliss, N.H., Jr., 2001, Wetland restoration 

in the prairie pothole region of North America—a literature 

review: Reston, Va., U.S. Geological Survey, Biological 

Resources Division, Biological Science Report, 

USGS/BRD/BSR 2001-0006.

Lal, R., Kimble, J.M., Follett, R.F., and Cole, C.V., 1998, The 

potential for U.S. cropland to sequester carbon and mitigate 

the greenhouse effect: Chelsea, Mich., Ann Arbor Press.

Mann, L.K., 1986, Changes in soil carbon storage after cultivation: Soil Science, v. 142, p. 279–288.

Merbach, W., Kalettka, T., Rudat, C., and Augustin, J., 2002, 

Trace gas emissions from riparian areas of small eutrophic 

inland waters in Northeast-Germany, in Broll, G., Merbach, 

W., and Pfeiffer, E.V., eds., Wetlands in Central Europe, soil 

organisms, soil ecological processes, and trace gas emissions: Berlin, Springer, p. 235–244.

Page, A.L., Miller, R.H., and Keeney, D.R., eds., 1982, Methods of soil analysis, part 2—Chemical and microbiological 

properties (2d ed.): Madison, Wis., Soil Science Society of 

America.

SAS Institute, Inc., 1999, SAS/STAT user’s guide: Cary, N.C., 

SAS Institute, Inc., Online Doc Version 8.

U.S. Environmental Protection Agency, 2003, Inventory of 

U.S. greenhouse gas emissions and sinks—1990–2001: 

Washington, D.C., U.S. Environmental Protection Agency, 

596 p.

van der Valk, A.G., and Davis, C.B., 1978, The role of seed 

banks in the vegetation dynamics of prairie glacial marshes: 

Ecology, v. 59, p. 322–335.

30 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Chapter D: Floodwater Storage

By Robert A. Gleason and Brian A. Tangen

Synopsis

Traditionally wetlands in the Prairie Pothole Region 

have been considered valuable resources for attenuating and 

storing water that would otherwise contribute to offsite or 

“downstream” flooding, but the current status of floodwater 

storage potential of wetlands in the Prairie Pothole Region 

is vague. Wetland drainage for agricultural use has significantly decreased wetland storage volume (Dahl, 1990; Dahl 

and Johnson, 1991), and this reduction has been linked to 

increased frequency of flooding in the Prairie Pothole Region 

(Brun and others, 1981; Miller and Frink, 1984; Miller and 

Nudds, 1996; Manale, 2000). In an effort to mitigate wetland 

losses, numerous wetlands have been restored through various 

Federal, State, and private programs. For example, during the 

past 19 years, enrollment in the U.S. Department of Agriculture (USDA) Conservation Reserve Program (CRP) and Wetlands Reserve Program (WRP) has resulted in the restoration 

of approximately 168,554 ha (416,497 acres) of wetlands on 

2,199,476 ha (5,434,905 acres) of program lands in the Prairie 

Pothole Region (table A–1). Aside from wildlife benefits (see 

chap. F), floodwater attenuation is one of the most widely 

recognized ecosystem services provided by restored wetlands, 

even though estimates of storage potential are lacking.

The objective of this chapter is to quantify the waterstorage potential of wetlands on program lands in the Prairie 

Pothole Region. To address this goal we used morphometry 

data collected on 497 wetlands in the Prairie Pothole Region 

to develop models that define relationships between wetland 

surface area, wetland volume, and upland zone area. These 

models were used to estimate maximum water-storage 

capacity and interception area of wetlands on program lands. 

We estimated that wetland catchments on program lands 

in the Prairie Pothole Region could intercept precipitation 

across approximately 444,574 ha (1,098,542 acres) and store 

approximately 56,513 ha-m (458,151 acre-ft) of water if filled 

to maximum capacity, which equates to an average storage volume of 0.34 ha-m∙ha-1 (1.1 acre-ft∙acre-1) of wetland. 

Water-storage estimates presented in this paper are believed to 

provide a reasonable first approximation of flood-storage benefits derived from USDA conservation programs in the Prairie 

Pothole Region, but estimates likely are conservative because 

databases used to estimate total wetland area tend to underestimate wetland areas on lands in the Prairie Pothole Region. 

Further, our static estimates of maximum wetland water storage do not account for dynamic hydrologic processes, such 

as evapotranspiration, ground-water recharge, and infiltration, that slow the rates that wetlands fill. Consequently, the 

flood-storage service provided by wetlands is greater than the 

maximum total water-storage potential reported in this study. 

Essential to future development and application of methods 

to quantify flood-storage benefits is the availability of quality 

spatial data that can be used to determine important habitat 

features, such as individual wetlands, and specific management actions, such as hydrologic restoration, nondrained restoration, seeded areas, nonseeded areas, that affect water input 

rates and amounts of water storage. Availability of such data 

will facilitate application of models to better quantify dynamic 

floodwater-storage benefits at both site-specific and watershed 

scales.

Methods

Topographic Surveys

We used morphometry data collected on 497 depressional 

wetland catchments, including 386 catchments sampled during 

the 1997 and 2004 surveys (tables A–2, A–3, and fig. A–3) 

and 111 catchments surveyed as part of other U.S. Geological Survey studies (Gleason and others, 2007). Morphometry 

of each catchment was surveyed by using a Nikon model 

DTM 750 total station during 1997 and a Trimble 5700 GPS 

system during 2004. Features surveyed included drainage 

plugs, tile drains, surface outlets and inlets, and surface water 

elevation. We used the software program ForeSight (Tripod 

Data Systems, 1997) to compute the surface area and volume 

of the wetland zone and the surface area of the upland zone 

(fig. A–6). The maximum area of the wetland zone was based 

on the elevation at which surface water would flow out of 

the wetland (fig. A–6). Wetland volume was determined by 

specifying the maximum elevation of the wetland in ForeSight 

and calculating the fill volume for each wetland polygon. The 

upland zone is defined as the area that contributes surface 

runoff to a wetland and was defined by interpreting contour 

maps and digital elevation models constructed by using the 

survey data. Upland areas sloping toward a wetland basin were 

considered part of the catchment, whereas areas sloping away 

from the wetland basin were considered outside of the catchment.

Model Development

We used linear regression analysis (SAS Institute, Inc., 

2003) to determine the relationship of wetland zone area to 

wetland volume and upland zone area. For all regression models, areas and volumes were transformed by using the natural 

logarithm. Initial results indicated that relationships among 

variables differed among each of the physiographic regions 

of the Prairie Pothole Region, which vary in topographic 

relief (fig. A–3). Therefore, we developed unique models for 

each physiographic region to improve estimates. Coefficients 

of determination (r2) for wetland volume regression models 

Chapter D: Floodwater Storage 31
varied from 0.91 to 0.94 and for upland zone models ranged 

from 0.49 to 0.65 (table D–1). Across a range of wetland 

surface areas (1–10 ha [2.47–24.7 acres]) typical of the 

Prairie Pothole Region, our models predicted greater storage 

volumes and upland zone areas for catchments in the prairie 

coteau, followed by the Missouri coteau and glaciated plains 

(fig. D–1).

Estimating Water Storage, Upland Zones of 

Catchments, and Interception Areas

The regression models we developed generally are 

applied to surface areas of individual depressional wetlands, 

but this information was not available for wetlands on program 

lands. Since data on individual wetlands were not available 

as inputs for models presented in table D–1, we calculated a 

mean wetland area for seasonal and semipermanent wetlands 

surveyed in 2004 (table A–3). This mean wetland surface area 

of 1.6 ± 0.1 ha (4.0 ± 0.2 acres) was input into our regionspecific models (table D–1) to estimate an average storage 

volume and upland zone area per hectare of wetland. The 

region-specific estimates were applied to the total area of 

wetlands on program lands (table A–1) within each State/

Major Land Resource Area (MLRA) combination (fig. A–4). 

For State-MLRA combinations that occurred in more than one 

physiographic region, we assigned estimates from the physiographic region that encompassed the most land area. Application of this approach assumes that the average surface area of 

seasonal and semipermanent wetlands entered into models is 

representative of wetland sizes on program lands. Seasonal 

and semipermanent wetlands were chosen because they are 

the most common catchment types restored on program lands. 

More precise estimates could be calculated if surface areas of 

individual wetlands on program lands were available.

Wetland and upland zone areas were combined to estimate the area of the entire catchment, which is also called the 

interception area of the wetland (fig. A–6). The interception 

area represents an area that intercepts precipitation and does 

not route surface water “downstream” in a watershed unless 

the wetland fills to capacity and overflows. Estimates of the 

upland zone and entire catchment areas were constrained by 

the area of land enrolled in conservation programs: the area of 

wetland catchments could not be greater than the area of land 

enrolled in conservation programs. This situation frequently 

occurs when wetlands are located in small tracts of conservation program lands that contain wetland zone areas but not the 

entire area of upland zones.

Results

We estimated that wetlands on program lands in the 

Prairie Pothole Region have a maximum water-storage 

capacity of 56,513 ha-m (458,151 acre-ft), with 53,680 ha-m 

(435,184 acre-ft) occurring on CRP lands and 2,833 ha-m 

(22,967 acre-ft) on WRP lands (table D–2). This estimate 

translates to an average storage volume of 0.34 ha-m∙ha-1

(1.1 acre-ft∙acre-1) of wetland. Total area of upland zones 

associated with wetlands was estimated to be 276,021 ha 

(682,048 acres) (table D–3) or approximately 1.6 ha 

(4.0 acres) of upland zone per hectare of wetland. Estimated 

catchment area was 444,574 ha (1,098,542 acres), which 

accounts for 20 percent of the total land area (2,199,476 ha 

[5,434,905 acres]) enrolled in the CRP and WRP in the Prairie 

Pothole Region.

Discussion

Attempts to estimate water-storage potential of program 

and nonprogram wetlands in the Prairie Pothole Region are 

constrained by lack of information on wetland volumes and 

catchment areas. The primary constraint is inadequate resolution of available databases, such as topographic and digital 

elevation maps, to determine the bathymetry of individual 

depressional wetlands. Given this constraint, we developed 

models that defined relationships between wetland surface 

area, wetland volume, and upland zone area (table D–1). For 

all models developed, wetland surface area was strongly correlated to wetland volume (r2

 = 0.91–0.94) and upland zone area 

(r2 = 0.49–0.65) (table D–1). Many other studies have used 

similar approaches to estimate wetland volumes from surface 

area estimates (Haan and Johnson, 1967; Best, 1978; Best and 

Moore, 1979; Hubbard, 1982; Bell and others, 1999; Bengtson 

and Padmanabhan, 1999; Hayashi and van der Kamp, 2000; 

Wiens, 2001; Gleason and others, 2007). Ideally, input data 

for these models would include the area of individual wetland 

basins, which often can be acquired from available spatial 

databases such as the National Wetlands Inventory (NWI). 

At the time of our study, however, information on areas of 

individual wetland basins on program lands was not available. 

Therefore, we used the mean size of wetlands surveyed for this 

study as a model input to estimate wetland storage volumes 

and upland areas per hectare of wetland. These estimates were 

applied to estimates of total wetland areas on program lands to 

calculate volumes and upland zone areas. Using this approach, 

we estimated an average storage volume of 0.34 ha-m∙ha-1

(1.1 acre-ft∙acre-1) of wetland and an average upland zone area 

of 1.6 ha (4.0 acres) per hectare of wetland, which are within 

the range of values found in other studies (Haan and Johnson, 

1967; Best, 1978; Best and Moore, 1979; Hubbard, 1982; 

Arndt and Richardson, 1988; Bell and others, 1999; Bengtson 

and Padmanabhan, 1999; Hayashi and van der Kamp, 2000; 

Wiens, 2001).

We believe that our estimates provide a reasonable first 

approximation of the potential flood-storage benefit derived 

from USDA programs. The greatest source of uncertainty 

associated with our storage estimate is the estimate of total 

wetland area on program lands. The availability of quality 

spatial data that can be used to differentiate habitat features 

of interest, such as individual wetlands, and specific management actions, such as hydrologic restoration, nondrained 

restoration, seeded areas, and nonseeded areas, is critical to 

32 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Table D–1. Models developed to estimate wetland volume and upland zone area by physiographic region in the Prairie Pothole Region.

[Size refers to wetland area for volume models and to upland zone area for upland zone area models. V, predicted wetland volume, in hectare meters; UA, predicted upland zone area, in hectares; A, maximum wetland area, in hectares, from ground survey or spatial data, such as the National Wetlands Inventory]

Predicted 

variable

Physiographic 

region Number

Size, in hectares

Model

(volume or area)

Coefficient of 

determination 

(r2 Mean Range )

Wetland volume Glaciated plains 288 0.92 0.002–9.25 V = 0.25A1.4742 0.91

Wetland volume Missouri coteau 186 1.28 0.01–11.29 V = 0.398A1.542 0.91

Wetland volume Prairie coteau 23 2.22 0.24–7.08 V = 0.458A1.5611 0.94

Upland zone area Glaciated plains 288 2.19 0.06–12.99 UA = 2.24A0.4647 0.49

Upland zone area Missouri coteau 186 2.70 0.07–18.56 UA = 2.42A0.5172 0.62

Upland zone area Prairie coteau 23 3.85 0.62–9.03 UA = 2.27A0.6603 0.65

future development and application of methods to estimate 

any ecological service derived from conservation programs. 

Existing databases, such as the NWI, can be used to identify 

some wetlands on program lands, but many drained wetlands 

that are subsequently restored often are not mapped by NWI 

(Gleason and others, 2007). Consequently, development of 

a spatial database of wetlands on program lands likely will 

require the use of existing spatial databases in conjunction 

with input from field personnel responsible for implementing 

USDA conservation practices.

We estimated that wetland catchments on program lands 

in the Prairie Pothole Region could intercept precipitation 

across approximately 444,574 ha (1,098,542 acres) and could 

store approximately 56,513 ha-m (458,151 acre-ft) of water 

if filled to maximum capacity. These estimates suggest that 

wetlands on program lands have significant potential to intercept and store precipitation that otherwise might contribute 

to “downstream” flooding. The potential of program lands to 

reduce flooding offsite was not addressed in this study, but 

other studies in the Prairie Pothole Region have demonstrated 

the benefits of wetlands at a watershed scale to intercept and 

store water. Ludden and others (1983) reported that depressional wetlands in the Devils Lake basin of North Dakota 

could store approximately 72 and 41 percent of the total runoff 

volume from a 2-year and 100-year frequency runoff event, 

respectively. Vining (2002) reported that pothole wetlands 

in the Starkweather Coulee subbasin (more than 80,000 ha 

[197,680 acres]) in the watershed of Devils Lake were capable 

of storing more than 8,000 ha-m (64,856 acre-ft) of water. 

Additionally, Malcolm (1979) reported that a complex of 

wetlands retained all local runoff plus 58 percent of additional inflow, and Gleason and others (2007) reported restoring drained and farmed wetlands could increase the water 

retention capacity of a watershed in the Prairie Pothole Region 

of Minnesota by up to 63 percent.

The water-storage benefit of wetlands on program or nonprogram lands is much more complex than simply estimating 

a “static” maximum water-storage potential. Such estimates 

only represent a gross storage volume and do not account for 

how wetlands process and store precipitation. The capacity 

of wetland catchments to intercept, process, and store water 

is influenced by many factors, including timing and amount 

of precipitation, land use, vegetation, topographic relief, soil 

type, evapotranspiration, temperature, and type of groundwater connection. For example, studies have demonstrated 

that wetlands surrounded by croplands generally receive 

greater surface water inputs than do wetlands surrounded by 

grasslands (Euliss and Mushet, 1996; Gleason, 1996). This 

difference is due, in part, to the ability of plants to slow runoff 

and increase the infiltration capacity of the soil. Consequently, 

conversion of cultivated cropland to grassland cover as part 

of conservation programs results in a reduction in surface 

water runoff and, ultimately, reduces the rate at which a basin 

fills and overflows. Wetland catchments also remove large 

quantities of water via transpiration and evaporation (Shjeflo, 

1968; Millar, 1971; Winter, 1989; Parkhurst and others, 

1998). Although it is a relatively slow process, wetlands also 

recharge ground-water supplies through infiltration (Shjeflo, 

1968; Winter and Rosenberry, 1995). Hence, there are many 

hydrologic processes, such as water gains and losses, occurring within wetland catchments that need to be considered to 

improve the accuracy and precision of flood-storage estimates. 

These factors must be incorporated into existing models to 

provide a better understanding of the capacity of wetlands 

to attenuate and store water over time (Gleason and others, 

2007).

Another often overlooked water-storage benefit of USDA 

conservation programs is that planting of catchments to perennial cover extends the topographic life of basins by reducing 

the inflow of sediments from the uplands as a result of erosion, 

thus maintaining storage volumes (Gleason and Euliss, 1998; 

Gleason, 2001). Gleason (2001) projected that, after 200 years 

of cultivation, 35 percent of his study wetlands (n = 77) would 

no longer be able to attain water depths great enough to 

overtop and kill tall, robust, emergent plants, such as cattails 

(Typha sp.), thus altering natural vegetation communities. 

Additionally, 17 and 21 percent of wetlands from the 1997 and 

2004 surveys, respectively, had soil horizons buried to depths 

Chapter D: Floodwater Storage 33
0

2

4

6

8

10

12

14

16

18

Prairie coteau

Missouri coteau

Glaciated plains

WETLAND SURFACE AREA, IN HECTARES

PREDICTED UPLAND ZONE AREA, IN HECTARES

0

2

4

6

8

10

12

Prairie coteau

Missouri coteau

Glaciated plains

A

B

1 2 3 4 5 6 7 8 9 10

PREDICTED WETLAND VOLUME, IN HECTARE METERS

WETLAND SURFACE AREA, IN HECTARES

1 2 3 4 5 6 7 8 9 10

Figure D–1. Models developed to predict upland zone areas 

(A) and wetland volumes (B) for the primary physiographic 

regions of the Prairie Pothole Region. For each predicted 

variable, the models generally depict greater values for the 

prairie coteau, followed by the Missouri coteau and glaciated 

plains.

ranging from 9 to 116 cm (3.5 to 45.7 in), indicating considerable losses in water-storage volumes (see chap. C).

In summary, we developed models to estimate waterstorage capacity and upland zone areas of wetlands on 

program lands. Application of these models was limited by 

the uncertainty associated with estimates of wetland areas on 

program lands; however, water-storage estimates presented in 

this paper are believed to provide a reasonable and conservative first approximation of flood-storage benefits derived from 

USDA conservation programs in the Prairie Pothole Region. 

Water-storage estimates are likely conservative because the 

databases used to estimate total wetland areas on program 

lands tend to underestimate wetland area (Gleason and others, 2005, 2007). Further, our static estimates of maximum 

wetland water storage do not account for dynamic hydrologic 

processes that attenuate the rate at which wetlands fill and 

overflow. Consequently, the flood-storage service provided by 

wetlands is greater than the maximum water-storage potential 

reported in this study.

Essential to future development and application of 

methods to quantify all ecological services, including floodstorage benefits, is the availability of quality spatial data that 

can be used to identify important habitat features, such as 

individual wetlands, and specific management actions, such as 

hydrologic restoration, nondrained restoration, seeded areas, 

and nonseeded areas. Availability of such data will facilitate 

application of models to better quantify dynamic floodwaterstorage benefits at both site-specific and watershed scales.

References

Arndt, J.L., and Richardson, J.L., 1988, Hydrology, salinity 

and hydric soil development in a North Dakota prairiepothole wetland system: Wetlands, v. 8, p. 93–108.

Bell, A., Eckhardt, D., and Pucherelli, M., 1999, Wetlands 

inventory and drained wetlands water storage capacity estimation for the St. Joe-Calio Coulee subbasin of the greater 

Devils Lake basin, North Dakota: Denver, Colo., U.S. 

Department of the Interior, Bureau of Reclamation, Technical Memorandum No. 8260–99–02.

Bengtson, M.L., and Padmanabhan, G., 1999, Hydrologic 

model for assessing the influence of wetlands on flood 

hydrographs in the Red River basin—development and 

application: Fargo, North Dakota State University, North 

Dakota Water Research Institute, report submitted to the 

International Joint Commission Red River Task Force.

Best, R.G., 1978, Utilization of color-infrared aerial photography to characterize prairie potholes, in PECORA IV, 

Proceedings of the Symposium on Application of Remote 

Sensing Data to Wildlife Management: Sioux Falls, S. Dak., 

National Wildlife Federation, Scientific and Technical 

Series 3, p. 180–187.

34 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Table D–2. Wetland areas (table A–1) and estimated maximum water storage volumes of wetlands enrolled in U.S. Department of 

Agriculture conservation programs in the Prairie Pothole Region. The ranges of maximum volumes are based on the mean (± standard 

error) wetland area of surveyed seasonal and semipermanent wetlands (see “Methods,” this chapter).

[ft, feet; CRP, Conservation Reserve Program; WRP, Wetlands Reserve Program; --, no data]

State

Wetland area, in hectares 

(acres)

Maximum volume, in hectare meters 

(acre-ft)

CRP WRP CRP WRP

Iowa 24,172

(59,729)

5,076

(12,543)

7,251–7,735

(58,784–62,708)

1,523–1,624

(12,347–13,166)

Minnesota 51,848

(128,116)

3,168

(7,828)

15,554–16,591

(126,096–134,503)

950–1,014

(7,702–8,220)

Montana 2,996

(7,403)

--

--

1,468–1,558

(11,901–12,631)

--

--

North Dakota 61,669

(152,384)

199

(492)

19,154–20,422

(155,281–165,561)

60–64

(486–519)

South Dakota 18,887

(46,670)

539

(1,332)

8,496–9,130

(68,877–74,017)

207–223

(1,678–1,808)

Prairie Pothole Region totals 159,572

(394,302)

8,982

(22,195)

51,923–55,436

(420,940–449,420)

2,740–2,925

(22,213–23,713)

Table D–3. Wetland zone areas (table A–1) and estimated upland zone and catchment areas of wetlands enrolled in U.S. Department 

of Agriculture conservation programs in the Prairie Pothole Region. The areas are based on the mean (± standard error) wetland area of 

surveyed seasonal and semipermanent wetlands (see “Methods,” this chapter).

[CRP, Conservation Reserve Program; WRP, Wetlands Reserve Program; --, no data]

State

Wetland zone area, in 

hectares (acres) Upland zone area, in hectares (acres) Catchment area, in hectares (acres)

CRP WRP CRP WRP CRP WRP

Iowa 24,172

(59,729)

5,076

(12,543)

1

29,011

(71,686)

6,106–6,110

(15,088–15,098)

1

53,182

(131,413)

11,182–11,186

(27,631–27,641)

Minnesota 51,848

(128,116)

3,168

(7,828)

81,465–84,584

(201,300–209,007)

4,732–4,800

(11,693–11,861)

133,313–136,432

(329,416–337,123)

7,900–7,968

(19,521–19,689)

Montana 2,996

(7,403)

--

--

5,693–6,053

(14,067–14,957)

--

--

8,690–9,049

(21,473–22,360)

--

--

North Dakota 61,669

(152,384)

199

(492)

106,107–114,089

(262,190–281,914)

341–367

(843–907)

167,776–175,758

(414,575–434,298)

540–566

(1,334–1,399)

South Dakota 18,887

(46,670)

539

(1,332)

34,731–36,864

(85,820–91,091)

957–1,020

(2,365–2,520)

53,618–55,751

(132,490–137,761)

1,496–1,559

(3,697–3,852)

Prairie Pothole 

Region totals

159,572

(394,302)

8,982

(22,195)

257,007–270,601

(635,064–668,655)

12,136–12,297

(29,988–30,386)

416,579–430,172

(1,029,367–1,062,955)

21,118–21,279

(52,183–52,580)

1

 Range is not presented; the high and low estimates were the same as a result of constraining the estimates by the area of conservation program lands (see 

“Methods,” this chapter).

Chapter D: Floodwater Storage 35
Best, R.G., and Moore, D.G., 1979, Landsat interpretation of 

prairie lakes and wetlands of eastern South Dakota, in Satellite Hydrology, Proceedings of the Fifth Annual William T. 

Pecora Memorial Symposium on Remote Sensing: American Water Resources Association Technical Publication 

Series TPS 81–1, p. 499–506.

Brun, L.J., Richardson, J.W., Enz, J.W., and Larsen, J.K., 

1981, Stream flow changes in the southern Red River valley of North Dakota: North Dakota Farm Research, v. 38, 

p. 11–14.

Dahl, T.E., 1990, Wetland losses in the United States 1780s to 

1980s: Washington, D.C., U.S. Department of the Interior, 

Fish and Wildlife Service.

Dahl, T.E., and Johnson, C.E., 1991, Status and trends of 

wetlands in the coterminous United States, mid-1970s to 

mid-1980s: Washington, D.C., U.S. Department of the Interior, Fish and Wildlife Service.

Euliss, N.H., Jr., and Mushet, D.M., 1996, Water-level fluctuation in wetlands as a function of landscape condition in the 

prairie pothole region: Wetlands, v. 16, p. 587–593.

Gleason, R.A., 1996, Influence of agricultural practices on 

sedimentation rates, aquatic invertebrates, and bird-use in 

prairie wetlands: Arcata, Calif., Humboldt State University, 

master’s thesis.

Gleason, R.A., 2001, Invertebrate egg and plant seed banks 

in natural, restored, and drained wetlands in the prairie 

pothole region (USA) and potential effects of sedimentation 

on recolonization of hydrophytes and aquatic invertebrates: 

Brookings, South Dakota State University, Ph.D. dissertation.

Gleason, R.A., and Euliss, N.H., Jr., 1998, Sedimentation of 

prairie wetlands: Great Plains Research, v. 8, p. 97–112.

Gleason, R.A., Euliss, N.H., Jr., McDougal, R.L., and Kermes, 

K.E., 2005, Potential of restored prairie wetlands in the 

glaciated North American prairie to sequester atmospheric 

carbon: Grand Forks, N. Dak., Energy and Environmental 

Research Center, Plains CO2 Reduction Partnership topical 

report August 2005.

Gleason, R.A., Tangen, B.A., Laubhan, M.K., Kermes, K.E., 

and Euliss, N.H., Jr., 2007, Estimating water storage capacity of existing and potentially restorable wetland depressions in a subbasin of the Red River of the North: U.S. 

Geological Survey Open-File Report 2007–1159, 36 p.

Haan, C.T., and Johnson, H.P., 1967, Geometrical properties 

of depressions in north-central Iowa: Iowa State Journal of 

Science, v. 42, p. 149–160.

Hayashi, M., and van der Kamp, G., 2000, Simple equations 

to represent the volume-area-depth relations of shallow wetlands in small topographic depressions: Journal of Hydrology, v. 237, p. 74–85.

Hubbard, D.E., 1982, Surface area-volume relationship of 

wetland basins in the interior of the Coteau Des Prairies: 

Proceedings of the South Dakota Academy of Sciences, 

v. 61, p. 154–158.

Ludden, A.P., Frink, D.L., and Johnson, D.H., 1983, Water 

storage capacity of natural wetland depressions in the Devils Lake basin of North Dakota: Journal of Soil and Water 

Conservation, v. 38, no. 1, p. 45–48.

Malcolm, J.M., 1979, The relationship of wetland drainage to 

flooding and water quality problems and its impacts on the 

J. Clark Salyer National Wildlife Refuge: Upham, N. Dak., 

U.S. Department of the Interior, Fish and Wildlife Service, 

J. Clark Salyer National Wildlife Refuge.

Manale, A., 2000, Flood and water quality management 

through targeted, temporary restoration of landscape functions—paying upland farmers to control runoff: Journal of 

Soil and Water Conservation, v. 55, p. 285–295.

Millar, J.B., 1971, Shoreline-area ratio as a factor in rate of 

water loss from small sloughs: Journal of Hydrology, v. 14, 

p. 259–284.

Miller, J.E., and Frink, D.L., 1984, Changes in flood response 

of the Red River of the North basin, North Dakota-Minnesota: U.S. Geological Survey Water-Supply Paper 2243.

Miller, M.W., and Nudds, T.D., 1996, Prairie landscape change 

and flooding in the Mississippi River Valley: Conservation 

Biology, v. 10, p. 847–853.

Parkhurst, R.S., Winter, T.C., Rosenberry, D.O., and Sturrock, 

A.M., 1998, Evaporation from a small prairie wetland in the 

Cottonwood Lake area, North Dakota—an energy-budget 

study: Wetlands, v. 18, p. 272–287.

SAS Institute, Inc., 2003, SAS software release 9.1: Cary, 

N.C., SAS Institute, Inc.

Shjeflo, J.B., 1968, Evapotranspiration and the water budget 

of prairie potholes in North Dakota: U.S. Geological Survey 

Professional Paper 585–B.

Tripod Data Systems, 1997, ForeSight for Windows: Corvallis, 

Oreg., Tripod Data Systems, Inc.

36 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Vining, K.C., 2002, Simulation of streamflow and wetland 

storage, Starkweather Coulee subbasin, North Dakota, water 

years 1981–98: U.S. Geological Survey Water-Resources 

Investigations Report 02-4113.

Wiens, L.H., 2001, Surface area volume relationship for 

prairie wetlands in the upper Assiniboine River basin, 

Saskatchewan: Canadian Water Resources Journal, v. 26, 

p. 503–513.

Winter, T.C., 1989, Hydrologic studies of wetlands in the 

northern prairie, in van der Valk, A., ed., Northern prairie 

wetlands: Ames, Iowa State University Press, p. 16–54.

Winter, T.C., and Rosenberry, D.O., 1995, The interaction of 

ground water with prairie pothole wetlands in the Cottonwood Lake Area, east Central North Dakota, 1979–1990: 

Wetlands, v. 15, p. 193–211.

Chapter D: Floodwater Storage 37
Chapter E: Reduction of Sedimentation and Nutrient Loading

By Brian A. Tangen and Robert A. Gleason

Synopsis

In terms of quantity, sediment is the largest pollutant of 

wetlands, lakes, estuaries, and reservoirs in the United States 

(Baker, 1992; U.S. Environmental Protection Agency, 1995). 

Though soil erosion and sedimentation occur naturally, agricultural activities often accelerate soil erosion above natural 

baselines and result in excessive sedimentation of aquatic 

habitats. This process is especially true of depressional wetlands in the Prairie Pothole Region, where most native grasslands that once mitigated soil erosion and surface runoff have 

been converted to cropland. Consequently, prairie wetlands in 

cultivated catchments often receive soils eroded from upland 

zones that contribute to accelerated sedimentation or filling of 

wetland depressions. Studies have demonstrated that prairie 

wetlands within cropland catchments have greater sediment 

inputs than do wetlands in grasslands (Adomaitis and others, 

1967; Martin and Hartman, 1987; Gleason, 1996; Gleason 

and Euliss, 1998, Gleason 2001). These sediment inputs can 

directly or indirectly affect wetland functions, such as floodwater storage and wildlife habitat, by reducing the topographic 

life of depressional basins and altering biotic communities 

and overall wetland productivity. A primary benefit of U.S. 

Department of Agriculture (USDA) conservation programs is 

the reduction of wind and water soil erosion when grassland is 

reestablished on erosive or environmentally sensitive cropland as part of the Conservation Reserve Program (CRP) and 

Wetlands Reserve Program (WRP). More than 2.2 million ha 

(5.4 million acres) of grassland and wetland habitats have been 

restored in the Prairie Pothole Region through these programs; 

however, the potential of these programs to reduce sedimentation and nutrient loading of prairie wetlands has not been 

quantified.

The objective of this chapter is to quantify the potential 

of the CRP and the WRP to reduce upland soil losses and 

potential nutrient loading and sedimentation of wetland basins 

in the Prairie Pothole Region. We used the Revised Universal 

Soil Loss Equation (RUSLE) to estimate the change in soil 

erosion rates on upland zones of catchments when tillage 

was replaced with perennial cover as part of the CRP and 

WRP. We estimated that conversion of cultivated cropland to 

perennial cover reduced total soil loss by 1,760,666 Mg∙yr-1

(1,940,254 tons∙yr-1) on 276,021 ha (682,048 acres) of upland 

zones on Prairie Pothole Region lands enrolled in the CRP 

and WRP. For this same area, we estimated that nitrogen 

and phosphorus losses would be reduced by 5,102 Mg∙yr-1

(5,622 tons∙yr-1) and 68 Mg∙yr-1 (75 tons∙yr-1), respectively. 

Assuming that reduction in annual losses remains static, we 

estimated a cumulative soil loss reduction of 21,156,125 Mg 

(23,314,050 tons) and a cumulative reduction in nitrogen and 

phosphorus losses of 60,772 Mg (66,971 tons) and 798 Mg 

(879 tons), respectively, since lands have been enrolled in 

conservation programs. Our results indicate that conservation 

practices can significantly reduce soil and nutrient losses from 

upland zones of catchments, thereby improving the sustainability of other ecological services, such as wildlife habitat and 

floodwater storage, provided by wetlands through lowering 

unnatural deposition rates of these substances in the wetland 

zone of catchments.

Methods

We used the RUSLE to estimate pre- and post-program 

soil erosion rates of catchments on CRP and WRP lands. The 

RUSLE is defined as follows:

A = R∙K∙L∙S∙C∙P,

where

A is the estimated average annual soil loss per 

unit area caused by rainfall,

R is the climatic erosivity factor (the erosion 

force of rainfall as determined by kinetic 

energy and 30-minute intensity),

K is the soil erodibility factor (the susceptibility 

of soil to erosion and rate of runoff),

L and S are the slope length and steepness factors,

C is the cover and management factor (the effect 

of plants, soil cover, soil biomass, and soildisturbance activities relative to erosion), 

and

P is the supporting practice factor (the impact 

of support practices on erosion rate [for 

example, contouring or stripcropping 

relative to row farming parallel to slope, on 

erosion rate]).

We calculated average values for R, K, and C by using 

data obtained from the 1997 National Resources Inventory 

(NRI) database (U.S. Department of Agriculture, 2000) for 

soil series common to both cultivated croplands and program 

lands within each Major Land Resource Area (MLRA) in the 

Prairie Pothole Region (table E–1 and fig. A–4). The NRI 

does not include information for lands enrolled in the WRP. 

Therefore, we assumed that soil data obtained from NRI for 

CRP lands were representative of WRP lands because lands 

and restoration methods are often comparable among these 

two programs. The P value was set at 1 for all soil-loss estimates because specific cropping practices are unknown and a 

P value of 1 does not have an effect on the RUSLE estimates. 

An average topographic factor LS (table E–1), which replaces 

the individual L and S factors in RUSLE (Renard and others, 

38 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Table E–1. Revised Universal Soil Loss Equation (RUSLE) factor values used to estimate average annual soil losses for cultivated 

croplands and conservation program lands.

[CRP, Conservation Reserve Program; MLRA, Major Land Resource Area; RUSLE, Revised Universal Soil Loss Equation; WRP, Wetlands Reserve Program]

MLRA

Common 

soil 

series 

(number)

RUSLE1 factor values

Climate 

erosivity 

(R)

2

Soil 

erodibility 

(K)

2

Slope 

length 

(L)

3

Steepness 

(S)

3

Practice 

factor 

(P)

Cover management

(C)

2 LS4

Cropland CRP/WRP Cropland CRP/WRP

102A 64 104.21 0.28 33.82 0.02 1 0.24 0.015 0.33 0.32

102B 27 120.48 0.30 65.97 0.02 1 0.25 0.014 0.40 0.36

103 74 144.06 0.25 51.63 0.04 1 0.26 0.020 0.52 0.47

53A 29 42.53 0.32 56.20 0.07 1 0.30 0.016 1.17 1.02

53B 48 57.45 0.28 47.44 0.07 1 0.21 0.020 1.10 0.98

53C 18 71.42 0.31 55.00 0.02 1 0.15 0.010 0.30 0.28

55A 36 52.51 0.27 40.22 0.03 1 0.21 0.022 0.35 0.33

55B 66 68.29 0.27 43.05 0.05 1 0.23 0.015 0.76 0.68

55C 23 95.96 0.30 49.04 0.03 1 0.22 0.010 0.44 0.40

1 RUSLE equation: A = R∙K∙L∙S∙C∙P, where A = average annual soil loss per unit area caused by rainfall.

2 Values from 1997 National Resources Inventory data for soil series common to cultivated cropland and CRP lands.

3 Values based on mean upland zone slope length and steepness (percent) obtained from 2004 topographic surveys (for MLRA 102B, values were calculated 

from the 1997 National Resources Inventory because of the lack of survey data).

4 LS values calculated by using tables from Renard and others (1997).

1997), was estimated by using morphometry data (L and S

values) collected from 270 catchments surveyed during 2004 

(table A–3 and fig. A–3). Morphometry of each catchment was 

surveyed by using a Trimble 5700 GPS system. The software 

program ForeSight (Tripod Data Systems, 1997) was used to 

compute the average grade (S) and length (L) of slopes in the 

upland zone (fig. A–6). Average RUSLE values (table E–1) 

were then used to calculate an annual soil-loss estimate for 

cropland and program lands within each MLRA (table E–2). 

Cropland and program land soil-loss estimates were then 

multiplied by the total area estimates of upland zones of 

catchments on program lands (table D–3) within each MLRA. 

Methods used to estimate upland zone areas on program lands 

are described in chapter D. Potential reduction in soil losses 

attributable to program lands was calculated as the difference 

between soil loss estimated for cropped lands and that for 

program lands.

To estimate nutrient loading associated with estimates 

of soil erosion, we multiplied soil-loss estimates by the mean 

total phosphorus and nitrogen concentrations in the soils of 

the upland zones of cropland and restored catchments. Nutrient data were from the 2004 survey of 270 catchments in the 

Prairie Pothole Region, which included 56 cropland catchments and 179 catchments on program lands. Soil samples for 

nutrient determinations were collected along four transects 

that radiated from the center of the wetland zone and extended 

in cardinal directions to the catchment boundary. Along each 

transect, we collected soil samples to a depth of 15 cm (6 in) 

in each upland subzone (toe-slope, mid-slope, and shoulderslope; fig. A–6) for determination of total nitrogen and 

phosphorus using standard methods (Page and others, 1982; 

Klute, 1986). The three upland subzone estimates within each 

catchment were combined to provide an average estimate of 

total nitrogen and phosphorus concentrations. These estimates 

were then used to estimate nitrogen and phosphorus losses due 

to soil erosion.

Results

We estimated that conversion of cultivated cropland to 

perennial cover as part of USDA conservation programs would 

reduce soil erosion rates by an average of 6.36 Mg∙ha-1∙yr-1

(2.84 tons∙acre-1∙yr-1) (table E–2), which is equivalent to a 

94 percent reduction in soil loss. Across the entire Prairie 

Pothole Region, our results suggest that total soil losses would 

be reduced by 1,760,666 Mg∙yr-1 (1,940,254 tons∙yr-1) on 

the estimated 276,021 ha (682,048 acres) of upland zones of 

catchments on program lands (table E–3). When considering the cumulative annual reduction in soil loss since lands 

have been enrolled in conservation programs, we estimated 

a total reduction of 21,156,125 Mg (23,314,050 tons) 

(table E–3). Similarly, average nitrogen losses were reduced 

by 0.02 Mg∙ha-1∙yr-1 (0.009 tons∙acre-1∙yr- 1) and average 

phosphorus losses were reduced by 0.0002 Mg∙ha-1∙yr-1

(0.00009 tons∙acre-1∙yr-1). Estimated total reductions in nitrogen and phosphorus loss are 5,102 Mg∙yr-1 (5,622 tons∙yr-1) 

Chapter E: Reduction of Sedimentation and Nutrient Loading 39
Table E–2. Mean soil-loss values calculated by using the 

Revised Universal Soil Loss Equation (RUSLE); factor input values 

are presented in table E–1. Mean reduction in soil loss is defined 

as the mean soil loss for conservation program lands subtracted 

from the mean soil loss for croplands. In all cases, estimates for 

croplands are considerably higher than those for conservation 

program lands. The overall mean reduction values are 

6.36 Mg∙ha-1∙yr-1 (2.84 tons∙acre-1∙yr-1) and 94 percent.

[Mg, megagrams; ha, hectares; CRP, Conservation Reserve Program; MLRA, 

Major Land Resource Area; WRP, Wetlands Reserve Program]

MLRA

Mean soil loss 

Mg∙ha-1∙yr-1

(tons·acre-1·yr-1)

Mean reduction 

in soil loss

Croplands CRP/WRP

Mg∙ha-1∙yr-1

(tons·acre-1·yr-1) Percent

102A 5.26

(2.35)

0.31

(0.14)

4.95

(2.21)

94.11

102B 8.04

(3.59)

0.40

(0.18)

7.64

(3.41)

95.02

103 10.76

(4.80)

0.75

(0.33)

10.01

(4.46)

93.03

53A 10.67

(4.76)

0.51

(0.23)

10.17

(4.54)

95.31

53B 8.20

(3.66)

0.71

(0.32)

7.48

(3.34)

91.22

53C 2.29

(1.02)

0.13

(0.06)

2.16

(0.96)

94.32

55A 2.37

(1.06)

0.23

(0.10)

2.15

(0.96)

90.72

55B 7.24

(3.23)

0.44

(0.20)

6.80

(3.03)

93.92

55C 6.11

(2.73)

0.25

(0.11)

5.86

(2.61)

95.91

and 68 Mg∙yr-1 (75 tons∙yr-1), respectively, with cumulative reductions in nitrogen and phosphorus of 60,772 Mg 

(66,971 tons) and 798 Mg (879 tons), respectively (table E–4).

Discussion

The RUSLE is an erosion model intended to estimate 

long-term average annual soil losses that result from surface 

runoff from individual field slopes with specific cropping and 

management systems (Renard and others, 1997). Since sitespecific data typically are not available at large spatial scales, 

we applied mean factor values to the RUSLE to estimate soil 

losses for catchments on conservation program lands across 

the Prairie Pothole Region. This approach allowed us to evaluate USDA conservation programs by making broad generalizations that do not require detailed information about catchment 

areas and soil types on program lands; however, this approach 

assumes that RUSLE factors obtained from the NRI database 

and those calculated from our survey of catchments are representative of program lands (table E–1). Consequently, more 

precise estimates of reduction in soil loss could be calculated 

if areas of individual wetlands on program lands were available.

Our results suggest that significant differences in average 

annual soil-loss estimates exist between cultivated croplands 

and restored program lands for soil series from all MLRAs 

(table E–2). On the basis of our calculations, estimated 

average annual soil losses can be reduced, on average, by 

approximately 94 percent (table E–2) as a result of converting 

cultivated croplands to grasslands. More specifically, restored 

catchments in the Prairie Pothole Region have the potential 

to reduce soil losses by approximately 1,760,666 Mg∙yr-1

(1,940,254 tons∙yr-1) (table E–3), but this estimate is conservative because wetland catchments represent only 20 percent 

of the total land (approximately 2.2 million ha [5.4 million 

acres]) enrolled in conservation programs throughout the 

Prairie Pothole Region. Assuming that annual reductions 

remain static every year that lands are enrolled, reductions are 

even more significant because they would accrue throughout 

the duration of the contract. For example, a catchment enrolled 

in the WRP for 10 years that reduced soil loss by 10 Mg∙yr-1

(11 tons∙yr-1) would have the potential to reduce soil losses by 

100 Mg (110 tons) over the enrollment term. By factoring in 

contract length, the potential reduction in soil losses is more 

than 21 million Mg (23 million tons) (table E–3).

The RUSLE was developed to assess onsite soil losses 

but not offsite sediment accumulation (Mutchler and others, 

1994). Thus, we cannot quantify the benefits of reducing soil 

and nutrient loss to areas downstream from a wetland or other 

areas outside of catchments. Similarly, we are unable to determine the fate of soils transported within a catchment or the 

amount of soil that is actually delivered to a wetland; however, 

in a cropped catchment containing a wetland we can assume 

that some portion of the soil lost to erosion in the upland zone 

would move downslope and into a wetland basin over time. 

In contrast, much less soil would be expected to move into a 

wetland basin when the upland zone is dominated by perennial cover. For example, Gleason (1996) reported significantly 

lower sedimentation rates among wetlands surrounded by 

grasslands than in wetlands surrounded by summer fallow, 

40 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Table E–3. Potential reduction in total soil loss when upland zone catchment areas (table D–3) are converted to perennial cover as part of the U.S. D

Conservation Reserve and Wetlands Reserve Programs in the Prairie Pothole Region. Soil-loss estimates were calculated by using the Revised Unive(RUSLE). Reduction is defined as soil-loss estimates for conservation program lands subtracted from estimates from cultivated croplands.[Mg, megagrams; yr, year; CRP, Conservation Reserve Program; WRP, Wetlands Reserve Program]

State Program

Total area of upland 

zones of catchments, 

in hectares 

(acres)

Total soil loss, 

in Mg∙yr-1

(tons·yr-1) Total reduction, in Mg∙yr-1

(tons·yr-1)

Cropland CRP/WRP 

Iowa CRP 229,011

(71,686)

2312,172

(344,014)

221,877

(24,108)

2290,295

(319,905)

WRP 6,106–6,110

(15,088–15,098)

65,579–65,607

(72,268–72,299)

4,588–4,589

(5,056–5,057)

60,991–61,018

(67,212–67,242)

Minnesota CRP 81,465–84,584

(201,300–209,007)

650,962–667,370

(717,360–735,442)

43,079–44,036

(47,473–48,528)

607,883–623,334

(669,887–686,914)

WRP 4,732–4,800

(11,693–11,861)

46,063–46,416

(50,761–51,150)

3,173–3,194

(3,497–3,520)

42,890–43,222

(47,265–47,631)

Montana CRP 5,693–6,053

(14,067–14,957)

60,773–64,611

(66,972–71,201)

2,887–3,069

(3,181–3,382)

57,886–61,542

(63,790–67,819)

North Dakota CRP 106,107–114,089

(262,190–281,914)

510,748–548,853

(562,844–604,836)

36,731–39,467

(40,478–43,493)

474,017–509,386

(522,367–561,343)

WRP 341–367

(843–907)

1,846–1,986

(2,034–2,189)

123–132

(136–145)

1,723–1,854

(1,899–2,043)

South Dakota CRP 34,731–36,864

(85,820–91,091)

197,042–209,449

(217,140–230,813)

11,609–12,329

(12,793–13,587)

185,433–197,120

(204,347–217,226)

WRP 957–1,020

(2,365–2,520)

6,337–6,769

(6,983–7,459)

321–343

(354–378)

6,016–6,426

(6,630–7,081)

Total CRP 257,007–270,601

(635,064–668,655)

1,731,697–1,802,455

(1,908,330–1,986,305)

116,183–120,778

(128,034–133,097)

1,615,514–1,681,677

(1,780,296–1,853,208)

Total WRP 12,136–12,297

(29,988–30,386)

119,825–120,778

(132,047–133,097)

8,205–8,258

(9,042–9,100)

111,620–112,520

(123,005–123,997)

Total Prairie Pothole Region 269,143–282,898

(665,052–699,041)

1,851,522–1,923,233

(2,040,377–2,119,403)

124,388–129,036

(137,076–142,198)

1,727,134–1,794,197

(1,903,302–1,977,205)

1 Total reduction multiplied by the number of years that the lands have been enrolled in restoration program.2 Range is not presented; the high and low estimates were the same as a result of constraining the estimates by the area of conservation program lands (see “Methods,” this cha
Table E–4. Estimated potential reduction in nitrogen and phosphorous loss when upland zone catchment areas (table D–3) are converted to perenni

Department of Agriculture Conservation Reserve and Wetlands Reserve Programs in the Prairie Pothole Region. Reduction is defines as nutrient-loss program lands subtracted from estimates from cultivated croplands.[N, nitrogen; Mg, megagrams; yr, year; P, phosphorus; CRP, Conservation Reserve Program; WRP, Wetlands Reserve Program]

State Program

Total N loss, 

in Mg∙yr-1

(tons·yr- 1)

Total P loss, 

in Mg∙yr-1

(tons·yr-1)

Total reduction, 

in Mg∙yr-1

(tons·yr-1)

Croplands CRP/WRP Croplands CRP/WRP N P 

Iowa CRP 21,004

(1,106)

248

(53)

215

(17)

20.4

(0.44)

2956

(1054)

214.6

(16.1)

21

(1

WRP 3211

(233)

310

(11)

33

(3.3)

30.09

(0.099)

3201

(222)

32.9

(3.2)

3

(1

Minnesota CRP 2,048–2,097

(2,257–2,311)

108–111

(119–122)

328

(31)

30.8

(0.88)

1,940–1,986

(2,138–2,189)

327.2

(30.0)

23,99

(26,44

WRP 147–148

(162–163)

37

(7.7)

32

(2.2)

30.06

(0.066)

140–141

(154–155)

31.9

(2.1)

1,04

(1,15

Montana CRP 114–121

(126–133)

35

(5.5)

31

(1.1)

30.03

(0.033)

109–116

(120–128)

31.0

(1.1)

1,50

(1,65

North Dakota CRP 1,246–1,339

(1,373–1,476)

94–101

(104–111)

15–16

(16.5–17.6)

30.6

(0.66)

1,152–1,238

(1,270–1,364)

14.4–15.4

(15.9–17.0)

14,86

(16,38

WRP 35

(5.5)

30.3

(0.33)

30.06

(0.066)

30.002

(0.0022)

4.7

(5.2)

30.058

(0.064)

2

(2

South Dakota CRP 528–561

(582–618)

32–34

(35–37)

5–6

(5.5–6.6)

30.19

(0.209)

496–527

(547–581)

4.8–5.8

(5.3–6.4)

5,55

(6,12

WRP 18–19

(20–21)

31

(1.1)

30.2

(0.22)

30.006

(0.0066)

17–18

(19–20)

30.19

(0.21)

13

(14

Total CRP 4,940–5,122

(5,444–5,644)

287–299

(316–329)

64–66

(71–73)

32

(2.2)

4,653–4,823

(5,128–5,315)

62–64

(68–71)

56,69

(62,47

Total WRP 381–383

(420–422)

318

(20)

5

(5.5)

30.16

(0.176)

363–365

(400–402)

35

(5.5)

2,99

(3,30

Total Prairie Pothole Region 5,321–5,505

(5,864–6,067)

305–317

(336–349)

69–71

(76–78)

32

(2.2)

5,016–5,188

(5,528–5,717)

67–69

(74–76)

59,69

(65,77

1 Total reduction multiplied by the number of years that the lands have been enrolled in restoration program.2 Range is not presented; the high and low estimates were the same as a result of constraining the estimates by the area of conservation program lands (see “Methods,” this cha3 Range is less than 1.
and Euliss and Mushet (1996) documented that water-level 

fluctuations of wetlands in cropped catchments were more 

extreme than in grassland catchments because of alterations in 

surface water flow, indicating an increased potential for sediment transport in cropped catchments. Furthermore, 17 and 

21 percent of catchments with a cultivation history, including 

those that have been restored and those with cropland, from 

the 1997 and 2004 surveys, respectively, had buried A or 

O soil horizons with average burial depths of 35 cm (14 in; 

range 12–98 cm [5–39 in]) in 1997 and 56 cm (22 in; range 

9–116 cm [4–46 in]) in 2004, indicating considerable sediment 

accumulation in cropland catchments.

Increased sedimentation rates in prairie wetlands can 

have a significant effect on many wetland functions and 

values, such as water storage, plant and invertebrate communities, and wildlife habitat. Increased sediment inputs can 

partially or completely fill depressional wetlands, drastically 

altering water depths and storage volumes (Gleason and 

Euliss, 1998; Gleason, 2001). Amplified inputs of sediments 

and nutrients can also influence plant and invertebrate communities (Jurik and others, 1994; Wang and others, 1994; Gleason 

and Euliss, 1998; Gleason and others, 2003) that are essential 

sources of food and habitat for waterfowl and other wildlife.

In summary, we applied a relatively simple approach to 

estimate potential reduction in soil loss when uplands surrounding wetlands are converted from cultivated agriculture to 

perennial cover as part of USDA conservation programs. We 

estimated an annual reduction in soil loss of 1,760,666 Mg∙yr-1

(1,940,254 tons∙yr-1) and a cumulative reduction of more 

than 21 million Mg (more than 23 million tons). The primary 

benefit of reduced soil erosion is maintenance of the full range 

of water depths and storage volumes of wetland depressions, 

which are critical to sustaining all ecosystem services derived 

from wetlands. For example, maintenance of depressional 

volume is key to floodwater-storage potential and cycling of 

vegetation during wet and dry cycles (Gleason and Euliss, 

1998; Gleason, 2001). Reducing sediment inputs prevents 

the burial of persistent seed and invertebrate egg banks that 

are critical for establishment of wetland flora and fauna that 

provide wildlife habitat and food-chain support. Additionally, 

reducing inputs of nitrogen to wetlands potentially reduces 

emissions of nitrous oxide, a potent greenhouse gas (Gleason 

and others, 2005).

In this study we did not address offsite benefits associated with the reduction of soil loss; however, reduction in soil 

erosion will undoubtedly reduce delivery of sediments and 

nutrients that impair water quality to lakes, streams, and rivers. 

Sediments from agricultural lands have long been recognized 

as a primary pollutant of our Nation’s waters. To better quantify the benefits associated with reduction in soil erosion at 

site-specific and watershed scales will require detailed spatial 

data not only on program lands but also on all land areas 

within watersheds of interest.

References

Adomaitis, V.A., Kantrud, H.A., and Shoesmith, J.A., 1967, 

Some chemical characteristics of aeolian deposits of snowsoil on prairie wetlands: Proceedings of the North Dakota 

Academy of Science, v. 21, p. 65–69.

Baker, L.A., 1992, Introduction to nonpoint source pollution in 

the United States and prospects for wetland use: Ecological 

Engineering, v. 1, p. 1–26.

Euliss, N.H., Jr., and Mushet, D.M., 1996, Water-level 

fluctuation in wetlands as a function of landscape condition 

in the prairie pothole region: Wetlands, v. 16, p. 587–593.

Gleason, R.A., 1996, Influence of agricultural practices on 

sedimentation rates, aquatic invertebrates, and bird-use in 

prairie wetlands: Arcata, Calif., Humboldt State University, 

master’s thesis.

Gleason, R.A., 2001, Invertebrate egg and plant seed banks 

in natural, restored, and drained wetlands in the prairie 

pothole region (USA) and potential effects of sedimentation 

on recolonization of hydrophytes and aquatic invertebrates: 

Brookings, South Dakota State University, Ph.D. dissertation.

Gleason, R.A., and Euliss, N.H., Jr., 1998, Sedimentation of 

prairie wetlands: Great Plains Research, v. 8, p. 97–112.

Gleason, R.A., Euliss, N.H., Jr., Hubbard, D.E., and Duffy, 

W.G., 2003, Effects of sediment load on emergence of 

aquatic invertebrates and plants from wetland soil egg and 

seed banks: Wetlands, v. 23, p. 26–34.

Gleason, R.A., Euliss, N.H., Jr., McDougal, R.L., and Kermes, 

K.E., 2005, Potential of restored prairie wetlands in the 

glaciated North American prairie to sequester atmospheric 

carbon: Grand Forks, N. Dak., Energy and Environmental 

Research Center, Plains CO2 Reduction Partnership topical 

report August 2005.

Jurik, T.W., Wang, S-C., and van der Valk, A.G., 1994, Effects 

of sediment load on seedling emergence from wetland seed 

banks: Wetlands, v. 14, p. 159–165.

Klute, A., ed., 1986, Methods of soil analysis, part 1—Physical and mineralogical methods (2d ed.): Madison, Wis., Soil 

Science Society of America.

Martin, D.B., and Hartman, W.A., 1987, The effect of cultivation on sediment composition and deposition in prairie 

pothole wetlands: Water, Air, and Soil Pollution, v. 34, 

p. 45–53.

Chapter E: Reduction of Sedimentation and Nutrient Loading 43
Mutchler, C.K., Murphree, C.E., and McGregor, K.C., 1994, 

Laboratory and field plots for erosion research, in Lal, R., 

ed., Soil erosion research (2d ed.): Delray Beach, Fla., 

Soil and Water Conservation Society and St. Lucie Press, 

p. 11–37.

Page, A.L., Miller, R.H., and Keeney, D.R., eds., 1982, 

Methods of soil analysis, part 2—Chemical and microbiological properties (2d ed.): Madison, Wis., Soil Science 

Society of America.

Renard, K.G., Foster, G.R., Weesies, G.A., McCool, K.K., and 

Yoder, D.C., coordinators, 1997, Predicting soil erosion by 

water—a guide to conservation planning with the revised 

universal soil loss equation (RUSLE): Washington, D.C., 

U.S. Department of Agriculture, Agriculture Handbook 

No. 703.

Tripod Data Systems, 1997, ForeSight for Windows: Corvallis, 

Oreg., Tripod Data Systems, Inc.

U.S. Department of Agriculture, 2000, Summary report—1997 

National Resources Inventory (revised December 2000): 

Washington, D.C., Natural Resources Conservation Service.

U.S. Environmental Protection Agency, 1995, National water 

quality inventory—1994 report to Congress: Washington, D.C., U.S. Environmental Protection Agency, EPA 

Report 841-R-95-005.

Wang, S-C., Jurik, T.W., and van der Valk, A.G., 1994, Effects 

of sediment load on various stages in the life and death of 

cattail (Typha × glauca): Wetlands, v. 14, p. 166–173.

44 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Chapter F: Proposed Approach to Assess Potential Wildlife Habitat Suitability on 

Program Lands

By Murray K. Laubhan, Kevin E. Kermes, and Robert A. Gleason

Synopsis

The social and economic values of fish and wildlife as an 

ecosystem service often are not fully appreciated even though 

an estimated 82 million United States residents annually 

spend $108 billion to fish, hunt, or observe wildlife (Cordell 

and Herbert, 2002; U.S. Department of the Interior, 2002). 

Although difficult to quantify, concurrent benefits of lands 

managed for wildlife also include improvement of water 

quality, reduction in flood risk, and enhancement of carbon 

sequestration (Knutsen and Euliss, 2001; Euliss and others, 

2007; Gleason and others, 2007). Currently, the most influential Government programs affecting the quantity and quality 

of wildlife habitat on private lands are the U.S. Department of 

Agriculture (USDA) Conservation Reserve Program (CRP) 

and Wetlands Reserve Program (WRP) authorized by the 

Conservation Title of the 1985 Food Security Act. The CRP 

and WRP have resulted in the restoration and enhancement of 

approximately 2,200,000 ha (5,436,200 acres) of wetlands and 

grasslands in the Prairie Pothole Region of the United States 

(table A–1). Because of the expanse of the area enrolled, 

program lands (lands enrolled in the CRP and the WRP) have 

much potential to improve habitat conditions for many wildlife 

species. For example, research on CRP lands has documented 

positive impacts on select wildlife guilds or species, including increased production or survival of ducks, ring-necked 

pheasants, and grassland-dependent birds (Haufler, 2005). 

Although information documenting wildlife use of WRP sites 

largely is lacking, research on wildlife response to wetland 

restoration activities similar to those implemented in the WRP 

suggests positive impacts for many species (Rewa, 2005). In 

many cases, species that benefit include those of economic or 

recreational value, as well as those considered to be of conservation concern because of habitat loss or declining populations.

Although program lands have inherent value as wildlife 

habitat, survival and reproduction of many species depend on 

specific spatial and structural requisites, such as type and size 

of habitats, juxtaposition of habitat types, structural features of 

vegetation, or floristic composition. Because of the fragmented 

spatial distribution of remaining native grasslands and wetlands, the value of a particular tract of program land may vary 

depending not only on conditions within the tract but also on 

conditions in the surrounding landscape (Knopf and Samson, 

1995). Further, biological systems are dynamic and composed 

of complex, interacting factors that function as drivers of 

community composition and size (Pickett and White, 1985). 

Changes in climate or land-use practices surrounding the 

tract also may cause wildlife use to change over time (Hobbs 

and Norton, 2004). Therefore, the value of program lands 

as wildlife habitat cannot be considered in isolation, nor can 

particular wildlife values typically be attributed to the same 

tract in every year. Hence, the most objective means of assessing the importance of program lands to wildlife is to evaluate 

habitat quality over time. Developing approaches to document 

and report the myriad of wildlife values provided by program 

lands, although difficult, is important, considering directives to 

quantify the outcomes of program activities in terms of quality 

rather than simply the amount of area restored.

This chapter provides an overview of one approach 

that facilitates periodic assessment of multiple ecosystem 

services, including wildlife, provided by conservation programs. Outcomes are measured in terms of potential habitat 

suitability for select species based on relationships between 

the life requisites of selected species and measures of various spatial and structural habitat features. In an analysis of a 

single example township, the CRP resulted in the conversion 

of 1,792 ha (4,428 acres) of cropland to grassland between 

1987 and 2005. Within this area, 313 ha (773 acres) of 

wetlands (500 seasonal, 234 temporary, and 18 semipermanent) shifted from cropland to grassland catchments. These 

changes resulted in an increased number of grassland polygons (contiguous areas of grassland) that exceeded published 

area requirements for all five area-sensitive grassland birds 

considered in our evaluation (table F–1). In a separate evaluation based on the interquartile range (25–75 percent) of upland 

vegetation obstruction measurements, our analysis indicated 

that restored seasonal catchments potentially provide suitable nesting habitat for all nine avian species we evaluated, 

whereas restored temporary and restored semipermanent 

catchments provide potential nesting habitat for seven and 

eight of the nine species evaluated, respectively (table F–2). 

These results suggest that restored catchments, regardless of 

wetland type, provide at least some resources that are required 

by a diversity of bird species but are not provided in cropland 

catchments. The justification of this approach is based on the 

assumptions that habitat conditions are a primary determinant 

of wildlife community composition and the variables used to 

assess change are the most appropriate and provide acceptable 

results. Therefore, the number and types of variables included 

(measurement methods used to estimate variables, spatial scale 

considered, and the relative importance of different wildlifehabitat relationships) are examples of critical factors that 

must be considered to make the approach applicable. Further, 

estimates resulting from this approach are limited to community composition because population size varies inter-annually 

and intra-annually depending on numerous spatial and temporal factors operating at regional, national, or international 

Chapter F: Proposed Approach to Assess Potential Wildlife Habitat Suitability on Program Lands 45
Table F–1. Change in the number of suitable grassland patches for five grassland-dependent bird species in a Prairie Pothole Region 

township.

[CRP, Conservation Reserve Program; >, greater than; Mo., Missouri; <, less than; Nebr., Nebraska; Ill., Illinois; %, percent; N. Dak., North Dakota. Scientific 

names of species are given in table F–3]

Species Spatial metric

Requirement of 

bird, 

in hectares 

(acres) State Citation

Number of patches

Pre-CRP Post-CRP Change

Upland sandpiper Minimum area >10 (25)

>70 (173)

Mo.

Mo.

Samson, 1980

Winter, 1998

26

4

34

13

+8

+9

Perimeter: area <0.008 (0.02) Nebr. Helzer and Jelinski, 1999 6 21 +15

Savannah sparrow Minimum area >75 (185) Ill. Walk and Warner, 1999 4 13 +9

50% incidence >40 (99) Ill. Herkert, 1994 10 21 +11

Territory >15 (37) Ill. O’Leary and Nyberg, 2000 21 30 +9

Vesper sparrow Minimum area >10 (25) Mo. Samson, 1980 26 34 +8

50% incidence >20 (49) Maine Vickery and others, 1994 18 27 +9

Grasshopper sparrow Minimum area >12 (30) Ill. Walk and Warner, 1999 22 32 +10

50% incidence >30 (74)

>70 (173)

Ill.

Iowa

Herkert, 1994

Horn, 2000

15

4

25

13

+10

+9

Perimeter: area <0.018 (0.04)

<0.023 (0.06)

Nebr.

Nebr.

Helzer and Jelinski, 1999

Helzer and Jelinski, 1999

28

32

36

38

+8

+6

Territory >15 (37) Ill. O’Leary and Nyberg, 2000 21 30 +9

Bobolink 50% incidence >50 (124)

>80 (198)

Ill.

N. Dak.

Herkert, 1994

Horn, 2000

8

3

20

13

+12

+10

Perimeter: area <0.018 (0.04) Nebr. Helzer and Jelinski, 1999 28 36 +8

scales. The utility of this method is the capability to efficiently 

estimate potential wildlife species richness over time, which 

complements population estimates provided by traditional 

wildlife surveys.

Methods

The approach we developed to estimate potential habitat 

suitability can be applied to any wildlife species given that sufficient information is available to define key habitat requirements. In this example, we restricted evaluation to the impact 

of CRP lands on a select suite of migratory birds that use 

the Prairie Pothole Region as breeding or migration habitat. 

Birds are an excellent group for this type of approach because 

they are well known, disperse widely, and are highly visible 

(Knopf and Samson, 1995). Prior to measuring vegetation and 

abiotic variables, we recorded bird species using each of the 

270 catchments surveyed in 2004 and compiled a list of all 

species detected. Species were documented opportunistically 

during a single survey that was not constrained by unfavorable 

time or weather conditions. Thus, only some portion of the 

avian species using these catchments likely was observed, and 

no inferences can be made regarding overall avian richness 

or abundance. We selected 10 species from this list on the 

basis of availability of habitat requirement information in 

the literature that matched the variables we collected during surveys. We also attempted to select species that defined 

a broad spectrum of spatial and structural vegetation habitat 

requirements and also are considered to be of conservation 

concern or recreational value. Species selected may not be 

the most appropriate for a full-scale evaluation, but they are 

adequate for demonstrating the approach. We identified two 

important parameters—minimum area requirements and visual 

obstruction of vegetation at nest sites—that were determinants 

of habitat suitability and searched the scientific literature for 

quantitative information on these parameters. Species differ in 

habitat requirements; thus, both parameters were not applicable to all species selected. Initially, we restricted our search 

to studies conducted in the northern Prairie Pothole Region, 

but sufficient information was not available, so we expanded 

our search to include studies completed in other regions. The 

use of the information developed in areas outside the Prairie 

Pothole Region may not be directly applicable to the Prairie 

Pothole Region. For example, area requirements developed 

in one area for grassland birds may not be applicable in other 

areas because of differences in location relative to the range of 

the species or landscape conditions (Johnson and Igl, 2001); 

46 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Table F–2. Range (50 percent of observations) of visual obstruction measurements in the upland zone of 54 catchments sampled in the vicinity of the 

glaciated plains, and the range of visual obstruction estimates at nest sites of nine bird species reported in the literature.[Species that could occur in each land-use treatment/catchment type combination based on visual obstruction measurements are denoted with an “X.” Scientific names for specie

Catchment type

Interquartile range 

of upland vegetation 

obstruction, 

in centimeters 

(inches)

Bird species, and range of reported visual obstruction,1 in centimeters (inche

Mallard2

14.7–42.0

(5.8–16.5)

Sharp–tailed

grouse3

15.0–30.0

(5.9–11.8)

Northern

harrier4

10.0–48.0

(3.9–18.9)

Willet5

0.0–20.0

(0.0–7.9)

Upland

sandpiper5

0.0–40.0

(0.0–15.7)

Clay–colored

sparrow6

16.0–46.3

(6.3–18.2)

Grasshopper

sparrow7

13.0–33.6

(5.1–13.2)

Cropland

Temporary (n=4) 0.0–2.5

(0.0–1.0)

X X

Seasonal (n=4) 0.0–0.0

(0.0–0.0)

X X

Semipermanent (n=4) 0.0–0.0

(0.0–0.0)

X X

Restored

Temporary (n=12) 22.5–40.6

(8.9–16.0)

X X X X X X 

Seasonal (n=12) 20.0–40.0

(7.9–15.7)

X X X X X X X 

Semipermanent (n=12) 21.3–36.3

(8.4–14.3)

X X X X X X 

Native prairie

Temporary (n=2) 18.8–32.5

(7.4–12.8)

X X X X X X X 

Seasonal (n=2) 31.3–41.3

(12.3–16.3)

X X X X X X 

Semipermanent (n=2) 17.5–25.0

(6.9–9.8)

X X X X X X X 

1 Values obtained for each species are based on broadest possible range and include minimum, maximum, and mean measurements reported at nest sites.2 Minimum (Montana, Holm, 1984); maximum (North Dakota, Hertel, 1987).3 Minimum (North Dakota, Kantrud and Higgins, 1992); maximum (North Dakota, Kohn, 1982).4 Minimum (North Dakota, Kantrud and Higgins, 1992); maximum (North Dakota, Sedivec, 1994).5 Minimum (North Dakota, Kantrud and Higgins, 1992); maximum (North Dakota, Kantrud and Higgins, 1992).6 Minimum (North Dakota, Renken, 1983); maximum (North Dakota, Nenneman, 2003).7 Minimum (Montana, Dieni and Jones, 2003); maximum (Kansas, Winter and others, 2003).8 Minimum (South Dakota, Fritcher and others, 2004); maximum (Iowa, Patterson and Best, 1996).9 Minimum (North Dakota, Hertel, 1987); maximum (North Dakota, Scheiman and others, 2003).
however, we considered this information to be more reliable 

and defensible in our example than relying on subjective 

determinations.

Assessing the impact of USDA programs on the suite 

of 10 bird species was accomplished by using a combination 

of digital land-use covers and vegetation data collected as 

part of the extensive 2004 survey. To illustrate this approach, 

we selected a single township (93.2 km2 [36.0 mi2]) in the 

glaciated plains of the Prairie Pothole Region for analysis. 

The township was near two of the sample points originally 

established for other portions of this study, and vegetation data 

from 54 catchments within or near the township were available 

for estimation of structural conditions of vegetation.

We constructed two land-use covers of the township representing conditions before and after the USDA implemented 

the CRP. A base land cover was created by reclassifying the 

1992 digital National Land Cover Data (NLCD) into cropland, 

grassland, tree/shrubland, wetland, and urban categories; by 

replacing areas classified as wetland or urban with surrounding land uses; and by smoothing the edge and transition zones. 

This process resulted in a base land cover composed of three 

land-use classes: cropland, grassland, and tree/shrubland. 

For the pre-CRP land cover, the 2005 CRP spatial data were 

categorized as cropland and added to update the base land 

cover and to check for CRP tracts implemented prior to 

1992, which we deduced from signup dates. For the pre-CRP 

land cover, this check resulted in four tracts being reclassified from cropland back to grassland following the base land 

cover for the tract because CRP was implemented after 1992 

or sign-up dates were not present in the database so the tracts 

were treated as existing grassland. Thus, the pre-CRP cover 

approximates terrestrial land-use conditions present in 1987 

(first year of CRP), and existing grassland tracts were assumed 

to be native tracts subjected to different types and intensities of 

human activities, such as idle, grazing, or haying. Some tracts, 

however, were possibly agricultural lands enrolled in earlier 

conservation programs, such as Soil Bank. For the post-CRP 

land cover, we assumed that all grassland tracts in the 2005 

CRP spatial cover were CRP lands even though some potentially originated from other Government programs. To estimate 

changes in the area and number of wetlands relative to catchment land use, we intersected the pre- and post-CRP landcover maps with wetland type and location data obtained from 

the National Wetlands Inventory (NWI). Finally, previous 

research indicates that roads cause fragmentation by removing 

habitat and creating high-contrast edges (Miller and others, 

1996) that can result in declines in species that are areasensitive or exhibit limited dispersal capabilities (Saunders and 

others, 1991). Therefore, we intersected the pre- and post-CRP 

covers with a layer of primary and secondary roads obtained 

from the North Dakota Department of Transportation via an 

online geographic information system hub (http://www.nd.gov/

gis, accessed February 2006). We buffered the road data to a 

total width of 7 meters (23 feet), which closely approximated 

the observed road width based on photographic analysis, and 

intersected the pre- and post-CRP covers with the buffered 

road data, resulting in the addition of the urban land-use class 

to the base land cover. When roads bisected a land-use category, we used the road to create separate polygons with unique 

identities. We used Arc-Info (ESRI, Redlands, Calif.), Patch 

Analyst (http://flash.lakeheadu.ca/~rrempel/patch/, accessed 

February 2006), and SAS (SAS Institute, Inc., 2003) to calculate several landscape metrics for both covers to describe 

general changes in land use during the 19-year period. We also 

calculated the area of each grassland polygon in both covers 

and constructed a frequency table of the number of polygons 

that exceeded the reported area requirements (minimum area, 

perimeter:area ratio, territory size) of selected area-dependent 

grassland bird species.

In a separate evaluation, we used data collected from 

54 catchments within or near the township to evaluate the 

influence of upland vegetation obstruction on avian habitat 

suitability. Catchments were classified on the basis of wetland 

type (semipermanent, seasonal, temporary) and land-use treatment (cropped, restored, native prairie), which resulted in nine 

catchment types. In each catchment, vegetation obstruction 

was estimated from four directions at one location in each of 

the three upland subzones (shoulder-slope, mid-slope, and toeslope; fig. A–6). We calculated a mean visual obstruction for 

each subzone by averaging the four measurements collected 

at each sample location and used these estimates to compute 

an interquartile range (25–75 percent) of upland vegetation 

obstruction across all land-use/catchment type combinations; 

number of catchments in each combination ranged from 2–12 

(table F–2). This range was compared with reported visual 

obstruction readings collected at breeding sites of each bird 

species selected for evaluation to assess potential habitat availability provided by each land-use treatment.

Results

Seventy-seven avian species were recorded during the 

2004 survey of 263 catchments (table F–3). Thirty-eight taxa 

were recorded in native prairie catchments compared to 40 

and 65 taxa in cropped and restored catchments, respectively. 

At least one bird species was observed in 24 (82.8 percent) of 29 native prairie catchments, 149 (84.2 percent) of 

177 restored catchments, and 20 (64.9 percent) of 37 cropped 

catchments. No species were observed in 5 native prairie, 

28 restored, and 20 cropped catchments. In contrast, the 

maximum number of species observed in a single catchment 

was 8 in native prairie catchments, 9 in cropped catchments, 

and 15 in restored catchments. These results indicate that all 

catchment types were used by at least some avian species; 

however, no inferences can be made regarding avian richness 

or abundance because we did not use standardized techniques. 

Of these species, 10 were selected for evaluation, including 6 

that are considered to be of conservation concern at various 

spatial scales according to the “Birds of Conservation Concern 

2002” (U.S. Fish and Wildlife Service, 2002), 2 that are considered species of concern by the Northern Plains and Prairie 

48 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Table F–3. Bird species recorded by observation from vantage points and one walking survey conducted prior to measuring 

vegetation and abiotic variables in 263 catchments in the Prairie Pothole Region in 2004.—Continued

[No., number; %, percent]

Common name Scientific name

Land-use treatment

Cropped Restored Native prairie

No. %1 No. %1 No. %1

American bittern Botaurus lentiginosus 2 3.5 5 2.8 1 3.5

American coot Fulica americana 2 3.5 6 3.4 2 6.9

American goldfinch Carduelis tristis 1 1.8 4 2.3 1 3.5

American robin Turdus migratorius 1 1.8 2 1.1 0 0.0

American white pelican Pelecanus erythrorhynchos 1 1.8 1 0.6 0 0.0

American wigeon Anas americana 0 0.0 0 0.0 1 3.5

Barn swallow Hirundo rustica 6 10.5 10 5.7 2 6.9

Black tern Chlidonias niger 3 5.3 10 5.7 0 0.0

Black-crowned night-heron Nycticorax nycticorax 1 1.8 5 2.8 0 0.0

Blue-winged teal Anas discors 3 5.3 40 22.6 5 17.2

Bobolink Dolichonyx oryzivorus 0 0.0 36 20.3 6 20.7

Brewer’s blackbird Euphagus cyanocephalus 0 0.0 2 1.1 0 0.0

Brown-headed cowbird Molothrus ater 0 0.0 5 2.8 0 0.0

Canada goose Branta canadensis 1 1.8 0 0.0 0 0.0

Canvasback Aythya valisineria 0 0.0 0 0.0 1 3.5

Chipping sparrow Spizella passerina 0 0.0 15 8.5 2 6.9

Clay-colored sparrow Spizella pallida 1 1.8 18 10.2 0 0.0

Cliff swallow Petrochelidon pyrrhonota 0 0.0 1 0.6 0 0.0

Common grackle Quiscalus quiscula 1 1.8 2 1.1 1 3.5

Common tern Sterna hirundo 1 1.8 0 0.0 0 0.0

Common yellowthroat Geothlypis trichas 2 3.5 31 17.5 2 6.9

Downy woodpecker Picoides pubescens 0 0.0 2 1.1 0 0.0

Eastern kingbird Tyrannus tyrannus 1 1.8 8 4.5 2 6.9

Field sparrow Spizella pusilla 1 1.8 5 2.8 0 0.0

Forster’s tern Sterna forsteri 0 0.0 1 0.6 0 0.0

Franklin’s gull Larus pipixcan 2 3.5 0 0.0 0 0.0

Gadwall Anas strepera 1 1.8 6 3.4 3 10.3

Grasshopper sparrow Ammodramus savannarum 4 7.0 26 14.7 2 6.9

Gray partridge Perdix perdix 0 0.0 1 0.6 0 0.0

Great blue heron Ardea herodias 0 0.0 3 1.7 0 0.0

Great egret Ardea alba 0 0.0 1 0.6 0 0.0

Greater yellowlegs Tringa melanoleuca 2 3.5 1 0.6 0 0.0

Hooded merganser Lophodytes cucullatus 0 0.0 0 0.0 1 3.5

Horned grebe Podiceps auritus 0 0.0 1 0.6 0 0.0

Killdeer Charadrius vociferus 18 31.6 8 4.5 2 6.9

Lark sparrow Chondestes grammacus 0 0.0 9 5.1 0 0.0

Le conte’s sparrow Ammodramus leconteii 0 0.0 1 0.6 0 0.0

Least sandpiper Calidris minutilla 0 0.0 1 0.6 0 0.0

Least tern Sterna antillarum 0 0.0 0 0.0 1 3.5

Lesser yellowlegs Tringa flavipes 0 0.0 0 0.0 1 3.5

Chapter F: Proposed Approach to Assess Potential Wildlife Habitat Suitability on Program Lands 49
Table F–3. Bird species recorded by observation from vantage points and one walking survey conducted prior to measuring 

vegetation and abiotic variables in 263 catchments in the Prairie Pothole Region in 2004.—Continued

[No., number; %, percent]

Common name Scientific name

Land-use treatment

Cropped Restored Native prairie

No. %1 No. %1 No. %1

Long-eared owl Asio otus 0 0.0 0 0.0 1 3.5

Mallard Anas platyrhynchos 4 7.0 38 21.5 5 17.2

Marsh wren Cistothorus palustris 3 5.3 39 22.0 6 20.7

Mourning dove Zenaida macroura 1 1.8 5 2.8 0 0.0

Northern harrier Circus cyaneus 0 0.0 3 1.7 3 10.3

Northern pintail Anas acuta 0 0.0 1 0.6 0 0.0

Northern shoveler Anas clypeata 1 1.8 5 2.8 0 0.0

Orchard oriole Icterus spurius 0 0.0 0 0.0 1 3.5

Pied-billed grebe Podilymbus podiceps 0 0.0 2 1.1 0 0.0

Red-tailed hawk Buteo jamaicensis 1 1.8 1 0.6 0 0.0

Red-winged blackbird Agelaius phoeniceus 14 24.6 72 40.7 5 17.2

Redhead Aythya americana 0 0.0 1 0.6 1 3.5

Ring-billed gull Larus delawarensis 1 1.8 1 0.6 0 0.0

Ring-necked pheasant Phasianus colchicus 1 1.8 27 15.3 1 3.5

Ruddy duck Oxyura jamaicensis 1 1.8 2 1.1 0 0.0

Savannah sparrow Passerculus sandwichensis 3 5.3 17 9.6 0 0.0

Sedge wren Cistothorus platensis 0 0.0 14 7.9 0 0.0

Semipalmated sandpiper Calidris pusilla 0 0.0 0 0.0 1 3.5

Sharp-tailed grouse Tympanuchus phasianellus 1 1.8 1 0.6 1 3.5

Short-eared owl Asio flammeus 0 0.0 2 1.1 0 0.0

Song sparrow Melospiza melodia 1 1.8 5 2.8 1 3.5

Sora Porzana carolina 0 0.0 6 3.4 1 3.5

Spotted sandpiper Actitis macularia 0 0.0 2 1.1 0 0.0

Swainson’s hawk Buteo swainsoni 0 0.0 1 0.6 1 3.5

Tree swallow Tachycineta bicolor 1 1.8 8 4.5 0 0.0

Upland sandpiper Bartramia longicauda 1 1.8 0 0.0 1 3.5

Vesper sparrow Pooecetes gramineus 0 0.0 4 2.3 1 3.5

Virginia rail Rallus limicola 0 0.0 6 3.4 0 0.0

Western kingbird Tyrannus verticalis 2 3.5 3 1.7 0 0.0

Western meadowlark Sturnella neglecta 2 3.5 10 5.7 0 0.0

Willet Catoptrophorus semipalmatus 0 0.0 1 0.6 1 3.5

Wilson’s phalarope Phalaropus tricolor 0 0.0 0 0.0 1 3.5

Wilson’s snipe Gallinago delicata 1 1.8 2 1.1 0 0.0

Wood duck Aix sponsa 0 0.0 3 1.7 1 3.5

Yellow warbler Dendroica petechia 0 0.0 2 1.1 0 0.0

Yellow-headed blackbird Xanthocephalus xanthocephalus 6 10.5 32 18.1 5 17.2

Yellow-rumped warbler Dendroica coronata 0 0.0 1 0.6 0 0.0

1

 Percent occurrence in cropland (n = 57), restored (n = 177), and native prairie (n = 29) catchments.

50 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Pothole Region shorebird plan (Skagen and Thompson, 2003), 

and 3 that are included on the Stewardship or Watch List in 

the “Partners in Flight North American Landbird Conservation 

Plan” (Rich and others, 2004) (table F–4).

Prior to implementation of the CRP, land use within the 

township was composed of 54 cropland polygons that constituted 85.5 percent of the township, 134 grassland (assumed to 

be native prairie) polygons that accounted for 13.9 percent of 

the township, and 63 polygons of tree and shrubland that occupied 0.6 percent of the township (fig. F–1A and table F–5). 

Within these land-use classes were 3,616 wetlands, of which 

2,771 (76.6 percent) were in cropland, 378 (10.5 percent) 

were in grassland, 7 (0.2 percent) were in tree/shrubland, 

and 460 (12.7 percent) were in catchments with more than 

one land-use category. Wetland area made up 14.9 percent 

(1,376 ha [3,400 acres]) of the township and included 1,131 ha 

(2,795 acres) in cropland, 227 ha (561 acres) in grassland, and 

18 ha (44.5 acres) in tree/shrubland (fig. F–1A).

In contrast, following implementation of the CRP, 

cropland area declined 19.4 percent to encompass only 

66.2 percent of the township, grassland increased 19.4 percent to encompass 33.3 percent of the township, wetland area 

in cropland catchments decreased 22.7 percent, and tree/

shrubland did not change (fig. F–1B and table F–5). This shift 

resulted from conversion of 1,792 ha (4,428 acres) of cropland 

to grassland between 1987 and 2005. In addition, the number 

of grassland polygons decreased from 134 in 1987 to 114 in 

2005, whereas cropland patches increased from 54 to 87 during the same period. The increase in grassland area, coupled 

with a decrease in number of grassland polygons, indicates 

that CRP grasslands connected some preexisting grassland 

polygons and resulted in larger grassland polygons than would 

have occurred solely as a result of implementing the CRP. To 

determine the extent that CRP tracts connected pre-existing 

grassland area, we calculated the amount of grassland area 

(core area) more than 100 m (328 ft) from an edge. This 

analysis revealed that core area increased by approximately 

1,078 ha (2,664 acres) from 1987 (442 ha [1,092 acres]) to 

2005 (1,520 ha [3,756 acres]). Total wetland area (1,376 ha 

[3,400 acres]) remained the same between 1987 and 2005 

because we used the same NWI digital data coverage; however, 22.7 percent (313 ha [773 acres]) of wetland area shifted 

from cropland to grassland catchments. The most dramatic 

shifts occurred in seasonal and temporary wetlands; 500 seasonal and 234 temporary wetlands in cropland catchments 

during 1987 were in grassland catchments in 2005 (table F–5). 

In addition, 18 semipermanent wetlands in cropland catchments in 1987 were completely within grassland catchments in 

2005, whereas the number of wetlands within tree/shrubland 

remained unchanged.

Information on spatial habitat requirements of breeding areas was available for five grassland-dependent species 

(bobolink [Dolichonyx oryzivorus], grasshopper sparrow 

[Ammodramus savannarum], savannah sparrow [Passerculus 

sandwichensis], upland sandpiper [Bartramia longicauda], 

and vesper sparrow [Pooecetes gramineus]) that we selected 

for evaluation, four of which are considered to be of conservation concern by regional and national plans (table F–4). 

Area requirements in the published literature vary among and 

within species depending on the type of metric considered. For 

example, minimum area requirements for the upland sandpiper ranged from more than 10 ha (25 acres; Samson, 1980) 

to more than 70 ha (173 acres; Winter, 1998). Differences in 

reported requirements likely are related to studies being conducted in different landscapes, the use of different analyses, a 

focus on different dependent variables, such as territory size 

or nesting area, or a combination of these factors. Regardless 

of the metric considered, implementing the CRP resulted in an 

increased number of grassland polygons that exceeded breeding area requirements for each species evaluated. The magnitude of change varied from an increase of 6 suitable polygons 

for the grasshopper sparrow to 15 suitable polygons for the 

upland sandpiper (table F–1).

Visual obstruction caused by upland vegetation in 

cropped treatments exhibited low variability. All obstruction estimates in the upland zone of seasonal and semipermanent cropped catchments were 0.0 cm (0.0 in), whereas 

the interquartile range of observations in cropped temporary catchments was 0.0–2.5 cm (0.0–1.0 in), and the largest estimate was 5.0 cm (2.0 in) (fig. F–2). In contrast, the 

interquartile range of vegetation obstruction estimates was 

22.5–40.6 cm (8.9–16.0 in) in restored temporary catchments, 

20.0–40.0 cm (7.9–15.7 in) in restored seasonal catchments, 

and 21.3–36.3 cm (8.4–14.3 in) in restored semipermanent 

catchments. Native prairie catchments also supported upland 

vegetation that had a wider range of visual obstruction compared to cropped catchments, but ranges appeared similar to 

those in restored catchments (fig. F–2). The interquartile range 

of vegetation obstruction estimates in native prairie temporary 

catchments was 18.8–32.5 cm (7.4–12.8 in), whereas in native 

prairie seasonal and native prairie semipermanent catchments 

the interquartile range was 31.3–41.3 cm (12.3–16.3 in) and 

17.5–25.0 cm (6.9–9.8 in), respectively (table F–2).

Visual obstruction values at nest sites were determined 

for 9 (bobolink, clay-colored sparrow [Spizella pallida], dickcissel [Spiza americana], grasshopper sparrow, mallard [Anas 

platyrhynchos], northern harrier [Circus cyaneus], sharptailed grouse [Tympanuchus phasianellus], upland sandpiper, 

and willet [Catoptrophorus semipalmatus]) of the 10 species 

evaluated. Comparisons of these values with the interquartile 

range of upland vegetation obstruction in surveyed catchments 

indicate that cropped catchments (regardless of wetland type) 

potentially provide suitable nesting habitat for only two (willet 

and upland sandpiper) of the nine species for which information was available (table F–2). In contrast, restored seasonal, 

native prairie temporary, and native prairie semipermanent 

catchment types potentially provide suitable nesting habitat 

for all nine species. Restored temporary and native prairie 

seasonal catchments provide potential nesting habitat for 

all species except the willet and bobolink, whereas restored 

semipermanent catchments provide suitable nesting habitat 

for all species except the willet. Overall, these comparisons 

Chapter F: Proposed Approach to Assess Potential Wildlife Habitat Suitability on Program Lands 51
Table F–4. Conservation status of avian species selected for evaluation.

[Species listed in “Birds of Conservation Concern 2002” are denoted with an “X.” Species listed in the “Partners in Flight North American Landbird Conservation Plan” as Stewardship or Watch List species in the Prairie Avifaunal Biome are denoted with an “R,” and species of continental importance are denoted 

with an “N.” Designations listed in the shorebird plan are as follows: C = species of concern; B, M = region is highly important to population for breeding and 

migrating, respectively. “North American Waterfowl Management Plan” represents objectives for the midcontinent region. For scientific names of the species, 

see table F–3. BCR, Bird Conservation Region]

Species

Birds of Conservation Concern 

20021

North American 

Landbird 

Conservation Plan2

Northern Plains 

Prairie Potholes Regional 

Shorebird Conservation 

Plan3

North American 

Waterfowl 

Management 

Plan4 BCR 11 Region 6 National Watch Steward

Mallard 8.2 million

Sharp-tailed grouse R, N

Northern harrier X X X

Willet X B, M

Upland sandpiper X X X C, B, M

Clay-colored sparrow

Vesper sparrow

Grasshopper sparrow X X X R, N

Dickcissel X X R, N

Bobolink X

1 U.S. Fish and Wildlife Service, 2002.

2 Rich and others, 2004.

3 Skagen and Thompson, 2003.

4 U.S. Fish and Wildlife Service and others, 1999.

indicate that program lands increase vegetation structure and 

provide suitable nesting habitat for more species than cropland; however, this assessment is based on a limited number of 

samples and only one structural variable. Finally, these results 

should not be misconstrued to imply that a single catchment 

type provides all necessary requisites for completion of a species breeding cycle; rather, each catchment type considered 

suitable potentially provides some of the necessary resources 

required by that species.

Discussion

Our example, although limited to a single township and 

one structural variable, illustrates the influence of program 

lands on wildlife in the Prairie Pothole Region, including species considered to be of conservation concern. Our analysis 

also indicates that these habitat benefits can be enhanced for 

some area-sensitive species if program lands were placed strategically on the landscape to take advantage of existing favorable land uses (Johnson and Igl, 2001). For example, enrolling 

cropland tracts that split existing grassland tracts can expand 

grassland areas beyond the area enrolled. In addition, such a 

strategy also may increase variability of vegetation structure 

because larger areas often exhibit more heterogeneous topography, slope, and aspect than smaller areas.

We did not statistically compare vegetation obstruction between restored and native prairie catchments, but the 

range of vegetation obstruction values we measured indicate 

that CRP grasslands overlap with native prairie grasslands, 

at least in that portion of the Prairie Pothole Region that is 

composed of mixed-grass prairie (fig. F–2). As a result, the 

number of species potentially supported is similar between 

these two land-use treatments for the species we evaluated. 

In contrast, vegetation obstruction of both restored and native 

prairie grasslands differed markedly from cropland, and this 

difference restricts the suitability of habitat for a number 

of bird species that use the Prairie Pothole Region. Vegetation obstruction was the only habitat variable we evaluated, 

however, and this relationship may not be true for other habitat 

parameters.

The approach we used indicates conservation programs 

are of value to wildlife. However, for most species, the most 

objective means of evaluating effectiveness of conservation 

programs is to determine if habitat for a large diversity of 

wildlife species is provided over temporal scales that encompass the full range of natural climatic variability. Thus, much 

additional work will be required if this approach is used to 

report the temporal variability in wildlife values across a 

broad geographic area. First, spatial data for the entire Prairie 

Pothole Region must be processed to identify and delineate 

past and current land-use treatments. We used a combination 

52 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
A B

Figure F–1. Land-use treatments (A) prior to and (B) following implementation of the Conservation Reserve Program in a single towns(93.0 km2 [36.0 mi2]) in the glaciated plains of the Prairie Pothole Region (NWI, National Wetlands Inventory).
Table F–5. Change in number of polygons and area of land-use classes prior to and following implementation of the Conservation 

Reserve Program in a single township in the glaciated plains of the Prairie Pothole Region.

[CRP, Conservation Reserve Program; --, no data]

Land-use class

Number of patches Area, in hectares (acres)

Pre-CRP Post-CRP Change Pre-CRP Post-CRP Change

Cropland/wetland complex

Upland 54 87 +33 6,752.07

(16,684.36)

5,272.99

(13,029.56)

-1,479.08

(-3,654.81)

Temporary wetlands 926 692 -234 99.80

(246.61)

75.04

(185.42)

-24.76

(-61.18)

Seasonal wetlands 1,803 1,303 -500 790.32

(1,952.88)

531.06

(1,312.25)

-259.26

(-640.63)

Semipermanent wetlands 42 24 -18 37.91

(93.68)

22.64

(55.94)

-15.27

(-37.73)

Partial wetlands1 -- -- -- 202.80

(501.12)

188.98

(466.97)

-13.82

(-34.15)

All wetlands 2,771 2,019 -752 1,130.83

(2,794.28)

817.72

(2,020.59)

-313.11

(-773.69)

Total 2,825 2,106 -719 7,882.90

(19,478.65)

6,090.71

(15,050.14)

-1,792.19

(-4,428.50)

Grassland/wetland complex

Upland 134 114 -20 1,055.32

(2,607.70)

2,534.40

(6,262.50)

+1,479.08

(+3,654.81)

Temporary wetlands 157 388 +231 17.68

(43.69)

42.06

(103.93)

+24.38

(60.24)

Seasonal wetlands 210 668 +458 81.45

(201.26)

280.93

(694.18)

+199.48

(+492.92)

Semipermanent wetlands 11 31 +20 7.19

(17.77)

23.05

(56.96)

+15.86

(+39.19)

Partial wetlands -- -- -- 120.46

(297.66)

193.85

(479.00)

+73.39

(+181.35)

All wetlands 378 1,087 +709 226.78

(560.37)

539.89

(1,334.07)

+313.11

(+773.69)

Total 512 1,201 +689 1,282.10

(3,168.07)

3,074.29

(7,596.57)

+1,792.19

(+4,428.50)

Tree/shrub wetland complex

Upland 63 63 0 40.39

(99.80)

40.39

(99.80)

0

(0)

Temporary wetlands 3 3 0 0.92

(2.27)

0.92

(2.27)

0

(0)

Seasonal wetlands 4 4 0 0.42

(1.04)

0.42

(1.04)

0

(0)

Semipermanent wetlands 0 0 0 0.0

(0.0)

0.0

(0.0)

0

(0)

Partial wetlands -- -- -- 16.74

(41.36)

16.74

(41.36)

0

(0)

All wetlands 7 7 0 18.08

(44.68)

18.08

(44.68)

0

(0)

Total 70 70 0 58.47

(144.48)

58.47

(144.48)

0

(0)

1 Wetlands with upland catchments composed of more than one land-use class.

54 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
VISUAL VEGETATION OBSTRUCTION, IN CENTIMETERS

LAND-USE TREATMENT

CROPLAND RESTORED NATIVE

Temporary

Seasonal

Semipermanent

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

Figure F–2. Median (|), interquartile (25–75 percent) range (box), and 10–90 quantile 

(10–90 percent) range (stems) of vegetation obstruction measurements for nine land-use 

treatment/catchment type (temporary, seasonal, semipermanent) combinations in the vicinity 

of the Prairie Pothole Region township that was used as an example to illustrate a habitatbased approach for determining wildlife habitat suitability.

of NLCD, NWI, and CRP land data in our township to identify 

land-use treatments because they were available nationally; 

however, spatial resolution of this data did not allow accurate 

assignment of wetlands and grassland tracts. Therefore, in 

some cases we assumed that grassland present prior to 1987 

was native prairie and that all additional grassland occurring after 1987 resulted from enrollment in the CRP. These 

assumptions, however, may not be valid at all spatial scales 

because factors other than the CRP obviously influences 

cropland conversion. For example, several Federal and State 

programs, such as Soil Bank and U.S. Fish and Wildlife 

Service Waterfowl Production Areas, facilitated establishment 

of grasslands in the Prairie Pothole Region prior to the CRP. 

Increased classification accuracy is possible, however, with 

existing spatial technology and data (Skidmore, 2002; Ustin, 

2004). For example, land-cover data from the National Aeronautics and Space Administration’s (NASA) GeoCover2000 

(14.5 m [47.6 ft] resolution) are available for the Prairie 

Pothole Region, and the NLCD 2001 is in various stages of 

completion. More advanced imagery also can be acquired 

from other sources, including NASA and the U.S. Geological 

Survey Center for Earth Resources Observation and Science. 

These types of data could facilitate separating land uses into 

more distinct subcategories (for example, hayed grassland, 

burned grassland) that would improve the ability to assess suitability of habitats for wildlife.

Second, additional wildlife species and associated habitat 

parameters must be incorporated to more broadly assess 

wildlife benefits of conservation programs. Selection of species should be based on the range of habitat conditions that 

support all fauna of interest. For example, spatial requirements 

of grassland-dependent birds provide useful criteria for judging program success relative to area; however, other spatial 

criteria, such as corridors, interwetland distances, and wetland 

density, would be required to determine area suitability for 

other taxonomic groups. Developing this species list may 

seem overwhelming, but it is possible to select a species pool 

composed of relatively few species. For example, although 

330 bird species occur on the Great Plains (Johnsgard, 1979), 

protecting avian diversity may require that only 32 species 

receive priority for conservation (Knopf and Samson, 1995).

Third, following identification of a full complement of 

species to evaluate, a search of the published information must 

be conducted to compile quantitative measures that define habitat quality for each species. Habitat conditions vary throughout the year; thus, multiple parameters will be required. For 

example, breeding sites require adequate foraging, brood, and 

pair habitat in addition to suitable nesting habitat. Similarly, 

upland vegetation structure is extremely important during the 

breeding cycle for ground-nesting waterfowl, but it is less 

important during migration. Unfortunately, detailed knowledge of exact features that influence habitat suitability in the 

Chapter F: Proposed Approach to Assess Potential Wildlife Habitat Suitability on Program Lands 55
Prairie Pothole Region is lacking (Johnson and Igl, 2001). 

Thus, information for some parameters likely will not be 

available or, if available, may be of uncertain applicability 

because it was developed in areas different from the Prairie 

Pothole Region. In these cases, information will have to be 

obtained and verified through monitoring or research. In other 

cases, some information already has been compiled in various 

bibliographies and databases, but it must still be synthesized 

and electronically linked to spatial land-cover data to facilitate 

processing and evaluation. For example, in our analysis we 

used vegetation obstruction information developed outside the 

Prairie Pothole Region to determine bird habitat requirements. 

In addition, we were unable to assign vegetation obstruction 

values to each tract because of limited data. Consequently, it 

was not possible to determine if grassland tracts of suitable 

area also provided appropriate vegetation obstruction. To 

resolve this issue, each habitat variable considered must be 

evaluated relative to its importance in defining habitat suitability, as well as to the ease and rapidity that the variable can 

be measured at the spatial scale of interest. Technology exists 

to develop many habitat estimates either directly or by using 

surrogate measures, but additional research involving remote 

sensing likely will be required to develop reliable estimators.

Finally, the fully developed approach must undergo 

scientific scrutiny to determine applicability, including veracity evaluation, sensitivity analysis, and cost:benefit analysis. 

Veracity evaluation and sensitivity analysis will require conducting or obtaining results of wildlife surveys to determine 

if precision and accuracy of the approach are adequate to 

meet the needs of the USDA. If the results of these analyses indicate that the approach is inadequate, then additional 

evaluation will be required to determine if inclusion of more 

or different habitat variables would resolve the problem. A 

cost:benefit analysis also will be required to determine if 

implementing the approach periodically to ascertain temporal 

changes in wildlife values is cost effective. The intent is not to 

replace existing wildlife surveys, as surveys provide population estimates and other data that can not be obtained from 

the habitat-based approach recommended here; however, the 

capability to periodically document population changes in 

numerous species simultaneously by using wildlife survey 

methods would require substantial funds, involve extensive 

coordination, and require much time to enter and analyze data. 

In contrast, the cost of using habitat conditions as a surrogate 

measure for assessing wildlife values is theoretically lower, 

particularly if existing methods are available or if methods 

could be developed to remotely acquire information necessary 

to predict habitat suitability. Thus, conducting wildlife surveys 

periodically would complement a habitat-based approach by 

providing values not estimated by the habitat approach. In 

concert, these surveys could be used to evaluate and improve 

the predictive capability of a habitat-based approach.

References

Cordell, H.K., and Herbert, N.G., 2002, The popularity of 

birding is still growing: Birding, February 2002.

Dieni, J.S., and Jones, S.L., 2003, Grassland songbird nest site 

selection patterns in northcentral Montana: Wilson Bulletin, 

v. 115, p. 388–396.

Euliss, N.H., Jr., Laubhan, M.K., and Gleason, R.A., 2007, 

Wildlife Benefits, in Kimble, J.M., Rice, C.W., Reed, D. 

Mooney, S., Follett, R.F., and Lal, R., eds., Soil carbon 

management—economic, environmental and societal benefits: Boca Raton, Fla., CRC Press, p. 193–198.

Gleason, R.A., Tangen, B.A., Laubhan, M.K., Kermes, 

K.E., and Euliss, N.H., Jr., 2007, Estimating water storage capacity of existing and potentially restorable wetland 

depressions in a subbasin of the Red River of the North: 

U.S. Geological Survey Open-File Report 2007–1159, 36 p.

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, p. 351–357.

Haufler, J.B., ed., 2005, Fish and wildlife benefits of Farm Bill 

conservation programs—2000–2005 update: The Wildlife 

Society Technical Review 05–2.

Helzer, C.J., and Jelinski, D.E., 1999, The relative importance 

of patch area and perimeter-ratio to grassland breeding 

birds: Ecological Applications, v. 9, p. 1448–1458.

Herkert, J.R., 1994, The effects of habitat fragmentation on 

midwestern grassland bird communities: Ecological Applications, v. 4, p. 461–471.

Hertel, D.R., 1987, Effects of grazing systems on habitats used 

by upland nesting waterfowl in south central North Dakota: 

Fargo, North Dakota State University, master’s thesis.

Hobbs, R.J., and Norton, D.A., 2004, Ecological filters, 

thresholds, and gradients in resistance to ecosystem reassembly, in Temperton, V.M., Hobbs, R.J., Nuttle, T., and 

Halle S., eds., Assembly rules and restoration ecology: 

Washington, D.C., Island Press, p. 72–95.

Holm, J.W., 1984, Nest success and cover relationships of 

upland-nesting ducks in northcentral Montana: Bozeman, 

University of Montana, master’s thesis.

Horn, D.J., 2000, The influence of habitat features on grassland birds nesting in the Prairie Pothole Region of North 

Dakota: Ames, Iowa State University, Ph.D. dissertation.

56 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Johnsgard, P.A., 1979, Birds of the Great Plains: Lincoln, 

University of Nebraska Press.

Johnson, D.H., and Igl, L.D., 2001, Area requirements of 

grassland birds—a regional perspective: Auk, v. 188, 

p. 24–34.

Kantrud, H.A., and Higgins, K.F., 1992, Nest and nest site 

characteristics of some ground-nesting, non-passerine birds 

of northern grasslands: Prairie Naturalist, v. 24, p. 67–84.

Knopf, F.L., and Samson, F.B., 1995, 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: The Netherlands, Kluwer 

Academic Publishers, p. 121–133.

Knutsen, G.A., and Euliss, N.H., Jr., 2001, Wetland restoration in the Prairie Pothole Region of North America—a 

literature review: Reston, Va., U.S. Geological Survey, 

Biological Resources Division, Biological Science Report, 

USGS/BRD/BSR-2001-0006.

Kohn, S.C., 1982, Sharp-tailed grouse nesting habitat in 

southwestern North Dakota: Proceedings of the WildlifeLivestock Relationships Symposium, v. 10, p. 166–174.

Miller, J.R., Joyce, L.A., Knight, R.L., and King, R.M., 1996, 

Forest roads and landscape structure in the southern Rocky 

Mountains: Landscape Ecology, v. 11, p. 115–127.

Nenneman, M.P., 2003, Vegetation structure and floristics at 

nest sites of grassland birds in north central North Dakota: 

Missoula, University of Montana, master’s thesis.

O’Leary, C.H., and Nyberg, D.W., 2000, Treelines between 

fields reduce the density of grassland birds: Natural Areas 

Journal, v. 20, p. 243–249.

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.

Pickett, S.T.A., and White, P.S., eds., 1985, The ecology of 

disturbance and patch dynamics: New York, Academic 

Press.

Renken, R.B., 1983, Breeding bird communities and birdhabitat associations on North Dakota Waterfowl Production 

Areas of three habitat types: Ames, Iowa State University, 

master’s thesis.

Rewa, C.A., 2005, Wildlife benefits of the Wetlands Reserve 

Program, in Haufler, J.B., ed., Fish and wildlife benefits 

of Farm Bill Programs—2000–2005 update: The Wildlife 

Society Technical Review 05–2, p. 133–146.

Rich, T.D., Beardmore, C.J., Berlanga, H., Blancher, P.J., 

Bradstreet, M.S.W., Butcher, G.S., Demarest, D.W., Dunn, 

E.H., Hunter, W.C., Iñigo-Elias, E.E., Kennedy, J.A., Martell, A.M., Panjabi, A.O., Pashley, D.N., Rosenberg, K.V., 

Rustay, C.M., Wendt, J.S., and Will, T.C., 2004, Partners in 

Flight North American landbird conservation plan: Ithaca, 

N.Y., Cornell Lab of Ornithology.

Samson, F.B., 1980, Island biogeography and the conservation of nongame birds: Transactions of the North American 

Wildlife Conference, v. 45, p. 245–251.

SAS Institute, Inc., 2003, SAS software release 9.1: Cary, 

N.C., SAS Institute, Inc.

Saunders, D.A., Hobbs, R.J., and Margules, C.R., 1991, 

Biological consequences of ecosystem fragmentation—a 

review: Conservation Biology, v. 5, p. 18–32.

Scheiman, D.M., Bollinger, E.K., and Johnson, D.H., 2003, 

Effects of leafy spurge infestation on grassland birds: Journal of Wildlife Management, v. 67, p. 115–121.

Sedivec, K.K., 1994, Grazing treatment effects on and habitat 

use of upland nesting birds on native rangeland: Fargo, 

North Dakota State University, Ph.D. dissertation.

Skagen, S.K., and Thompson, G., 2003, Northern Plains/

prairie potholes regional shorebird conservation plan, U.S. 

shorebird conservation plan, accessed September 1, 2006, at 

http://shorebirdplan.fws.gov/RegionalShorebird/downloads/

NORPLPP2.doc

Skidmore, A., ed., 2002, Environmental modelling with GIS 

and remote sensing: New York, Taylor and Francis Publishing.

U.S. Department of the Interior, Fish and Wildlife Service 

and U.S. Department of Commerce, U.S. Census Bureau, 

2002, 2001 national survey of fishing, hunting, and wildlifeassociated recreation: Washington, D.C., U.S. Department 

of the Interior, Fish and Wildlife Service.

U.S. Fish and Wildlife Service, 2002, Birds of conservation 

concern 2002: Arlington, Va., Division of Migratory Bird 

Management, accessed September 1, 2006, at http://migratorybirds.fws.gov/reports/bcc2002.pdf

U.S. Fish and Wildlife Service, Instituto Nacional de Ecologia (Mexico), and Canadian Wildlife Service, 1999, North 

American waterfowl management plan—1998 update, 

expanding the vision: Hull, Quebec, Environment Canada, 

Canadian Wildlife Service, Wildlife Conservation Branch, 

NAWMP Implementation Office, 41 p.

Ustin, S.L., ed., 2004, Remote sensing for natural resource 

management and environmental monitoring—Manual of 

remote sensing (3d ed.), v. 4: Hoboken, N.J., John Wiley 

and Sons.

Chapter F: Proposed Approach to Assess Potential Wildlife Habitat Suitability on Program Lands 57
Vickery, P.D., Hunter, M.L., Jr., and Melvin, S.M., 1994, 

Effects of habitat area on the distribution of grassland birds 

in Maine: Conservation Biology, v. 8, p. 1087–1097.

Walk, J.W., and Warner, R.E., 1999, Effects of habitat area 

on the occurrence of grassland birds in Illinois: American 

Midland Naturalist, v. 141, p. 339–344.

Winter, M., 1998, Effects of habitat fragmentation on 

grassland-nesting birds in southwestern Missouri: 

Columbia, University of Missouri, Ph.D. dissertation.

Winter, S.L., Cully, J.R., Jr., and Pontius, J.S., 2003, Breeding 

season avifauna of prairie dog colonies and non-colonized 

areas in shortgrass prairie: Transactions of the Kansas 

Academy of Science, v. 106, p. 129–138.

Publishing support provided by:

Helena Publishing Service Center

For more information concerning this publication, contact:

Director, Northern Prairie Wildlife Research Center

U.S. Geological Survey

8711 37th Street Southeast

Jamestown, North Dakota 58401

(701) 253-5500

Or visit the Northern Prairie Wildlife Research Center Web site at:

http://www.npwrc.usgs.gov/

58 Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region
Gleason and others—Ecosystem Services Derived from Wetland Conservation Practices in the United States Prairie Pothole Region with an Emphasis on the 

U.S. Department of Agriculture Conservation Reserve and Wetlands Reserve Programs—Professional Paper 1745

Printed on recycled paper