USE OF NATURAL VEGETATIVE BARRIERS TO LIMIT BLACK-TAILED 

PRAIRIE DOG TOWN EXPANSION IN WESTERN SOUTH DAKOTA 

BY 

DAVID F. TERRALL 

A thesis submitted in partial fulfillment of the requirements for the 

Master of Science 

Major in Wildlife and Fisheries Sciences 

Wildlife Specialization 

South Dakota State University 

2006
ii

USE OF NATURAL VEGETATIVE BARRIERS TO LIMIT BLACK-TAILED 

PRAIRIE DOG TOWN EXPANTION IN WESTERN SOUTH DAKOTA 

This thesis is approved as a creditable and independent investigation by a 

candidate for the Master of Science degree and is acceptable for meeting the thesis 

requirements for this degree. Acceptance of this thesis does not imply that the 

conclusions reached by the candidate are necessarily the conclusions of the major 

department. 

_______________________________ 

Dr. Jonathan A. Jenks Date 

Thesis Advisor 

_______________________________ 

Dr. Charles G. Scalet Date 

Department Head of Wildlife 

And Fisheries Sciences 
iii

Acknowledgements 

I would like to thank my advisor Dr. Johathan A. Jenks for providing me with the 

opportunity to work on this project. I appreciate all of the patience and guidance he has 

shown throughout the rough spots in this project, as well as the additional opportunities 

to learn and grow in this field outside of my thesis research. I would also like to thank 

Dr. Daniel E. Hubbard (Wildlife and Fisheries Department), Dr. Dwight Galster (Math 

and Statistics Department), and Dr. Allen Branum (Graduate School) for serving on my 

committee and for the comments that they made on this thesis. 

I would also like to thank the agency personnel that helped me throughout this 

project. I would like to thank Art Smith, Wildlife Damage Management Program 

Administrator, for all of the opportunities he shared with me, especially in the field of 

wildlife damage management. I also thank Robert Hodorff, USDA Forest Service 

Biologist, for all of the help you gave in finding study sites and the heads up on the 

constantly changing prairie dog policies and landowner issues that were encountered 

during this project. 

This study would not have been possible without the help and cooperation of the 

landowners that participated in this study; J. Sides, E. Brunson, G. Schueth, M. Sheets, L. 

Hall, and J. Gilespie. These landowners understood the importance of looking for 

solutions to difficult problems and went out of there way to let prairie dogs stay on their 

property during a difficult time in western South Dakota. 
iv

I would like to thank my technician K. Herman for help during my first field 

season. The help she gave in setting up the study sites was truly appreciated, as well as 

the company on the long drives, and hot summer days in the field. Many of graduate 

students at South Dakota State University also deserve thanks for their comments, 

suggestions, inspiration, and intellectual stimulation. 

Lastly I would like to thank my family. The value of their support is 

immeasurable. I thank my parents for allowing me to stay with them when I was in the 

southwest portion of the state and being understanding when I came and went throughout 

the summers of this project. I would finally like to thank my wife, Amy and my two 

daughters, Gracie and Carlie. They were strong and understanding when daddy had to be 

away during the summer, and long hours at school. They are an inspiration for me to do 

better everyday. 

Funding for this project was provided by Federal Aid to Wildlife Restoration 

(Study No. 75120) administered by the South Dakota Department of Game, Fish and 

Parks, and South Dakota State University. 
v

Abstract 

USE OF NATURAL VEGETATIVE BARRIERS TO LIMIT BLACK-TAILED 

PRAIRIE DOG TOWN EXPANTION IN WESTERN SOUTH DAKOTA 

David F. Terrall 

July 2006 

Prairie dog (Cynomys ludovicianus) control has historically consisted of lethal 

methods to maintain, reduce, or eliminate populations. Non-lethal methods of control for 

prairie dogs are desired to meet changing management objectives. Use of naturally 

occurring buffer strips as vegetative barriers may be effective in limiting prairie dog town 

expansion. Objectives of this study were to evaluate effective width of vegetative 

barriers in limiting prairie dog town expansion, document characteristics of natural 

vegetation that affect expansion of prairie dog towns, and examine vegetation 

characteristics associated with prairie dog towns in western South Dakota. Five study 

sites were established in western South Dakota on rangelands containing prairie dog 

towns of adequate size (≥ 10 ha). Electric fences were constructed to exclude cattle and 

create buffer strips of naturally occurring grasses and shrubs. Buffer strips were 100 m 

long and 10, 25, and 40 m wide. Zero meter controls were included on all study sites. 

Prairie dogs were poisoned to create prairie dog free buffer zones within control areas. 

Grazing was allowed on both sides of buffer strips. When grazing pressure was not 

sufficient, mowing was used to simulate grazing. To quantify vegetation characteristics, 
vi

quadrats (25) were randomly distributed throughout buffer strips. Evaluation of study 

sites included visual obstruction (VOR), vegetation cover (%), vegetation frequency, 

vegetation height, and vegetation identification. Burrow density adjacent to buffers was 

quantified as an index to prairie dog population. Barrier penetration was evaluated by 

presence of new active burrows behind vegetative barriers (Breakthrough). Breakthrough 

was minimized with 40-cm vegetation height and 10-cm VOR. The predictive model for 

vegetation height and buffer width was Breakthrough=exp (2.410-0.004*Veg Height-0.036*Buffer 

Width). The predictive model for VOR and buffer width was Breakthrough=exp (2.48-

0.048*VOR-0.031*Buffer Width). Percent grass cover, percent forb cover, percent bare ground, 

percent litter cover, and burrow density did not add significantly to the model. Models 

were used to predict buffer width needed to prevent breakthroughs. Estimated buffer 

width to minimize breakthroughs ranged from 85.1 – 103.1 m. Vegetation characteristics 

indicated that visual obstruction was greater on buffers than on controls. Vegetation 

height was higher on treatment than control plots, and higher on eastern sites than 

western sites. Western wheatgrass (Pascopyrum smithii) was greater on eastern than 

western site. Bare ground was significantly greater on control areas compared to buffer 

areas. Vegetation characteristics associated with relative percent grass cover, forb cover, 

and litter indicated minor or no differences between controls and buffer, and eastern sites 

and western sites. Plant species richness was not different from control to buffer area, 

but was greater on eastern sites than western sites. 
vii

Table of Contents 

Acknowledgements............................................................................................................ iii

Abstract................................................................................................................................v 

Table of Contents.............................................................................................................. vii 

List of Tables ..................................................................................................................... ix 

List of Figures ......................................................................................................................x 

List of Appendices ............................................................................................................. xi 

Chapter 1. General Introduction .........................................................................................1 

 Status .......................................................................................................................1

 Natural History ........................................................................................................4 

 Literature Review ....................................................................................................6 

 Literature Cited......................................................................................................10 

Chapter 2. Use of natural vegetative barriers to limit expansion of blacktailed prairie dog towns...................................................................................13 

 Introduction ...........................................................................................................13 

 Study Area .............................................................................................................14 

 Methods .................................................................................................................16 

 Results ..................................................................................................................18 

 Discussion..............................................................................................................19 

 Literature Cited......................................................................................................26 

Chapter 3. Vegetation characteristics associated with black-tailed prairie 

dog town expansion .........................................................................................39 
viii

 Introduction ...........................................................................................................39 

 Study Area .............................................................................................................40 

 Methods .................................................................................................................41 

 Results ...................................................................................................................43 

 Discussion..............................................................................................................45 

 Literature Cited......................................................................................................50 

Chapter 4. Management Implications and Conclusions ...................................................59 

 Literature Cited......................................................................................................62 
ix

List of Tables 

Table 2.1. Mean (SE) of vegetation characteristics and breakthroughs 

(new active burrows) associated with prairie dog town 

expansion measured from five study sites in western South 

Dakota, August 2004 and 2005......................................................................30 

Table 2.2. Predicted buffer width needed (meters) to minimize prairie dog 

breakthrough (new active burrows) based upon visual 

obstruction readings (VOR) and vegetation height from sites 

with breakthroughs in western South Dakota during 2004 and 

2005 .................................................................................................................31 

Table 2.3. Precipitation as registered by the nearest weather station within 

25 km of study sites for 2004 and 2005..........................................................32 

Table 3.1. Mean (SE) of vegetation characteristics measured at five study 

sites in western South Dakota during August 2004 and 2005a

. .....................54 

Table 3.2. Relative percent canopy cover for top three most abundant 

species on five study sites in western South Dakota in August 

2005. ................................................................................................................55 

Table 3.3. Precipitation as registered by the nearest weather station within 

25 km of study sites for 2004 and 2005...........................................................57 
x

List of Figures 

Figure 2.1. Locations of study areas used in vegetative barrier study in 

western South Dakota in 2004 and 2005. .....................................................33 

Figure 2.2. Schematic of buffer strips used to reduce prairie dog town 

expansion for five study sites in western South Dakota in 

2004 and 2005................................................................................................34 

Figure 2.3. Non-linear model of breakthroughs (Breakout) of new, active 

prairie dog burrows versus visual obstruction (VOR, [cm]) for 

five study sites in western South Dakota during August 2004 

and 2005.........................................................................................................35 

Figure 2.4. Non-linear model of breakthroughs (BREAKOUT) of new, 

active prairie dog burrows versus vegetation height 

(VEGHEIGHT, [cm]) for five study sites in western South 

Dakota during August 2004 and 2005. ..........................................................36 

Figure 2.5. Non-linear model of breakthroughs (BREAKOUT) of new, 

active prairie dog burrows versus visual obstruction (VOR, 

[cm]) and buffer width (BUFFWIDTH, [m]) for five study 

sites in western South Dakota during August 2004 and 2005. ......................37 

Figure 2.6. Non-linear model of breakthroughs (BREAKOUT) of new, 

active burrows versus vegetation height (VEGHEIGHT, 

[cm]) and buffer width (BUFFWIDTH [M]) for five study 

sites in western South Dakota during August 2004 and 2005. ......................38 

Figure 3.1. Location of study areas used in vegetative barrier study in 

western South Dakota in 2004 and 2005. ......................................................58 
xi

List of Appendices 

Appendix A. Plant species identified on the Bad River Road study site, 

2004 and 2005.............................................................................................64 

Appendix B. Plant species identified on the Custer county site, 2004. ............................65 

Appendix C. Plant species identified on the Custer county site, 2005. ............................66 

Appendix D. Plants identified on Fall River county site, 2004 and 2005. .......................67 

Appendix E. Plant species identified on Fort Pierre study site, 2004 and 2005...............68 

Appendix F. Plant species identified on Winner study site, 2004 and 2005 ....................69 

Appendix G. Breakthroughs of new, active burrows, and vegetation 

characteristics associated with five study sites in western South Dakota, 

August 2004 and 2005. ......................................................................................................70 
1

Chapter 1 

General Introduction 

Status 

In 1998, the United States Fish and Wildlife Service (USFWS) received two 

petitions to list the black-tailed prairie dog (Cynomys ludovicianus) as threatened 

throughout its range; one petition from the National Wildlife Federation filed in July, and 

one petition from the Biodiversity Legal Foundation, the Predator Project, and Jon C. 

Sharps filed in August (U. S. Fish and Wildlife Service 2000). A positive, 90-day finding 

led to an investigation by the USFWS. The 12-month administrative finding found that 

the listing of the black-tailed prairie dog was warranted, but precluded due to other 

species of greater importance (U. S. Fish and Wildlife Service 2000). 

The 12-month finding found three major factors that were impacting black-tailed 

prairie dog populations. The first major impact was the loss and destruction of habitat, 

mainly caused by the conversion of native prairie grasslands to cropland. Extensive 

conversion of the eastern portion of the black-tailed prairie dog range into cropland 

occurred during the 1880’s and 90’s (U. S. Fish and Wildlife Service 2000). This 

conversion continued during the beginning of the 20th century and still continues to some 

extent today. Improved dry-land farming techniques and new crop hybrids have 

contributed to habitat loss by making farming profitable in areas previously unsuitable for 

cultivation (U. S. Fish and Wildlife Service 2000). 
2

The second major impact was large scale control efforts to reduce or eliminate 

large populations of prairie dogs. Due to competition with livestock, extensive control 

efforts of prairie dogs have occurred on rangeland including federal, state, tribal, and 

private lands (U. S. Fish and Wildlife Service 2000). Control efforts have often led to the 

complete loss of some populations of prairie dogs. Prairie dog control in South Dakota 

dates back to 1914 (Hanson 1988). Control of prairie dogs in South Dakota was 

conducted on a county by county basis using strychnine oat bait (Hanson 1988). Zinc 

phosphide oat bait and fumigants, such as aluminum phosphide, are currently used in 

South Dakota. In 2004, the South Dakota Game, Fish and Parks Department controlled 

just fewer than 11,000 ha, and Buffalo Gap National Grassland poisoned approximately 

3,200 ha of land along the border between federal and private lands in southwest South 

Dakota (South Dakota Department of Game Fish and Parks 2004). 

The third major factor found by USFWS to affect prairie dog populations was 

sylvatic plague. Sylvatic plague is caused by the transfer of the bacterium Yersinia pestis

from infected fleas to the host organism. Black-tailed prairie dogs are highly susceptible 

to outbreaks of sylvatic plague and Cully (1993) reported near 100% mortality for blacktailed prairie dogs from plague. Sylvatic plague is an exotic disease for which prairie 

dogs develop no antibodies or immunity against (Cully 1993). The near complete 

mortality from sylvatic plague results in epizootic outbreaks being short lived (Cully 

1993). South Dakota had its first recorded case of sylvatic plague in 2004 (South Dakota 

Department of Game, Fish and Parks 2004). Plague outbreaks expanded in 2005 in the 
3

southwest portion of the state with the focal point of the outbreak located on the western 

side of Shannon County. 

Other factors that contributed to the candidate status of the black-tailed prairie 

dog included concerns over exploitation due to recreational shooting and the inadequacy 

of existing regulatory mechanisms. At the time of petitioning, South Dakota categorized 

the black-tailed prairie dog as a state designated pest. Presence of prairie dogs was 

considered an infestation and control was required (U. S. Fish and Wildlife Service 

2000). South Dakota did require residents and non-residents to acquire a license to hunt 

prairie dogs, however, no limits were placed on the number harvested. 

The designation of the black-tailed prairie dog angered landowners, elevated the 

controversy surrounding prairie dog control on rangelands, and prompted South Dakota, 

as well as other states and agencies, to modify or create prairie dog management plans 

(Cooper and Gabriel 2005). Following the petition, the South Dakota Game, Fish and 

Parks Department, and the USDA Forest Service suspended control operations for prairie 

dogs. South Dakota entered into a multi-state, multi-agency cooperative effort to develop 

a comprehensive management strategy that would ensure that management and control of 

black-tailed prairie dogs remained the responsibility of states and not the federal 

government (Cooper and Gabriel 2005). Efforts were designed to remove or minimize 

threats to ensure the long-term conservation of the black-tailed prairie dog (Cooper and 

Gabriel 2005). South Dakota’s management plan included six objectives: 

1-Determine statewide preliminary population goals and special 

management areas. 
4

 2-Develop effective tools to monitor changes in prairie dog populations. 

3-Develop disease monitoring protocols including a contingency plan for 

sylvatic plague outbreaks in South Dakota. 

4-Determine and accommodate conservation needs for black-footed 

ferrets. 

5-Use public involvement techniques to gather input on management 

goals, objectives, and strategies. 

6-Use adaptive management to evaluate progress and make needed 

adjustments to reach program goals. 

Public opinion over the listing included concerns over landowner rights, control 

responsibilities, and other species associated with prairie dog towns, including the blackfooted ferret (Mustela nigripes), swift fox (Vulpes velox), and burrowing owl (Athene 

cunicularia). In August 2004, the USFWS removed the black-tailed prairie dog as a 

candidate species for listing as threatened and stated that the black-tailed prairie dog was 

not likely to become endangered due to new information indicating the species ability to 

exist over time, and increased management efforts by states within the prairie dog’s range 

(Cooper and Gabriel 2005). 

Natural History 

Black-tailed prairie dogs are small, ground dwelling members of the family 

Sciuridae. Five species of prairie dogs are found in North America; black-tailed, whitetailed (Cynomys leucurus), Utah (Cynomys parvidens), Gunnison’s (Cynomys gunnisoni), 
5

and Mexican (Cynomys mexicanus). Of the five species of prairie dogs, the black-tailed 

is the most numerous, has the largest geographic distribution, and is the most colonial 

(Hoogland 1995). Black-tailed prairie dogs range from northern Mexico in the south to 

southern Canada in the north, and from the eastern edge of the Rocky Mountains in the 

west, east into the mixed grass prairies of central North Dakota, South Dakota, Nebraska, 

Kansas, Oklahoma, and Texas (Hoogland 1995). Current distribution of prairie dogs in 

South Dakota includes the mixed- and short-grass prairies of the western two-thirds of 

the state (Sidle et al. 2001). Prairie dogs currently occupy approximately 1,665 km2 of 

land in South Dakota (Cooper and Gabriel 2005). 

One of the most striking aspects of the black-tailed prairie dog is the extensive 

social and colonial tendencies that are characteristic of the species (Hoogland 1995). 

Prairie dogs live in groups called colonies or towns (King 1955, Hoogland 1995). Within 

these colonies are subgroups called wards that are often separated by unsuitable habitat 

(Hoogland 1995). Harem-polygynous, territorial family groups found within colonies are 

termed coteries, and generally contain one breeding male, two to three adult females, and 

one or two yearlings of each sex (Hoogland 1995). Burrows that prairie dogs excavate 

and live in can have one to many holes and can be several meters in length and depth 

(Hoogland 1995). Female prairie dogs tend to remain in their natal coterie, while 

juvenile males will disperse to other areas (Hoogland 1995). Coterie members do not 

show territoriality towards other members, but will defend the coterie territory from nonmembers. 
6

Prairie dogs give birth to one litter of pups in the spring of each year in a single 

underground burrow that is defended by the female. Male and female prairie dogs 

typically reach sexual maturity at 2 years of age. Hoogland (1995) observed that only 

50% of females will bring a litter of pups to the surface. The leading cause of juvenile 

mortality is infanticide and can result in the partial or total loss of 39% of litters. 

Average size of litters that reach first emergence is 3-4. Larger groups of pups seen 

outside of burrow entrances are likely due to communal nursing (Hoogland 1995). First 

year mortality rate for both sexes is 50%; however, female prairie dogs that live past the 

first year can live up to eight years and males up to five years (Hoogland 1995). 

Black-tailed prairie dogs clip and maintain short vegetation throughout the 

colony. Short vegetation enhances predator detection within the colony (Hoogland 

1995). Maintenance of short vegetation in towns is seen as direct competition with 

livestock for range resources in areas where prairie dogs and cattle occur sympatrically. 

There is evidence that the use of buffer strips of native vegetation that is allowed to grow 

free of grazing pressure by livestock or prairie dogs may be an effective barrier in 

limiting prairie dog expansion. 

Literature Review 

Previous studies on the use of barriers to prairie dog town expansion have focused 

mainly on artificial barriers. Franklin and Garrett (1989) used 1-m high burlap fencing 

and cut ponderosa pine (Pinus ponderosa) trees as a method to control prairie dog town 

expansion on a study site at Wind Cave National Park, South Dakota. Use of control 
7

areas by prairie dogs was 3 times greater than on the treatment area using burlap fencing. 

The area of expansion was 54% on the control areas while only 8% on the treated area 

(Franklin and Garrett 1989). Cut pine trees were used as a visual barrier on a large 

colony in the Park and were successful at reducing the use and expansion of prairie dogs 

into the treated area (Franklin and Garrett 1989). Plastic snow fence was ineffective at 

reducing the expansion of black-tailed prairie dogs in central Nebraska (Hygnstrom 

1995). This study indicated that visual barriers with lower porosity or solid barriers 

might prove more effective. Additionally, barriers that were more durable and less 

vulnerable to environmental damage, and secured in trenches to prevent movement of 

prairie dogs under barriers might increase effectiveness of artificial barriers. Robinette 

(1992) unsuccessfully used electrified fencing and metal flashing to prevent prairie dogs 

from returning to burrows. Similarly, galvanized roofing material failed to prevent 

expansion of prairie dog towns in New Mexico (Merriman et al. 2004). 

Use of vegetation as a barrier to expansion of black-tailed prairie dog towns has 

focused on controlling grazing patterns of livestock to influence vegetative condition on 

rangeland. In 1977, a 44.5-ha prairie dog town in Kansas was reduced to 4.9 ha 

following four successive seasons of reduced grazing during the growing season (Snell 

and Hlavachick 1980). Methods to attract predators and increase vegetation growth with 

fertilizer also were utilized on this site; however, the most beneficial treatment at 

reducing prairie dogs was attributed to the reduction in grazing pressure. Following this 

time period, cattle were allowed back into this pasture during the growing season. The 

town expanded to 8.1 ha in two years. Cattle were removed and the town was reduced to 
8

2.3 ha by fall (Snell 1985). Lack of grazing by livestock following the termination of 

private grazing permits on the Wichita Mountains Wildlife Refuge in southwest 

Oklahoma is credited with the disappearance of a protected prairie dog town (Osborn and 

Allan 1949). Following the creation of the Wichita Mountains Wildlife Refuge, all 

grazing permits were cancelled and fences that contained a resident heard of bison (Bison 

bison) were removed. The resulting lack of grazing on the Grace Mountain prairie dog 

colony (20.2 ha) was credited with the disappearance of the town within 11 years 

(Osborn and Allan 1949). Cable and Timm (1988) observed a similar trend in reduction 

of prairie dog town expansion during the second year of a deferred grazing study. The 

first year of the study found no difference between control and treatment sites. Second 

year results of the study indicated reductions in natality and population growth on 

deferred sites when compared to grazed sites. Data collected during the second year also 

indicated that 4 of 5 deferred sites decreased in size and 6 of 8 grazed sites increased in 

size. High visibility through adjacent vegetation was a significant factor influencing 

prairie dog colonization of adjacent prairie (Cincotta et al. 1988) 

Use of a buffer strip of natural vegetation as a barrier to limit the expansion of 

black-tailed prairie dog towns may prove effective. Quantification of effective buffer 

width and vegetation structural characteristics (vegetation height and visual obstruction) 

to reduce prairie dog town expansion has not been done. The objectives of this study 

were to evaluate effective width of vegetative barriers in limiting prairie dog town 

expansion, and to document effect of vegetation height and visual obstruction of native 

vegetation on expansion of prairie dog towns. We also studied the vegetation 
9

characteristics associated with black-tailed prairie dog towns in western South Dakota 

and the post treatment response of vegetation to removal of grazing by prairie dogs and 

cattle. Knowledge gained in this study will supplement existing non-lethal methods for 

managing prairie dogs and further our understanding of prairie dog impacts on the 

environment. 
10

Literature Cited 

Cable, K. A., and R. M. Timm. 1988. Efficacy of deferred grazing in reducing prairie 

dog reinfestation rates. Pages 46-49 in D. W. Uresk, G. L. Schenbeck, and R. 

Cefkin, Technical Coordinators. Eighth Great Plains Wildlife Damage Control 

Workshop Proceedings, 28-30 April 1987, Rapid City, South Dakota. USDA 

Forest Service General Technical Report RM-154. 

Cincotta, R. P., D. W. Uresk, and R. M. Hansen. 1988. A statistical model of expansion 

in a colony of black-tailed prairie dogs. Pages 30-32 in D. W. Uresk, G. L. 

Schenbeck, and R. Cefkin, Technical Coordinators. Eighth Great Plains Wildlife 

Damage Control Workshop Proceedings, 28-30 April 1987, Rapid City, South 

Dakota. USDA Forest Service General Technical Report RM-154. 

Cooper, J, and L. Gabriel. 2005. South Dakota black-tailed prairie dog conservation and 

management plan. Final Draft-February 2005. South Dakota Department of 

Game, Fish and Parks, Pierre, South Dakota. 

Cully, J. F. 1993. Plague, prairie dogs, and black-footed ferrets. Pages 38-49 in J. 

Oldemeyer, D. Biggins, B. Miller, and R. Crete, Editors. Management of prairie 

dog complexes for the reintroduction of the black-footed ferret. U. S. Fish and 

Wildlife Service Biological Report No. 13. 

Franklin, W. L., and M. G. Garrett. 1989. Nonlethal control of prairie dog colony 

expansion with visual barriers. Wildlife Society Bulletin 17:426-430. 
11

Hanson R. 1988. A chronology of prairie dog control operations and related 

developments in South Dakota. Pages 121-122 in D. W. Uresk, G. L. Schenbeck, 

and R. Cefkin, Technical Coordinators. Eighth Great Plains Wildlife Damage 

Control Workshop Proceedings, 28-30 April 1987, Rapid City, South Dakota. 

USDA Forest Service General Technical Report RM-154. 

Hoogland, J. L. 1995. The black-tailed prairie dog: social life of a burrowing mammal. 

University of Chicago Press. Chicago, Illinois. 557pp. 

Hygnstrom, S. E. 1995. Plastic visual barriers were ineffective at reducing 

recolonization rates of prairie dogs. Pages 74-76 in R. E. Masters, and J. G. 

Huggins, Editors. Twelfth Great Plains Wildlife Damage Control Workshop 

Proceedings, 10-13 April 1995, Tulsa, Oklahoma. National Wildlife Research 

Center, Fort Collins, Co. 

King, J. A. 1955. Social behavior, social organization, and population dynamic in a 

black-tailed prairie dog town in the Black Hills of South Dakota. Contributions 

from the Laboratory of Vertebrate Biology Number 67. University of Michigan, 

Ann Arbor, Michigan. 

Merriman J. W., P. J. Zwank, C. W. Boal, and T. L. Bashore. 2004. Efficacy of visual 

barriers in reducing black-tailed prairie dog colony expansion. Wildlife Society 

Bulletin 32:1316-1320. 

Osborn, B., and P. F. Allan. 1949. Vegetation of an abandoned prairie-dog town in tall 

grass prairie. Ecology 30:322-332. 
12

Robinette, K. W. 1992. Black-tailed prairie dog management: translocation and barriers. 

M.S. Thesis, Colorado State University, Fort Collins, Colorado. 39pp. 

Sidle, J. G., D. H. Johnson, and B. R. Euliss. 2001. Estimated areal extent of colonies of 

black-tailed prairie dogs in the Northern Great Plains. Journal of Mammalogy 

82:928-936. 

Snell, G. P. 1985. Results of control of prairie dogs. Rangelands 7:30. 

Snell, G. P., and B. D. Hlavachick. 1980. Control of prairie dogs-the easy way. 

Rangelands 2:239-240. 

South Dakota Game, Fish and Parks. 2004. Division of Wildlife 2004 Annual Report. 

South Dakota Game, Fish and Parks, Pierre, South Dakota. 

U. S. Fish and Wildlife Service. 2000. Endangered and threatened wildlife and plants; 

12-month finding for a petition to list the black-tailed prairie dog as threatened. 

Federal Register 65(24):5476-5488. Department of the Interior, Washington, 

D.C. 
13

Chapter 2 

Use of natural vegetative barriers to limit expansion of 

Black-tailed prairie dog towns. 

Introduction 

In 2000, the U. S. Fish and Wildlife Service designated the black-tailed prairie 

dog (Cynomys ludovicianus) a candidate species for listing as threatened (U. S. Fish and 

Wildlife Service 2000). This designation angered ranchers, elevated the controversy 

surrounding prairie dog control on rangelands, and prompted South Dakota, as well as 

other states and agencies, to modify or create prairie dog management plans (Cooper and 

Gabriel 2005). Public opinion over the listing included concerns over landowner rights, 

control responsibilities, and other species associated with prairie dog towns including the 

black-footed ferret (Mustela nigripes), swift fox (Vulpes velox), and burrowing owl 

(Athene cunicularia). 

Black-tailed prairie dogs are small burring rodents (≈ 700g) that live in colonies 

called towns (Hoogland 1995). The extensive social and colonial tendencies of the blacktailed prairie dog are characteristic of the species. Of the five species of prairie dog, the 

black-tailed is the most numerous and has the largest geographic distribution. Blacktailed prairie dogs range from northern Mexico in the south to southern Canada in the 

north, and from the eastern edge of the Rocky Mountains in the west, east into the mixed 

grass prairies of central North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, and 
14

Texas (Hoogland 1995). The current distribution of prairie dogs in South Dakota 

includes the mixed- and short-grass prairies of the western two-thirds of the state (Sidle et 

al. 2001). Prairie dogs currently occupy approximately 1665 km2 of land in South 

Dakota (Cooper and Gabriel 2005). 

Black-tailed prairie dogs clip and maintain short vegetation throughout the 

colony. Short vegetation enhances predator detection within the colony (Hoogland 

1995). Maintenance of short vegetation in towns is seen as direct competition with 

livestock for range resources in areas where prairie dogs and grazing occur sympatrically. 

There is evidence that the use of buffer strips of native vegetation that is allowed to grow 

free of grazing pressure by livestock or prairie dogs may be effective in limiting prairie 

dog expansion (Osborn and Allan 1949, Snell and Hlavachick 1980, Franklin and Garrett 

1989). Use and success rate of a naturally occurring vegetative buffer strip as a barrier to 

prairie dog town expansion has not been quantified. The objectives of this study were: 1) 

to evaluate effective width of vegetative barriers in limiting prairie dog town expansion; 

2) to document effect of height and visual obstruction of native vegetation on expansion 

of prairie dog towns. Knowledge gained in this study will supplement existing non-lethal 

methods for managing prairie dogs. 

Study Area 

We selected five study sites on rangelands containing prairie dog towns ≥ 10-ha 

west of the Missouri River in South Dakota during 2004 and 2005. Study areas where 

located on rangelands in Custer, Fall River, Stanley, and Tripp Counties (Figure 2.1). A 
15

new site located 3.2 km NE of the 2004 site was established due to access issues. Study 

site locations were: Custer County (2004 - N43o38.2’ W103o4.1’, 2005 - N43o39.5’ 

W103o2.5’); Fall River County (N43o20.7’ W103o5.0’), Bad River Road (N44o14.1’ 

W100o55.7’), Fort Pierre (N44o23.0’ W100o31.6’), and Winner (N43o36.7’ W099o55.7’) 

Study areas where located in the Pierre Hills and Southern Plateaus physiographic 

regions in western South Dakota (Johnson et al. 1995). The Pierre Hills physiographic 

region is characterized by eroded rounded hills and ridges composed of primarily clay 

soils. The Southern Plateaus physiographic region is underlined by sandstone and 

mudstone containing mostly loam and silt loam soils that form highland benches and 

buttes (Johnson et al. 1995). Mean annual temperatures ranged from 8.3oC at the Fall 

River County site to 10.0oC at the Winner site (South Dakota Office of Climatology 

2006). Monthly mean temperatures ranged from a low of -7.7oC in January to a high of 

24.6oC in July. Mean annual rainfall ranged from 42.6 cm at Fort Pierre to 60.3 cm at the 

Winner site (South Dakota Office of Climatology 2006). 

Primary land use of the area was pasture and rangeland livestock grazing 

intermixed with crop production, which included wheat (Triticum aestivum), alfalfa 

(Medicago sativa), corn (Zea mays), and soybeans (Glycine max). Johnson and Larson 

(1999) classified the region as northern wheatgrass-needlegrass plains. Dominant 

vegetation in this area includes western wheatgrass (Pascopyrum smithii), Japanese 

brome (Bromus japonicus), needleandthread (Stipa comata), green needlegrass (Stipa 

viridula), blue grama (Bouteloua gracilis), buffalograss (Buchloe dactyloides), scarlet 
16

globemallow (Sphaeralcea coccinea), western wallflower (Erysimum asperum), and 

prickly pear (Opuntia macrorhiza) (Johnson and Larson 1999). 

Methods 

Study sites were established and monitored from 1 March 2004 to 30 October 

2005. We constructed electric fences for the purpose of excluding cattle and creating 

buffer strips of native grasses and shrubs. At the beginning of the study, we poisoned 

prairie dogs to create a prairie dog free buffer zone adjacent to active prairie dog towns. 

Grazing was allowed on both sides of the buffer strips. This created strips of naturally 

occurring vegetation between an area that contained both grazing and prairie dogs and an 

area with grazing only (Figure 2.2). Buffer strips were 100-m long and 10, 25, and 40 m 

in width. A zero m control was included on all study sites. 

Initial poisoning efforts took place in spring 2004 prior to the first emergence of 

young prairie dogs (Franklin and Garrett 1989). We used aluminum phosphide (Weevelcide, United Phosphorus Inc., Trenton, NJ) fumigant tablets (60% concentration) for the 

initial spring application. This was conducted by placing two to three tablets within all 

open burrow entrances; burrows were then sealed with sod or dirt. Fumigants, such as 

aluminum phosphide, are the only poisoning method approved for controlling prairie 

dogs in South Dakota during spring. Follow-up applications were conducted to establish 

a prairie dog free buffer. Poisoning for the 2005 field season was conducted the previous 

fall using zinc phosphide treated oats and aluminum phosphide tablets. Follow up 

applications of aluminum phosphide were done in spring of 2005. 
17

We evaluated study sites using visual obstruction (0.2 dm), vegetation cover (%), 

vegetation height (cm), vegetation composition, and burrow density adjacent to buffer 

strips. We established three transect lines to facilitate random distribution of quadrats. 

Transects extended the length of the buffer strip and were systematically spaced at 25, 50, 

and 75% positions across the width of buffer strips. Transects were separated into 1-m 

increments to establish potential quadrat locations. End points of transects were 

eliminated to reduce effect of buffer edge. We randomly chose 25 non-consecutive 

points along the total length of transects for evaluation. We measured visual obstruction 

(to nearest 0.2 dm) at each quadrat site using a modified Robel pole (Robel et al. 1970). 

Cover measurements for grasses, forbs, bare ground, and litter were estimated at 

sampling points (Daubenmire 1959). Quadrat size was 30 cm wide and 75 cm long. 

Modified cover classes were 0 (not present), 1 (trace-5%), 2 (6-25%), 3 (26-50%), 4 (51-

75%), 5 (76-95%), and 6 (96-100%). Median values for cover classes where used to 

calculate relative percent canopy coverage for vegetation classes, bare ground, and litter. 

Vegetation was grouped into two broad categories, graminoids and forbs. Graminoids 

were classified as members of the families Gramineae, Cyperaceae, and Juncaceae. 

Forbs were classified as all other broad-leaved herbaceous vegetation excluding the 

preceding three families of graminoids and any woody vegetation (Johnson and Larson 

1999). Vegetation height was obtained for each of the sampling points using a clear 30-

cm disc lowered until the bottom side of the disc was first touched by leafy vegetation 

(Higgins and Barker 1982). Vegetation identification followed that of Johnson and 

Larson (1999) and Stubbendieck et al. (2003). Burrow density was estimated by 
18

counting the number of burrows in three randomly spaced 1-ha plots adjacent to the study 

site. Mean burrow density was then used as an index to population density. We 

evaluated barrier penetration using the presence of new active burrows behind vegetative 

buffers. Burrow counts were completed in October and November to ensure all prairie 

dog breakthroughs were counted for that season. We used negative binomial regression 

models to analyze vegetation characteristics. 

Results

VOR and vegetation height were highly correlated (r2 = 0.86) and therefore, both 

variables were not used in the same model. Significant relationships were documented 

for both VOR and vegetation height. The predictive model for VOR was Breakthrough = 

exp (4.274 – 0.573*VOR); mean corrected r2

 was 0.71 (P<0.01) (Figure 2.3). The predictive 

model for vegetation height was Breakthrough = exp (4.883 – 0.143*vegetation height); mean 

corrected r2 was 0.61 (P<0.01) (Figure 2. 4). Breakthrough was minimized with 40-cm 

(SE = 0.021) vegetation height and 10-cm (SE = 0.064) VOR. Additional vegetation 

characteristics such as grass cover, forb cover, litter cover, and bare ground increased the 

mean corrected R2

 by less than 2% and thus, were not included in models. Burrow 

density adjacent to buffer strips also did not add significantly to the model. 

Breakthroughs decreased across sites from 2004 to 2005, ranging from a 36.4% decrease 

in controls between years to 69.4% decrease in the 40-m buffer between years (Table 

2.1). Visual obstruction increased across study sites from 2004 to 2005 and ranged from 

13.6% in the 10-m buffer to 52.2% in the 40-m buffer (Table 2.1). Vegetation height 
19

decreased in the control from 2004 to 2005 by 7.2%, but increased in the buffers from 

4.0% in the 10-m buffer to 40.7% in the 40-m buffer (Table 2.1). Bad River Road and 

Winner sites had no breakthroughs in 2005 at the 40-m buffer width. Analysis of 

variance indicated that a significant difference (F1,38=5.459, P=0.025) of new active 

prairie dog burrows occurred between breakthroughs between successful sites and the 

unsuccessful sites. Predictive models from these two sites were used to develop models 

that included buffer width. Models were used to estimate the buffer width needed given 

vegetation height and VOR measurements for unsuccessful sites. The predictive model 

for VOR with buffer width was Breakthrough=exp (2.48-0.048*VOR-0.031*Buffer Width); mean 

corrected R2 was 0.86 (P<0.01) (Figure 2.5). The predictive model for vegetation height 

was Breakthrough=exp (2.410-0.004*Veg Height-0.036*Buffer Width); mean corrected R2 was 0.85 

(P<0.01) (Figure 2.6). Based on the models, predicted buffer width necessary for zero 

breakthroughs ranged from 85.1 m to 103.1 m with means ranging from 91.3 m 

(SE=2.08) to 100.7 m (SE=0.92) (Table 2.2). Rainfall measurements were taken from 

nearest weather stations within 25 km of study sites (Table 2.3). Annual rainfall ranged 

from 37.95 cm at Fort Pierre to 48.82 cm at Bad River Road and Fall River county sites. 

Growing season rainfall was calculated from 1 April to 31 August for 2004 and 2005 

(Table 2.3). 

Discussion 

Our models indicated that both visual obstruction through the barrier and 

vegetation height were the most important factors limiting black tailed prairie dog town 
20

expansion. Visual obstruction alone, however, explained more of the variation (mean 

corrected r2

=0.71, P<0.01) in the data than did vegetation height (mean corrected r2=0.61, 

P<0.01). The addition of buffer width in the model increased the mean corrected R2 of 

both models. Models had similar mean corrected R2

 values (0.86 and 0.85) when buffer 

width was added to the model. 

Previous barrier studies have mainly focused on the use of artificial barriers to 

limit the expansion of prairie dog towns (Franklin and Garrett 1989, Robinette 1992, 

Hygnstrom 1995, Merriman et al. 2004). These studies have shown mixed results as to 

their effectiveness in controlling prairie dog town expansion. Our models indicated a 

decreasing trend in prairie dog expansion with increased visual obstruction. This is 

consistent with the findings of Franklin and Garrett (1989) who noted a significant 

decrease in the use of areas with visual barriers made from burlap cloth or cut ponderosa 

pine (Pinus ponderosa). Hygnstrom ( 1995), however, reported that visual barriers made 

from plastic snow fence material were ineffective at controlling prairie dog town 

expansion. Exclosures made of a polyweave material in Colorado also proved ineffective 

at keeping prairie dogs from returning to burrows (Robinette 1992). Merriman et al. 

(2004) used silt fence and galvanized steel sheeting as an artificial visual barrier. 

Presence of the visual barriers did not prevent prairie dog town expansion. 

One possible explanation for the success of our study and that of Franklin and 

Garrett (1989) was the inclusion of a depth component to the visual barrier. Our models 

indicated an increase in the mean corrected r2

 from 0.71 with just visual obstruction to 

0.86 with the addition of buffer width. Buffer width increased the mean corrected R2

 of 
21

the model with vegetation height from 0.61 to 0.85. Franklin and Garrett (1989) study 

design called for three parallel rows of visual barriers. Burlap visual barriers were placed 

10-m apart for a total barrier width of 20-m and ponderosa pine tree barriers were placed 

16.7-m apart for a total barrier width of 33.4-m. The addition of a third dimension, 

barrier depth, may be necessary to fully deter prairie dogs that would otherwise dig under 

or climb over a two-dimensional visual barrier. These studies also reported that 

maintenance of artificial barriers was high and that regular attention was needed to 

maintain the integrity of artificial barriers. Climactic conditions in western South Dakota 

can include extreme temperatures, high winds, and precipitation in the form of snow and 

ice. Establishing permanent buffer strips using barbed wire fences to exclude cattle could 

reduce many maintenance issues. 

High visibility through adjacent vegetation was a significant factor influencing 

prairie dog colonization of adjacent prairie (Cincotta et al. 1988). Our models indicated 

that there was a reduction in barrier penetration with increasing vegetation height. The 

use of naturally occurring vegetation as a deterrent to prairie dog town expansion also has 

been utilized on rangelands by controlling the timing and intensity of grazing. 

Reductions in grazing were associated with increases in vegetation height and density. In 

1977, a 44.5-ha prairie dog town in Kansas was reduced to 4.9 ha following four 

successive seasons of reduced grazing during the growing season (Snell and Hlavachick 

1980). Methods to attract predators and increase vegetation growth with fertilizer also 

were utilized on this site, however, the most beneficial treatment at reducing prairie dogs 

in this area was attributed to the reduction in grazing pressure. Following this time 
22

period, cattle were allowed back into this pasture during the growing season. The town 

expanded to 8.1 ha in two years. Cattle were removed and the town was reduced to just 

2.3 ha by the fall (Snell 1985). Lack of grazing by livestock following the termination of 

private grazing permits on the Wichita Mountains Wildlife Refuge in southwest 

Oklahoma was credited with the disappearance of a protected prairie dog town (Osborn 

and Allan 1949). Cable and Timm (1988) observed a similar trend in the reduction of 

prairie dog town expansion during the second year of a deferred grazing study. The first 

year of the study found no difference between control and treatment sites. Second year 

results indicated reductions in natality, and population growth on deferred sites when 

compared to grazed sites. The second year also indicated that 4 of 5 deferred sites 

decreased in size and 6 of 8 grazed sites increased in size. 

Decreases in above ground primary production and biomass have been associated 

with low soil moisture and reduced precipitation (Heitschmidt et al. 1999, Knapp and 

Smith 2001). Mean annual precipitation was a strong predictor of above ground net 

primary production (Knapp and Smith 2001). Cable and Timm (1988) suggested that 

precipitation may have played a role in the expansion of prairie dog towns. The first year 

of their study was a dry year in the Nebraska panhandle and sites received below average 

rainfall. The second year of the study had higher precipitation with sites receiving 

average or above average rainfall. Our study showed similar patterns in that none of the 

buffer strips was successful at preventing breakthroughs during the first year with 

drought conditions and below average rainfall. The second year of our study had 

precipitation during the growing season that was near or above average, which resulted in 
23

a decrease in the number of breakthroughs across study sites. Controlled burns and 

woody shrub removal were used to facilitate the expansion of prairie dog towns at 

Theodore Roosevelt National Park, North Dakota (Milne-Laux and Sweitzer 2006). The 

increases of prairie dog activity and expansion were observed on areas were vegetation 

height was reduced through burns and shrub removal. This is consistent with our results 

indicating the importance of vegetation structure on prairie dog town expansion. 

Methodology in our study, however, differed from the Milne-Laux and Sweitzer (2006) 

study in that our buffer strips were established within the boundaries of an active colony, 

while their treatment and control sites were established in unoccupied areas adjacent to 

prairie dog towns. Soil type and composition has been shown to be a factor influencing 

prairie dog colonization success in uncolonized areas (Sheets et al. 1971, Reading and 

Matchett 1997, Roe and Roe 2003). Placing our buffer strips on active colony sites 

increased our confidence that vegetation characteristics influenced prairie dog expansion 

and not other abiotic factors. 

Our models indicated a trend towards a decreased in breakthroughs with increased 

VOR, vegetation height, and buffer width. Model results indicate that barrier 

breakthroughs are minimized at vegetation heights of ≈ 40 cm and visual obstruction 

measuring ≈ 10 cm. During 2004, we noted that barriers were unable to prevent the 

movement of prairie dogs through barriers. Drought was prevalent during the first year 

of the study and no barriers were able to meet the minimum 40-cm vegetation height and 

10-cm visual obstruction requirement. However, 2005 had increased precipitation and 

two of the eastern sites did have vegetation characteristics that approached or exceeded 
24

the necessary requirements. No breakthroughs were observed on these sites in 2005. The 

increase in vegetation height and visual obstruction may be due to a combination of 

precipitation and plant species. The Bad River Road and Fall River county sites had 

similar annual precipitation, and Fall River County had higher growing season 

precipitation than did the Bad River Road site. Bad River Road, which had no 

breakthroughs in 2005, had a higher percentage (21.4%) of western wheatgrass 

(Pascopyrum smithii) in 2005 than did Fall River County (Chapter 2). Western 

wheatgrass has the potential to reach greater heights than buffalo grass (Buchloe 

dactyloides). Winner site also had high percentages of western wheatgrass (46.4%) in 

2005 and no breakthroughs. Fort Pierre is an eastern site that had 31.9% western 

wheatgrass, but was unsuccessful at preventing breakthroughs by prairie dogs in 2005. 

The Fort Pierre site had lower annual precipitation (37.95 cm) compared to the successful 

eastern sites (Bad River Road-48.82 cm, Winner-60.25 cm). This indicates that the 

combination of high precipitation and plant species capable of growing tall and dense is 

required to establish successful vegetative barriers. When conditions allow for ≈ 40 cm 

vegetation height and ≈ 10 cm VOR, a 40-m buffer strip is likely adequate at reducing 

black-tailed prairie dog expansion through barriers. Under less than ideal conditions or in 

areas where vegetation characteristics do not allow for the minimum VOR and vegetation 

height, a 100-m buffer strip is recommended. Further testing of the model should be 

conducted to determine if the predicted distance is sufficient to stop prairie dog town 

expansion. Cincotta et al. (1988) reported that distance from the colony edge was 

important. No new burrows further than 55-m from the existing colony edge where 
25

observed at Badlands National Park. However, this may be attributable to increased 

visual obstruction from plants outside the maintained vegetational boundaries of the 

colony. 

Our results indicate that burrow density next to buffer strips did not add 

significantly to the models. Increased active burrows, as an indicator to population 

density, was a significant parameter in predicting the colonization of adjacent prairie by 

prairie dogs in Badlands National Park, South Dakota (Cincotta et al. 1988). Severson 

and Plumb (1998) however, showed that burrow counts were not good indicators to 

population density when compared with mark recapture population counts, and that 

maximum visual counts should be used as an indicator to population density. This could 

explain why burrow density did not add significantly to our models. 

New prairie dogs found on the colony edge are often times immigrants that have 

undergone long-distance (inter-colony) dispersals from nearby colonies (Knowles 1985, 

Cincotta et al. 1988). Mean straight line distance traveled by radio-collared prairie dogs 

at Wind Cave National Park was 2.4-km (Garrett and Franklin 1988). Dispersing prairie 

dogs from adjacent towns may colonize areas on the other side of the buffer strips. The 

effectiveness of buffer strips as deterrence, therefore, may be influenced by proximity to 

other prairie dog towns. 
26

Literature Cited 

Cable, K. A., and R. M. Timm. 1988. Efficacy of deferred grazing in reducing prairie 

dog reinfestation rates. Pages 46-49 in D. W. Uresk, G. L. Schenbeck, and R. 

Cefkin, Technical Coordinators. Eighth Great Plains Wildlife Damage Control 

Workshop Proceedings, 28-30 April 1987, Rapid City, South Dakota. USDA 

Forest Service General Technical Report RM-154. 

Cincotta, R. P., D. W. Uresk, and R. M. Hansen. 1988. A statistical model of expansion 

in a colony of black-tailed prairie dogs. Pages 30-32 in D. W. Uresk, G. L. 

Schenbeck, and R. Cefkin, Technical Coordinators. Eighth Great Plains Wildlife 

Damage Control Workshop Proceedings, 28-30 April 1987, Rapid City, South 

Dakota. USDA Forest Service General Technical Report RM-154. 

Cooper, J, and L. Gabriel. 2005. South Dakota black-tailed prairie dog conservation and 

management plan. Final Draft-February 2005. South Dakota Department of 

Game, Fish and Parks, Pierre, South Dakota. 

Daubenmire, R. F. 1959. A canopy-coverage method of vegetational analysis. 

Northwest Science 33:43-64. 

Franklin, W. L., and M. G. Garrett. 1989. Nonlethal control of prairie dog colony 

expansion with visual barriers. Wildlife Society Bulletin 17:426-430. 

Garrett, M. G., and W. L. Franklin. 1988. Behavioral ecology of dispersal in the blacktailed prairie dog. Journal of Mammalogy 69:236-250. 
27

Heitschmidt, R. K., M.R. Haferkamp, M. G. Karl, and A. L. Hild. 1999. Drought and 

grazing: I. Effects on quantity of forage produced. Journal of Range Management 

52:440-446. 

Higgins, K. F., and W. T. Barker. 1982. Changes in vegetation structure in seeded 

nesting cover in the prairie pothole region. Special Scientific Report-Wildlife 242 

U. S. Fish and Wildlife Service, Washington, D. C. 27pp. 

Hoogland, J. L. 1995. The black-tailed prairie dog: social life of a burrowing mammal. 

University of Chicago Press. Chicago, Illinois. 557pp. 

Hygnstrom, S. E. 1995. Plastic visual barriers were ineffective at reducing 

recolonization rates of prairie dogs. Pages 74-76 in R. E. Masters, and J. G. 

Huggins, Editors. Twelfth Great Plains Wildlife Damage Control Workshop 

Proceedings, 10-13 April 1995, Tulsa, Oklahoma. National Wildlife Research 

Center, Fort Collins, Co. 

Johnson, J. R., and G. E. Larson. 1999. Grassland plants of South Dakota and the 

Northern Great Plains. South Dakota State University College of Agriculture and 

Biological Sciences, South Dakota Agricultural Experiment Station, Brookings, 

South Dakota. 288pp. 

Johnson, R. R., K. F. Higgins, and D. E. Hubbard. 1995. Using soils to delineate South 

Dakota physiographic regions. Great Plains Research 5:309-322. 

Knapp, A. K., and M. D. Smith. 2001. Variation among biomes in temporal dynamics of 

aboveground primary production. Science 291:481-484. 
28

Knowles C. J. 1985. Observation on prairie dog dispersal in Montana. The Prairie 

Naturalist 17:33-44. 

Merriman J. W., P. J. Zwank, C. W. Boal, and T. L. Bashore. 2004. Efficacy of visual 

barriers in reducing black-tailed prairie dog colony expansion. Wildlife Society 

Bulletin 32:1316-1320. 

Milne-Laux, S., and R. A. Sweitzer. 2006. Experimentally induced colony expansion by 

black-tailed prairie dogs (Cynomys ludovicianus) and implications for 

conservation. Journal of Mammalogy 87:296-303. 

Osborn, B., and P. F. Allan. 1949. Vegetation of an abandoned prairie-dog town in tall 

grass prairie. Ecology 30:322-332. 

Reading, R. P., and R. Matchett. 1997. Attributes of black-tailed prairie dog colonies in 

northcentral Montana. Journal of Wildlife Management 61:664-673. 

Robel, R. J., J. N. Briggs, A. D. Dayton, and L. C. Hulbert. 1970. Relationships between 

visual obstruction measurements and weight of grassland vegetation. Journal of 

Range Management 23:295-297. 

Roe, K. A., and C. M. Roe. 2003. Habitat selection guidelines for black-tailed prairie 

dog relocations. Wildlife Society Bulletin 31:1246-1253. 

Robinette, K. W. 1992. Black-tailed prairie dog management: translocation and barriers. 

M.S. Thesis, Colorado State University, Fort Collins, Colorado. 39 pp. 

Severson, K. E., and G. E. Plumb. 1988. Comparison of methods to estimate population 

densities of black-tailed prairie dogs. Wildlife Society Bulletin 26:859-866 
29

Sheets, R. G., R. L. Linder, and R. B. Dahlgran. 1971. Burrow systems of prairie dogs 

in South Dakota. Journal of Mammalogy 52:451-453. 

Sidle, J. G., D. H. Johnson, and B. R. Euliss. 2001. Estimated areal extent of colonies of 

black-tailed prairie dogs in the Northern Great Plains. Journal of Mammalogy 

82:928-936. 

Snell, G. P. 1985. Results of control of prairie dogs. Rangelands 7:30. 

Snell, G. P., and B. D. Hlavachick. 1980. Control of prairie dogs-the easy way. 

Rangelands 2:239-240. 

South Dakota Office of Climatology. 2006. Temperature and Precipitation Archives. 

South Dakota State University . Brookings, South Dakota. 

http://climate.sdstate.edu/climate_site/archive_data.htm. Accessed 7 June 2006. 

Stubbendieck, J. L., M. J. Coffin, and L. M. Landholt. 2003. Weeds of the Great Plains. 

Nebraska Department of Agriculture, Lincoln, Nebraska. 605pp. 

U. S. Fish and Wildlife Service. 2000. Endangered and threatened wildlife and plants; 

12-month finding for a petition to list the black-tailed prairie dog as threatened. 

Federal Register 65(24):5476-5488. Department of the Interior, Washington, 

D.C. 

Uresk, D. W., R. M. King, A. D. Apa, and R. L. Linder. 1987. Efficacy of zinc 

phosphide and strychnine for black-tailed prairie dog control. Journal of Range 

management 39:298-299.
Table 2.1. Mean (SE) of vegetation characteristics and breakthroughs (new active burrows) associated with prair

expansion measured from five study sites in western South Dakota, August 2004 and 2005.  Control 10m 25m 4

2004 2005 2004 2005 2004 2005 2004 

Break through 28.6 

(11.57) 

18.2 

(5.77) 

23.4 

(12.6) 

13.80 

(3.71) 

25.0 

(10.9) 

12.00 

(4.51) 

21.6 

(7.69) 

VOR (cm) 1.78 

(0.47) 

2.48 

(0.41) 

3.42 

(1.67) 

3.96 

(0.95) 

3.1 

(1.2) 

5.22 

(1.50) 

4.1 

(1.87) 

Vegetation Height (cm) 12.76 

(2.11) 

11.84 

(1.34) 

17.36 

(3.02) 

18.08 

(3.84) 

14.58 

(2.57) 

20.18 

(4.03) 

17.1 

(3.74) 

Graminoid cover (%) 36.48 

(11.72) 

42.30 

(8.27) 

51.34 

(10.99) 

67.34 

(5.75) 

49.2 

(14.48) 

62.98 

(8.23) 

51.5 

(14.04) 

Forb cover (%) 11.66 

(6.04) 

10.74 

(5.04) 

6.62 

(2.42) 

7.00 

(2.20) 

9.8 

(5.69) 

11.60 

(4.39) 

12.1 

(5.97) 

Liter cover (%) 21.14 

(6.70) 

16.74 

(5.19) 

26.3 

(12.70) 

10.78 

(2.50) 

24.0 

(13.07) 

10.62 

(2.36) 

22.1 

(12.16) 

Bare ground (%) 30.68 

(6.76) 

30.20 

(5.51) 

15.76 

(2.94) 

14.90 

(5.86) 

17.0 

(4.29) 

14.80 

(5.70) 

14.26 

(3.67) 
31

Table 2.2. Predicted buffer width needed (meters) to minimize prairie dog breakthrough 

(new active burrows) based upon visual obstruction readings (VOR) and vegetation 

height from sites with breakthroughs in western South Dakota during 2004 and 2005. 

 Mean Max Min 

 Fort Pierre 91.3m 100.1m 85.1m 

Visual Obstruction Custer County 98.6m 100.4m 97.8m 

 Fall River County 100.7m 103.1m 95.2m 

 

 Fort Pierre 97.5m 98.9m 96.1m 

Vegetation Height Custer County 97.9m 98.8m 95.0m 

 Fall River County 99.5m 100.2m 98.7m 
32

Table 2.3. Precipitation as registered by the nearest weather station within 25 km of 

study sites for 2004 and 2005. Growing season includes rainfall from 1 April to 31 

August. 

 Rainfall Total (cm) 

Site Average 

Annual 

Growing Season 

Ave. 

Growing Season 

2004 

Growing Season 

2005 

Bad River Rd 48.82 30.15 22.04 28.6 

Fort Pierre 37.95 26.95 23.34 22.05 

Winner 60.25 38.94 32.99 41.43 

Custer Cty 42.14 30.12 24.31 26.57 

Fall River Cty 48.82 29.69 11.48 42.29 
33

Figure 2.1. Locations of study areas used in vegetative barrier study in western South 

Dakota in 2004 and 2005. 

0 75 150 225 300 37.5

Kilometers

Fall River

Custer

Stanley

Tripp
34

Figure 2.2. Schematic of buffer strips used to reduce prairie dog town expansion for five 

study sites in western South Dakota in 2004 and 2005. 

Cattle and Prairie dogs Cattle with no prairie dogs 

No cattle, No prairie dogs 

Control
35

0 5 10 15

VOR

0

20

40

60

80

B

R

E

A

K

O

U

T

Figure 2.3. Non-linear model of breakthroughs (Breakout) of new, active prairie dog 

burrows versus visual obstruction (VOR, [cm]) for five study sites in western South 

Dakota during August 2004 and 2005. 
36

0 10 20 30 40 50

VEGHEIGHT

0

20

40

60

80

B

R

E

A

K

O

U

T

Figure 2.4. Non-linear model of breakthroughs (BREAKOUT) of new, active prairie dog 

burrows versus vegetation height (VEGHEIGHT, [cm]) for five study sites in western 

South Dakota during August 2004 and 2005. 
37

0

10 20 30 40 50

BUFFWIDTH

0

5

10

15

VOR

4

8

12

B

R

E

A

KO

U

T

Figure 2.5. Non-linear model of breakthroughs (BREAKOUT) of new, active prairie dog 

burrows versus visual obstruction (VOR, [cm]) and buffer width (BUFFWIDTH, [m]) for 

five study sites in western South Dakota during August 2004 and 2005. 
38

0

10 20 30 40 50

BUFFWIDTH

10

20

30

40

50

VEGHEIGHT

4

8

12

B

R

E

A

KO

U

T

Figure 2.6. Non-linear model of breakthroughs (BREAKOUT) of new, active burrows 

versus vegetation height (VEGHEIGHT, [cm]) and buffer width (BUFFWIDTH [M]) for 

five study sites in western South Dakota during August 2004 and 2005. 
39

Chapter 3 

Vegetation characteristics associated with black-tailed prairie dog 

towns in western South Dakota. 

Introduction 

The black-tailed prairie dog (Cynomys ludovicianus) is considered by some to be 

a keystone species of the prairie ecosystem (Kotliar et al. 1999, Miller et al. 2000). 

Prairie dogs serve as prey to a wide variety of predators including black-footed ferrets 

(Mustela nigripes), coyotes (Canis latrans), bobcats (Felis rufus), and badgers (Taxidea 

taxus), as well as a many birds of prey (Hoogland 1995, Kotliar et al. 1999). Prairie dogs 

can drastically alter their environment providing nesting habitat, foraging, and shelter for 

many species (Kotliar et al. 1999). Plant community structure and composition, nutrient 

cycling, and ecosystem processes can be affected by prairie dog activities (Whicker and 

Detling 1988). 

Black-tailed prairie dogs are small burring rodents (≈ 700g) that live in colonies 

called towns (Hoogland 1995). The extensive social and colonial tendencies of the blacktailed prairie dog are characteristic of the species. Of the five species of prairie dog, the 

black-tailed is the most numerous and has the largest geographic distribution. Blacktailed prairie dogs range from northern Mexico in the south to southern Canada in the 

north, and from the eastern edge of the Rocky Mountains in the west, east into the mixed 

grass prairies of central North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, and 
40

Texas (Hoogland 1995). South Dakota lies along the northeastern edge of the prairie 

dog’s range. Current distribution of prairie dogs in South Dakota includes the mixedand short-grass prairies of the western two-thirds of the state (Sidle et al. 2001). Prairie 

dogs currently occupy approximately 1665 km2

 of land in South Dakota (Cooper and 

Gabriel 2005). 

The objective of this study is to examine vegetation characteristics associated 

with prairie dog towns in western South Dakota. Results of this study will provide 

managers with a better understanding of post-treatment responses of vegetation following 

the elimination of prairie dogs and cattle from rangelands. 

Study Area 

We selected five study sites on rangelands containing prairie dog towns ≥ 10-ha 

west of the Missouri River in South Dakota in 2004 and 2005. Western study areas 

where located on rangelands in Custer and Fall River counties, while eastern study areas 

where located in Stanley, and Tripp counties (Figure 3.1). In 2005, the Custer County 

site was established at a new location 3.2 km NE of the 2004 site due to access issues. 

Study site locations were: Custer County (2004 - N43o38.2’ W103o4.1’, 2005 - 

N43o39.5’ W103o2.5’); Fall River County (N43o20.7’ W103o5.0’), Bad River Road 

(N44o14.1’ W100o55.7’), Fort Pierre (N44o23.0’ W100o31.6’), and Winner (N43o36.7’ 

W099o55.7’) Study areas where located in the Pierre Hills and Southern Plateaus 

physiographic regions in western South Dakota (Johnson et al. 1995). The Pierre Hills 

physiographic region is characterized by eroded rounded hills and ridges composed of 

primarily clay soils. The Southern Plateaus physiographic region is underlined by 
41

sandstone and mudstone containing mostly loam and silt loam soils that form highland 

benches and buttes (Johnson et al. 1995). Mean annual temperatures ranged from 8.3oC 

at the Fall River County site to 10.0oC at the Winner site (South Dakota Office of 

Climatology 2006). Monthly mean temperatures ranged from a low of -7.7oC in January 

to a high of 24.6oC in July. Mean annual rainfall ranged from 42.6 cm at the Fort Pierre 

to 60.3 cm at the Winner site (South Dakota Office of Climatology 2006). 

Primary land use of study areas was pasture and rangeland livestock grazing 

intermixed with crop production, which included wheat (Triticum aestivum), alfalfa 

(Medicago sativa), corn (Zea mays), and soybeans (Glycine max). Johnson and Larson 

(1999) classified the region as northern wheatgrass-needlegrass plains. Dominant 

vegetation in this area includes western wheatgrass (Pascopyrum smithii), Japanese 

brome (Bromus japonicus), needleandthread (Stipa comata), green needlegrass (Stipa 

viridula), blue grama (Bouteloua gracilis), buffalograss (Buchloe dactyloides), scarlet 

globemallow (Sphaeralcea coccinea), western wallflower (Erysimum asperum), and 

prickly pear (Opuntia macrorhiza) (Johnson and Larson 1999). 

Methods 

Study sites were established and monitored from 1 March 2004 to 30 October 

2005. We constructed electric fences for the purpose of excluding cattle and creating 

treatment areas of native grasses and shrubs. At the beginning of the study, we poisoned 

prairie dogs to create a prairie dog free zone adjacent to active prairie dog towns. 

Livestock grazing was allowed outside of the treatment area. Poisoning created a 100-m 
42

long and 40-m wide treatment area of naturally occurring vegetation adjacent to a control 

area that contained both grazing and prairie dogs. 

Initial poisoning efforts took place in spring 2004 prior to the first emergence of 

young prairie dogs (Franklin and Garrett 1989). We used aluminum phosphide (Weevelcide, United Phosphorus Inc., Trenton, NJ) fumigant tablets (60% concentration) for the 

initial spring application. This was conducted by placing two to three tablets within all 

open burrow entrances; burrows were then sealed with sod or dirt. Fumigants, such as 

aluminum phosphide, are the only poisoning method approved for controlling prairie 

dogs in South Dakota during spring. Follow-up applications were conducted to establish 

a prairie dog free treatment area. Poisoning for the 2005 field season was conducted the 

previous fall using zinc phosphide treated oats and aluminum phosphide tablets. Follow 

up applications of aluminum phosphide were conducted in spring 2005. 

We evaluated study sites using visual obstruction (0.2 dm increments), vegetation 

cover (%), vegetation height (cm), and vegetation composition. We established three 

transect lines to facilitate random distribution of quadrats. Transects extended the length 

of the treatment area and control areas, and were equally spaced at 25, 50, and 75% 

positions across the width of the treatment area. Transects were separated into 1-m 

increments to establish potential quadrat locations. End points of transects were 

eliminated to reduce the effect of the treatment area edge. We randomly chose 25 nonconsecutive points along the total length of transects for evaluation. We measured visual 

obstruction (to nearest 0.2 dm) at each quadrat site using a modified Robel pole (Robel et 

al. 1970). Cover measurements for graminoids, forbs, bare ground, and litter were 
43

estimated at sampling points (Daubenmire 1959). Quadrat size was 30-cm-wide and 75-

cm-long. Modified cover classes were 0 (not present), 1 (trace-5%), 2 (6-25%), 3 (26-

50%), 4 (51-75%), 5 (76-95%), and 6 (96-100%). Median values for cover classes where 

used to calculate relative percent canopy coverage for vegetation classes, bare ground, 

and litter. Vegetation was grouped into two broad categories; graminoids and forbs. 

Graminoids were classified as members of the families Gramineae, Cyperaceae, and 

Juncaceae. Forbs were classified as all other broad-leaved herbaceous vegetation 

excluding the preceding three families of graminoids and any woody vegetation (Johnson 

and Larson 1999). Vegetation height was obtained for each of the sampling points using 

a clear 30-cm disc lowered until the bottom side of the disc was first touched by leafy 

vegetation (Higgins and Barker 1982). Vegetation identification followed that of 

Johnson and Larson (1999), and Stubbendieck et al. (2003). A 2-factor Analysis of 

Variance was used to detect significant differences between the main effects of treatment 

(prairie dogs vs. no prairie dogs), location (east vs. west), and the interaction between 

factors. 

Results 

Vegetation characteristics were obtained from control and 40-m x 100-m 

treatment areas for three eastern sites (Fort Pierre, Bad River Road, and Winner) and two 

western study sites (Custer county, and Fall River county) in western South Dakota 

during August 2004 and 2005 (Table 3.1). A 2-factor Analysis of Variance indicated that 

there was a significant (F1,16=4.046, P=0.061) interaction effect between treatment and 
44

location for visual obstruction. Visual obstruction was higher in the treatment than 

control plots for eastern sites, but not western sites. No significant (P>0.10) interaction 

between the main effects (treatment and location) was found for vegetation height, 

relative percent graminoid cover, forb cover, bare ground, or litter cover. 

Vegetation height was significantly higher in treatment than in control plots 

(F1,16=8.243, P=0.011) and in east versus west sites (F1,16=10.805, P=0.005). We 

recorded an increase (F1,16=3.754, P=0.071) in relative percent grass cover from the 

control to the treatment. Relative percent graminoid cover did not differ (F1,16=2.506, 

P=0.133) between locations. Forb relative percent canopy coverage did not differ by 

treatment (F1,16=0.007, P=0.934), or location (F1,16=1.127, P=0.304). Bare ground was 

greater (F1,16=11.339, P=0.004) in control than treatment plots, and greater (F1,16=3.732, 

P=0.071) on western than eastern sites. Relative percent litter cover did not differ 

between control and treatment plots (F1,16=0.149, P=0.704), or east versus west sites 

(F1,16=2.850, P=0.111). There was no difference (F1,36<0.000, P=1.000) in the number of 

species of plants identified between the treatment and control plots. Eastern sites 

contained 33% more plant species (F=11.958, P=0.001) than in western sites. Western 

wheatgrass (Pascopyrum smithii) had higher relative percent grass cover on eastern than 

western sites (Table 3.2). Scarlet globemallow (Sphaeralcea coccinea) was the dominant 

forb on both western sites, while kochia (Kochia scoparia) was the only forb to rank in 

the top three species on an eastern site (Table 3.2). Japanese brome (Bromus japonicus) 

was similar in relative canopy cover for Bad River Road (41.0%) and Fall River County 

(39.4%) sites. Annual rainfall ranged from 37.95 cm at Fort Pierre to 48.82 cm at Bad 
45

River Road and Fall River county sites. Growing season rainfall was calculated from 1 

April to 31 August for 2004 and 2005 (Table 3.3). 

Discussion 

Visual obstruction can be utilized as an indicator of above ground biomass for 

plant species on rangelands. Robel et al. (1970) showed that visual obstruction 

measurements taken from a distance of 4 m and a height of 1 m explained 95.5% of the 

variation in the weight of vegetation collected from rangelands. Similar results were 

found by Vermeire and Gillen (2001) who observed a linear relationship between visual 

obstruction and standing crop biomass with at least 90% of the variation in biomass 

explained by visual obstruction. Many studies on prairie dog impacts have focused on 

the amount of above ground biomass. Because of the relationship between visual 

obstruction and plant biomass, our study is directly comparable to studies that measured 

above ground and standing crop plant biomass. Our study indicated that there was higher 

visual obstruction in treatment than control plots on eastern sites. Visual obstruction was 

3.7 times greater on treatment plots in the east. Our results from eastern sites are 

supported by Johnson-Nistler et al. (2004) who found total standing crop biomass was 2 

times greater on uncolonized sites as compared to colonized sites in north central 

Montana. Total above ground plant biomass was always greater off colony when 

compared to on colony sites during a three-year study conducted at Badlands National 

Park, South Dakota (Fahnestock and Detling 2002). Total live biomass was similarly 

higher on uncolonized sites than on recently colonized sites at Wind Cave National Park, 
46

South Dakota, but was not significantly different for areas colonized for longer than 26 

years. (Coppock et al.1983). This finding was attributed to similar amounts of 

graminoids (85%) for colonized and recently colonized (≤ 2 years) sites (Coppock et al. 

1983). Prairie dog colonies in Texas had 3 to 4 times the herbaceous standing crop off 

colony sites compared to on colony sites (Weltzin 1997). Winter et al. (2002) observed 

lower visual obstruction on prairie dog colonies compared to random sites in Kanasas. 

We observed no difference in visual obstruction between treatment and control areas on 

our western sites. Above ground net primary production of on colony sites was similarly 

not significantly different than off colony sites at Wind Cave National Park, South 

Dakota (Whicker and Detling 1988). Wind Cave National Park is located in the 

southwest corner of South Dakota, and has similar vegetation and precipitation 

characteristics as our two western sites. 

Vegetation height was affected by clipping of vegetation by prairie dogs and 

cattle grazing. Vegetation height was two times higher on treatment sites than on control 

sites in the east and 1.4 times higher for the treatment than control in the west. 

Vegetation height was observed to be lower for prairie dog colonies when compared to 

random sites in southwest Kansas (Winter et al. 2002). Milne-Laux and Sweitzer (2006) 

observed greater prairie dog activity and expansion into areas with reduced vegetation 

height following controlled burns and mechanical shrub removal. 

Studies often indicate a reduction in grass cover and an increase in forb cover on 

prairie dog towns (Coppock et al. 1983, Fahnestock and Detling 2002). We noted only a 

slight increase in the relative percent canopy coverage of grass from control to treatment 
47

plots, and no significant differences in relative forb canopy coverage between treatment 

and control. This finding is supported by Johnson-Nistler et al. (2004) who observed 

minimal differences in forb cover between on and off colony sites. However, an increase 

in forb abundance and decrease in grass abundance was observed following colonization 

at Badlands National Park (Fahnestock and Detling 2002). Minor differences in forb and 

grass cover between our treatment and controls may be the result of the short duration (2 

years) our sites had been established. Prairie dog colonies, especially those that have 

been established for long periods of time can take considerable time to revert back to precolonization conditions (Osborn and Allen 1949). Uresk (1985) indicated that it may 

take ≥4 years for plant production to show increases on rangelands where prairie dogs 

were established. Evidence suggests that intensive grazing by prairie dogs can lead to a 

shift toward shorter ecotypes of plants (Whicker and Detling 1988). Forb biomass 

increased on areas colonized 3-8 years at Wind Cave National Park, South Dakota, and 

this was the time of maximum species diversity of plants (Coppock et al. 1983). 

Litter and bare ground also can be affected by prairie dog grazing. Our study site 

however, showed no significant differences in the amount of litter observed between 

treatment and control plots and location (east to west). Bare ground was greater on the 

control as compared to the treatment areas (2.6 times in East, 1.9 times in West). 

Johnson-Nistler et al. (2004) observed an increased amount of litter (23% to 27%) from 

colonized sites to uncolonized rangeland and an increase in bare ground from 17% on 

uncolonized to 27% on colonized prairie. Similar trends were reported by Fahnestock 

and Detling (2002). Prairie dogs clip and maintain short vegetation as a mechanism for 
48

predator detection (Hoogland 1995); therefore, litter is less likely to accumulate within 

the boundaries of prairie dog towns. The short duration of treatment establishment and 

the drought conditions from the previous year may have contributed to the similarities 

between the control and treatment plots relative to litter during our study. Accumulation 

of dead plant biomass was limited due to drought conditions that occurred prior to and 

during the first year of the study. 

We observed no difference in plant species richness between the control and 

treatment plots. This finding is supported by a Texas study that indicated all plant 

species found on colony sites also were found off colony and were common to the area 

(Weltzin et al. (1997). Coppack et al. (1983) also observed little change seen in the 

number of plant species areas colonized for 2 years or less. Our results contrast with 

Fahnestock and Detling (2002) who found that species richness was greater on colony 

than off colony because of an increased forb community. Prairie dog colonies may act as 

colonization sites for annual forbs due to the increase in soil disturbance found in an 

active prairie dog colony (Fahnestock and Detling 2002). However, Johnson-Nistler et al. 

(2004) indicated that plant species richness was lower on colonized (13) as compared to 

uncolonized (17) sites. This finding is likely due to the duration of occupancy of the 

prairie dog colony. 

Prairie dogs influence plant communities differently in different portions of their 

range. Differences in vegetative characteristics caused by location may be more the 

result of precipitation changes. Annual precipitation in South Dakota increases from 

west to east (South Dakota Office of Climatology 2006). At our study areas, however, 
49

average annual precipitation was similar for Fall River County and Bad River Road. 

Winner site had the highest precipitation and the Fort Pierre site had the lowest. Johnson 

and Larson (1999) stated that this precipitation gradient creates bands of vegetation types 

running north and south in South Dakota. This gradient may explain the variation in the 

increased relative contribution of western wheatgrass to the plant communities in the 

eastern sites. Johnson and Larson (1999) indicated that scarlet globemallow increases on 

drier sites, which may explain the higher amounts on western sites. The similarities for 

Japanese brome between Fall River county and Bad River Road may be due to the 

similarities in average annual precipitation. Variation in relative canopy coverage may 

be characteristic of the prairie biome. Knapp and Smith (2001) found that variation in net 

primary production as a response to interseasonal fluctuations in precipitation was 

highest in prairie biomes when compared to forest, arctic, and desert biomes. Vegetation 

responses in both species composition and net primary production may affect the amount 

and type of influence prairie dogs have on their environment. 
50

Literature Cited 

Cooper, J, and L. Gabriel. 2005. South Dakota black-tailed prairie dog conservation and 

management plan. Final Draft-February 2005. South Dakota Department of 

Game, Fish and Parks, Pierre, South Dakota. 

Coppock, D. L., J. K. Detling, J. E. Ellis, and M. I. Dyer. 1983. Plant-herbivore 

interactions in a North American Mixed-grass prairie. I. Effects of black-tailed 

prairie dogs on interseasonal aboveground plant biomass and nutrient dynamics 

and plant species diversity. Oecologia 56:1-9. 

Daubenmire, R. F. 1959. A canopy-coverage method of vegetational analysis. 

Northwest Science 33:43-64. 

Fahnestock, J. T., and J. K. Detling. 2002. Bison-prairie dog-plant interactions in a 

North American mixed-grass prairie. Oecologia 132:86-95. 

Franklin, W. L., and M. G. Garrett. 1989. Nonlethal control of prairie dog colony 

expansion with visual barriers. Wildlife Society Bulletin 17:426-430. 

Higgins, K. F., and W. T. Barker. 1982. Changes in vegetation structure in seeded 

nesting cover in the prairie pothole region. Special Scientific Report-Wildlife 242 

U. S. Fish and Wildlife Service, Washington, D. C. 27pp. 

Hoogland, J. L. 1995. The black-tailed prairie dog: social life of a burrowing mammal. 

University of Chicago Press. Chicago, Illinois. 557pp. 
51

Johnson, J. R., and G. E. Larson. 1999. Grassland plants of South Dakota and the 

Northern Great Plains. South Dakota State University College of Agriculture and 

Biological Sciences, South Dakota Agricultural Experiment Station, Brookings, 

South Dakota. 

Johnson, R. R., K. F. Higgins, and D. E. Hubbard. 1995. Using soils to delineate South 

Dakota physiographic regions. Great Plains Research 5:309-322. 

Johnson-Nistler, C. M., B. F. Sowell, J. W. Sherwood, and C. L. Wambolt. 2004. Blacktailed prairie dog effects on Montana’s mixed-grass prairie. Journal of Range 

Management 57:641-648. 

Kotliar, N. B., B. W. Baker, and A. D. Whicker. 1999. A critical review of assumptions 

about the prairie dog as a keystone species. Environmental Management 24:177-

192. 

Miller, B., R. Reading, J. Hoogland, T. Clark, G. Ceballos, R. List, S. Forrest, L. 

Hanebury, P. Manzano, J. Pacheco, and D. Uresk. 2000. The role of prairie dogs 

as a keystone species: response to Stapp. Conservation Biology 14:318-321. 

Milne-Laux, S., and R. A. Sweitzer. 2006. Experimentally induced colony expansion by 

black-tailed prairie dogs (Cynomys ludovicianus) and implication for 

conservation. Journal of Mammalogy 87:296-203. 

Osborn, B., and P. F. Allan. 1949. Vegetation of an abandoned prairie-dog town in tall 

grass prairie. Ecology 30:322-332. 
52

Robel, R. J., J. N. Briggs, A. D. Dayton, and L. C. Hulbert. 1970. Relationships between 

visual obstruction measurements and weight of grassland vegetation. Journal of 

Range Management 23:295-297. 

Sidle, J. G., D. H. Johnson, and B. R. Euliss. 2001. Estimated areal extent of colonies of 

black-tailed prairie dogs in the Northern Great Plains. Journal of Mammalogy 

82:928-936. 

Snell, G. P., and B. D. Hlavachick. 1980. Control of prairie dogs-the easy way. 

Rangelands 2:239-240. 

South Dakota Office of Climatology. 2006. Temperature and Precipitation Archives. 

South Dakota State University . Brookings, South Dakota. 

http://climate.sdstate.edu/climate_site/archive_data.htm. Accessed 7 June 2006. 

Stubbendieck, J. L., M. J. Coffin, and L. M.Landholt. 2003. Weeds of the Great Plains. 

Nebraska Department of Agriculture. Lincoln, Nebraska. 605pp. 

Uresk, D. W. 1985. Effects of controlling black-tailed prairie dogs on plant production. 

Journal of Range Management 38:466-468. 

Vermeire, L., T., and R. L. Gillen. 2001. Estimating herbage standing crop with visual 

obstruction in tallgrass prairie. Journal of Range Management 54:57-60. 

Weltzin, J. F., S. L. Dowhower, and R. K. Heitschmidt. 1997. Prairie dog effects on 

plant community structure in southern mixed-grass prairie. The Southwestern 

Naturalist 42:251-258. 

Whicker, A. D., and J. K. Detling. 1988. Ecological consequences of prairie dog 

disturbances. BioScience 38:778-785. 
53

Winter, S. L., J. F. Cully, Jr., and J. S. Pontius. 2002. Vegetation of prairie dog colonies 

and non-colonized short-grass prairie. Journal of Range Management 55:502-

508. 
54

Table 3.1. Mean (SE) of vegetation characteristics measured at five study sites in 

western South Dakota during August 2004 and 2005a

. Visual obstruction (VOR) and 

vegetation height (Veg. Height) presented in cm. Graminoid cover, forb cover, bare 

ground, and litter cover are relative percent canopy cover. 

 East West 

 Treatment Control Treatment Control 

VOR 8.583 (1.888) 2.317 (0.254) 2.950 (0.967) 1.850 (0.741) 

Veg. Height 29.65 (4.934) 14.383 (0.655) 13.00 (2.169) 9.175 (2.030) 

Graminoid Cover 65.850 (7.241) 46.183 (8.238) 49.875 (16.444) 29.20 (11.072) 

Forb Cover 15.633 (5.484) 11.733 (5.575) 5.6 (2.308) 10.40 (5.024) 

Bare Ground 10.117 (1.789) 26.317 (2.319) 19.150 (6.814) 36.575 (9.574) 

Litter Cover 8.383 (2.625) 15.750 (2.608) 25.375 (14.888) 23.725 (9.700) 

No. of Species 24.3 (6.7) 24.3 (1.3) 16.3 (2.6) 16.3 (5.0) 

a

 East Treatment n=6, East Control n=6, West Treatment n=4, West Control n=4. 
55

Table 3.2. Relative percent canopy cover for top three most abundant species on five 

study sites in western South Dakota in August 2004 and 2005. 

Site 2004 2005 

Pascopyrum smithii 24.7 Pascopyrum smithii 31.9 

Fort Pierrea Bromus japonicus 10.8 Bromus japonicus 16.2 

Kochia scoparia 10.8 Kochia scoparia 9.4 

Total 46.3 57.5 

Buchloe dactyloides 51.7 Buchloe dactyloides 41.0 

Bad River Roada Pascopyrum smithii 7.0 Pascopyrum smithii 21.4 

Vulpia octoflora 7.1 Carex spp. 8.6 

Total 65.8 71.0 

Pascopyrum smithii 42.0 Pascopyrum smithii 46.4 

Winnera Bromus inermis 2.6 Bromus japonicus 4.6 

Bromus japonicus 2.6 Agropyron cristatum 3.1 

Total 47.2 54.1 

Buchloe dactyloides 25.6 Agropyron cristatum 39.2 

Custer Cty.b Carex durius 10.4 Sphaeralcea coccinea 9.1 

Aristida purpurea 10.8 Pascopyrum smithii 3.4 

Total 46.8 1.7 
56

(Table 3.2 Continued) 

Site 2004 2005 

Buchloe dactyloides 1.8 Bromus japonicus 39.4 

Fall River Cty.b Carex durius 1.8 Pascopyrum smithii 9.3 

Sphaeralcea coccinea 0.5 Buchloe dactyloides 8.1 

Total 4.1 56.8 

a

 Eastern sites. 

b

 Western Sites. 
57

Table 3.3. Precipitation as registered by the nearest weather station within 25 km of 

study sites for 2004 and 2005. Growing season includes rainfall from 1 April to 31 

August. 

 Rainfall Total (cm) 

Site Average 

Annual 

Growing Season 

Ave. 

Growing Season 

2004 

Growing Season 

2005 

Bad River Rd 48.82 30.15 22.04 28.6 

Fort Pierre 37.95 26.95 23.34 22.05 

Winner 60.25 38.94 32.99 41.43 

Custer Cty 42.14 30.12 24.31 26.57 

Fall River Cty 48.82 29.69 11.48 42.29 
58

Figure 3.1. Location of study areas used in vegetative barrier study in western South 

Dakota in 2004 and 2005. 

0 75 150 225 300 37.5

Kilometers

Fall River

Custer

Stanley

Tripp
59

Chapter 4 

Management Implications and Conclusions 

Prairie dog control has historically consisted of lethal methods to maintain, 

reduce, or eliminate populations in South Dakota and throughout the range of the species 

(Schenbeck 1982, Boddicker 1983, Uresk et al. 1987, Hanson 1988, Knowles 1988, 

Hanson 1993). Non-lethal methods of control are needed to meet changing management 

objectives for the black-tailed prairie dog. These objectives include long-term, selfsustaining populations of prairie dogs while reducing landowner conflicts (Cooper and 

Gabriel 2005). Development of non-lethal methods of control is necessary for areas such 

as preserves, parks, and private lands where lethal methods are not allowed or use is 

limited. 

Negative binomial models were constructed to describe the relationship between 

black-tailed prairie dog town expansion and characteristics associated with vegetation of 

buffer strips as well as the mean density of active burrows next to the buffer strips. 

Vegetation height and visual obstruction were important variables in the models. 

Vegetation height and visual obstruction alone had a mean corrected r2

 of 0.61 and 0.71, 

respectively. Models indicated that breakthroughs (presence of new active burrows) were 

minimized at 40-cm of vegetation height and 10-cm visual obstruction. The addition of 

buffer width into models increased the mean corrected R2

 to 0.85 for vegetation height 

and 0.86 for visual obstruction indicating that buffer width plays a significant role in 
60

limiting prairie dog town expansion. Prairie dogs utilize short vegetation as a means of 

predator avoidance (King 1955, Hoogland 1995). Having a barrier that includes a depth 

component may utilize this behavior to create a zone where prairie dogs are 

uncomfortable and therefore will avoid. Addition of vegetation characteristics such as 

relative percent graminoid cover, forb cover, bare ground, and litter did not improve 

models. Mean number of active burrow densities adjacent to buffer strips also did not 

improve models. 

Vegetation characteristics of the property can play an important role in the 

success of natural vegetative buffers as a barrier to the expansion of black-tailed prairie 

dogs. Vegetation communities need to be composed of species that have potential to 

increase in height and density with increased precipitation, consequently, this method of 

control of expansion of prairie dog towns may be more effective in the eastern edge of 

black-tailed prairie dog distribution where taller, more robust species are present, and 

precipitation is greater. In areas that have vegetation capable of meeting the minimum 

requirements of our models (40-cm vegetation height, and 10-cm visual obstruction) a 

40-m wide buffer strip may be effective at limiting prairie dog town expansion. In areas 

that are not able to meet the minimum vegetation height (40-cm) and visual obstruction 

(10-cm), our modeling indicated that a buffer of about ≈ 100-m in width would be 

required to minimize breakthroughs. However, predictions from models that are outside 

of the range of the data used to generate them need to be evaluated and we would 

recommend further study of increased buffer widths in areas with lower vegetation and 

visual obstruction measurements. We would also recommend evaluating prairie dog 
61

populations based on visual counts rather than an index based on active burrow counts to 

determine the effect of prairie dog population size on expansion through barriers. 

Vegetation characteristics were recorded for treatment and control areas at each 

study site during 2004 and 2005. Vegetation characteristics were compared for treatment 

and control areas as well as in eastern and western study sites. Visual obstruction was 

greater on treatment areas compared to control areas in eastern sites while vegetation 

height increased from treatment to controls and from east to west. Bare ground also was 

greater on controls than on treatment areas. Grass cover, forb cover, and litter cover 

showed only minor changes between treatment and controls, and eastern and western 

sites. Plant species richness was not different between study sites, but increased species 

richness was observed on eastern compared to western sites. Buffer strips that are 

established longer than 2 years may show greater changes in vegetation from control 

areas. Effectiveness of buffer strips may increase as the age of the buffer strip increases. 

Increases in taller ecotypes of graminoid species over time may increase the mean 

vegetation height and visual obstruction of the buffer strip. 

Prairie dog control efforts take a substantial amount of time and money from 

state, federal, and private landowners. Buffer strips offer economical alternatives to 

traditional lethal controls. Collins et al. (1984) found that initial investments in lethal 

control were not justified given the rate of recolonization in one area of western South 

Dakota. Buffer strips that reduced or eliminated the expansion of prairie dog towns 

would make lethal controls more effective. 
62

Literature Cited 

Boddicker, M. L. 1983. Prairie dogs. Pages B-75-84 in Prevention and Control of 

Wildlife Damage. Cooperative Extension Service, Institute of Agriculture and 

Natural Resources, University of Nebraska-Lincoln, Lincoln, Nebraska. 

Collins, A. R., J. P. Workman, and D. W. Uresk. 1984. An economic analysis of blacktailed prairie dog (Cynomys ludovicianus) control. Journal of Range Management 

37:358-361. 

Cooper, J, and L. Gabriel. 2005. South Dakota black-tailed prairie dog conservation and 

management plan. Final Draft-February 2005. South Dakota Department of 

Game, Fish and Parks, Pierre, South Dakota. 

Hanson, R. 1988. A chronology of prairie dog control operations and related 

developments in South Dakota. Pages 121-122 in D. W. Uresk, G. L. Schenbeck, 

and R. Cefkin, Technical Coordinators. Eighth Great Plains Wildlife Damage 

Control Workshop Proceedings, 28-30 April 1987, Rapid City, South Dakota. 

USDA Forest Service General Technical Report RM-154. 

Hanson, R. 1993. Control of prairie dogs and related developments in South Dakota. 

Pages 5-7 in J. L. Oldemeyer, D. E. Biggings, B. J. Miller, and R. Crete, Editors. 

Proceedings of the Symposium on the Management of Prairie Dog Complexes for 

the Reintroduction of the Black-footed Ferret. U.S. Fish and Wildlife Service, 

Biological Report 13. 

Hoogland, J. L. 1995. The black-tailed prairie dog: social life of a burrowing mammal. 

University of Chicago Press. Chicago, Illinois. 557pp. 
63

King, J. A. 1955. Social behavior, social organization, and population dynamics in a 

black-tailed prairie dog town in the Black Hills of South Dakota. Contributions 

from the Laboratory of Vertebrate Biology Number 67. University of Michigan, 

Ann Arbor, Michigan. 

Knowles, C. J. 1988. An evaluation of shooting and habitat alteration for control of 

black-tailed prairie dogs. Pages 53-56 in D. W. Uresk, G. L. Schenbeck, and R. 

Cefkin, Technical Coordinators. Eighth Great Plains Wildlife Damage Control 

Workshop Proceedings, 28-30 April 1987, Rapid City, South Dakota. USDA 

Forest Service General Technical Report RM-154. 

Schenbeck, G. L. 1982. Management of black-tailed prairie dogs on the national 

grasslands. Pages 207-213 in R. M. Timm and R. J. Johnson, Editors. 

Proceedings Fifth Great Plains Wildlife Damage Control Workshop, 13-15 

October 1981, Lincoln Nebraska. Institute of Agriculture and Natural Resources, 

Lincoln, Nebraska. 

Uresk, D. W., R. M. King, A. D. Apa, and R. L. Linder. 1987. Efficacy of zinc 

phosphide and strychnine for black-tailed prairie dog control. Journal of Range 

Management 39:298-299. 
64

Appendix A. Plant species identified on the Bad River Road study site, 2004 and 2005. 

Scientific Name Common Name Class 

 

Astragalus lotiflorus Low milkvetch Forb 

Astragalus vexilliflexus Bentflower milkvetch Forb 

Atriplex argentea Silverscale saltbush Forb 

Bouteloua gracilis Blue grama Grass 

Bromus japonicus Japanese brome Grass 

Buchloe dactyloides Buffalo grass Grass 

Camelina microcarpa Smallseed falseflax Forb 

Carex sp. Sedge Grass 

Coryphantha sp. Pincushion Forb 

Euphorbia glyptosperma Ridgeseed spurge Forb 

Euphorbia marginata Snow-on-the-Mountain Forb 

Euphorbia serpens Matted sandmat Forb 

Grindelia squarrosa Curlycup gumweed Forb 

Helianthus annuus Annual sunflower Forb 

Lepidium densiflorum Greenflower pepperweed Forb 

Linum rigidum Stiffstem flax Forb 

Medicago sativa Alfalfa Forb 

Melilotus officinalis Yellow sweetclover Forb 

Mirabilis linearis Narrowleaf four-o'-clock Forb 

Monolepis nuttalliana Nuttall povertyweed Forb 

Opuntia macrorhiza Bigroot pricklypear Forb 

Panicum capillare Witchgrass Grass 

Pascopyrum smithii Western wheatgrass Grass 

Plantago patagonica Indianwheat Forb 

Polygonum ramosissimum Bushy knotweed Forb 

Sphaeralcea coccinea Scarlet globemallow Forb 

Stipa viridula Green needlegrass Grass 

Taraxacum officinale Common dandelion Forb 

Verbena bipinnatifida Dakota mock vervain Forb 

Vicia americana American vetch Forb 

Vulpia octoflora Sixweeks fescue Grass 
65

Appendix B. Plant species identified on the Custer county site, 2004. 

Scientific name Common Name Class 

 

Agropyron cristatum Crested wheatgrass Grass 

Aristida purpurea Red threeawn Grass 

Artemisia ludoviciana Cudweed sagewort Forb 

Asclepias pumila Plains milkweed Forb 

Bouteloua gracilis Blue grama Grass 

Bromus japonicus Japanese brome Grass 

Buchloe dactyloides Buffalo grass Grass 

Carex duriuscula Needleleaf sedge Grass 

Carex filifolia Threadleaf sedge Grass 

Convolvulus arvensis Field bindweed Forb 

Coryphantha sp. Pincushion Forb 

Dalea purpurea Purple prairie clover Forb 

Echinacea angustifolia Purple coneflower Forb 

Erysimum asperum Western wallflower Forb 

Euphorbia glyptosperma Ridgeseed spurge Forb 

Euphorbia strictospora Slimseed sandmat Forb 

Gaura coccinea Scarlet gaura Forb 

Grindelia squarrosa Curlycup gumweed Forb 

Haplopapus spinulosus Cutleaf goldenweed Forb 

Hedeoma hispida Rough falsepennyroyal Forb 

Hymenoxys acaulis Stemless hymenoxys Forb 

Ipomoea leptophylla Bush morningglory Forb 

Lappula occidentalis Western sticktight Forb 

Lepidium densiflorum Greenflower pepperweed Forb 

Liatris puncata Dotted gayfeather Forb 

Lygodesmia juncea Rush skeletonplant Forb 

Opuntia macrorhiza Bigroot prickly pear Forb 

Pascopyrum smithii Western wheatgrass Grass 

Plantago elongata Prairie plaintain Forb 

Plantago patagonica Indianwheat Forb 

Potentilla pensylvanica Pennsylvania cinquefoil Forb 

Psoralea tenuiflora Slimflower scurfpea Forb 

Salsola collina Slender Russian thistle Forb 

Schedonnardus paniculatus Tumblegrass Grass 

Schizachyrium scoparium Little bluestem Grass 

Sisymbrium altissimum Tumble mustard Forb 

Solanum triflorum Cutleaf nightshade Forb 

Solidago missouriensis Missouri goldenrod Forb 

Solidago mollis Soft goldenrod Forb 

Solidago rigida Stiff goldenrod Forb 

Sphaeralcea coccinea Scarlet globemallow Forb 

Stipa viridula Green needlegrass Grass 

Tradescantia bracteata Bracted spiderwort Forb 
66

Appendix C. Plant species identified on the Custer county site, 2005. 

Scientific Name Common Name Class 

 

Agropyron cristatum Crested wheatgrass Grass 

Amaranthus albus Tumble pigweed Forb 

Buchloe dactyloides Buffalo grass Grass 

Chenopodium sp. Goosefoot Forb 

Dyssodia papposa Fetid marigold Forb 

Euphorbia glyptosperma Ridgeseed spurge Forb 

Grindelia squarrosa Curlycup gumweed Forb 

Helianthus annuus Annual sunflower Forb 

Lepidium densiflorum Greenflower pepperweed Forb 

Melilotus officinalis Yellow sweetclover Forb 

Opuntia microrhiza Bigroot prickly pear Forb 

Pascopyrum smithii Western wheatgrass Grass 

Solanum rostratum Buffalobur Forb 

Solanum triflorum Cutleaf nightshade Forb 

Sphaeralcea coccinea Scarlet globemallow Forb 

Verbena bracteata Prostrate vervain Forb 
67

Appendix D. Plants identified on Fall River county site, 2004 and 2005. 

Scientific Name Common Name Class 

 

Bromis japonicus Japanese brome Grass 

Buchloe dactyloides Buffalo grass Grass 

Carex duriuscula Needleleaf sedge Grass 

Kochia scoparia Kochia Forb 

Lepidium densiflorum Greenflower pepperweed Forb 

Medicago sativa Alfalfa Forb 

Melilotus officinalis Yellow sweetclover Forb 

Opuntia macrorhiza Bigroot prickly pear Forb 

Pacopyrum smithii Western wheatgrass Grass 

Rumex stenophyllus Narrowleaf dock Forb 

Solanum rostratum Buffalobur nightshade Forb 

Sphaeralcea coccinea Scarlet globemallow Forb 

Stipa viridual Green needlegrass Grass 

Taraxacum officinale Common dandelion Forb 
68

Appendix E. Plant species identified on Fort Pierre study site, 2004 and 2005. 

Scientific Name Common Name Class 

 

Agropyron cristatum Crested wheatgrass Grass 

Artemisia frigida Fringed sagebrush Forb 

Astragalus lotiflorus Low milkvetch Forb 

Atriplex argentea Silverscale saltbush Forb 

Bouteloua gracilis Blue grama Grass 

Bromis japonicus Japanese brome Grass 

Buchloe dactyloides Buffalo grass Grass 

Camelina microcarpa Smallseed falseflax Forb 

Chenopodium sp. Goosefoot Forb 

Collomia lenearis Slenderleaf collomia Forb 

Convolvulus arvensis Field bindweed Forb 

Corispermum netidum Shiny bugseed Forb 

Euphorbia glyptosperma Ridgeseed spurge Forb 

Grindelia squarrosa Curlycup gumweed Forb 

Gutierrezia sarothrae Broom snakeweed Forb 

Helianthus annuus Annual sunflower Forb 

Hordeum jubatum Foxtail barley Grass 

Kochia scoparia Kochia Forb 

Lactuca serriola Prickly lettuce Forb 

Lepidium densiflorum Greenflower pepperweed Forb 

Lotus purshianus American deervetch Forb 

Melilotus officinalis Yellow sweetclover Forb 

Monolepis nuttalliana Nuttall povertyweed Forb 

Pascopyrum smithii Western wheatgrass Grass 

Plantago elongata Prairie plaintain Forb 

Poa pratensis Kentucky bluegrass Grass 

Polygonum ramosissimum Bushy knotweed Forb 

Portulaca oleracea Common purslane Forb 

Rumex stenophyllus Narrowleaf dock Forb 

Schedonnardus paniculatus Tumblegrass Grass 

Sphaeralcea coccinea Scarlet globemallow Forb 

Taraxacum officinale Common dandelion Forb 
69

Appendix F. Plant species identified on Winner site, 2004 and 2005. 

Scientific Name Common Name Class 

 

Agropyron cristatum Crested wheatgrass Grass 

Amaranthus albus Tumble pigweed Forb 

Astragalus vexilliflexis Bentflower milkvetch Forb 

Atriplex argentea Silverscale saltbush Forb 

Bouteloua gracilis Blue grama Grass 

Bromus inermis Smooth brome Grass 

Bromus japonicus Japanese brome Grass 

Buchloe dactyloides Buffalo grass Grass 

Carex filifolia Threadleaf sedge Grass 

Carex inops Sun sedge Grass 

Carex sp. Sedge Grass 

Chenopodium sp. Goosefoot Forb 

Cirsium arvense Canada thistle Forb 

Convolvulus arvensis Field bindweed Forb 

Ellisia nyctelea Waterpod Forb 

Euphorbia glyptosperma Ridgeseed spurge Forb 

Euphorbia strictospora Slimseed sandmat Forb 

Grindelia squarrosa Curlycup gumweed Forb 

Hedeoma hispida Rough falsepennyroyal Forb 

Helianthus annuus Annual sunflower Forb 

Kochia scoparia Kochia Forb 

Lactuca serriola Prickly lettuce Forb 

Lepidium densiflorum Greenflower pepperweed Forb 

Lotus purshianus American deervetch Forb 

Malva rotundifolia Roundleaf mallow Forb 

Melilotus officinalis Yellow sweetclover Forb 

Monolepis nuttaliana Muttal povertyweed Forb 

Panicum capillare Witchgrass Grass 

Pascopyrum smithii Western wheatgrass Grass 

Plantago patagonica Indianwheat Forb 

Polygonum ramosissimum Bushy knotweed Forb 

Portulaca oleracea Common purslane Forb 

Salsola collina Slender Russian thistle Forb 

Schedonnardus paniculatus Tumblegrass Grass 

Solanum rostratum Buffalobur Forb 

Sphaeralcea coccinea Scarlet globemallow Forb 

Taraxacum officinale Common dandelion Forb 

Tradescantia bracteata Bracted spiderwort Forb 

Verbascum thapus Common mullein Forb 

Verbena bracteata Prostrate vervain Forb 
Appendix G. Breakthroughs of new, active burrows, and vegetation characteristics associated with five study sit

South Dakota, August 2004 and 2005. 

Bad River Road 

 Control 10m 25m 4

2004 2005 2004 2005 2004 2005 2004 

Break through 9 0 7 8 7 5 5 VOR (cm) 1.9 2.0 2.7 2.8 2.6 2.7 2.6 Vegetation Height (cm) 14.6 11.3 17.4 16.4 12.8 20.5 14.2 Graminoid cover (%) 62.4 69.7 72.5 81.4 84.4 88.8 85.3 Forb cover (%) 2.6 3.6 3.9 4.6 3.6 3.5 3.4 Liter cover (%) 8.9 7.1 6.3 6.3 3.9 4.7 2.9 Bare ground (%) 26.0 19.6 17.3 7.6 7.8 3.0 8.4 
(Appendix G Continued) 

Fort Pierre 

 Control 10m 25m 4

2004 2005 2004 2005 2004 2005 2004 

Break through 10 11 3 9 9 5 5 VOR (cm) 1.9 2.1 9.9 7.2 7.6 9.4 11.3 Vegetation Height (cm) 14.5 15.1 28.0 28.5 23.0 26.1 30.6 Graminoid cover (%) 17.6 27.3 59.2 73.8 37.6 57.4 42.9 Forb cover (%) 28.8 29.9 14.5 14.8 32.2 24.6 34.6 Liter cover (%) 17.8 16.8 11.2 8.0 11.4 10.7 6.3 Bare ground (%) 35.8 26.0 15.0 3.5 19.0 7.3 16.1 
(Appendix G Continued) 

Custer County 

 Control 10m 25m 4

2004 2005 2004 2005 2004 2005 2004 

Break through 40 20 23 17 22 16 36 VOR (cm) 2.6 3.4 1.7 3.0 2.8 3.4 3.1 Vegetation Height (cm) 14.3 8.6 15.5 9.5 15.1 10.2 17.2 Graminoid cover (%) 54.5 33.4 62.6 52.2 73.5 38.1 69.8 Forb cover (%) 23.8 11.9 9.4 7.4 5.9 19.4 10.0 Liter cover (%) 11.0 4.5 21.1 6.0 13.4 6.5 14.7 Bare ground (%) 10.7 50.1 7.0 34.4 7.2 36.0 5.4 
(Appendix G Continued) 

Fall River County 

 Control 10m 25m 4

2004 2005 2004 2005 2004 2005 2004 

Break through 69 40 72 27 67 28 44 VOR (cm) 0.0 1.4 0.5 1.9 0.4 2.3 0.4 Vegetation Height (cm) 4.4 9.4 9.3 10.6 7.0 12.5 7.7 Graminoid cover (%) 0.7 28.2 9.2 74.1 2.3 68.9 2.9 Forb cover (%) 0.7 5.2 0.6 1.5 0.7 3.1 0.9 Liter cover (%) 46.3 33.1 76.1 17.8 75.7 13.4 69.6 Bare ground (%) 52.2 33.5 14.2 6.6 21.4 14.5 26.6 
(Appendix G Continued) 

Winner 

 Control 10m 25m 4

2004 2005 2004 2005 2004 2005 2004 

Break through 15 10 12 8 20 6 18 VOR (cm) 2.5 3.5 2.3 4.9 2.1 8.3 3.0 Vegetation Height (cm) 16.0 14.8 16.6 25.4 15.0 31.6 16.0 Graminoid cover (%) 47.2 52.9 53.2 55.2 47.8 61.7 56.7 Forb cover (%) 2.4 3.1 4.7 6.7 6.8 7.4 11.7 Liter cover (%) 21.7 22.2 16.8 15.8 15.7 17.8 16.8 Bare ground (%) 28.7 21.8 25.3 22.4 29.8 13.2 14.8