Effects of Prairie Dogs and Cattle on Vegetation Disappearance on Prairie Dog Towns in Mixed-Grass Prairie

South Dakota State University Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange South Dakota Beef Report, 2004 Animal Science Reports 2004 Effects of Prairie Dogs and Cattle on egetV ation Disappearance on Prairie Dog Towns in Mixed- Grass Prairie Matthew .B Stoltenberg South Dakota State University Patricia S. Johnson South Dakota State University Alexander J. Smart South Dakota State University Lax Xu South Dakota State University Follow this and additional works at: http://openprairie.sdstate.edu/sd_beefreport_2004 Part of the Animal Sciences Commons Recommended Citation Stoltenberg, Matthew B.; Johnson, Patricia S.; Smart, Alexander J.; and Xu, Lax, "Effects of Prairie Dogs and Cattle on eV getation Disappearance on Prairie Dog Towns in Mixed-Grass Prairie" (2004). South Dakota Beef Report, 2004. Paper 18. http://openprairie.sdstate.edu/sd_beefreport_2004/18 This Report is brought to you for free and open access by the Animal Science Reports at Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. It has been accepted for inclusion in South Dakota Beef Report, 2004 by an authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For more information, please contact [email protected]. Effects of Prairie Dogs and Cattle on Vegetation Disappearance on Prairie Dog Towns in Mixed-Grass Prairie Matthew B. Stoltenberg1, Patricia S. Johnson2, Alexander J. Smart3, and Lan Xu4,5 Department of Animal and Range Sciences BEEF 2004 – 17 Abstract be adjusted to account for forage disappearance 12345 due to prairie dogs. Quantitative data is lacking on competition between prairie dogs and cattle for forage on Introduction mixed-grass prairie pastures. The objective of this study was to determine the disappearance The black-tailed prairie dog (Cynomys of vegetation attributable to cattle and prairie ludovicianus Ord) is a native rodent found dogs on pastures with prairie dog towns. During throughout the shortgrass and mixed-grass the summers of 2002 and 2003, biomass prairies of North America. Presence of prairie estimates were made periodically on three dog towns and their effect on forage availability mixed-grass prairie pastures in south central for large ungulates, such as cattle, has been South Dakota that had varying degrees of prairie very controversial. Ranchers contend that dog town coverage (percent of pasture area). prairie dogs severely reduce forage available to Two types of grazing exclosures were their livestock, increase weeds, and increase established. Cattle exclosures allowed grazing erosion, while other groups claim that a variety by prairie dogs only. Cattle/prairie dog of studies suggest that prairie dogs have a exclosures excluded both herbivores. beneficial or neutral effect on livestock (e.g. Permanent plots outside cages were established National Wildlife Federation, 1998). It is known that allowed grazing by both species. Biomass that prairie dogs clip vegetation in addition to estimates on individual vegetation species were what they eat in order to see predators. obtained both inside the exclosures and on Laboratory studies have revealed how much permanent plots outside the exclosures two prairie dogs eat, yet little work has been done to times in 2002 and 2003. Forage removed was quantify total disappearance of vegetation estimated and compared for cattle alone, prairie attributed to prairie dogs. Level of competition dogs alone, and cattle and prairie dogs together between cattle and prairie dogs is another area in each year. Forage removed by prairie dogs of concern. Cattle and prairie dogs have similar on the on-town sites was nearly three times as diets, which consist of approximately 87% great as forage removed by cattle on the on- graminoids (Uresk, 1984; Uresk, 1986) town sites for the June and July sampling suggesting considerable overlap and periods. Cattle removed two times more forage competition between the two herbivores. on off-town sites than on on-town sites. Total Competition between cattle and prairie dogs forage removed on on-town sites (cattle + prairie may create a problem when stocking cattle on dogs) was almost two times greater than on off- pastures supporting prairie dog towns. The town sites. Livestock forage was significantly objective of this study was to determine the reduced on prairie dog towns compared to difference in disappearance of vegetation due to unoccupied sites. Classic carrying capacity cattle and prairie dogs on pastures with prairie calculations overestimate forage availability dog towns. when prairie dog towns are present. Stocking rates on pastures with prairie dog towns should Materials and Methods Research was conducted in south central South 1Graduate Student Dakota on mixed-grass prairie rangelands 2 Professor approximately 25 miles west of Mission. Climate 3 Assistant Professor 4 of the region is continental and semiarid with hot Research Associate I 5 The authors would like to thank North Central Region summers and cold winters. Annual precipitation SARE Graduate Student Program and USDA Higher averages approximately 19 inches near Mission, Education Tribal Colleges Research Grants Program for SD (NOAA, 2000), and over half of the yearly their financial support of this research project. 94 precipitation falls during the growing season. use by prairie dogs (CATTLE EXCL), and 3) Soils in the study area are predominantly silts plots covered by cages which excluded both and loams (USDA SCS, 1974). Vegetation is prairie dogs and cattle (ALL EXCL). All plots typical of the mixed-grass prairie, with a variety were 0.30 yd2. of warm- and cool-season species. Common grass species in the area include western Forty NONE EXCL plots were established on wheatgrass (Pascopyrum smithii [Rydb.] A. each prairie dog town and 20 on each off-town Love), little bluestem (Schizachyrium scoparium site. These plots were “permanent”, that is, the (Michx.) Nash), needleandthread (Stipa comata same plots were used for all sampling periods in Trin. & Rupr.), prairie sandreed (Calamovilfa both years. To avoid marking these plots with longifolia [Hook.] Scribn.), blue grama stakes or flags which would attract herbivores to (Bouteloua gracilis (H.B.K.) Lag. Ex Griffiths) them, we obtained a GPS location for each, and buffalograss (Buchloe dactyloides [Nutt.] marked the corners of each plot with metal Engelm.). stakes driven into the ground, and then used those coordinates and stakes to relocate each Three mixed-grass prairie pastures grazed by plot at each sample date. cattle with varying degrees of prairie dog town coverage (percent of pasture area) were used. Ten CATTLE EXCL plots were established on Data collection took place on the three pastures each prairie dog town. These were fenced by during the summers of 2002 and 2003. creating an exclosure with barbed wire and Vegetation samples were collected during two fence posts to ensure availability to prairie dogs sampling periods in each year: late spring (June) (we were concerned prairie dogs might not go and mid-summer (July) in an effort to adequately into exclusion cages, even though the wire mesh sample both the cool- and warm-season species would have permitted their entry). Another 10 common to the region. Two sites were selected CATTLE EXCL plots were established on each on each study pasture. One site was the prairie off-town site. These were covered with an dog town (on-town site). The second site (off- exclusion cage constructed with a large mesh town site) was near the prairie dog town but had wire over a metal frame. no prairie dog activity. Off-town sites were chosen based on similarity of soils with their Ten ALL EXCL plots were established on each paired on-town site. Soils on all on-town and prairie dog town; none were established on the off-town sites were evaluated by a Natural off-town sites since these sites were not utilized Resources Conservation Service soil scientist by prairie dogs. The ALL EXCL plots were prior to final selection. covered with an exclusion cage constructed of chicken wire mesh over a metal frame to prevent It was important to this study that the soils were access by prairie dogs and cattle. matched within each pair of on- and off-town sites, because sites with the same soils have At the end of each 3-week sampling period (one potential for production of similar quantity and in June of each year and one in July of each composition of vegetation. Differences in year), biomass was estimated by species on all species and/or production can then be more plots. Estimates for aboveground biomass by closely tied to differences in use. On-town sites species were obtained using two methods. For in this study were dominated by annual grasses all plots in 2002, all NONE EXCL plots in 2003, and forbs as well as by the shorter perennial and the on-town CATTLE EXCL plots in 2003, grasses including blue grama, buffalograss, and double sampling methods appropriate for each sedge (Carex) species (grouped as species were used, including the use of cover, shortgrasses), and red threeawn (Aristida reference units (Andrew et al, 1979, 1981), and pupurea Nutt). Off-town sites were dominated plant volume (Johnson et al., 1988) as by perennial forbs and grasses including the estimators. In 2003, all plots underneath shortgrasses, needleandthread and prairie movable cages (off-town CATTLE EXCL plots sandreed. and ALL EXCL plots) were clipped and sorted by species. Biomass estimations were made for Three types of plots were used in this study: 1) individual species with the exception of two uncaged plots open to grazing by both prairie groups which were lumped together: blue dogs and cattle (NONE EXCL), 2) plots grama, buffalograss, and sedge species were fenced/caged so as to exclude cattle but allow grouped together as shortgrasses and downy 95 brome and Japanese brome were grouped as removed by cattle on the on-town sites (Table annual brome.

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