Document Type
Thesis - University Access Only
Award Date
2009
Degree Name
Master of Science (MS)
Department / School
Animal Science
Abstract
The potential for prairie dogs to remove forage otherwise available to livestock is a growing concern. Studies are lacking that document the extent of competition between prairie dogs and livestock. Forage losses due to prairie dogs are of interest to those who use rangelands for livestock production. However, few studies have documented the proportion of total forage disappearance on-town attributed to prairie dogs and cattle. Research on the effects of prairie dogs on plant communities has yielded inconsistent results. Differences between studies can be attributed to location (mixed- vs. shortgrass prairie) and climate, particularly precipitation. Also, for vegetation comparisons between colonized sites and non-colonized sites to be meaningful, the soils and associated ecological sites for both sites should be similar. Otherwise, it is difficult to determine if vegetation differences between colonized and non-colonized sites can be attributed to prairie dog activity or edaphic or other site factors. Many studies failed to ensure that on and off-town plant communities were on similar soils, and others provided only one year of data. The objectives of this project were to 1) quantify and compare forage removal on prairie dog towns by prairie dog activity and by cattle grazing, 2) quantify and compare the amount of forage used by cattle on- and off-town, 3) estimate the impacts of prairie dog towns on height and mass of forage, and 4) to quantify impacts of a) prairie dog activity, b) relative vegetation cover, c) year, and d) season of growth (cool- vs. warm season) on plant species composition and richness on mixed grass prairie pastures in western South Dakota. This study was initiated in May 2007 on four different pastures in the Buffalo Gap National Grasslands of western South Dakota. A fifth pasture was included in 2008 to replace one of the original four pastures where plague had eliminated most of the prairie dog population. Three sites with matching soils and ecological sites were selected in each pasture, two on-town and one off-town. Plots were established using appropriate cages, exclosures, or their lack on the three sites in each pasture. Vegetation sampling occurred during June and July in 2007 and 2008. Average height, disappearance, and biomass were collected for every species. Analysis of species composition and forage disappearance indicated that prairie dogs significantly altered the vegetation composition on-town compared to off-town sites and reduced forage availability to cattle on prairie dog towns. Prairie dogs were the main source of forage removal on-town, removing more than four times as much forage compared to cattle on-town. In this study approximately 70% of the forage disappearance during the growing season due to prairie dogs was estimated to be due to non-consumptive activities by prairie dogs in 2007 ( dry year) and over 90% in 2008 (wet year). Overtime, prairie dog activities cause shifts in the vegetation community. In this study, graminoids dominated off-town sites and forbs dominated on-town sites. Species richness results mirrored species composition; species richness for graminoids was greater off-town and forb species richness was greater on-town. Species richness varied with sampling season and year. On-town vegetation is maintained at a relatively low height (5-9cm) and utilization of on-town sites is high, which further reduces forage availability to cattle. This reduction in forage will ultimately reduce appropriate livestock stocking rates in pastures associated with prairie dogs.
Library of Congress Subject Headings
Forage plants -- Losses -- South Dakota -- Buffalo Gap National Grassland
Forage plants -- Effect of grazing on -- South Dakota -- Buffalo Gap National Grassland
Black-tailed prairie dog -- South Dakota -- Buffalo Gap National Grassland
Cattle -- South Dakota -- Buffalo Gap National Grassland
Rangelands -- South Dakota -- Buffalo Gap National Grassland
Format
application/pdf
Number of Pages
170
Publisher
South Dakota State University
Recommended Citation
Gabrielson, Melissa L., "Effects of Black-tailed Prairie Dogs (Cynomys ludovicianus) and Cattle on Vegetation Composition and Disappearance in the Mixed-Grass Prairie" (2009). Electronic Theses and Dissertations. 1572.
https://openprairie.sdstate.edu/etd2/1572
