Theses and Dissertations at Montana State University (MSU)
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Item Impacts of recreational shooting on prairie dog colonies(Montana State University - Bozeman, College of Letters & Science, 1996) Vosburgh, Timothy CharlesThe BLM has encouraged recreational shooting as a means of controlling prairie dog populations and as a recreational use of public lands. I investigated the impacts of recreational shooting on prairie dog population dynamics, activity patterns, and vegetation conditions in prairie dog towns. I monitored shooting pressure on BLM hunted colonies, measured the strength of association between shooting effort and changes in population size/structure and activity patterns, and compared vegetation between hunted and unhunted colonies. Marked subsamples were used to estimate prairie dog densities during the spring and fall on 10 hunted colonies in 1994 and 9 hunted and 8 non-hunted (control) colonies in 1995. Mean number of prairie dogs killed on colonies open to hunting was 27% in 1994 and 53 in 1995. In 1995, prairie dog density declined 33% on hunted colonies and 15% on non-hunted colonies. The percentage of marked prairie dogs recaptured during the fall was higher on non-hunted colonies (53%) than on hunted colonies (41%). I also found a positive correlation between shooting pressure and change in density on hunted colonies. Although age structure did not change from spring to fall, recreational shooting may have resulted in higher female mortality during 1995. Prairie dogs spent more time in alert postures and less time foraging on hunted than on unhunted towns. Prairie dogs could also be approached more closely on non-hunted colonies than on hunted colonies. Of the 4 approaches I used to monitor prairie dogs: (mark-recapture, burrow counts, vegetation analysis, and counting prairie dogs), above ground counts were the best approach for assessing prairie dog populations.Item Recovery of black-tailed prairie dog colonies following a sylvatic plague epizootic(Montana State University - Bozeman, College of Letters & Science, 2002) Fennell, Jeffry DwightBlack-tailed prairie dogs suffered a 94-99%' reduction in habitat during the twentieth century. In recent decades, the introduced pathogen responsible for sylvatic plague has led to local extirpation of prairie dog colonies, reduction in colony size, and increased isolation between surviving colonies. Consequently, plague has become the biggest challenge to prairie dog conservation. For this study I estimated prairie dog densities on the Northern Cheyenne Indian Reservation following a sylvatic plague epizootic in the 1990s. I estimated densities using mark-recapture techniques and visual counting methods. I compared variations in densities based upon a colony’s plague history and colony size. I hypothesized that densities would be higher on colonies that most recently experienced the plague. In 2000, prairie dog densities ranged between 11-91 prairie dogs/ha from 21 colonies. Densities ranged between 5-90 prairie dogs/ha from 23 colonies in 2001. Prairie dog density did not differ between years. There was no significant difference in densities based upon presence or absence of past plague or colony size. Colonies that had most recently recovered from a sylvatic plague had the highest densities. I also examined factors relating to a colony’s probability of having had the plague, such as nearest neighbor distances, habitat between nearest neighbor, and distance to nearest road. I predicted that colonies would be more likely to contract plague if distances between neighboring colonies were small, the habitat between colonies facilitated dispersal, or colonies were on or near migration corridors. The distances to the nearest plagued colony and nearest non-plagued colony were the best predictors of a colony’s probability of having experienced sylvatic plague. For those colonies that had sylvatic plague in the 1990s, distances to other colonies with plague were shorter (x = 3.1 km) than to colonies that did not experience plague (x = 19.7 km).