Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Pattern correlation of mammalian teeth as a means of identification(Montana State University - Bozeman, College of Agriculture, 1939) Buck, Charles L.Item Effects of fluorides on Peromyscus maniculatus in Glacier National Park(Montana State University - Bozeman, College of Agriculture, 1974) Fogelsong, Mark LeroyItem Small mammal abundance and distribution in the Missouri River Breaks, Montana(Montana State University - Bozeman, College of Agriculture, 1978) Trout, Robert GarstItem Small mammal populations in clearcuts of various ages in south central Montana(Montana State University - Bozeman, College of Agriculture, 1973) Heath, Martin LyleItem Small mammal communities after two recent fires in Yellowstone National Park(Montana State University - Bozeman, College of Agriculture, 1981) Wood, Marilyn AnitaItem Studies on native small mammals as intermediate hosts of Echinococcus multilocularis(Montana State University - Bozeman, College of Agriculture, 1981) Feigley, Harvey PeterItem Ecological distribution of small mammals at Sarpy Creek, Montana, with special consideration of the deer mouse, Peromyscus maniculatus(Montana State University - Bozeman, College of Agriculture, 1981) Scow, Kenneth LeeItem Cheatgrass invasion of sagebrush steppe : impacts of vegetation structure on small mammals(Montana State University - Bozeman, College of Letters & Science, 2014) Bachen, Daniel Allen; Chairperson, Graduate Committee: Andrea Litt; Andrea R. Litt and Claire Gower were co-authors of the article, 'Effects of cheatgrass invasion on food accessibility for small mammals in sagebrush steppe' submitted to the journal 'Journal of wildlife management' which is contained within this thesis.; Andrea R. Litt and Claire Gower were co-authors of the article, 'Changes in predation risk for deer mice (Peromyscus maniculatus) with plant invasions: understanding mechanisms' submitted to the journal 'Journal of wildlife management' which is contained within this thesis.Nonnative plants can affect habitat quality for native animals directly, through changes in resources like cover or food, and indirectly, through changes in access to resources or predation risk. Understanding these effects is crucial to develop management techniques and maintain ecosystem processes. In sagebrush steppe, brome grasses such as cheatgrass (Bromus tectorum) can invade and form dense stands, increasing the depth and persistence of litter, as well as the density of standing vegetation. These structural changes alter abundance and composition of the small mammal community. We used a series of experiments to explore whether changes in vegetation structure associated with the invasion of cheatgrass would alter foraging and predation risk of small mammals, to better understand mechanisms driving documented population- and community-level effects. In the first experiment, we placed a measured amount of grain at stations with either increased litter or stem density, and examined how much grain was removed nightly. We found that adding litter reduced the amount of grain removed in 2 of our 3 study areas. In the second experiment, we timed animals fleeing a simulated predator through various depths of litter or densities of stems. We found that dense stems impeded movement more than litter. In the third experiment, we recorded animals moving through native sagebrush steppe and cheatgrass monocultures, and analyzed these recordings to detect differences in the volume of noise created, especially for frequencies detected by common predators. We found that animals moving through cheatgrass made more noise at high frequencies, compared to native sagebrush steppe. Based on these experiments, cheatgrass monocultures may reduce habitat quality for small mammals by decreasing foraging efficiency and increasing vulnerability to predators. Mitigation strategies should focus on reducing the density of standing vegetation where predation is a limiting factor and litter depth where small mammals are food-limited.