RANGE-WIDE OCCUPANCY ANALYSIS OF MOHAVE GROUND SQUIRRELS.
Erica L. Orcutt; University of California, Davis; Enviro Sci & Policy, 2133 Wickson Hall, One Shields Avenue, Davis, CA, 95616; (408) 507-8362; elorcutt@ucdavis.edu; Barbara M. Leitner, David K. Delaney, Philip Leitner
The Mohave ground squirrel (Xerospermophilus mohavensis) is a California Threatened species, found only in the western Mojave Desert. Research on its resource requirements has identified key food plants in an area of high-quality habitat in the northern portion of the range. However, these data are not necessarily representative of the species' resource-use in other areas. This study represents the first range-wide analysis of resource selection for Mohave ground squirrels and aims to test if resources found to be important in the northern portion of the range are also important for other populations. Camera surveys were conducted on public lands in 2011-2012 to determine detection/non-detection and were paired with vegetation surveys on the camera sites. Occupancy analysis was then employed to assess the importance of herbaceous and shrub species for site occupancy. This analysis revealed a strong negative relationship between Mohave ground squirrel site occupancy in areas with increasing creosote (Larrea tridentata) density and in sites where alien grasses dominated native herbs. While these results failed to clearly show positive resource selection for particular food plants, they suggest an additional negative impact of invasive grasses in the Mojave Desert.
Ecology and Conservation of Mammals IV   Student Paper