Effects of a Highway on Mojave Desert Rodent Populations

The present study was conducted from March 1979 through February 1980 near a divided, four-lane highway in a northern Mojave desert Larrea-AmbrosiaYucca community in southern Nevada. During 12,000 trap nights, 612 rodents of eight species were captured; of these, 387 were recaptured at least once. Analysis of recapture data indicated that some individuals of each species moved distances sufficient to cross the highway (> than 47 m); however, only an adult male Ammospermophilus leucurus was recorded as having crossed. No road mortality was noted on the study area, and there was no relationship between proximity to the highway and home range size or trap-revealed life span. Perognathus formosus, Dipodomys merriami, A. leucurus, Neotoma lepida and Onychomys torridus densities were unaffected by proximity to the road. However, Spermophilus tereticaudus and Thomomys umbrinus were more abundant near the highway, whereas Peromyscus eremicus was less abundant. The decrease in P. eremicus abundance near the highway was attributed to a scarcity of Yucca near the highway, due to natural habitat heterogeneity.