Small mammal populations in a grazed and ungrazed riparian habitat in Nevada

This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain. degree in wildlife management from Colorado State University in 1959, and a Ph.D. degree in range ecosystems from Colorado State University in 1976. His research has included studies in mule deer ecology, big-game range improvement , mule deer population modeling, and nongame bird and small mammal ecology and habitat management. WARREN P. CLARY is project leader of the lntermountain Station's Riparian-Stream Ecology and Management research work unit at Boise, ID. He received a B.S. degree in agriculture from the University of Nebraska and an M.S. degree in range management and a Ph.D. degree in botany (plant ecology) from Colorado State University. ACKNOWLEDGMENTS We gratefully acknowledge the field and office assistance provided unpublished information about the study location and grazing history. Craig R. Contor designed the cover illustration. Community composition and relative abundance of small mammal populations were compared between an aspen (Populus tremuloides)lwillow (Salix spp.) riparian habitat seasonally grazed by cattle and a comparable adjoining habitat protected from grazing for the previous 11 years by an exclosure. The exclosure, constructed in 1977, is on the West Fork of Deer Creek in northeastern Nevada. Small mammal populations were compared by removal trapping over a 5-day period in late summer 1988. Four species accounted for 82 percent of the total number of individual animals trapped. These were deer mouse (Peromyscus maniculatus), western jumping mouse (Zapus princeps), least chipmunk (Tamias minimus), and Great Basin pocket mouse (Perognathus parvus). Other small mammals trapped either irregularly or in smaller numbers on the study site included golden-mantled ground squirrel (Spermophilus lateralis), vagrant shrew (Sorex vagrans), long-tailed vole (Microtus longicaudus), montane vole (Microtus montanus), Townsend's ground squirrel (Spermophilus townsendi~), northern pocket gopher (Thomomys talpoides), and bushy-tailed woodrat (Neotoma cinerea). Estimated density of small mammals was over a third higher in the ungrazed habitat as compared to the grazed area. Small mammal standing crop biomass, species richness , and species diversity were 3.24, 1.83, and 1.25 times higher, respectively, on the ungrazed site. Each of the 11 species recorded during the study was trapped inside the protected area. Only six species were trapped in the grazed habitat. The grazed study site did not appear to have received excessive use by cattle in recent years compared to nearby riparian habitats. The use of trade or firm names …