EFFECT OF BUFFELGRASS (CENCHRUS CILIARIS) ON SONORAN DESERT RODENT DIVERSITY AND POPULATION DENSITY

Buffelgrass ( Cenchrus ciliaris, syn. Pennisetum ciliare) is exotic to the Sonoran Desert and has caused drastic changes in this ecosystem. Yet, little research has documented the impact of buffelgrass on wildlife in the region, including small mammals. The objective of this study was to estimate abundance of native nocturnal rodents and characterize habitat structure in an area with native vegetation and buffelgrass prairies to assess the effect of this exotic grass on the diversity and population density of this community in the Sonoran Desert, located in the municipality of La Colorada, in central Sonora, Mexico. We trapped nocturnal rodents in a buffelgrass prairie site and in a site with native vegetation (with two trapping plots at each site), before and during the summer rainy season, and observed the differences in species composition between sites. We used capture-mark-recapture and distance sampling models to estimate population density of the two most common species, Dipodomys merriami and Chaetodipus penicillatus. Despite differences in habitat structural diversity between buffelgrass prairies and native vegetation, our results suggest that buffelgrass does not seem to affect dominance or population density of these two heteromyids, whereas evenness and species richness showed some differences between buffelgrass prairies and native vegetation sites.