Habitat and Resource Utilization by Rodents of a California Coastal Sage Scrub Community

Abstract

Aspects of habitat and food utilization were studied in 6 heteromyid and cricetid rodents during a 13 mo. period in a 2.3 ha coastal sage scrub community near Irvine, California [USA]; these rodents included Dipodomys agilis, Perognathus longimembris, Reithrodontomys megalotis, Peromyscus maniculatus, P. eremicus and P. californicus. The community had maximum species numbers, population densities and diversity in spring and summer. All rodent species had stable or increasing population numbers in spring-summer 1971. Analysis of spatial distribution suggested little evidence for strong habitat preferences, except for that of D. agilis for stations having high sand/bare ground cover and of P. californicus and P. eremicus for stations with high shrub cover and low grass and forb cover. Food habit determinations indicated that the heteromyids and P. californicus and P. eremicus had relatively specialized diets of grass-annual seeds, and perennial shrub seeds and fruits, respectively. In contrast, R. megalotis and P. maniculatus had generalized diets of insects, and seeds, fruits and foliage of shrubs and annuals. Predation, nest/burrow competition and water availability were apparently not important factors limiting rodent populations.