Spatial Relationships of Rodents in a Sagebrush Community

Abstract

Twelve species of nocturnal rodents were studied on a 2.7-ha plot of sagebrush desert in westcentral Nevada. Species richness appeared to be augmented by food resource allocation, microhabitat selection, temporal partitioning, and the establishment of an interspecific dominance hierarchy. Three species ( Dipodomys mi-crops, Perognathus formosus , and Neotoma lepida ) were restricted to the shadscale habitat. One species, D. ordii was restricted to sand dunes, and one species, D. panamintinus , was restricted to big sage habitat. Three species, D. merriami, P. longimembris , and Peromyscus maniculatus , appear to be habitat generalists. Intraspecific overlap values indicate that D. merriami and P. longimembris are the most social of the heteromyids studied, although Peromyscus maniculatus was the only species exhibiting intraspecific overlap throughout the year. Between-sex overlap was greatest during reproduction. Male-male overlap was most prevalent for all species except P. longimembris , which exhibited greater female-female overlap. The magnitude of total overlap tolerated by a species showed a positive density relationship although on an individual basis, overlap values tended to remain fairly constant. Interspecific overlap was low except for the habitat generalists, which tended to use more habitat patches. By using principal component analysis to study changes in home range shape, size, and orientation, one can assess changes in overlap and space utilization. This technique should enhance our knowledge of small mammal social structure.