Habitat Selection of the Salt Marsh Harvest Mouse and Sympatric Rodent Species

Abstract

Abstract We evaluated interspecific habitat use within a salt marsh small mammal assemblage on Mare Island, Solano County, California, USA, from 1989 to 1992, with emphasis on the endangered salt marsh harvest mice (Reithrodontomys raviventris). We livetrapped small mammals during 125 trap sessions at 20 different areas throughout Mare Island for a total of 55,189 trap-nights. We captured the salt marsh harvest mouse 4,147 times; the house mouse (Mus musculus), 1,936 times; the California vole (Microtus californicus), 372 times; and the shrew (Sorex spp.), 117 times, among 12,927 captures. We captured fewer than 10 rats (Rattus spp.), and we did not capture any western harvest mice (Reithrodontomys megalotis) or deer mice (Peromyscus maniculatus). We sampled vegetation characteristics at each trap location during 79 of 125 trap sessions for a total of 5,523 trap locations. During the summer, breeding, and fall seasons, habitats characterized by increased cover of forbs, particularly fat hen (Atriplex patu...