Trap-revealed microhabitat use by small mammals in monoculture grasslands

This study was conducted to determine if microhabitat differences in canopy cover of weeping lovegrass (Eragrostis curvula) monoculture grasslands inf luenced presence of small mammals. Canopy cover of weeping lovegrass was me asured at 12 trapping grids of 100 traps each. Traps were pooled and separa ted into four categories (0 to 25%, 26 to 50%, 51 to 75% and 76 to 100%) ba sed on percentage of weeping lovegrass canopy cover at each trap location. First captures of small mammals were analyzed using the chi square test sta tistic. Four species, cotton rat (Sigmodon hispidus; n=100), western harves t mouse (Reithrodontomys megalotis; n=173), hispid pocket mouse (Chaetodipu s hispidus; n=28), and deer mouse (Peromyscus maniculatus; n=41) were captu red in sufficient numbers for statistical comparison. Captures for P. manic ulatus and C. hispidus differed from the expected distribution of captures (X-2, 3 df, P less than or equal to 0.01) with more captures in open trap s ites and fewer captures in sites with increased cover. In contrast, capture s for S. hispidus and R. megalotis differed from the expected distribution (X-2, 3 df, P less than or equal to 0.001) with more captures in densely ve getated trap sites and fewer captures in open trap sites. Canopy cover appe ars to influence small mammal microhabitat selection during the spring in w eeping lovegrass monocultures. Land management decisions which affect micro habitat characteristics may impact small mammal community structure.