DEVELOPMENT AND EVALUATION OF HABITAT MODELS FOR HERPETOFAUNA AND SMALL MAMMALS

We evaluated the ability of discriminant analysis (DA), logistic regre ssion (LR), and multiple regression (MR) to describe habitat use by am phibians, reptiles, and small mammals found in California oak woodland s. We also compared models derived from pitfall and live trapping data for several species. Habitat relations modeled by DA and LR produced similar results, averaging about 70% classification success of the tra pping stations to the correct group (capture or noncapture habitat). A lthough more variables were included in DA (4-5) th an in LR (2-3), th ose included in LR were typically a subset of those in DA. On average, MR habitat models accounted for 56% of the variation in the index of relative species' abundance. The variables included in the MR models w ere seldom the same as those for DA and LR. Most differences between M R and the other two methods were related to differences in spatial sca le: MR modeled habitat among grids, whereas DA and LR modeled habitat within grids. Habitat models for the same species differed between the trapping methods used. Live traps are most useful for describing gene ral habitat relations of some small mammal species across large geogra phic areas, whereas pitfall traps are useful for intensive sampling of a larger portion of the vertebrate community within smaller geographi c areas. Thus, the choice of trapping methods must be based on the stu dy goals, biology of the species, and the spatial scale of study.