Competition and Habitat Selection in a Forest-Floor Small Mammal fauna

In a study of habitat exploitation in a forest-floor small mammal community, we have collected habitat and population data for Peromyscus leucopus (white-footed mouse), Ochrotomys nuttalli (golden mouse) and Tamias striatus (eastern chipmunk). Using multiple regression analysis, we estimate the effects of habitat selection and competition on the local distributions of these species during three seasons. Each of the partial regression coefficients relating the density of an independent species to the density of the dependent species is negative. This result indicates that competition (i.e., mutual inhibition) is pervasive among these species. Competitive ability and habitat selectivity both increase in the order PeromyscusTamiasOchrotomys. Peromyscus is a poorly competitive habitat generalist, Ochrotomys is a strongly competitive habitat specialist, and Tamias is intermediate in both respects. The competitive hierarchy is stable between seasons. These results both confirm the conclusions reached in previous studies of this small mammal community and suggest the design of experiments to further clarify the mode and consequences of interaction between these species.