Microhabitats in a Forest‐Floor Small Mammal Fauna

Abstract

This study examines microhabitat configurations for 3 small mammal species occupying second—growth mesic forest on Walker Branch Watershed in eastern Tennessee. Small mammal populations were sampled in oak—hickory, chestnut oak and pine forest types, with three 0.36—ha live—trapping grids per forest type. There were 255 total captures for 4 forest—floor species during 9,696 trap nights between 1 May and 16 August 1973. These captures included 2% Blarina brevicauda, 66% Peromyscus leucopus, 5% Ochrotomys nuttalli and 27% Tamias striatus. Blarina was captured most frequently in the pine forest type, Peromyscus and Tamias most frequently in the oak—hickory, and Ochrotomys exclusively in the pine. Twenty—nine variables describing proximate habitat structure were measured at each sample mammal capture site. There were significant overall species differences on 18 of these variables. A subset of variables was identified for each of the 3 most frequently observed species, consisting of only the variables of particular significance for distinguishing the capture sites of that species from those of the other species collectively. Discriminant analysis of these few variables both described the average microhabitat configuration, for a species and indicated the relative importance of each variable for characterizing or describing that configuration, subject to the assumptions of the analysis. The observed differences between species microhabitat configuration are consistent with both the composition by forest type of each species sample and the literature information for each species. Microhabitat segregation among these species is discussed with reference to recent theories of habitat selection, ecological, specialization and resource partitioning in equilibrium faunas.