MESIC DECIDUOUS FOREST AS PATCHES OF SMALL-MAMMAL RICHNESS WITHIN AN APPALACHIAN MOUNTAIN FOREST

Abstract

Forests of Southern Appalachia are critical habitats with respect to biodiversity, with a large portion of these forests residing on public multiuse lands. With pressure to extract timber from maturing forests, there is a need to identify the relative importance of forest types within the larger forest matrix. We examined small-mammal populations at 350 sample points across 157 km 2 of forested habitat in the George Washington and Jefferson National Forests, Virginia, to determine landscape and habitat correlates of species abundance and richness. A total of 3,955 individuals representing 20 species were captured using live trap and pitfall sampling at each point during 1996 and 1997. Nine species were sufficiently common to examine their abundance relative to landscape and habitat features. We found species abundance and richness to be highest in mesic deciduous forest types, with the exception of Peromyscus leucopus. Soil moisture capacity and the proportion of mesic habitat within 100 m of the sample point were also important for several species. If mesic deciduous forest can be considered patches within a matrix of xeric forest, then the abundance of 4 species and species richness could be predicted based on the distance of the sample point to the nearest mesic patch and the abundance of 3 species inside mesic patches was related to patch size. At least 73% of mesic patches within this forest were ,25 ha and separated from other patches by .100 m. Our results indicate that mesic forest patches contain the bulk of the species richness for small mammals in the Southern Appalachian ecotype. Designing timber harvests that minimize use of mesic deciduous forest type and that does not decrease patch numbers would achieve the largest benefits to small mammals within the region.