Effects of vegetation and topography on snowshoe hare relative abundance at the southern range periphery

The conservation of snowshoe hares (Lepus americanus) and their habitat is a major focus in the American West, largely because of their importance to the federally threatened Canada lynx (Lynx canadensis). Understanding the habitat relationships of snowshoe hare populations at the southern periphery of their distribution is particularly important because a warming climate is reducing the mesic forests and persistent snow cover they require. Using fecal pellet density as an index, we examined the factors influencing snowshoe hare relative abundance at 2 study areas in the Southern Rocky Mountains by comparing suites of candidate models containing fine-scale vegetation and topographical covariates. The Birdseye Gulch study area is within an extensive area containing high elevations, mesic forests, and Canada lynx occurrence. The Three Peaks study area consists of an isolated zone of high elevation and mesic forests surrounded by inadequate habitat and is absent of Canada lynx. Mean hare pellet density in Birdseye Gulch was 2.48 pellets & PLUSMN; 0.46 (SE)/m2 ${{\rm{m}}}<^>{2}$ (n = 49) versus 2.24 & PLUSMN; 0.48/m(2) (n = 57) at Three Peaks. Models containing fine-scale vegetation variables best explained pellet densities at Birdseye Gulch. Pellet densities at Three Peaks were best explained by topographical variables, with much unexplained variation within all models. The differing trends in these areas may be due to the absence of resident Canada lynx at Three Peaks and differences in topography between the areas. Our results indicate that snowshoe hare populations can persist in the type of isolated habitat that is increasingly common at the southern range periphery; however, the use of vegetation management to conserve habitat in these areas may be less effective because of weaker associations with vegetation structure.