Jon Atwood, PhD
Department of Environmental Studies
The impact of human-created trails in nature preserves on the common game and furbearer species of Southern New Hampshire has not been widely studied. While trails are often constructed to enable humans to enjoy the nature preserves, any changes in habitat use by resident species due to that disturbance needs to be understood. This study was conducted by tracking mammals in shallow (<20cm) snow on transects laid out on trails as well as in parallel control transects. Twelve pairs of trails and control transects were monitored at publicly accessible nature areas in the winter of 1999. All wildlife tracks that crossed the transect were recorded as well as canopy cover and type of human trail traffic. Of eleven mammal species found, the fisher (Martes pennanti), the mink (Mustela vison), and the red squirrel (Tamiasiurus hudsonicus) showed possible difference in track densities among the various canopy covers. With the probability that canopy cover influences where some species are more active, the examination of differences in habitat use between trail and control areas was performed within each canopy cover type. With the exception of fisher activities in areas of mixed hardwood/softwood, most comparisons of track densities between trail and control sites showed no significant differences. Measures of fisher activity were approximately two times greater along control transects than along trails; however, this difference was only marginally significant. This preference, for the fisher, is consistent with its documented habitat use. Based on these results, human created trails do not appear to be a significant impediment to habitat use for most species, although no native mammal species prefers the disturbance of trails. Therefore, managers of wildlife sanctuaries have no obvious reason to clear forest areas of downed woody debris, underbrush, or other components of vertical variation, if biodiversity is to be maximized in the overall habitat.