Ski-pistes are ecological barriers to forest small mammals

From the beginning of the last century, the expansion of the ski industry has significantly altered alpine environments. The aim of this research was to study the impacts of forest ski-pistes on small mammals by assessing (1) whether ski-pistes were used or avoided and (2) whether they acted as ecological barriers to local movements. Two ski-developed valleys of the Western Italian Alps were considered. Most of the fieldwork occurred in the Sessera valley (Piedmont); a minor part was carried out in the Ayas valley (Aosta valley). In the main study site, three capture–mark–recapture studies on core species were carried out to assess habitat use (one study) and the capability of crossing ski-pistes (two studies: spontaneous crossing and individual translocation). Two radiotracking surveys of the most vagile species, the fat dormouse, were carried out to locate home ranges and resting sites in relation to ski-pistes. In the habitat use experiment, virtually all individuals (245 out of 249) were captured outside the ski-piste. In the spontaneous crossing test, recaptures of marked individuals showed that they moved on one side of the ski-piste only and never crossed it. However, in translocation experiments, 18.6 % of translocated individuals were able to cross the ski-piste and come back to the original forest patch. Fat dormice maintained home ranges on one side of the ski-piste and they never crossed it. Resting sites were mostly underground, between rocks, in boulders and in rocky crevices, never in the ski-piste. Our study clearly suggests that forest ski-pistes represent habitat loss and are ecological, semi-permeable barriers to small mammals. To mitigate habitat loss and make movements between forest patches easier, a possible management intervention could be maintaining a partial shrub cover or adding woody debris, both relatively easy methods for ski areas to implement in order to maintain small mammal communities.