Human influence on the choice of winter dens by European brown bears in Slovenia

Abstract

The Slovenian brown bear ( Ursus arctos ) population is the only viable population in Central and Western Europe, and it coexists with humans in a multi-use landscape. Bears are most vulnerable to human disturbances during denning. To assess the influence of humans on the choice of winter dens by bears we compared availability and use of caves suitable for denning in central Slovenia. Surprisingly, all direct measures of human influence showed no or only a small effect on the use of the caves by bears. We found that the landscape type (big dolines, canyons, river valleys, and karst plateau) was the most important variable. The less accessible a landscape type is, the more it is used. The probability that a cave in a big doline is used is about 200 times higher than on the karst plateau. Furthermore bears preferred long caves with small entrances away from villages. Bears did not use any cave <540 m distance to the next village. In total, three quarters of all caves were predicted correctly by our model of being used or unused. For conservation and human safety reasons, human activity should be banned from steep ravines and large karst dolines in winter.