Steep and deep: Terrain and climate factors explain brown bear (Ursus arctos) alpine den site selection to guide heli-skiing management

Winter recreation and tourism continue to expand worldwide, and where these activities overlap with valuable wildlife habitat, there is greater potential for conservation concerns. Wildlife populations can be particularly vulnerable to disturbance in alpine habitats as helicopters and snowmachines are increasingly used to access remote backcountry terrain. Brown bears (Ursus arctos) have adapted hibernation strategies to survive this period when resources and energy reserves are limited, and disturbance could negatively impact fitness and survival. To help identify areas of potential conflict between helicopter skiing and denning brown bears in Alaska, we developed a model to predict alpine denning habitat and an associated data-based framework for mitigating disturbance activities. Following den emergence in spring, we conducted three annual aerial surveys (2015–2017) and used locations from three GPS-collared bears (2008–2014) to identify 89 brown bear dens above the forest line. We e..., Brown bear den sites were located by aerial survey where latitude and longitude coordinates were collected on handheld GPS. Additional den sites were located by brown bears instrumented with GPS collars. Habitat factors were extracted from the IfSAR dataset and standardized (x-͞x /SD(x)) prior to analysis. To estimate resource availability, we generated randomly distributed locations at the scale of the study area (second-order selection) [82, 83] at a mean density of 500 locations per km2 [84].
, Den Data

Brown bear (Ursus arctos) den site locations in Haines, Alaska, U.S.A. (2008-2017). The data file includes fields that were included in the analysis of the resource selection function models.  Response of 1 indicates a den site and 0 indicates an available point. We describe the year and geographic mountain range where the den was located, the lifezone (alpine, subalpine), elevation (dtm), slope (slope), topographic position index (tpi), vegetation height index (vhi), vector ruggedness measure (vrm), solar radiation (solrad), terrain wetness index (twi), and snow load (snowload). We calculated a snow load factor as the product of two elements, elevation scaled (0–1) across the entire range of elevations, and a bearing exposure component that was at a maximum opposite from the prevalent wind bearing [66]. These habitat factors were scaled (_s) and squared (_sq) for analyses.

Specific bear den locations are confidential under Alaska ...,