Spatial ecology and habitat selection of cub-rearing wolverine females

Sammanfattning: Suitable den sites is presumably important for reproduction of wolverines (Gulo gulo), but little information is available about selection of den and rendezvous sites for female wolverines. I examined patterns of den and rendezvous site selection in and around Sarek National Park, Sweden, from 1993 to 2004. I also assessed movements of females with cubs after den abandonment. The study included 81 den sites used by 36 radio-marked females and 177 rendezvous sites used by 33 females. Female wolverines selected den sites in alpine heath/meadow at elevations between 700 - 800 and 900 - 1000 m a. s. l., and slopes between 10 – 40 degrees. Most dens were located in southwest aspects; where the greatest accumulation of snow was found, and northeast; where most snow drifts are built up and snow thaw is late. Nearly 50% of the dens were located within 100 meters from mountain birch tree line, and most dens were located in non-forested areas. After den abandonment females moved their cubs further and further away from the den site. There was a declining pattern in the distance travelled between the den site and rendezvous sites by time. Early rendezvous sites were located at lower elevations compared to dens, often in or close to conifer forest. As spring thaw goes on cubs are moved to higher elevations above tree line and primarily in north-eastern aspects. There was a stronger preference for north-eastern aspects during the rendezvous period, indicating that snow is important also for rendezvous site selection. Females without tree cover within their home range located rendezvous sites at lower elevations than den sites, compared to females with forest within home range.