Epsilon Archive for Student Projects

Abstract

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.