Locations of dens with respect to space use, pre- and post-denning movements of brown bears in the Russian Far East

Abstract

Space use and the use of a den during the winter period as an adaptation of the brown bear (Ursus arctos) to increase survival during a period of food shortage, are important aspects of the ecology in the practice of the population management. Despite this, the subject of the den locations in relation to space use of brown bears and movements associated with a den entry and exit were practically not considered by researchers. Using radio-telemetry methods between 1993–2012, we studied the space use of 15 brown bears in Sikhote-Alin, three in Kamchatka and two on Sakhalin. The location of 25 dens of tagged animals was determined. The majority of brown bears, mostly males, used space further from the den than from the average of all locations, and the overwhelming majority of dens were outside the core area of their home ranges. So, for brown bears, the spatial location of dens was away from preferred locations in the non-denning period. The same brown bears selected den sites in different denning seasons, both at relatively small distance from each other (1.3 km) and at a considerable distance (20.2 km). Females on Sakhalin moved to dens 7–9 days before the den entry. After leaving their dens, two females in Kamchatka moved 1.7 and 5.0 km on the first day, while on Sakhalin, two females did not move more than 0.1 km from their dens for the first 4 and 10 days. Female that gave birth to cubs in the denning period lingered the longest at the den. The distance of females from their dens and their movement activity decreased in the pre-denning period (10 days before denning, the variations in movement stabilised at a low level) and increased in the post-denning period (specifically after 10 days from the moment of emergence).

Keywords

• daily movements
• denning location
• home range
• population management
• spatial ecology
• ursus arctos