Relationships among grizzly bears, roads, and habitat in the Swan Mountains, Montana.

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Synopsis: The study examined the relationships between grizzly bears, habitat and roads in the Swan Mountains, Montana. The study showed complex spatial and temporal relationships between grizzly bears and habitat resources. Resource selection was expressed relative to strength and association of road and habitat parameters and relationships varied by landscape scale, level of selection, season and individual. Selection was greatest for unroaded cover types and declined as road densities increased. Grizzly bears were found to tolerate habitat resources proximate to roads when roads are either closed or limited to less than 10 vehicles per day, particularly in the spring near cutting units and chutes that terminate proximate to roads. Few bears exhibited selection for habitat near roads having greater than 60 vehicles per day. These findings are consistent with findings related to the conservation values of unroaded habitats for other species, elsewhere. The study is significant as there is minimal research on grizzly bear habitat selection in roaded, multiple-use environments.

The results suggest that grizzly bears can use roaded habitats, but spatial avoidance will increase and survival will decrease as traffic levels, road densities and human settlement increases. The study notes that land tenure appears to influence mortality as habituation and mortality levels are higher on or adjacent to private lands. The study recommends that road density standards and road closure programmes should be developed and that these programmes incorporate seasonal habitat requirements of grizzly bears.