Grizzly bears and resource-extraction industries: effects of roads on behaviour, habitat use and demography

Authors(s): B. N. McLellan and D. M. Shackleton

Publication: Journa of Applied Ecology

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Publication Date: 0000-00-00

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Abstract: (1) Roads are an integral part of the development of resource-extraction industries. We wanted to know whether grizzly bears were displaced by these roads from adjacent habitats. Over 7 years twenty-seven grizzly bears were captured and radio-collared in 264 km2 of the Rocky Mountains, containing active tree-felling and petrocarbon developments. (2) Most bears used habitats within 100 m of roads less than expected. This is equivalent to a habitat loss of 8.7%. This is significant because many habitats close to roads contain important bear foods. Avoidance of roads was independent of traffic volume, suggesting that even a few vehicles can displace bears. (3) Roads and nearby areas were used at night but avoided in the day. Yearlings and females with cubs used habitats near roads more than other bears. These areas may have been relatively secure because they were avoided by potentially aggressive adult males. (4) Limited data indicated minimal demographic effects during our study, but roads increased access for legal and illegal hunters, the major source of adult grizzly mortality. (5) When roads are developed for resource industries in grizzly bear habitat, the bear population becomes highy vulnerable unless vehicle access and people with firearms are controlled.

Keywords: animal, mammal, bear, Ursidae, grizzly bear, Ursus arctos horribilis, habitat, food, forage, human activity, hunting, radio collar, Rocky Mountains, population, mortality, oil and gas drilling