The Effects of Forest Management on Habitat Quality for Black Bears in the Southern Appalachians
Type of DegreeDissertation
Forestry and Wildlife Sciences
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Studies of habitat selection have been used to understand the effects of forest management on habitat quality for black bears (Ursus americanus), but results have been incomplete because all behavioral studies have been conducted at only one spatial scale and no study has used direct measures of fitness (e.g., survival, reproduction, etc.). I evaluated how black bears in the Pisgah Bear Sanctuary, in western North Carolina, responded behaviorally and demographically to clearcuts and roads. I linked estimates of hard mast and soft mast with estimates of bear survival, recruitment, and population growth to evaluate resource limitation by bears during 1981-2002. I also linked availability of clearcuts, in which soft mast was high, with estimates of demography. At both the individual and population levels, I linked estimates of habitat preference for roads with estimates of survival. Results of behavioral analyses showed females preferred young clearcuts when selecting resources within home ranges, but not when establishing home ranges. Male and female bears avoided areas near gravel roads, but not paved roads, during both summer and fall for both orders of selection. Results of demographic analyses showed the additive availability of hard mast and soft mast contributed most to population growth. Availability of young clearcuts helped explain recruitment, but not population growth. Avoidance of areas near gravel roads explained individual survival and population survival rate. Based on life history of bears, my results indicate the negative effects of gravel roads on bear survival likely outweighed the positive effects of clearcuts on bear recruitment. Because clearcuts are spatially associated with gravel roads, strategies to increase bear habitat in forested areas by implementing clearcuts must consider not only how clearcuts change availability of bear resources but also how gravel roads associated with clearcuts affect habitat quality. The research approach I used has broad application because it provides a way to distinguish among limiting resources, important resources, and resources that are relatively unimportant for populations of wild animals. By using direct measures of fitness, my approach provides a rigorous method for testing the effects of disturbances on habitat quality for wild animals.