Responses of two ecologically similar bear species (American black bear and Asiatic black bear) to human-dominated landscapes and consumptive use

In addition to being closely related evolutionarily, the American black bear (Ursus americanus) and Asiatic black bear ( Ursus thibetanus) share strikingly similar ecologies. Both are opportunistic generalists that rely on diverse diets and occur across vast geographic ranges. Forest fragmentation, agricultural development, and other landscape-level changes arising from increasing human density have dramatically altered the continents inhabited by these species resulting in range contractions and population declines for both. In recent decades American black bears have rebounded throughout much of the Upper Midwestern United States in response to a cessation of unsustainable hunting. In contrast, declines of Asiatic black bears continue, driven at least in part by persistent, illegal killing. In this dissertation I present data from a study of movement, habitat use, and activity of subadult American black bears that occupied a region of west-central Wisconsin where forests were heavily fragmented, human activity was high yet bears were thriving. Movement, activity, habitat use, and proximity to roads and waterways were influenced by dispersal status and all bears capitalized on small forest patches when navigating the fragmented landscape. Direction of dispersal was not random, possibly influenced by varying densities of bears from north to south. I also present data from studies of free-ranging and captive Asiatic black bears in central China. The study of free-ranging bears was based on comparing concentrations of glucocorticoid metabolites in feces of Asiatic black bears collected in and around 8 nature reserves in central China. Natural food abundance and location of samples with respect to the boundaries of nature reserves were important factors in my analysis, underscoring the value of nature reserves in conserving superior habitats. My study of captive bears focused on documenting endocrinological differences between bears farmed for bile and those at a rehabilitation center, and tracking changes in endocrine parameters (hair and fecal glucocorticoids) that occurred in bears after removal from bile farms. Circulating levels of glucocorticoids declined markedly in Asiatic black bears removed from bile farms while responsiveness to various stimuli indicated resilience of the hypothalamic-pituitary-adrenal axis in this species.