a b s t r a c tAs landscapes across the globe experience increasing human development, it is critical to identify the behavioral responses of wildlife to this change given associated shifts in resource availability and risk from human activity. This is particularly important for large carnivores as their interactions with people are often a source of conflict, which can impede conservation efforts and require extensive management. To examine the adaptations of a large carnivore to benefits and risks associated with human development we investigated black bear behavior in three systems in the western United States. Our objectives were to (1) identify temporal patterns of selection for development within a year and across years based on natural food conditions, (2) compare spatial patterns of selection for development across systems, and (3) examine individual characteristics associated with increased selection for development. Using mixed effects resource selection models we found that bear selection for development was highly dynamic, varying as a function of changing environmental and physiological conditions. Bears increased their use of development in years when natural foods were scarce, throughout the summer-fall, as they aged, and as a function of gender, with males exhibiting greater use of development. While patterns were similar across systems, bears at sites with poorer quality habitat selected development more consistently than bears at sites with higher quality habitat. Black bears appear to use development largely for food subsidy, suggesting that conflicts with bears, and potentially other large carnivores, will increase when the physiological demand for resources outweighs risks associated with human activity.Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

The general public often prefers nonlethality when dealing with problem black bears (Ursus americanus). We evaluated the efficacy of nonlethal deterrent techniques on 62 bears in the Lake Tahoe Basin of the Sierra Nevada range. We contrasted animals randomly assigned to a control (no treatment) group (n = 21), an experimental (treatment) group (n = 21), or a treatment + dog group (n = 20). Experimental bears were peppersprayed, shot with 12‐gauge rubber buckshot and a rubber slug, and exposed to cracker shells. Bears in the treatment + dog group were chased by hounds in addition to the combination of other deterrents. We tested and modeled the effectiveness of deterrents and dogs using a survival analysis with Cox proportional hazards and ANOVA. Relative success was evaluated by the latency of time (days) between treatment and return to the urban patch (RUP). Predictor variables in the saturated model included age, weight, season, sex, distance moved, and treatment. Only treatment remained in the most parsimonious model. However, mean number of days until RUP did not vary among the 3 treatment levels (ANOVA, P = 0.55). In all but 5 of 62 cases, bears eventually returned to the urban patch in which they were captured; 33 of 62 bears (53%) returned within 1 month and 70% (n = 44) of all bears returned in ≤40 days. We conclude that in the Lake Tahoe Basin the most common nonlethal deterrents, used by agencies responsible for black bear management, are not very effective at altering bear behavior over periods of time >1 month.

Black bears (Ursus americanus) were once abundant in Nevada and distributed throughout the state, yet recognition of the species' historical occurrence in the state is uncommon and has therefore been ignored in published distribution maps for North America. The lack of representation on distribution maps is likely due to the lack of any scientific data or research on bears in Nevada until 1987. Historical records dating back to the 1840s compiled by Nevada Department of Wildlife (NDOW) biologist Robert McQuivey indicate presence of black bears throughout the state in the 1800s through about 1930. The paucity of historical references after 1931 suggest extirpation of black bears from Nevada's interior mountain ranges by this time. We report on historical records of black bears in the state of Nevada and the results of a current population estimate of black bears derived from a sample of marked bears (n = 420) captured 707 times between 1997 and 2008. Using Pradel and Cormack–Jolly–Seber models in Program MARK, we estimated overall population size, finite rate of growth (λ = 1.16), quarterly and annual survival rates for males and females, seasonal capture probabilities, and recruitment rates. Our results indicate an overall population size of 262 ± 31 adult black bears in western Nevada. These results suggest that the once abundant, then extirpated population of black bears in Nevada is increasing at an annual average rate of 16%. Although the current distribution is limited to the western part of the state, our findings suggest possible expansion of the population into historical habitat within the interior and eastern portions of the state that have been absent of bears for >80 years. Finally, based on historical records, we present suggested revised historical distribution maps for black bears that include the Great Basin ranges in Nevada. © 2013 The Wildlife Society.

No abstract