Conserving viable large carnivore populations requires managing their interactions with humans outside of protected areas in increasingly anthropogenic landscapes. Cultural carrying capacities for these influential species hinge on the ability of managers to minimize negative human-wildlife interactions. Faced with declining budgets and escalating wildlife conflicts, agencies in North America continue to grapple with the efficacy of socially divisive management actions, such as recreational harvest and lethal control, as means to reduce conflict. We used multistate capture-reencounter methods to estimate cause-specific mortality for a large sample (3,533) of American black bears (Ursus americanus) in northwestern New Jersey, USA over a 33-year period. Specifically, we focused on factors that might influence the probability of bears being harvested, lethally controlled, or dying from other causes. We analyzed temporal correlations between 26,582 human-black bear incidents reported to the New Jersey Division of Fish and Wildlife (NJDFW) between 2001-2013, and estimates of harvest from newly implemented public hunts, lethal management, and total mortality rates.
Results/Conclusions
Black bear harvest probability was best explained by an interaction between age and sex: adult females were twice as likely (0.163 ± 0.014) as adult males (0.087 ± 0.012) to be harvested. Cubs (0.444 ± 0.025) and yearlings (0.372 ± 0.022) had a higher probability of dying from other causes, primarily vehicle strikes, than adults (0.199 ± 0.008). Reports of nuisance behaviors in year t + 1 declined with increasing mortality resulting from harvest plus lethal management in year t (P = 0.028, R2 = 0.338, β = -136.5 conflicts per 0.10 increase in mortality components). Reports of nuisance behaviors in year t + 1 was only weakly correlated with total mortality in year t, suggesting declines in undesirable behaviors were largely attributable to preceding harvest and lethal management rates, not simply a numeric response resulting from population reductions. Our best-fitting behavioral model corroborated these results: adult bears previously designated a nuisance and/or threat were more likely to be harvested (0.176 ± 0.025) than those never identified as a problem (0.109 ± 0.010). Within human-dominated systems, the integration of a well-regulated black bear harvest with incident-response protocols and educational outreach programs, can result in subsequent reductions in problem behaviors reported.