Reproductive class influences risk tolerance during denning and spring for American black bears (Ursus americanus)
2019
Gantchoff, M. G. | Beyer, D. | Belant, J. L.
Den sites are important for many species’ ecology, and individuals should choose den sites that minimize risk and maximize energy gain. We examined den site selection and spring space use for black bears (Ursus americanus) at the individual level, and analyzed support for the anthropogenic risk avoidance and infanticide avoidance hypotheses. We obtained telemetry data for 94 individual bears (71 F and 23 M) and collected 162 den locations from Michigan (2009–2011 and 2013–2015), Missouri (2010–2016), and Mississippi (2008–2017), USA. Of 71 females, 37 were monitored during multiple reproductive states. We used generalized linear mixed models to evaluate the influence of reproductive state (female with cubs, female with yearlings, female alone, or male) on den distance to the nearest road, two road indexes (den emergence and spring), spring home range size, mean spring road distance, and a NDVI selection index. All black bears, except females with cubs, chose den locations farther from roads than available to them, supporting the anthropogenic risk avoidance hypothesis. Additionally, females with cubs displayed the smallest spring home ranges among females, as well as denned closer to roads and used areas closer to roads during spring than females with yearlings, supporting the infanticide avoidance hypothesis. The differential responses by the same females when having cubs or yearlings point to strategies to maximize reproductive success. By investigating behavior considering individual availability, we revealed patterns that might not be detected by population‐level assessments.
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