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Regulated hunting re-shapes the life history of brown bears

Abstract

Management of large carnivores is among the most controversial topics in natural resource administration. Regulated hunting is a centrepiece of many carnivore management programmes and, although a number of hunting effects on population dynamics, body-size distributions and life history in other wildlife have been observed, its effects on life history and demography of large carnivores remain poorly documented. We report results from a 30-year study of brown bears (Ursus arctos) analysed using an integrated hierarchical approach. Our study revealed that regulated hunting has severely disrupted the interplay between age-specific survival and environmental factors, altered the consequences of reproductive strategies, and changed reproductive values and life expectancy in a population of the world’s largest terrestrial carnivore. Protection and sustainable management have led to numerical recovery of several populations of large carnivores, but managers and policymakers should be aware of the extent to which regulated hunting may be influencing vital rates, thereby reshaping the life history of apex predators.

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Fig. 1: The lives and deaths of instrumented brown bears in Sweden.
Fig. 2: Vital rates and important determinants for brown bears in Scandinavia.
Fig. 3: Age-specific vital rates in brown bears.
Fig. 4: Changes in life history descriptors for female bears in response to different levels of hunting pressure.

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Acknowledgements

We are grateful for the support of the Center for Advanced Study in Oslo, Norway, that funded and hosted our research project ‘Climate effects on harvested large mammal populations’ during the academic year of 2015–2016. R.B. and J.S. received additional funding from the Polish-Norwegian Research Program (GLOBE No POL-NOR/198352/85/2013). This research was supported in part by the computing cluster of the Pôle Bioinformatique Lyonnais. We thank S. Frank and A. Hertel for preparation of select environmental data, A. Ordiz, J. Kindberg, and V. Vazquez for constructive comments on the manuscript, and the Swedish Association for Hunting and Wildlife Management for the Large Carnivore Observation Index (LCOI), which was used to derive the density index. This is scientific paper 244 of the Scandinavian Brown Bear Research Project.

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R.B. and C.B. conceived the study with J.E.S., A.M. and T.C. J.E.S., A.Z. and A.F. coordinated collection and compilation of field data. R.B., I.M.R. and A.Z. extracted and formatted intrinsic and extrinsic covariates. R.B. and C.B. developed, implemented and analysed the model. R.B. wrote the first draft of the paper; all authors contributed to subsequent versions.

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Correspondence to Richard Bischof.

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Supplementary Figures 1–3, Supplementary Tables 1–9; Supplementary reference; description of Supplementary data files

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Supplementary Data Set 1

Data for Figure 1

Supplementary Data Set 2

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Supplementary Data Set 3

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Supplementary Data Set 4

Multistate model for JAGS

Supplementary Data Set 5

Data for Supplementary Figure 2

Supplementary Data Set 6

Data for Supplementary Figure 3

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Bischof, R., Bonenfant, C., Rivrud, I.M. et al. Regulated hunting re-shapes the life history of brown bears. Nat Ecol Evol 2, 116–123 (2018). https://doi.org/10.1038/s41559-017-0400-7

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