Investigating factors underlying human-wildlife conflicts in agricultural landscapes is important for both preventing crop damage and wildlife conservation. Although environments surrounding crop fields are considered causal factors, incorporating individual aspects of animals, such as demographic and physical characteristics, into the investigation may aid the prediction of how nuisance control affects wildlife population structures. Here, we assessed the relationship of corn consumption by Hokkaido brown bears (Ursus arctos) with both demographic (sex and age) and physical (body size) characteristics and environmental factors (human presence and crop accessibility). We estimated the proportion of corn in the lifespan diet for both female (n = 61) and male (n = 62) bears using carbon and nitrogen stable isotope analyses. Then, we analyzed the factors correlated with corn consumption using a generalized linear model. Female and male bears consumed corn from 1.3 to 30.9% and 1.3 to 42.0% of their lifespan diet, respectively. Corn consumption by female bears was not correlated with any explanatory variables, whereas that of male bears was positively correlated with their body size and crop accessibility but negatively correlated with human presence. Large male bears were more likely to have consumed more corn than small male bears, but the selective harvest of large bears may cause dwarfism of their overall population, impacting the local population dynamics. To reduce agricultural damage and population structure alteration of brown bears, the opportunity for them to learn to eat crops must be eliminated through border management between forests and agricultural fields and the relocation of agricultural fields when possible.
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We are grateful to the members of Hokkaido University Ecosystem management group for their helpful discussions during this study.
This study was supported by JSPS KAKENHI grant number JP24580034 and partly conducted using a Joint Usage/Research Grant from the Center for Ecological Research, Kyoto University.
Conflict of interest
The authors declare that they have no conflict of interest.
This article contains no studies performed by any of the authors involving animals.
Informed consent was obtained from each participant included in the study.
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Sakiyama, T., Morimoto, J., Matsubayashi, J. et al. Factors influencing lifespan dependency on agricultural crops by brown bears. Landscape Ecol Eng (2021). https://doi.org/10.1007/s11355-021-00446-x
- Agricultural landscape
- Body size
- Human-wildlife conflict
- Stable isotope
- Ursus arctos