Sex-biased natal dispersal in Hokkaido brown bears revealed through mitochondrial DNA analysis
Understanding natal dispersal patterns is fundamental in the ecology and conservation biology of large wild carnivores. In this study, we used two approaches to determine genetic variation and dispersal patterns of brown bears in the Shiretoko Peninsula, eastern Hokkaido, Japan. The first approach was a large-scale genetic analysis. We analyzed haplotypes from the mitochondrial DNA (mtDNA) control region of 760 individual samples collected throughout the peninsula during 1998–2016. We detected seven haplotypes, including two that were confirmed for the first time. In females, the distribution of haplotypes was geographically structured, whereas haplotypes in males were distributed widely throughout the peninsula. Only some males in the lower peninsula had haplotypes that were not detected within the peninsula. The second approach was a local-scale genetic analysis, including intensive focal sampling in the Rusha area, a special wildlife protection area on the peninsula. Proportions of mtDNA haplotypes in adult bears were investigated and compared between the sexes. Although more than half of the females had the same haplotype, males had more diverse haplotypes, suggesting that they came to the Rusha area from other regions. Thus, our study revealed that mtDNA haplotype distribution has been maintained by female philopatry, and that bears exhibit male-biased dispersal. Furthermore, the lower peninsula appears to act as a contact zone between the peninsula and mainland Hokkaido, which is important for maintaining genetic diversity.
KeywordsBrown bears Dispersal Haplotype Mitochondrial DNA Ursus arctos
We wish to thank Hatsusaburo Ose, the president of Shiretoko Fishery Cooperative, and all members of the cooperative for their kind support. We thank all members of Shiretoko Nature Foundation and South Shiretoko Brown bear Information Center for generous support. We also thank all people involved in the field research.
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This study was conducted as part of the Kim-un Kamuy Project which was financially supported by AIR DO Co., Ltd. This study was financially supported also by Daikin Industries, Ltd. and The Mitsui & Co. Environment Fund.
Compliance with ethical standards
All procedures were conducted in accordance with the Guidelines for Animal Care and Use of Hokkaido University, and were approved by the Animal Care and Use Committee of the Graduate School of Veterinary Medicine, Hokkaido University (Permit Number: JU1106, JU1151, JU1152 and 15009).
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