記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER  

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.

DOI： 10.1007/s10344-018-1222-x

Web of Science

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：HOKKAIDO UNIV  

Chest girth and body mass of 3,576 brown bears (Ursus arctos yesoensis) harvested for conflict management in Hokkaido, Japan during 1991-2012 were used to establish methods to assess body condition and to compare the body condition of bears by sex, month, year, and reproductive status. The body mass was estimated based on the chest girth in cases with no measurements of the bear body mass. Using the measured and estimated body mass, a growth curve by age was demonstrated to ascertain the mean asymptotical body mass (245 kg for males, 114 kg for females) and ages at 95% asymptotic body mass (14.2 years for males, 7.1 years for females). The body condition value of bears was evaluated as body mass difference (kg) between the individual body mass and the standard body mass as estimated from the growth curve. Body condition value changed seasonally with a low in summer and the highest in the autumnal hyperphagic period. Female body condition value was higher than the males during September. Fluctuation in annual body condition value was found for females; however, there was no difference between solitary adult females and females with offspring (cubs, yearlings, or offspring of unknown age). No significant fluctuation was found for males. Our body condition evaluation method using chest girth and body mass of brown bears is useful to elucidate different trends across sex, year, and season.

DOI： 10.14943/jjvr.66.2.71

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1371/journal.pone.0176251

Web of Science

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：INT ASSOC BEAR RESEARCH & MANAGEMENT-IBA  

The reproductive tracts of 130 adult female brown bears (Ursus arctos) in Hokkaido, Japan, euthanized during 2010-2013 for conflict management, were examined for the presence and number of corpora lutea (CL) in the ovary and placental scars (PS) in the uterine horns. We scored PS on a 0-5 scale based on morphological features including their rim and color. They were characterized as representing either current-year parturition, as determined by accompanying cubs, or previous year parturition, as determined by accompanying yearlings. In total, 128 females were divided into 3 reproductive categories: 44 females with current-year parturition, 39 with previous-year parturition, and 45 solitary females that had not given birth for >2 years. The estimated ovulation rate was 2.21 +/- 0.55 (mean +/- SD), the implantation rate was 1.91 +/- 0.74, and the litter size was 1.54 +/- 0.51. Implantation rates were lower than ovulation rates and changed annually during 2010-2013. Systematic observation of PS and CL allowed us to evaluate the reproductive history and parameters in Hokkaido brown bears and ascertain their annual variation.

DOI： 10.2192/URSU-D-16-00005.1

Web of Science

記述言語：日本語   出版者・発行元：鹿児島県農業開発総合センター  

CiNii Research

J-GLOBAL

J-GLOBAL

開催年月日： 2025年10月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：北九州市千草ホテル  

開催年月日： 2025年10月

記述言語：日本語  

開催年月日： 2025年9月

記述言語：日本語  

開催年月日： 2024年11月

記述言語：日本語  

開催地：熊本市  

開催年月日： 2023年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：鹿児島県鹿児島市  

対象： 企業

種別：セミナー・ワークショップ