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Shimozuru M, Jimbo M, Adachi K, Kawamura K, Shirane Y, Umemura Y, Ishinazaka T, Nakanishi M, Kiyonari M, Yamanaka M, Amagai Y, Ijuin A, Sakiyama T, Kasai S, Nose T, Shirayanagi M, Tsuruga H, Mano T, Tsubota T, Fukasawa K, Uno H. Estimation of breeding population size using DNA-based pedigree reconstruction in brown bears. Ecol Evol 2022; 12:e9246. [PMID: 36091344 PMCID: PMC9448969 DOI: 10.1002/ece3.9246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 07/18/2022] [Accepted: 07/27/2022] [Indexed: 11/11/2022] Open
Abstract
Robust estimates of demographic parameters are critical for effective wildlife conservation and management but are difficult to obtain for elusive species. We estimated the breeding and adult population sizes, as well as the minimum population size, in a high-density brown bear population on the Shiretoko Peninsula, in Hokkaido, Japan, using DNA-based pedigree reconstruction. A total of 1288 individuals, collected in and around the Shiretoko Peninsula between 1998 and 2020, were genotyped at 21 microsatellite loci. Among them, 499 individuals were identified by intensive genetic sampling conducted in two consecutive years (2019 and 2020) mainly by noninvasive methods (e.g., hair and fecal DNA). Among them, both parents were assigned for 330 bears, and either maternity or paternity was assigned to 47 and 76 individuals, respectively. The subsequent pedigree reconstruction indicated a range of breeding and adult (≥4 years old) population sizes: 128-173 for female breeders and 66-91 male breeders, and 155-200 for female adults and 84-109 male adults. The minimum population size was estimated to be 449 (252 females and 197 males) in 2019. Long-term continuous genetic sampling prior to a short-term intensive survey would enable parentage to be identified in a population with a high probability, thus enabling reliable estimates of breeding population size for elusive species.
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Affiliation(s)
- Michito Shimozuru
- Laboratory of Wildlife Biology and Medicine, Faculty of Veterinary MedicineHokkaido UniversitySapporoJapan
| | - Mina Jimbo
- Laboratory of Wildlife Biology and Medicine, Faculty of Veterinary MedicineHokkaido UniversitySapporoJapan
- Hokkaido Research OrganizationSapporoJapan
| | - Keisuke Adachi
- Laboratory of Wildlife Biology and Medicine, Faculty of Veterinary MedicineHokkaido UniversitySapporoJapan
| | - Kei Kawamura
- Laboratory of Wildlife Biology and Medicine, Faculty of Veterinary MedicineHokkaido UniversitySapporoJapan
| | - Yuri Shirane
- Laboratory of Wildlife Biology and Medicine, Faculty of Veterinary MedicineHokkaido UniversitySapporoJapan
- Hokkaido Research OrganizationSapporoJapan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | - Toshio Tsubota
- Laboratory of Wildlife Biology and Medicine, Faculty of Veterinary MedicineHokkaido UniversitySapporoJapan
| | - Keita Fukasawa
- Center for Environmental Biology and Ecosystem StudiesNational Institute for Environmental StudiesTsukubaJapan
| | - Hiroyuki Uno
- Faculty of AgricultureTokyo University of Agriculture and TechnologyTokyoJapan
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Kawamura K, Jimbo M, Adachi K, Shirane Y, Nakanishi M, Umemura Y, Ishinazaka T, Uno H, Sashika M, Tsubota T, Shimozuru M. Diel and monthly activity pattern of brown bears and sika deer in the Shiretoko Peninsula, Hokkaido, Japan. J Vet Med Sci 2022; 84:1146-1156. [PMID: 35811130 PMCID: PMC9412065 DOI: 10.1292/jvms.21-0665] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mammals exhibit several types of diel activity pattern, including nocturnal, diurnal,
crepuscular, and cathemeral. These patterns vary inter- and intra-specifically and are
affected by environmental factors, individual status, and interactions with other
individuals or species. Determining the factors that shape diel activity patterns is
challenging but essential for understanding the behavioral ecology of animal species, and
for wildlife conservation and management. Using camera-trap surveys, we investigated the
species distributions and activity patterns of terrestrial mammals on the Shiretoko
Peninsula, Hokkaido, Japan, with particular focus on brown bears and sika deer. From June
to October 2019, a total of 7,530 observations were recorded by 65 camera-traps for eight
species, including two alien species. The diel activity pattern of brown bears was
diurnal/crepuscular, similar to that of bears in North America, but different from
European populations. Bear observations were more frequent during the autumnal hyperphagia
period, and adult females and sub-adults were more diurnal than adult males. In addition,
bears inside the protected area were more diurnal than those outside it. These findings
suggest that appetite motivation, competitive interactions between conspecifics, and human
activities potentially affect bear activity patterns. Similar to other sika deer
populations and other deer species, the diel activity patterns of sika deer were
crepuscular. Deer showed less variation in activity patterns among months and sex-age
classes, while adult males were observed more frequently during the autumn copulation
period, suggesting that reproductive motivation affects their activity patterns.
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Affiliation(s)
- Kei Kawamura
- Faculty of Veterinary Medicine, Hokkaido University
| | - Mina Jimbo
- Faculty of Veterinary Medicine, Hokkaido University
| | | | - Yuri Shirane
- Faculty of Veterinary Medicine, Hokkaido University.,Hokkaido Research Organization
| | | | | | | | - Hiroyuki Uno
- Institute of Agriculture, Tokyo University of Agriculture and Technology
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Jimbo M, Ishinazaka T, Shirane Y, Umemura Y, Yamanaka M, Uno H, Sashika M, Tsubota T, Shimozuru M. Diet selection and asocial learning: Natal habitat influence on lifelong foraging strategies in solitary large mammals. Ecosphere 2022. [DOI: 10.1002/ecs2.4105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Mina Jimbo
- Faculty of Veterinary Medicine Hokkaido University Sapporo Japan
| | | | - Yuri Shirane
- Faculty of Veterinary Medicine Hokkaido University Sapporo Japan
- Hokkaido Research Organization Sapporo Japan
| | | | | | - Hiroyuki Uno
- Faculty of Agriculture Tokyo University of Agriculture and Technology Tokyo Japan
| | - Mariko Sashika
- Faculty of Veterinary Medicine Hokkaido University Sapporo Japan
| | - Toshio Tsubota
- Faculty of Veterinary Medicine Hokkaido University Sapporo Japan
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Tomiyasu J, Kayano M, Hazano K, Matsui M, Nemoto Y, Naganuma T, Koike S, Yamazaki K. Associations between plasma testosterone levels and season, nutritional status, age, and body size in free-ranging male Asian black bears (Ursus thibetanus) in central Honshu, Japan. Gen Comp Endocrinol 2021; 309:113794. [PMID: 33887270 DOI: 10.1016/j.ygcen.2021.113794] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 04/13/2021] [Accepted: 04/16/2021] [Indexed: 10/21/2022]
Abstract
Testosterone is an important regulator of male reproduction in terms of spermatogenesis and physiological changes in the accessory reproductive organs. Despite the important role of the testosterone level in male reproduction, testosterone levels vary among male bears even during the breeding season, and the causative underlying factors remain unknown. We postulated that testosterone levels are higher during the breeding season than during other seasons in free-ranging male bears, and that testosterone levels increase with advancing age, larger body size, and better nutritional status. We assessed potential factors (season, time of sampling, body condition index, head circumference, and age) associated with the testosterone level in 80 blood samples collected from free-ranging Asian black bears (Ursus thibetanus) captured in barrel traps in the Ashio-Nikko Mountains and Okutama Mountains in central Honshu Island, Japan. The plasma testosterone level was higher during the breeding season (May-July) than during the non-breeding season (August-November). The body condition index was significantly and positively associated with the plasma testosterone level. None of the other factors were significantly associated with the plasma testosterone level. Therefore, the body condition index may be essential for maintaining high plasma testosterone levels. These findings imply that testosterone secretion might be activated in free-ranging males during the breeding season, and animals with good nutritional status may be able to maintain high plasma testosterone levels. This study uncovered an association between nutritional conditions and reproductive activity in male bears.
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Affiliation(s)
- Jumpei Tomiyasu
- Department of Biodiversity Protection, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn 10-748, Poland
| | - Mitsunori Kayano
- Research Center for Global Agromedicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan
| | - Ken Hazano
- Department of Applied Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan
| | - Motozumi Matsui
- Department of Applied Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan
| | - Yui Nemoto
- Okutama Practice Forest, Tokyo University of Agriculture, Okutama Town, Tokyo 198-0212, Japan
| | - Tomoko Naganuma
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan
| | - Shinsuke Koike
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan; Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan
| | - Koji Yamazaki
- Department of Forest Science, Tokyo University of Agriculture, Setagaya, Tokyo 156-8502, Japan.
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Shirane Y, Jimbo M, Yamanaka M, Nakanishi M, Mori F, Ishinazaka T, Sashika M, Tsubota T, Shimozuru M. Dining from the coast to the summit: Salmon and pine nuts determine the summer body condition of female brown bears on the Shiretoko Peninsula. Ecol Evol 2021; 11:5204-5219. [PMID: 34026001 PMCID: PMC8131783 DOI: 10.1002/ece3.7410] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/06/2021] [Accepted: 02/18/2021] [Indexed: 11/10/2022] Open
Abstract
Body condition in mammals fluctuates depending on energy intake and expenditure. For brown bears (Ursus arctos), high-protein foods facilitate efficient mass gain, while lipids and carbohydrates play important roles in adjusting dietary protein content to optimal levels to maximize energy intake. On the Shiretoko Peninsula, Hokkaido, Japan, brown bears have seasonal access to high-lipid pine nuts and high-protein salmon. To assess seasonal and annual fluctuation in the body condition of adult female brown bears in relation to diet and reproductive status, we conducted a longitudinal study in a special wildlife protection area on the Shiretoko Peninsula during 2012-2018. First, analyses of 2,079 bear scats revealed that pine nuts accounted for 39.8% of energy intake in August and salmon accounted for 46.1% in September and that their consumption by bears varied annually. Second, we calculated the ratio of torso height to torso length as an index of body condition from 1,226 photographs of 12 adult females. Results indicated that body condition continued to decline until late August and started to increase in September when salmon consumption increased. In addition, body condition began to recover earlier in years when consumption of both pine nuts and salmon was high. Furthermore, females with offspring had poorer body condition than solitary females, in particular in late August in years with low salmon consumption. Our findings suggest that coastal and subalpine foods, which are unique to the Shiretoko Peninsula, determine the summer body condition of female brown bears, as well as their survival and reproductive success.
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Affiliation(s)
- Yuri Shirane
- Graduate School of Veterinary MedicineHokkaido UniversitySapporoJapan
| | - Mina Jimbo
- Graduate School of Veterinary MedicineHokkaido UniversitySapporoJapan
| | | | | | - Fumihiko Mori
- Graduate School of Veterinary MedicineHokkaido UniversitySapporoJapan
| | | | - Mariko Sashika
- Graduate School of Veterinary MedicineHokkaido UniversitySapporoJapan
| | - Toshio Tsubota
- Graduate School of Veterinary MedicineHokkaido UniversitySapporoJapan
| | - Michito Shimozuru
- Graduate School of Veterinary MedicineHokkaido UniversitySapporoJapan
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Tomita K, Hiura T. Reforestation provides a foraging habitat for brown bears (Ursus arctos) by increasing cicada Lyristes bihamatus density in the Shiretoko World Heritage site. CAN J ZOOL 2021. [DOI: 10.1139/cjz-2020-0222] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reforestation, which converts abandoned farmland back into forestland by planting woody species, can provide habitat for wildlife, including the brown bear (Ursus arctos Linnaeus, 1758). In the Shiretoko World Heritage site, northern Japan, where brown bears occur at high density, conifers have been planted since the 1970s to reforest abandoned farmland. In this area, brown bears were first observed digging for cicada Lyristes bihamatus Motschulsky, 1861 = Auritibicen bihamatus (Motschulsky, 1861) nymphs from 2000. Our preliminary observations suggested that the emergence of digging behavior might be associated with reforestation. We examined whether reforestation provided a foraging habitat for brown bears. We found that digging occurred only within the restored conifer forests, but not within the natural forest. The densities of cicada nymphs in the restored forests were higher than in the natural forest. These results indicate that the reforestation of abandoned farmland provides a foraging habitat for brown bears by increasing the availability of cicada nymphs in the Shiretoko World Heritage site.
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Affiliation(s)
- K. Tomita
- Graduate School of Environmental Science, Hokkaido University, N10 W5 Sapporo, Hokkaido 060-0810, Japan
| | - T. Hiura
- Graduate School of Agriculture and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
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Maternal human habituation enhances sons' risk of human-caused mortality in a large carnivore, brown bears. Sci Rep 2020; 10:16498. [PMID: 33020503 PMCID: PMC7536428 DOI: 10.1038/s41598-020-73057-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 09/11/2020] [Indexed: 01/06/2023] Open
Abstract
Human habituation of large carnivores is becoming a serious problem that generates human-wildlife conflict, which often results in the removal of animals as nuisances. Although never tested, human habituation potentially reduces the fitness of adult females by reducing their offspring's survival as well as their own, due to an increased likelihood of human-caused mortality. Here, we tested this hypothesis in brown bears inhabiting Shiretoko National Park, Japan. We estimated the frequency of human-caused mortality of independent young (aged 1-4 years) born to mothers living in areas with different maternal levels of human habituation and different proximities to areas of human activity. The overall mortality rate was higher in males than in females, and in females living near a town than those in a remote area of park. Surprisingly, more than 70% of males born to highly habituated mothers living around a remote wildlife protection area were killed by humans; this proportion is greater than that for males born to less-habituated mothers living in almost the same area. The current study clarified that interactions among maternal human habituation, birthplace (proximity to town), age, and sex determine the likelihood of human-caused mortality of brown bears at an early stage of life.
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