Research activity information

• Post-bottleneck increase in mitochondrial DNA diversity in Yaku sika deer (Cervus nippon yakushimae) on Yakushima Island, Japan
  Yoshimi Agetsuma-Yanagihara; Takashi Hayakawa; Naoki Agetsuma
  SCIENTIFIC REPORTS, 15, 1, 12 Nov. 2025, [Peer-reviewed], [Lead author, Corresponding author]
  English, Scientific journal
• Sodium Availability and Fecal Aldosterone Concentration of Wild and Captive Japanese Macaques and Sika Deer
  Goro Hanya; Naoki Agetsuma; Yoshimi Agetsuma-Yanagihara; Toru Oi; Takashi Kondo; Yoshiyuki Tabuse; Takafumi Suzumura; Tianmeng He; Takeaki Honda; Tamihisa Ohta; Kodzue Kinoshita
  Mammal Study, 50, 4, Mammalogical Society of Japan, 30 Jun. 2025, [Peer-reviewed]
  Scientific journal
• Plant constituents affecting food selection by sika deer
  Naoki Agetsuma; Yoshimi Agetsuma‐Yanagihara; Hino Takafumi; Tatsuro Nakaji
  The Journal of Wildlife Management, 83, 3, 669, 678, Wiley, 04 Dec. 2018, [Peer-reviewed]
  Scientific journal, ABSTRACT
  
  We directly observed the feeding behaviors of Yaku sika deer (Cervus nippon yakushimae), the smallest subspecies of Japanese sika deer, by following 6 wild, habituated, and individually identifiable animals in a natural warm‐temperate forest on the island of Yakushima, southern Japan, 2005–2006. Deer fed on various plant species and parts but predominantly on the fallen leaves, fruits, seeds, and flowers of woody plants (∼82% of food items) at 59 natural feeding plots. We analyzed 8 key plant constituents of eaten and uneaten items at the feeding plots, and examined the effects of each constituent on food selection by multivariate and univariate generalized linear mixed models. The multivariate analysis, which evaluated the effect of each plant constituent on food selection by controlling influences of the other constituents in the food items, showed that deer selected food items with higher contents of crude fat, crude protein, and total phenolics but with lower contents of lignin and condensed tannin from the available items at the feeding plots. Neither soluble nor structural carbohydrate, nor ash content affected selection of food items. It may be advantageous for these small ungulates with shorter gastrointestinal tracts to select foods that are relatively rich in fat because of the higher energy content of fat compared with carbohydrates. Furthermore, it appears that non‐tannin phenolics may have beneficial functions in this species. The univariate analyses showed different effects of crude protein and structural carbohydrate on food selection compared to those derived from the multivariate analysis. We demonstrate that accounting for influences of other plant constituents by using multivariate analyses is important to ensure that any effects of individual plant constituents are not overlooked or overstated. © 2018 The Wildlife Society.
• Regeneration of natural vegetation under high sika deer density after a mudslide in a warm temperate evergreen forest in Yakushima, Japan
  Naoki Agetsuma; Yoshimi Agetsuma-Yanagihara
  Japanese Journal of Conservation Ecology, 23, 145, 153, 2018, [Peer-reviewed]
• Effects of time and environmental conditions on the quality of DNA extracted from fecal samples for genotyping of wild deer in a warm temperate broad-leaved forest
  Yoshimi Agetsuma-Yanagihara; Eiji Inoue; Naoki Agetsuma
  Mammal Research, 62, 2, 201, 207, Springer Science and Business Media LLC, 05 Jan. 2017, [Peer-reviewed], [Lead author, Corresponding author]
  Scientific journal
• Impact of anthropogenic disturbance on the density and activity pattern of deer evaluated with respect to spatial scale-dependency
  Naoki Agetsuma; Ryosuke Koda; Riyou Tsujino; Yoshimi Agetsuma-Yanagihara
  Mammalian Biology, 81, 2, 130, 137, Springer Science and Business Media LLC, Mar. 2016, [Peer-reviewed]
  Scientific journal
• Effective spatial scales for evaluating environmental determinants of population density in Yakushima macaques
  Naoki Agetsuma; Ryosuke Koda; Riyou Tsujino; Yoshimi Agetsuma‐Yanagihara
  American Journal of Primatology, 77, 2, 152, 161, Wiley, 17 Sep. 2014, [Peer-reviewed]
  Scientific journal, Population densities of wildlife species tend to be correlated with resource productivity of habitats. However, wildlife density has been greatly modified by increasing human influences. For effective conservation, we must first identify the significant factors that affect wildlife density, and then determine the extent of the areas in which the factors should be managed. Here, we propose a protocol that accomplishes these two tasks. The main threats to wildlife are thought to be habitat alteration and hunting, with increases in alien carnivores being a concern that has arisen recently. Here, we examined the effect of these anthropogenic disturbances, as well as natural factors, on the local density of Yakushima macaques (Macaca fuscata yakui). We surveyed macaque densities at 30 sites across their habitat using data from 403 automatic cameras. We quantified the effect of natural vegetation (broad‐leaved forest, mixed coniferous/broad‐leaved forest, etc.), altered vegetation (forestry area and agricultural land), hunting pressure, and density of feral domestic dogs (Canis familiaris). The effect of each vegetation type was analyzed at numerous spatial scales (between 150 and 3,600‐m radii from the camera locations) to determine the best scale for explaining macaque density (effective spatial scale). A model‐selection procedure (generalized linear mixed model) was used to detect significant factors affecting macaque density. We detected that the most effective spatial scale was 400 m in radius, a scale that corresponded to group range size of the macaques. At this scale, the amount of broad‐leaved forest was selected as a positive factor, whereas mixed forest and forestry area were selected as negative factors for macaque density. This study demonstrated the importance of the simultaneous evaluation of all possible factors of wildlife population density at the appropriate spatial scale. Am. J. Primatol. 77:152–161, 2015. © 2014 Wiley Periodicals, Inc.
• Autumn Long-distance Movements of Male Japanese Sika deer Cervus nippon yesoensis in Western Hokkaido, Japan
  Agetsuma Naoki; Agetsuma-Yanagihara Yoshimi; Takafumi Hino
  Eurasian journal of forest research, 14, 1, 13, 19, Aug. 2011, [Peer-reviewed]
• Food habits of Japanese deer in an evergreen forest: Litter-feeding deer
  Naoki Agetsuma; Yoshimi Agetsuma-Yanagihara; Hino Takafumi
  Mammalian Biology, 76, 2, 201, 207, Springer Science and Business Media LLC, Mar. 2011, [Peer-reviewed]
  Scientific journal
• A proposal of the method of deer density estimate without fecal decomposition rate: a case study of fecal accumulation rate technique in Japan
  Ryosuke Koda; Naoki Agetsuma; Yoshimi Agetsuma‐Yanagihara; Riyou Tsujino; Noboru Fujita
  Ecological Research, 26, 1, 227, 231, Wiley, 24 Aug. 2010, [Peer-reviewed]
  Scientific journal, Abstract
  
  The accuracy of estimating deer density using the fecal pellet count method is greatly limited by variability of the fecal decomposition rate. The fecal accumulation rate technique can avoid the issue of decomposition rate. However, the precision of this technique is not clear when the decomposition rate is relatively high, such as in Japanese forests. We estimated deer population densities on Yakushima Island by the fecal accumulation rate technique and compared them between seasons. The estimated densities were similar to reported estimates, and did not differ seasonally, in accord with reports that deer on Yakushima do not migrate seasonally. Thus, we conclude that the fecal accumulation rate technique is applicable in Japanese forests.
• History of forest utilization in the World Natural Heritage Area of western Yakushima Island
  Tatsuya Otani; Naoki Agetsuma; Yoshimi Agetsuma-Yanagihara
  Japanese Journal of Conservation Ecology, 12, 1, 78, 85, 2007, [Peer-reviewed]
  Japanese, Scientific journal
• Alien mammals, raccoon dog, feral dog, feral cat, and feral goat in western and northwestern part of lowland forest on Yakushima Island in Kagoshima prefecture
  Riyou Tsujino; Yoshimi Agetsuma-Yanagihara
  Japanese Journal of Conservation Ecology, 11, 167, 171, Jun. 2006, [Peer-reviewed]
  Japanese, Scientific journal
• Process of establishing an introduced raccoon (Procyon loter) population in Aichi and Gifu Prefectures, Japan: Policy for managing threats posed by introduced raccoons
  Yoshimi Agetsuma-Yanagihara
  Mammalian Science, 44, 2, 147, 160, Nov. 2004, [Peer-reviewed], [Lead author, Corresponding author]
  Japanese, Scientific journal
• Population density and group composition of Japanese sika deer (Cervus nippon yakushimae) in an evergreen broad‐leaved forest in Yakushima, southern Japan
  Naoki Agetsuma; Hideki Sugiura; David A. Hill; Yoshimi Agetsuma‐Yanagihara; Toshiaki Tanaka
  Ecological Research, 18, 5, 475, 483, Wiley, 03 Sep. 2003, [Peer-reviewed]
  Scientific journal, The population density of Japanese sika deer (Cervus nippon yakushimae Kuroda and Okada) in an evergreen broad‐leaved forest in Yakushima, southern Japan, was surveyed over 4 years from 1998 to 2001. Two approximately 50 ha study sites, Hanyama and Kawahara, were established with a total of 4 km of census trails at each site. The estimated densities of sika deer at the two sites were 43–70 deer km⁻² at Hanyama and 63–78 deer km⁻² at Kawahara, although these values might be underestimates. The adult sex ratio (number of adult males : number of adult females) ranged from 0.6 to 1.0 at Hanyama, and from 0.4 to 0.9 at Kawahara. Mean group size was 1.9 deer (male group, 1.5 deer; female group, 1.6 deer; mixed group, 3.6 deer). The population density of sika deer was relatively high compared to other sites in Japan, with the exception of very small (<10 km²) islands. Possible explanations for this naturally high density of sika deer in an evergreen broad‐leaved forest in Yakushima are discussed.

• Long-term observation of population density in wild Japanese macaques in Yakushima
  SUGIURA Hideki; AGETSUMA Naoki; AGETSUMA-YANAGIHARA Yoshimi; FUJITA Shiho; TANAKA Toshiaki; SUZUKI Mariko; AIBA Kana; KODA Hiroki; HARASAWA Makiko; MUROYAMA Yasuyuki; SHIMIZU Momoko; KAWAZOE Tatsuro; SAWADA Akiko; SUGIURA Yoko; ASAI Takayuki; HAYAISHI Shuhei; KOBAYASHI Ritsuko, Primate Research Supplement, 34, 57, 57, 01 Jul. 2018
  屋久島西部地域には，野生ニホンザルが高密度で生息しており，ここを通過する道路では，容易にサルを観察できる。1999年から2016年の17年間にわたり，毎年8月に道路を歩いてサルの頭数をカウントした。発見率の長期的な変化は，場所によって異なっていた。国立公園外の区域や，公園内の北部地域で，減少傾向がみられる一方，公園内の南部では，高密度が保たれていることが示唆された。, Primate Society of Japan, Japanese
• Long-term observation of population parameters in wild Japanese macaques in Yakushima
  SUGIURA Hideki; AGETSUMA Naoki; AGETSUMA-YANAGIHARA Yoshimi; FUJITA Shiho; TANAKA Toshiaki; SUZUKI Mariko; AIBA Kana; KODA Hiroki; HARASAWA Makiko; MUROYAMA Yasuyuki; SHIMIZU Momoko; KAWAZOE Tatsuro; SAWADA Akiko; SUGIURA Yoko; ASAI Takayuki; HAYAISHI Shuhei; KOBAYASHI Ritsuko; GOSHIMA Wataru, Primate Research Supplement, 33, 50, 51, 2017
  屋久島西部地域には，野生ニホンザルが高密度で生息しており，ここを通過する道路では，容易にサルを観察できる。1999年から2016年の17年間にわたり，毎年8月に道路を歩いてサルの頭数をカウントした。1999年にはサルの大量死が起こったが，その後，約10年間の間，出産率は2年周期で増減を繰り返した。その後，このような周期性は見られなくなった。このような増減の繰り返しは，宮城県金華山島など類似している。また，国立公園外ではサルの発見率が減少傾向にあり，サルが減少している可能性がある。, Primate Society of Japan, Japanese
• Population dynamics of Japanese macaques in Yakushima Island
  SUGIURA Hideki; MATSUBARA Miki; UNO Takeharu; KIYONO Mieko; SUZUKI Mariko; NISHIKAWA Mari; MUROYAMA Yasuyuki; TANAKA Toshiaki; AGETSUMA Naoki; HAYAKAWA Sachiko; KODA Hiroki; HAYAISHI Shuhei; YANAGIHARA Yoshimi; HANYA Goro; FUJITA Shiho, Primate Research Supplement, 22, 0, 53, 53, 2006, [Peer-reviewed]
  ［目的］ 屋久島西部海岸域では、1998年の秋～1999年冬にかけて、ニホンザルの大量死が観察された。大量死からの回復過程を明らかにし、大量死がその後の個体群動態に与えた影響を探る。
  ［方法］ 毎年7-8月にニホンザルの頭数調査を行い、個体数やアカンボウの数を数えた。また、定期的に道路を歩いてサルを探し、その構成を数えることでも、個体群パラメータの推定をした。さらに集中的な調査の行われている群れでは、個体識別に基づいて、出産、消失などを随時記録した。
  ［結果］ 大量死の後2年は頭数が急速に増えたが、その後は頭打ちになってきている可能差異があった。また、大量死の際にアカンボウの数が極端に少なくなったことが原因で、出産率の高い年と低い年が交互に現れた。
  ［考察］ 大量死によって、一時的に密度が下がり、そこから個体数が増加したと考えられる。しかし、その傾向がどこまで続くのか、あるいは、すでに終わっているのかは明かではない。また、大量死後は出産率の変動が大きいが、今後収束していくかどうかは、その原因の追及を含めて、未解決である。分析を進めると共に、今後もモニタリングが必要である。, Primate Society of Japan, Japanese