Researcher Database

Naoki Agetsuma
Field Science Center for Northern Biosphere Forest Research Station Tomakomai Experimental Forest
Associate Professor

Researcher Profile and Settings

Affiliation

  • Field Science Center for Northern Biosphere Forest Research Station Tomakomai Experimental Forest

Job Title

  • Associate Professor

Degree

  • Doctor of Science(Kyoto University)
  • Master of Science(Kyoto University)

URL

Research funding number

  • 60285690

J-Global ID

Research Interests

  • forest ecology   animal ecology   feeding ecology   mammal   

Research Areas

  • Life sciences / Biodiversity and systematics
  • Life sciences / Animals: biochemistry, physiology, behavioral science
  • Life sciences / Forest science
  • Life sciences / Ecology and environmental science

Academic & Professional Experience

  • 2020/04 - Today 北海道大学 北方生物圏フィールド科学センター 南管理部長
  • 2018/04 - Today Hokkaido University Field Science Center for Northern Biosphere
  • 2018/04 - Today Hokkaido University Field Science Center for Northern Biosphere
  • 2007/04 - Today Hokkaido University Field Science Center for Northern Biosphere
  • 2009/04 - 2018/03 Hokkaido University Field Science Center for Northern Biosphere
  • 2006/04 - 2007/03 Hokkaido University Field Science Center for Northern Biosphere
  • 2001/04 - 2006/03 Hokkaido University Field Science Center for Northern Biosphere
  • 2000/04 - 2001/03 Hokkaido University Faculty of Agriculture
  • 1996/04 - 2000/03 Akita University of Ecolonics and Law Faculty of Economics Lecturer
  • 1995/04 - 1996/03 Postdoctoral Fellowships of Japan Society for the Promotion of Science Fellow PD (experimental psychology) Fellow PD (experimental psychology)
  • 1995/02 - 1996/03 Postdoctoral Fellowships of Japan Society for the Promotion of Science Fellow PD (ecology)
  • 1993/04 - 1995/01 Postdoctoral Fellowships of Japan Society for the Promotion of Science Fellow DC (ecology)

Education

  •        - 1995  Kyoto University
  •        - 1991  Kyoto University
  •        - 1989  Tohoku University  Faculty of Science  Department of Biology

Association Memberships

  • 日本動物行動学会   日本生態学会   

Research Activities

Published Papers

  • The effect of deer exclusion on tick abundance in Japan; the verification based on field experiment for controlling deer density
    Hiroyuki Matsuyama, Naoki Agetsuma, Ayumi Okada, Maki Suzuki
    Medical Entomology and Zoology 70 (3) 153 - 159 2019/10 [Refereed][Not invited]
  • 紀伊半島南部で確認された巣箱で冬眠するヤマネ Glirulus japonicus.
    芝田史仁, 細田徹治, 揚妻直樹, 鈴木慶太, 清水善吉
    南紀生物 61 (1) 19 - 22 2019/06 [Refereed][Not invited]
  • House names in the Hirai Village in the Kumano Region, Japan.
    Naoki Agetsuma, Fumiyo Konishi
    Research bulletin of the Hokkaido University Forests 71 (1) 39 - 46 2019/05 [Refereed][Not invited]
  • Present Situation of Traditional Apiculture (Beekeeping) in the Kozagawa Basin, in the Kumano Region of Japan
    揚妻直樹, 岸田治, 油田照秋, 揚妻-柳原芳美
    北海道大学演習林研究報告 71 (1) 1 - 9 2019/05 [Refereed][Not invited]
  • Plant constituents affecting food selection by sika deer.
    Naoki Agetsuma, Yoshimi Agetsuma-Yanagihara, Hino Takafumi, Tatsuro Nakaji
    Journal of Wildlife Management 83 (3) 669 - 678 2019/04 [Refereed][Not invited]
  • A simple method for calculating minimum estimates of previous population sizes of wildlife from hunting records.
    AGETSUMA Naoki
    PLOS ONE 13 (6) e0198794  2018/06 [Refereed][Not invited]
  • シカの高密度生息地で観察された土石流後の植生回復:屋久島西部照葉樹林での事例.
    揚妻直樹, 揚妻-柳原芳美
    保全生態学研究 23 (1) 145 - 153 2018/05 [Refereed][Not invited]
  • Yoshimi Agetsuma-Yanagihara, Eiji Inoue, Naoki Agetsuma
    MAMMAL RESEARCH 62 (2) 201 - 207 2199-2401 2017/04 [Refereed][Not invited]
     
    Extraction of DNA from non-invasive samples (feces) has been used increasingly in genetic research on wildlife. For effective and reliable genetic analyses, knowledge about which samples should be selected in the field is essential. For this reason, we examined the process of DNA degradation in feces of deer. We collected fresh fecal pellets from three wild deer living in a warm temperate forest. We then assessed the effects of time (3, 5, and 10 days) under three environmental conditions (on the forest floor, on exposed ground, and inside the laboratory) on the rates of correct genotyping (CG), amplification failure (NA), genotyping error among positive amplification (ER), false alleles (FA), and allelic dropout (AD) of 15 microsatellite loci. The rate of CG significantly decreased, and those of NA and FA increased with increasing lapse of time. Rates of CG tended to be highest and those of NA, ER, FA, and AD to be lowest in feces kept inside, followed by those on the forest floor. Suitability of samples for DNA extraction was lowest in fecal pellets left on exposed ground, and we suspect that rain may hasten DNA degradation. NA rate could serve as a reliable indicator of the quality of fecal pellets because it was significantly positively correlated with ER rate. For efficient genetic analyses using deer feces in warm temperate zones, we recommend collecting fecal pellets within 3 days of defecation, during periods without rainfall and from under the cover of trees.
  • Naoki Agetsuma, Ryosuke Koda, Riyou Tsujino, Yoshimi Agetsuma-Yanagihara
    MAMMALIAN BIOLOGY 81 (2) 130 - 137 1616-5047 2016/03 [Refereed][Not invited]
     
    This study examined the influence of anthropogenic disturbance (agriculture, forestry, hunting and feral domestic dogs) on the population density and daily activity pattern of deer. We quantified the effects of land use (broad-leaved forest, mixed coniferous/broad-leaved forest, natural grassland, subalpine vegetation, forestry area, and agricultural land), along with hunting pressure, and densities of feral domestic dogs and wild macaques on deer. The effects of land use were analyzed at various spatial scales and a model selection procedure (generalized mixed model) was used to examine the effects of factors on density and daily activity pattern of deer at each spatial scale. The combinations of influential factors differed between density and daily activity pattern and changed with spatial scale. The spatial scale with the smallest Akaike's Information Criterion value was defined as the effective spatial scale for each of density and daily activity pattern. Deer density was affected positively by the percentage of area covered by broad-leaved forest, natural grassland and macaque density, and negatively by percentage of area covered by agricultural land and mixed forest at the effective spatial scales. For the daily activity pattern of deer, agricultural land, forestry area, natural grassland, subalpine vegetation and dog density reduced diurnal and increased nocturnal activity. Crepuscular activity increased with hunting pressure and sub alpine vegetation, and decreased with agricultural land. Thus, daily activity pattern was sensitive to more types of anthropogenic disturbance than density. Detecting the appropriate spatial scales at which significant anthropogenic disturbance should be managed is essential for effective wildlife conservation. (C) 2015 Deutsche Gesellschaft fur Saugetierkunde. Published by Elsevier GmbH. All rights reserved.
  • Naoki Agetsuma, Ryosuke Koda, Riyou Tsujino, Yoshimi Agetsuma-Yanagihara
    AMERICAN JOURNAL OF PRIMATOLOGY 77 (2) 152 - 161 0275-2565 2015/02 [Refereed][Not invited]
     
    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 400m 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. (c) 2014 Wiley Periodicals, Inc.
  • David A. Hill, Dai Fukui, Naoki Agetsuma, Andrew J. J. MacIntosh
    MAMMAL STUDY 39 (4) 229 - 236 1343-4152 2014/12 [Refereed][Not invited]
     
    Bats that typically forage in the forest understorey can be difficult to capture using mist nets or harp traps alone. We assessed the effectiveness of an ultrasonic lure for increasing capture rates of vespertilionid bats in two forest zones in Japan. One sequence of stimuli was modelled on social calls of four species that typically forage in narrow-space; the other on those of four species that forage along edges and in forest gaps. The lure increased capture rates by 24.5 times in cool temperate deciduous forest in Hokkaido, and 9.75 times in warm temperate evergreen rain forest in Yakushima, compared with the control condition. Narrow-space foraging bats of the genus Murina dominated the catch at both sites and were caught most frequently when the trap was located in the cluttered environment of the forest understorey. There was no significant effect of call type on capture rate. The lure is an effective method for increasing capture rates of bats and particularly for narrow-space foraging species within the forest, which are otherwise difficult to catch. Acoustic lures have great potential for enhancing study and survey capabilities for forest bats.
  • Naoki Agetsuma, Ryosuke Koda, Riyou Tsujino, Yoshimi Agetsuma-Yanagihara
    Mammalian Biology 79 (6) 414  1618-1476 2014/11/01 [Refereed][Not invited]
  • Goro Hanya, Mieko Fuse, Shin-Ichiro Aiba, Hino Takafumi, Riyou Tsujino, Naoki Agetsuma, Colin A. Chapman
    AMERICAN JOURNAL OF PRIMATOLOGY 76 (6) 596 - 607 0275-2565 2014/06 [Refereed][Not invited]
     
    Comparing animal consumption to plant primary production provides a means of assessing an animal's impact on the ecosystem and an evaluation of resource limitation. Here, we compared annual fruit and leaf consumption by Japanese macaques (Macaca fuscata) relative to the annual production of these foods in the lowlands and highlands of Yakushima Island, Japan. We estimated consumption by macaques by the direct observation of macaque groups for 1 year in each habitat. We estimated leaf production as the sum of leaf litter fall (corrected for the effect of translocated organic and inorganic matter) and folivory by insects (assumed to be 10%) and by macaques. We estimated fruit production as the sum of fruit litter fall and consumption by birds (estimated by the seed fall) and macaques. The impact of macaque folivory at the community level was negligible relative to production (approximate to 0.04%) compared with folivory by insects (assumed to be 10%); however, for some species, macaque folivory reached up to 10.1% of production. Tree species on which macaques fed did not decline in abundance over 13 years, suggesting that their folivory did not influence tree species dynamics. For the three major fleshy-fruited species in the highland site, macaques consumed a considerable portion of total fruit production (6-40%), rivaling the consumption by birds (32-75%). We conclude that at the community level, macaque folivory was negligible compared with the leaf production, but frugivory was not. Am. J. Primatol. 76:596-607, 2014. (c) 2013 Wiley Periodicals, Inc.
  • 本州西部と四国におけるコウモリ寄生ハエ類(クモバエ科、コウモリバエ科)の記録.
    山内健生, 宮本大右, 大島康宏, 山田勝, 揚妻直樹
    倉敷市立自然史博物館研究報告 29 45 - 46 2014/03 [Not refereed][Not invited]
  • Naoki Agetsuma, Ryosuke Koda, Riyou Tsujino, Yoshimi Agetsuma-Yanagihara
    Mammalian Biology 79 (1) 44 - 51 1616-5047 2014/01 [Refereed][Not invited]
     
    Anthropogenic disturbance modifies various ecological traits of wildlife. The magnitude of the effects will change depending on spatial scale. Therefore, for wildlife conservation, the effective spatial scale at which the disturbance has the greatest effects on wild populations must be determined. This study examined the influence of anthropogenic disturbance on two ecological traits (population density and daily activity pattern) of deer. We quantified the effects of land use (broad-leaved forest, mixed coniferous/broad-leaved forest, natural grassland, subalpine vegetation, forestry area, and agricultural land), hunting risk, and densities of feral domestic dogs and wild monkeys. The effects of land use were analyzed at various spatial scales and a model selection procedure (generalized mixed model) was used to examine significant variables on the two ecological traits at each spatial scale. Combinations of selected variables differed with ecological traits and spatial scales. The spatial scale of the best model was defined as the most effective spatial scale for each ecological trait. Deer density was affected positively by areas of natural grassland and monkey density, and negatively by areas of forestry, mixed forest and agricultural land at the most effective spatial scale. For the daily activity pattern, larger areas of agricultural land, smaller natural grassland areas and higher hunting risk reduced diurnal and induced nocturnal activity. The most effective spatial scale explaining population density was smaller than that of daily activity pattern. This study showed that agricultural land, forestry areas and hunting risk affected deer ecology as anthropogenic disturbance. However, each disturbance factor modified different ecological traits or modified both ecological traits at different spatial scales. Detecting the appropriate spatial scales at which anthropogenic disturbance should be managed is essential for wildlife conservation. © 2013 Deutsche Gesellschaft für Säugetierkunde.
  • Tamihisa Ohta, Shigeru Niwa, Naoki Agetsuma, Tsutom Hiura
    PEDOBIOLOGIA 57 (4-6) 257 - 262 0031-4056 2014 [Refereed][Not invited]
     
    Many studies have shown the effects of aboveground plant species on soil organisms due to differences in litter quality. However, the calcium concentration in soil has received less attention as a controlling factor of soil invertebrate communities, even though it is an essential element for many animals, especially crustaceans. Litter of Japanese cedar (Cryptomeria japonica) plantations, which account for 19% of the forested area in Japan, has a higher calcium concentration compared to other taxa such as broad-leaved trees. We predicted that C. japonica plantations affect soil invertebrates by altering calcium availability. We compared soil properties including exchangeable calcium concentration and soil invertebrate communities between C. japonica plantations and natural broad-leaved forests. Exchangeable calcium was significantly higher in soil from cedar plantations than in that from broad-leaved forests. The invertebrate community composition differed between the two forest types and was best explained by the exchangeable calcium concentration. In particular, two major taxa of soil crustaceans (Talitridae and Ligidium japonicum) were found only in cedar plantations. Our results suggest that calcium concentrations in soil are altered in C. japonica plantations and that this affects soil invertebrate communities. (C) 2014 Elsevier GmbH. All rights reserved.
  • 野生シカによる農業被害と生態系改変:異なる二つの問題の考え方.
    揚妻 直樹
    生物科学 65 (2) 117 - 126 2013/10 [Refereed][Not invited]
  • シカの異常増加を考える.
    揚妻 直樹
    生物科学 65 (2) 108 - 116 2013/10 [Refereed][Not invited]
  • Moeko Minoshima, Mayura B. Takada, Naoki Agetsuma, Tsutom Hiura
    Ecoscience 20 (1) 55 - 64 1195-6860 2013/03 [Refereed][Not invited]
     
    The effects of sika deer (Cervus nippon) browsing and understory productivity on web-building spiders' density were experimentally examined. We particularly focused on the nonlinear effects of these 2 factors and their underlying mechanisms. Our field experiments controlling deer density and understory productivity revealed that the deer affected the densities of 2 abundant spider species nonlinearly: the deer effect was unimodal or constant in lower productivity plots and negative in higher productivity plots. The nonlinear effects seemed to occur because the response trend of the spiders' limiting factors to deer impact differed between lower and higher productivity plots. In lower productivity plots, the density of the most abundant spider species, Prolinyphia longipedella, was limited by dicot cover, and both spider density and dicot cover had unimodal-shaped responses to deer density. This spider species was limited by the availability of twigs in higher productivity plots and responded negatively to deer density. Deer seemed to affect web-building spider density in understory vegetation by changing the number of available sites for webs through browsing. However, the precise limiting factors differed with understory productivity. Since forest understory productivity is expected to show large variation at various spatial scales due to differences in canopy tree density, the availability of nutrients, and other environmental factors, considering nonlinear effects is important when predicting the impact of large herbivores on invertebrates in forest understories.
  • 災害時孤立集落の「不安」と「安心」の要因-台風12号における高齢山村、平井区の事例-
    湯崎真梨子, 揚妻直樹, 塚田晃司, 中島敦司
    日本地域政策研究 11 53 - 62 2013/03 [Refereed][Not invited]
  • AGETSUMA Naoki
    Japanese Journal of Conservation Ecology 17 (1) 131 - 136 2012/05 [Refereed][Not invited]
  • Takeo Yamauchi, Naoki Agetsuma, Natsuko Araki, Moe Fukushima
    INTERNATIONAL JOURNAL OF ACAROLOGY 38 (3) 214 - 216 0164-7954 2012 [Refereed][Not invited]
     
    Ixodid ticks were collected from the endemic raccoon dog Nyctereutes procyonoides albus (Hornaday) and the alien raccoon Procyon lotor (Linnaeus) in southern Hokkaido, Japan. Ixodes ovatus Neumann was the most abundant species collected from both host species, followed by Ixodes persulcatus Schulze. Haemaphysalis flava Neumann, I. ovatus, I. persulcatus, and Ixodes pavlovskyi Pomerantzev were first collected from N. p. albus. Procyon lotor is a new host for I. pavlovskyi. This report is the southernmost distributional record of I. pavlovskyi.
  • Goro Hanya, Nelly Menard, Mohamed Qarro, Mohamed Ibn Tattou, Mieko Fuse, Dominique Vallet, Aya Yamada, Moe Go, Hino Takafumi, Riyou Tsujino, Naoki Agetsuma, Kazuo Wada
    PRIMATES 52 (2) 187 - 198 0032-8332 2011/04 [Refereed][Not invited]
     
    Habitat, diet and leaf chemistry are compared between Japanese and Barbary macaques to reveal the similarities and differences in dietary adaptations of temperate primates living at the eastern and western extremes of the genus Macaca. Tree species diversity and proportion of fleshy-fruited species are much higher in Japan than in North Africa. Both species spend considerable annual feeding time on leaves. Japanese macaques prefer fruits and seeds over leaves, and Barbary macaques prefer seeds. These characteristics are adaptive in temperate regions where fruit availability varies considerably with season, since animals can survive during the lean period by relying on leaf and other vegetative foods. The two species are different with respect to the higher consumption of herbs by Barbary macaques, and the leaves consumed contain high condensed and hydrolysable tannin for Barbary but not for Japanese macaques. Barbary macaques supplement less diverse tree foods with herbs. Because of the low species diversity and high tannin content of the dominant tree species, Barbary macaques may have developed the capacity to cope with tannin. This supports the idea that digestion of leaves is indispensable to survive in temperate regions where fruit and seed foods are not available for a prolonged period during each year.
  • Autumn long-distance movements of male Japanese sika deer Cervus nippon yesoensis in western Hokkaido, Japan.
    Naoki Agetsuma, Yoshimi Agetsuma-Yanagihara, Takafumi Hino
    Eurasian Journal of Forest Research 14 (1) 13 - 19 2011 [Refereed][Not invited]
  • Naoki Agetsuma, Yoshimi Agetsuma-Yanagihara, Hino Takafumi
    MAMMALIAN BIOLOGY 76 (2) 201 - 207 1616-5047 2011 [Refereed][Not invited]
     
    We observed the feeding behaviors of wild Japanese sika deer (Cervus nippon yakushimae) in a warm temperate broad-leaved evergreen forest of the island of Yakushima using the focal animal sampling method from April 2002 to June 2006. Sika deer fed on species of at least 73 woody plants, 13 vines, 8 herbaceous plants, 8 ferns, 1 moss, and 3 fungi. We investigated time spent feeding on each food category in each season (spring: April-June; summer: July-September; autumn: October-December; winter: January-March). During each season, 45.6-59.8% of the deer diet consisted of fallen woody leaves. Half of the fallen leaves were those tinged with red and yellow colors. Fallen reproductive parts of plants constituted 8.7-23.7% of the seasonal deer diet. In contrast, living woody parts of plants and herbaceous plants, including ferns and moss, constituted 4.4-22.5% and 0.8-9.2% of the seasonal diet, respectively. Deer also fed on animal matters as minor food items, such as the feces of monkeys and raccoon dogs. bones of deer and monkeys, and bird carcasses. Animal matters constituted 0.3-1.6% of the seasonal diet. Sympatric monkeys supplied food to deer as a result of their daily activities. Monkey-supplied foods comprised 1.7-10.9% of the seasonal diet of sika deer. Monkeys tended to supply many fruits and seeds. Overall, 75.0% of the annual deer diet consisted of forest litter, even though deer had access to abundant living edible leaves in the study area. Therefore, sika deer in this forest ecosystem function ecologically as decomposers rather than primary consumers. (C) 2010 Deutsche Gesellschaft fur Saugetierkunde. Published by Elsevier GmbH. All rights reserved.
  • Ryosuke Koda, Naoki Agetsuma, Yoshimi Agetsuma-Yanagihara, Riyou Tsujino, Noboru Fujita
    ECOLOGICAL RESEARCH 26 (1) 227 - 231 0912-3814 2011/01 [Refereed][Not invited]
     
    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.
  • Dai Fukui, Naoki Agetsuma
    MAMMAL STUDY 35 (4) 227 - 233 1343-4152 2010/12 [Refereed][Not invited]
     
    We determined the food habit of the Asian parti-coloured bat Vespertilio sinensis from May to August by analysing their faecal samples. Eight orders of insects were identified in the faeces. Lepidoptera, Diptera and Coleoptera had high frequencies of occurrence, but the proportion of each order varied with the sampling period. A comparison between diet composition and relative insect abundance showed that proportions of Coleoptera in the diet were larger than those in insect abundance. This pattern also was true for Lepidoptera in some sampling periods. In contrast, proportions of Diptera in the diet were lower than those in insect abundance, although Diptera was a major prey item. These results suggest that the diet composition of V. sinensis may be biased towards larger-sized taxa. Furthermore, the lack of any significant differences between diet composition and insect abundance for the other five orders suggested that the diet composition of V. sinensis is also influenced by the seasonal prevalence of each insect taxon.
  • Nobuko Kazahari, Naoki Agetsuma
    BEHAVIOUR 147 (11) 1481 - 1500 0005-7959 2010/10 [Refereed][Not invited]
     
    We evaluated the effects of social monitoring and feeding competition on foraging success in relation to the feeding group size of wild Japanese macaques (Macaca fuscata). Social monitoring is visual scanning by group members that assists them in following their own group. Individuals in smaller feeding groups may frequently use social monitoring while foraging, because they have an increased risk of losing their group. Therefore, social monitoring could be a cost for group-foraging animals. We made four predictions: (1) individuals in smaller feeding groups tend to abandon food patches to follow group members; (2) social monitoring frequency is higher in smaller feeding groups; (3) feeding rate decreases with increased social monitoring frequency; and (4) feeding rate initially increases with feeding group size because decreased social monitoring outweighs increased feeding competition, but after the feeding group reaches a certain size, feeding rate declines with increasing feeding group size due to the high costs of feeding competition. These predictions were supported by our results. Thus, the relationship between feeding group size and feeding rate can show three patterns (positive, neutral and negative) in response to the balance between the costs of social monitoring and feeding competition.
  • 北海道大学・和歌山研究林における春季のニホンジカ(Cervus nippon centralis)分布パターン
    揚妻直樹, 前田純, 大西一弘, 土井一夫, 前田昌作, 鈴木清士, 久保田省悟, 浪花彰彦, 浪花愛子, 桝本浩志
    北海道大学演習林研究報告 67 (1) 1 - 5 2010 [Refereed][Not invited]
  • Research Bulletins of the Hokkaido University Forests
    Agetsuma N, Maeda J, Ohnishi K, Doi K, Maeda S, Suzuki K, Kubota S, Naniwa A, Naniwa A
    Research Bulletins of the Hokkaido University Forests 67 (1) 7 - 11 2010 [Refereed][Not invited]
  • Bat fauna in Nakagawa Experimental Forest
    Fukui D, Agetsuma N, Hill DA, Harada M
    Research Bulletins of the Hokkaido University Forests 67 (1) 13 - 23 2010 [Refereed][Not invited]
  • Fukui D, Agetsuma N, Hill DA, Harada M
    Research Bulletin of the Hokkaido University Forests Hokkaido University Forests 67 (1) 13  2010 [Refereed][Not invited]
  • Nobuko Kazahari, Naoki Agetsuma
    BEHAVIOUR 145 (6) 843 - 860 0005-7959 2008/06 [Refereed][Not invited]
     
    We evaluated the effects of social factors and food quality on patch use by a wild group of Japanese macaques (Macaca fuscata) that experienced no inter-group feeding competition or predation risk. We obtained the following results: (1) Food patch depletion and within-group scramble competition for food apparently did not affect patch use. (2) Within-group contest competition (aggressive interactions related to social-dominance rank) also did not strongly affect patch use. (3) The number of co-feeders in the same patch consistently showed positive effects on patch use, while food quality did not have consistent effects. These results suggest that the presence of co-feeders enhances foraging success in a patchy food environment.
  • G. Hanya, M. Kiyono, H. Takafumi, R. Tsujino, N. Agetsuma
    JOURNAL OF ZOOLOGY 273 (2) 140 - 147 0952-8369 2007/10 [Refereed][Not invited]
     
    Mature leaf food selection of Japanese macaques was studied in two different altitudinal zones of Yakushima: in the coniferous (1000-1200 m) and coastal forests (0-200 m). Logistic regression analysis was conducted to reveal the effect of chemical [neutral detergent fibre (NDF), crude protein, crude ash, crude lipid, condensed tannin, hydrolysable tannin and crude protein/NDF ratio] and availability properties (density of trees and total basal area) on the macaques' choice between the major food leaves and the rarely eaten or non-food leaves. In both forests, macaques selected leaves with a high crude ash and crude protein content, or a high crude protein/NDF ratio, as major foods. In the coniferous forest, macaques selected leaves with less condensed tannin, but this tendency was absent in the coastal forest. This was because macaques in the coniferous forest suffer from a greater risk of ingesting large amounts of condensed tannins, as their feeding time on mature leaves is seven times as long as that in the coastal forest. Among the chemical and availability properties, stepwise multiple regression analysis revealed that the number of trees (ha(-1)) was the only significant factor explaining the variations in feeding time among major food leaves, both in the coniferous and coastal forests. The present results suggest that the effect of travelling cost, which can be reduced by selecting common trees, exceeds the benefits gained by selecting high-quality foods.
  • Fumie Okabe, Naom Agetsuma
    JOURNAL OF MAMMALOGY 88 (4) 1090 - 1097 0022-2372 2007/08 [Refereed][Not invited]
     
    We investigated habitat use by introduced raccoons (Procyon lotor) and native raccoon dogs (Nyctereutes procyonoides albus) in a northern deciduous forest of Japan to examine the relationship between the 2 species. Spatial and temporal habitat use in the forest was monitored using infrared-triggered cameras. We also surveyed environmental factors at 2 spatial scales: at the macrohabitat scale, we examined forest growth stage, forest fragmentation, and distance from a water source; at the microhabitat scale, we examined forest structure, understory vegetation, and beetle abundance. We then analyzed the relationship between environmental factors and habitat use by each species using generalized linear model. Except for fern coverage, most environmental factors at the micro- and macrohabitat scales had different effects on the habitat use of these species. Moreover, the degree of diurnal activity also differed between the species. These spatial and temporal differences in habitat use between raccoons and raccoon dogs provide further evidence that competition between these 2 species may be limited in this area.
  • Naoki Agetsuma
    ECOLOGICAL RESEARCH 22 (3) 390 - 402 0912-3814 2007/05 [Refereed][Not invited]
     
    Mass production is a logical outcome of price competition in a capitalist economy. It has resulted in the need for large-scale logging and planting of commercial crops. However, such monotonous land use, or monoculture, has damaged various ecological functions of forests and eroded the beneficial public service provided by forests. In Japan, the most widespread monotonous land use is associated with coniferous plantations, the expansion of which was encouraged by Forest Agency policies from 1958 that were aimed at increasing wood production. By 1986, half of all forested lands had been transformed into single-species conifer plantations. These policies may damage the ecological functions of forests: to provide stable habitats for forest wildlife. In particular, food supplies for wildlife have fluctuated greatly after several decades of logging. Some species have therefore changed their ecology and begun to explore novel environments proactively in order to adapt to such extreme fluctuations. Such species have started to use farmlands that neighbor the plantations. In this sense, crop raiding by wildlife can be regarded as a negative result of monotonous land use due to the loss of ecological functions. Therefore, habitat management to rehabilitate ecological functions and to reorganize the landscape will be required in order to resolve the problem of crop raiding by wildlife. This study examines crop raiding by Japanese deer (Cervus nippon) and monkeys (Macaca fuscata) on the island of Yakushima, which typifies crop-raiding situations in Japan.
  • Naoki Agetsuma
    INTERNATIONAL JOURNAL OF PRIMATOLOGY 28 (1) 97 - 106 0164-0291 2007/02 [Refereed][Not invited]
     
    I estimated the minimum area required (MAR) for local populations of Japanese macaques (Macaca fuscata) from empirical data on habitat area and population viability. I used logistic regression analysis to examine the relationship between habitat area and survival/extinction among 50 populations over 50 yr. Estimated habitat areas satisfying 95-99% probability of a population persisting for 100-1000 yr range from 525 to 975 km(2). However, confidence limits of parameters in the logistic regression equation are very large. Moreover, the number of extinct population might be underestimated in the empirical data. Consequently, a much wider habitat area (>1000 km(2)) should be considered for actual conservation planning for local populations of Japanese macaques. The method involves fewer variables and assumptions than previous methods of MAR estimation, and therefore may be a more useful way to estimate MAR for various species and regions.
  • 大谷達也, 揚妻直樹, 揚妻-柳原芳美
    保全生態学研究 12 (1) 78 - 85 2007 [Refereed][Not invited]
  • Re-establishment process of Ezo sika deer (Cervus nippon yesoensis) in Iburi District, western Hokkaido
    Agetsuma N, Takafumi H, Okuyama S, Oikawa S, Okuda A, Sato T, Motomae T, Miyoshi H, Kumikawa S, Ishi T
    Research Bulletins of the Hokkaido University Forests 64 (1) 23 - 28 2007 [Refereed][Not invited]
  • Bat fauna in Nakagawa Experimental Forest
    Fukui D, Agetsuma N, Hill DA
    Research Bulletins of the Hokkaido University Forests 64 (1) 29 - 36 2007 [Refereed][Not invited]
  • Riyou Tsujino, Hino Takafumi, Naoki Agetsuma, Takakazu Yumoto
    JOURNAL OF VEGETATION SCIENCE 17 (3) 281 - 290 1100-9233 2006/06 [Refereed][Not invited]
     
    Questions: Do the population dynamics of trees differ among topographic positions and, if so, how does topographic position affect the population dynamics of species that are distributed in a topography-specific manner? Which is the most important life stage in determining vegetation patterns? Location: Primary and secondary warm temperate evergreen broad-leaved forest (40 - 280 m a.s.l.) on the western part of Yakushima Island, Japan. Methods: Mortality, recruitment, DBH growth and distribution of stems (2:5 cm DBH) in a 2.62-ha plot were surveyed in 1992 and 2002 to determine the relationships between population parameters and (1) topography and (2) distribution patterns of 17 common tree species. Results: Common species (n = 17) were classified into three distribution pattern groups: group A, distributed mainly on convex slopes; group B, on concave slopes, and group C, not aggregated with respect to topographic position. Stem mortality, recruitment and DBH growth were greater in group A than in group B within each topographic class. The hierarchy of stem mortality among topographic classes for groups A and B was convex > planar > concave. Stem recruitment density was relatively high on the convex and concave slopes, respectively, for groups A and B. Conclusions: The topographical positions of adult trees were not always most suited for adult survival and growth. For group A, the distribution pattern of adults was determined in the juvenile stage, while this was not the case for group B. Studies of juvenile stages are important for understanding the demographic basis of vegetation distribution patterns.
  • Geographical variation in the cranial and external characters of the little tube-nosed bat, Murina silvatica in Japanese archipelago
    Fukui, D, Maeda, K, Hill, D.A, Matsumura, S, Agetsuma, N
    Acta Theriologica 50 (3) 309 - 322 2005 [Refereed][Not invited]
  • 福井大, 河合久仁子, 佐藤雅彦, 前田喜四雄, 青井俊樹, 揚妻直樹
    哺乳類科学 45 (2) 181 - 191 2005 [Refereed][Not invited]
  • Fukui D, Kawai K, Sato M, Maeda K, Aoi T, Agetsuma N
    Mammal Sci. 45 181  2005 [Refereed][Not invited]
  • G Hanya, S Yoshihiro, K Zamma, H Matsubara, M Ohtake, R Kubo, N Noma, N Agetsuma, Y Takahata
    ECOLOGICAL RESEARCH 19 (5) 485 - 493 0912-3814 2004/09 [Refereed][Not invited]
     
    Altitudinal variations in relative group densities of the Japanese macaques on Yakushima were studied. This is an ideal place for studying resource limitations because it avoids various complicating factors that are difficult to quantify but might affect animal densities, such as predation, interspecific competition, and past catastrophes. The relative group density was high in the coastal forest (0-400 m), while it did not differ among the higher zones (400-800, 800-1200 and 1200-1886 m). To examine this variation, three habitat variables were analyzed: total basal area of food trees per unit area, seasonal variations in fruit abundance, and total annual fleshy fruit production. All of these variables indicate that fruit and seeds are most available in the coastal forest. Thus, altitudinal variations in the density of Japanese macaques on Yakushima are determined by the total annual food abundance.
  • D Fukui, N Agetsuma, DA Hill
    ZOOLOGICAL SCIENCE 21 (9) 947 - 955 0289-0003 2004/09 [Refereed][Not invited]
     
    Assessing the impact of forest management on bat communities requires a reliable method for measuring patterns of habitat use by individual species. A measure of activity can be obtained by monitoring echolocation calls, but identification of species is not always straightforward. We assess the feasibility of using analysis of time-expanded echolocation calls to identify free-flying bats in the Tomakomai Experimental Forest of Hokkaido University, Hokkaido, northern Japan. Echolocation calls of eight bat species were recorded in one or more of three conditions: from hand-released individuals, from bats flying in a confined space and from bats emerging from their roost. Sonograms of 171 calls from 8 bat species were analyzed. These calls could be categorized into 3 types according to their structure: FM/CF/FM type (Rhinolophus ferrumequinum), FM types (Murina leucogaster Murina ussuriensis, Myotis macrodactylus and Myotis ikonnikovi) and FM/QCF types (Eptesicus nilssonii, Vespertillo superans and Nyctalus aviator). Sonograms of the calls of R. ferrumequinum could easily be distinguished from those of all other species by eye. For the remaining calls, seven parameters (measures of frequency, duration and inter-call interval) were examined using discriminant function analysis, and 92% of calls were correctly classified to species. For each species, at least 80% of calls were correctly classified. We conclude that analysis of echolocation calls is a viable method for distinguishing between species of bats in the Tomakomai Experimental Forest, and that this approach could be applied to examine species differences in patterns of habitat-use within the forest.
  • N Agetsuma, H Sugiura, DA Hill, Y Agetsuma-Yanagihara, T Tanaka
    ECOLOGICAL RESEARCH 18 (5) 475 - 483 0912-3814 2003/09 [Refereed][Not invited]
     
    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 km(2)) islands. Possible explanations for this naturally high density of sika deer in an evergreen broad-leaved forest in Yakushima are discussed.
  • G Hanya, N Noma, N Agetsuma
    PRIMATES 44 (1) 51 - 59 0032-8332 2003/01 [Refereed][Not invited]
     
    Altitudinal and seasonal variations in the diet of Japanese macaques in Yakushima, southwestern Japan, were studied for 2 years by means of fecal analysis. The altitudinal range of fecal samples collected was 30 m to 1,203 m above sea level, and it was divided into three zones: low-zone forest (0-399 m), middle-zone forest (400-799 m), and high-zone forest (800 m-1,230 m). There was a considerable altitudinal and seasonal variation in the macaques' diet. Seed/fruit and animal matter were eaten more in the lower zones, whereas more fiber and fungi were consumed in the higher zones. In all of the zones, they ate seed/fruits the most in autumn (September-November) and the least in spring (March-April). They ate fibrous food the most in spring and the least in autumn. Macaques relied on seed/fruits heavily in the lower zone for a longer period than in the higher zones. Macaques in the high-zone forest ate almost no seed/fruit foods from March to May. Altitudinal variations in availability of seed/fruit foods seem to have influenced the altitudinal variations in diet. Total basal area of seed/ fruit-food trees, species richness of seed/fruit-foods, main seed/fruit-food types available, and annual fleshy-fruit production all decreased with increasing altitude. Both interannual variation and annual cyclicity of diet were found in all zones.
  • H Sugiura, N Agetsuma, S Suzuki
    INTERNATIONAL JOURNAL OF PRIMATOLOGY 23 (1) 69 - 84 0164-0291 2002/02 [Refereed][Not invited]
     
    We observed three cases of troop extinction and two cases of female fusion in the wild population of Japanese macaques on Yakushima Island, Japan. Troops P and T decreased in size relatively slowly over a few years until each troop consisted of only three monkeys. Several months later, the remaining adult female of P merged with the adjacent troop S, followed by the remaining female of T S subsequently also decreased in size and disappeared about 2 years later. In the early stage of troop decline, the mortality rate of adult females was as low as in a growing troop, but the birthrate was quite low. In the late stage of troop decline, the mortality rate increased and the birthrate remained low. An important factor leading to troop extinction may be an increase in population density and the resulting increase in intergroup competition. During the period when P and T declined and ceased to exist, the range of the adopted troop shifted to cover their previous ranges. In the fused troop, there was no severe aggression directed towards the immigrant females or harassment from residents of the adopted troop and there was affiliative social interaction between the immigrant females and resident members. These results agree with previous reports on female fusion: it occurs when the shrinking group consists of one or no adult member, and the immigrant females are not at a severe disadvantage in their adoptive group. A possible benefit for immigrant females is to avoid disadvantage of one-adult group in conflict with conspecifics. A possible cost for immigrant females is transfer to the other troop or to unfamiliar area or both. The cost to transfer to another group may not be high because the members of the adoptive troop are relatively tolerant to immigrants. The cost to transfer to unfamiliar range may be minimized by immigration to the troop whose range shifted to the immigrants' former range.
  • 西北海道・胆振地方の森林内におけるエゾシカ生息密度
    揚妻直樹, 大西敬, 松田道子, 福井大, 大西瑞木, 上杉あかね, 揚妻(柳原)芳美, 山本俊昭, 奥田篤志, 柳田智幸, 奥山悟, 三好等, 石井正, 本前忠幸
    『北海道大学演習林研究報告』 59 61 - 66 2002 [Refereed][Not invited]
  • Agetsuma N, Ohnishi K, Matsuda M, Fukui D, Ohnishi M, Uesugi A, Agetsuma Yanagihara Y, Yamamoto T, Okuda A, Yanagida T
    Research Bulletin of the Hokkaido University Forests (Japan) 2002 [Refereed][Not invited]
  • N Agetsuma
    ECOLOGICAL RESEARCH 16 (4) 759 - 763 0912-3814 2001/12 [Refereed][Not invited]
     
    Dietary selection by wild Japanese monkeys (Macaca fuscata yakui Kuroda) was examined in relation to body size. The monkeys were classified into three age-sex categories: adult males, adult females and immatures excluding suckling infants. Time spent feeding did not differ between age-sex classes, although time spent moving was longer in lighter classes. Heavier individuals fed relatively more on mature leaves, while lighter individuals fed on insects more frequently. Mature leaves were more abundant but had lower energy content than other food items in the forest. Heavier monkeys seemed to feed on greater amounts of lower quality food in this species. This finding agrees with the Jarman-Bell principle on ungulates.
  • K Okamoto, N Agetsuma, S Kojima
    PRIMATES 42 (2) 161 - 165 0032-8332 2001/04 [Refereed][Not invited]
     
    Party encounter situations were experimentally produced in a group of captive chimpanzees (Pan troglodytes verus) at the Primate Research Institute of Kyoto University, Japan. During weekends all subjects (two adult males and five adult females) usually stayed together in the rooms (Baseline condition). Under experimental conditions, we shut passages between rooms to divide the subjects into two groups. We examined the effects of temporal separation of group members on affiliative interactions, aggressive interactions, and simple proximity. The frequency of affiliative interactions between male and female chimpanzees and between female chimpanzees increased when they encountered one another after separation, irrespective of male identity or housing history. Therefore we considered affiliative interactions between males and females during party encounters as being the response between separated individuals. The same tendency was not found in the frequency of affiliative interactions between females or between males. Unlike affiliative interactions, neither aggressive interactions nor simple proximity were influenced by separation.
  • Aiba, S, Hill, D.A, Agetsuma, N
    Forest Ecology and Management 140 163 - 175 2001 [Refereed][Not invited]
  • Efficiency of harp trap for capturing bats in boreal broad-leaved forest in Japan
    Fukui, D, Ishii, T, Agetsuma, N, Aoi, T
    Eurasian Journal of Forest Research 3 23 - 26 2001 [Refereed][Not invited]
  • H Sugiura, C Saito, S Sato, N Agetsuma, H Takahashi, T Tanaka, T Furuichi, Y Takahata
    INTERNATIONAL JOURNAL OF PRIMATOLOGY 21 (3) 519 - 535 0164-0291 2000/06 [Refereed][Not invited]
     
    The nature of intergroup encounters differed between two populations of wild Japanese macaques (Macaca fuscata): the Yakushima and Kinkazan populations. In the Yakushima population, intergroup encounters were more likely to result in the displacement of one group, intergroup agonistic interaction was common, and intergroup dominance was usually distinct When displacement occurred at Yakushima, larger groups tended to dominate smaller ones. Conversely, in the Kinkazan population, intergroup encounters rarely resulted in displacement, intergroup agonistic interaction was rare, and intergroup dominance was usually unclear. Thus, monkeys in Yakushima appear to defend resources actively during encounters, while those in Kinkazan usually did not defend resources. The frequency of encounters was significantly higher in Yakushima than in Kinkazan. The two populations had very different group densities and traveling speeds, both of which directly influence the chance of encounters. Taking these differences into account we compared the observed frequency with those predicted by the ideal gas model. The observed frequencies in both populations were about one-third of the number expected with the model, which suggests that the differences in encounter frequency were caused by differences in group density and traveling speed. We discuss this intraspecific variation in light of economic defendability in connection to habitat differences and the evolutionary significance of resource defense behavior.
  • N Agetsuma
    INTERNATIONAL JOURNAL OF PRIMATOLOGY 21 (1) 103 - 111 0164-0291 2000/02 [Refereed][Not invited]
     
    I examined the influence of temperature on food intake in 4 captive macaques in a room with controlled temperature. I gave then? two types of artificial food pellets which were different in energy content per weighs in 6 conditions of air temperature. Total energy intake of macaques increased as temperature decreased Intake of low quality pellets increased significantly with decreasing temperature in 3 of 4 subjects. The other macaque, whose food intake was almost constant, decreased his body weight as ambient temperature decreased. These results suggest that energy requirements of macaques change with temperature as a result of changes in energy required for ther thermoregulation. Moreover temperature influenced the selectivity of lower quality food. I discuss the pattern of food selection found in this experiment from the view-point of optimal foraging strategy.
  • 「秋田経法大キャンパスの自然と地域におけるその重要性」
    揚妻直樹
    地域研究 11 47 - 51 2000 [Not refereed][Not invited]
  • Simulation of patch use by monkeys in operant schedule
    Agetsuma, N
    Journal of Ethology 16 49 - 55 1999 [Refereed][Not invited]
  • 「地球温暖化に対する地方自治体の取り組み,都道府県けのアンケート調査から」
    揚妻直樹, 木村浩一
    秋田経済法科大学経済学部紀要 29 19 - 33 1999 [Not refereed][Not invited]
  • Present situation of Japanese wildlife reviewed from economic backgrounds: An introduction for young students.
    Agetsuma, N
    The Journal of Economics Department of Akita University of Economics and Law 30 11 - 23 1999 [Not refereed][Not invited]
  • N Agetsuma, N Nakagawa
    PRIMATES 39 (3) 275 - 289 0032-8332 1998/07 [Refereed][Not invited]
     
    Feeding behaviors of Japanese monkeys (Macaca fuscata) were compared between a warm temperate habitat (Yakushima Island: 30 degrees N, 131 degrees E) and a cool temperate habitat (Kinkazan Island: 38 degrees N, 141 degrees E). The composition of diet and the activity budget in the two habitats were very different. Time spent feeding on Kinkazan Island was 1.7 times that on Yakushima Island. Two factors seem to be responsible for these: (1) the energy required for thermoregulation of monkeys on Kinkazan Island is greater than that on Yakushima Island; and (2) the food quality, which affects the intake speed of available energy, is lower on Kinkazan Island. However, monkeys in both habitats increased their moving time and decreased their feeding time when they fed on foods of relatively high quality. Such foraging strategies are predicted by optimal foraging models. Time spent social grooming on Yakushima Island was 1.9 times that on Kinkazan Island. although there were slight seasonal changes in both areas. The difference in time spent social grooming might be explained by the overall difference in feeding time and day length between the two habitats.
  • Y Takahata, S Suzuki, N Agetsuma, N Okayasu, H Sugiura, H Takahashi, J Yamagiwa, K Izawa, T Furuichi, DA Hill, T Maruhashi, C Saito, S Sato, DS Sprague
    PRIMATES 39 (3) 339 - 349 0032-8332 1998/07 [Refereed][Not invited]
     
    Wild Japanese macaque females of the Yakushima and Kinkazan populations exhibited similar reproductive features. (1) Births/female/year (BR: 0.27-0.35) was lower than those of provisioned troops, but (2) infant mortality (IM: 0.23-0.25) was higher than those of provisioned troops. (3) The interbirth interval (IBI) following the death of infants was 1.5-1.6 years, shorter than that following surviving infants (2.2-2.4 yrs). (4) Birth sex ratio (BSR) did not differ from 1:1. There was no consistent correlation between (5) female age and IM, (6) maternal rank and offspring BSR, or (7) maternal rank and reproductive success. On the other hand, (8) BR of Yakushima females was significantly lower than that of Kinkazan females. In particular, (9) Yakushima females stopped reproduction earlier than Kinkazan females, although (10) the first birth of Yakushima females was about one year earlier than Kinkazan females. (11) BR exhibited a humped curve against female age in Yakushima, but it was uncertain whether old-aged females of Kinkazan exhibited a post-reproductive life span (PRLS). (12) The survivorship for female juveniles was lower than that for male juveniles in Yakushima, whereas the survivorship for male juveniles was lower than that for female juveniles in Kinkazan. These data may indicate that Yakushima females more severely compete for resources than Kinkazan females, because of high population density, whereas the population density of Kinkazan might be limited by climate (e.g. heavy snow) rather than density dependent ecological effects.
  • C Saito, S Sato, S Suzuki, H Sugiura, N Agetsuma, Y Takahata, C Sasaki, H Takahashi, T Tanaka, J Yamagiwa
    PRIMATES 39 (3) 303 - 312 0032-8332 1998/07 [Refereed][Not invited]
     
    It is predicted that variation in intergroup relationships in group living primates reflects the cost and benefit of resource defense. We tested the applicability of the model by examining population difference, group difference, and seasonal difference in behaviors during intergroup encounters in two populations of Japanese macaques (Macaca fuscata), one of six groups from Yakushima Island, and the other of three groups from Kinkazan Island. We found that the nature of intergroup encounter varied with group identity, reproductive seasonality. and population. Yakushima groups showed aggressive behaviors more frequently than did Kinkazan groups and the difference was consistent with the food competition model, both because of the involvement of females, and because home ranges were smaller on Yakushima than on Kinkazan, and thus more defensive. Both sexes of animals participated in aggressive interactions, but males were more aggressive than females. Furthermore, Yakushima population showed more agonistic intergroup behaviors during the mating season than the non-mating season. Also during the encounters, intergroup mating was observed, but only in Yakushima. It is concluded that intergroup relationships reflect the mate guarding behavior by group males. However, the agonistic relationship during non-mating season, especially that of among females, is also consistent with the food competition model. It is also noted that males' behavior toward other groups can also be interpreted as a form of investigative behavior before possible transfer into a new group.
  • T Maruhashi, C Saito, N Agetsuma
    PRIMATES 39 (3) 291 - 301 0032-8332 1998/07 [Refereed][Not invited]
     
    The per capita home range area of Japanese macaques, Macaca fuscata, is significantly smaller in evergreen forest than in deciduous forest, though a corresponding difference in food resource utilization patterns has never been described. The present study compared the home range utilization pattern of Japanese macaques living in two habitats: the Yakushima population inhabits an evergreen forest, while the Kinkazan population inhabits a deciduous forest. We found that in the Yakushima population, (1) food density was higher; (2) inter-feeding bout sites distance was shorter; (3) daily travel distance was shorter; (4) home range size was smaller; and (5) the unit value of the main home range was higher, than in the Kinkazan population. Yakushima groups utilized a small home range area intensively, compared to Kinkazan groups. We also found that a Yakushima group shared 24% of its main home range with neighboring groups, though a Kinkazan group shared only 10% with other groups. It is supposed that food distribution affects daily ranging pattern, and ultimately the social relationships between groups in Japanese macaques.
  • Y Takahata, S Suzuki, N Okayasu, H Sugiura, H Takahashi, J Yamagiwa, K Izawa, N Agetsuma, D Hill, C Saito, S Sato, T Tanaka, D Sprague
    PRIMATES 39 (2) 245 - 251 0032-8332 1998/04 [Refereed][Not invited]
     
    For the wild Japanese macaques of Yakushima and Kinkazan Islands, we analyzed the relationship between the troop size or the number of adult females of each troop, infant/adult female ratio (IFR; crude birth rate), and infant mortality (IM) in habitats with no predators. In Yakushima, IFR was positively correlated to troop size and the number of adult females. In Kinkazan, however, IFR tended to decrease with the number of adult females. This difference may be due to the difference in troop size; i.e. in Yakushima, where troop size was small, IFR may increase with that of troop size, because a relatively larger troop is likely to the advantage in intertroop competition. In Kinkazan, where troop size was large, however, IFR is likely to decrease with troop size, because intratroop competition may increase. Thus, the present data roughly support WRANGHAM's model of the social structure of female-bonded primates, and suggests that there is an optimal troop size for birth rate (BR). On the other hand, there was no clear correlation between IM and the troop size or number of adult females of each troop.
  • 屋久島の野生ニホンザルによる農作物被害の発生過程とその解決策の検討
    揚妻直樹
    保全生態学研究 3 43 - 55 1998 [Refereed][Not invited]
  • The Distribution of Wild Yakushima Macaque (Macaca fuscata yakui). Troops around the Coast of Yakushima Island, Japan
    Yoshihiro, S, Fruichi, T, Manda, M, Ohkubo, N, Kinoshita, M, Agetsuma, N, Azuma, S, Matsubara, H, Sugiura, H, Hill, D, Kido, E, Kubo, R, Matsushima, K, Nakajima, K, Maruhashi, T, Oi, T, Sprague, D, Tanaka, T, Tsukahara, T, Takahata, Y
    Primate Research 14 179 - 187 1998 [Refereed][Not invited]
  • 矢作川中流域の哺乳動物相
    柳原芳美, 揚妻直樹
    矢作川研究 2 89 - 96 1998 [Not refereed][Not invited]
  • ワイルドライフマネイジメントと霊長類学の役割
    揚妻直樹
    秋田経済法科大学経済学部紀要 27 43 - 59 1998 [Not refereed][Not invited]
  • 矢作川中流域における植生群落回復の試み−竹林伐採による天然更新の可能性−
    室山泰之, 柳原芳美, 揚妻直樹
    矢作川研究 2 75 - 87 1998 [Not refereed][Not invited]
  • 矢作川中流域における川辺林の構造−竹林拡大の要因分析−
    揚妻直樹, 柳原芳美, 室山泰之
    矢作川研究 2 97 - 111 1998 [Not refereed][Not invited]
  • 東北地方の野生ニホンザルの分布と保全の問題点
    揚妻直樹
    ワイルドライフ・フォーラム 3 5 - 22 1997 [Refereed][Not invited]
  • 屋久島、西部林道における野生ニホンザルの餌付き方の調査−1993年と1995年の比較
    揚妻 直樹
    霊長類研究 13 (1) 41 - 51 1997 [Refereed][Not invited]
  • 矢作川中流域の植生−河川生態系の回復を目指して−
    揚妻直樹, 柳原芳美, 室山泰之
    矢作川研究 1 109 - 129 1997 [Not refereed][Not invited]
  • 屋久島の自然保護と野生生物
    揚妻直樹
    ワイルドライフ・フォーラム 2 23 - 32 1996 [Refereed][Not invited]
  • 冬季における屋久島西部林道の利用状況:世界遺産地域内の道路整備と野生生物保護の論議のために
    揚妻直樹
    霊長類研究 12 41 - 46 1996 [Refereed][Not invited]
  • DIETARY SELECTION BY YAKUSHIMA MACAQUES (MACACA-FUSCATA YAKUI) - THE INFLUENCE OF FOOD AVAILABILITY AND TEMPERATURE
    N AGETSUMA
    INTERNATIONAL JOURNAL OF PRIMATOLOGY 16 (4) 611 - 627 0164-0291 1995/08 [Refereed][Not invited]
     
    I examined dietary selection by Yakushima macaques (Macaca fuscata yakui) in relation to food availability and air temperature. Multiple regression analysis indicates that both food availability and temperature influenced the selection of foods. Feeding on young leaves, seeds, and flowers was affected more by availability while feeding on fruits, mature leaves, and fallen seeds was affected more by temperature. Feeding on insects is strongly correlated with temperature, perhaps because availability of insects increased with temperature. These results suggest that temperature influences dietary selection of Yakushima macaques by changing the energy expenditure required for thermoregulation and through its influence on the accessibility to insects, which are an important protein source for the monkeys.
  • FORAGING STRATEGIES OF YAKUSHIMA MACAQUES (MACACA-FUSCATA YAKUI)
    N AGETSUMA
    INTERNATIONAL JOURNAL OF PRIMATOLOGY 16 (4) 595 - 609 0164-0291 1995/08 [Refereed][Not invited]
     
    I investigated the activity budget and diet of Yakushima macaques (Macaca fuscata yakui) in warm temperate broad-leaved forest of Yakushima, Japan. Both time spent feeding and time spent moving varied considerably between half-months. However total time spent in active behaviors-feeding time plus moving time-was stable. The composition of the diet also showed considerable variation between half-months. The macaques fed mainly on fruits, seeds, mature leaves, fallen seeds, flowers, and young leaves, each of which accounted for more than 30% of feeding time in at least 1 half-month. They also ate insects and fungi, but each of them comprised less than or equal to 25 and less than or equal to 8% of feeding time in any half-month, respectively. Time spent feeding on mature leaves, young leaves, flowers, or fallen seeds is positively correlated with total time feeding and is negatively correlated with time moving. In contrast, time feeding on fruits, seeds, insects or fungi is negatively correlated with time feeding and is positively correlated with time moving. Foraging on foods that have a low energy content, a high density, and a relatively even distribution-mature leaves-or that need much manipulation to be processed-flowers and fallen seeds-increased feeding time, while foraging on foods for which monkeys must search intensively in the forest-fruits, seeds, insects, and fungi-led to increased moving time. I examined foraging strategies of Yakushima macaques in terms of moving costs and the quality of food items. Regarding time feeding on fruits, which have more energy and may need less manipulation than other foods, as a benefit and moving time as a cost, they seemed to employ a strategy that balanced the costs and benefits of foraging.
  • RAPID SHIFTING OF FORAGING PATTERN BY YAKUSHIMA MACAQUES (MACACA-FUSCATA-YAKUI) IN RESPONSE TO HEAVY FRUITING OF MYRICA-RUBRA
    N AGETSUMA, N NOMA
    INTERNATIONAL JOURNAL OF PRIMATOLOGY 16 (2) 247 - 260 0164-0291 1995/04 [Refereed][Not invited]
     
    We describe short-term changes in foraging behavior by wild Yakushima macaques (Macaca fuscata yakui), which inhabit a warm-temperate broad-leaved forest on Yakushima Island (30 degrees N, 131 degrees E), Japan. Rapid changes of dietary composition, activity budget, and range use by the monkeys occurred from May to dune, apparently associated with changes in the availability of the fruit of Myrica rubra Before the fruit ripened, monkeys spent less time moving and more time feeding on many species of leaves, which accounted for 40% of feeding time. However when M. rubra began to ripen, they fed intensively on the fruit, which accounted for three-fourths of feeding time, though the activity budget remained unaffected As fruit of M. rubra decreased, the monkeys fed more on the fruit of other species and on insects, and spent more time moving at higher speeds. There marked shifts in foraging pattern occurred within only two months. In terms of moving cost and dietary qualify, Yakushima macaques shifted their foraging pattern according to the availability of M. rubra from a ''low-cost low-yield'' strategy to a ''low-cost high-yield'' strategy, and then to a more costly strategy. The ability to make such rapid shifts in foraging pattern may allow the macaques to effectively use the highly variable food supply within their small range.
  • SUPRA-ANNUAL VARIATION IN THE INFLUENCE OF MYRICA-RUBRA FRUIT ON THE BEHAVIOR OF A TROOP OF JAPANESE MACAQUES IN YAKUSHIMA
    DA HILL, N AGETSUMA
    AMERICAN JOURNAL OF PRIMATOLOGY 35 (3) 241 - 250 0275-2565 1995 [Refereed][Not invited]
     
    Observations were made on a well-habituated natural troop of Japanese macaques (Macaca fuscata yakui), living in warm-temperate, lowland forest in Yakushima. Between mid-May and the end of June the macaques feed on the fruit of the evergreen tree Myrica rubra (Myricaceae). The fruit of this species are abundant in some years and scarce in others. Data were compared for two heavy-fruiting years (1988 and 1990) and one poor-fruiting year (1991) to examine the influence of fruit availability on patterns of foraging, ranging, and the frequency of inter-troop encounters. In both heavy-fruiting years M. rubra fruit accounted for a maximum of over 70% of foraging time, compared with a maximum of <5% in the poor-fruiting year. Heavy fruiting was also associated with a marked decrease in the overall time spent foraging. In early May of all three years troop movements were largely confined to northern parts of the home range. By early June of both heavy-fruiting years ranging had shifted to the south-west, and included an area with a high concentration of M. rubra trees. This area was rarely visited at other times, and was not visited during the study period in the poor-fruiting year. The overlap in range-use between the two heavy-fruiting years was significantly greater than that between the heavy-fruiting years and the poor-fruiting year. Heavy fruiting was also associated with an increase in the frequency of inter-troop encounters. (C) 1995 Wiley-Liss, Inc.
  • 屋久島・安房林道において餌付いたサルの社会構造と繁殖状態:野生動物保護に必要な観光客に対する指導と道路管理
    揚妻直樹
    霊長類研究 11 1 - 7 1995 [Refereed][Not invited]
  • Foraging synchrony in a group of Yakushima macaques (Macaca fuscata yakui)
    N Agetsuma
    FOLIA PRIMATOLOGICA 64 (4) 167 - 179 0015-5713 1995 [Refereed][Not invited]
     
    The synchrony of behaviour among individuals in a group of Yakushima macaques was evaluated in relation to group size and food resources. The degree of synchrony was greater when the group was small (5-8 individuals) than when it was large (15-19 individuals), Diet did not affect the degree of synchrony. However, the duration of the 'active phase', in which most members of the group synchronized feeding and moving, was shorter when they fed mostly on fruit and seeds (fruit- and seed-eating season) than when they fed mostly on leaves and fallen seeds (leaf- and fallen-seed-eating season). When the group was large, the monkeys ranged over a greater area and foraged in fewer trees during the fruit- and seed-eating season than during the leaf- and fallen-seed-eating season. However, this tendency was not so clear when the group was small. These results suggest that the extent to which the distribution of food resources determines patterns of foraging increases with group size and that monkeys in a larger group reduce levels of intragroup food competition in order to obtain sufficient food.
  • 野生動物を保護するための植生回復の検討
    揚妻直樹
    霊長類研究 11 133 - 145 1995 [Refereed][Not invited]
  • 野生ニホンザルを取り巻く社会問題と餌付けに関する意識調査
    田中俊明, 揚妻直樹, 杉浦秀樹, 鈴木滋
    霊長類研究 11 123 - 132 1995 [Refereed][Not invited]
  • 野生動物の生態情報に基づく環境計画
    揚妻直樹
    環境研究 98 118 - 124 1995 [Not refereed][Invited]
  • Preliminary survey of group density of Macaca fuscata yakui in relation to logging history at seven sites in Yakushima Japan
    Hill, D.A, Agetsuma, N, Suzuki, S
    Primate Research 10 85 - 93 1994 [Refereed][Not invited]
  • 屋久島の世界遺産地域を通過する西部林道が自然環境に与える影響
    揚妻直樹, 杉浦秀樹, 田中俊明
    霊長類研究 10 41 - 47 1994 [Refereed][Not invited]
  • 中国秦嶺山脈の野生ゴールデンモンキー(Rhinopithecus roxellanae roxellanae)
    揚妻直樹
    霊長類研究 10 49 - 56 1994 [Refereed][Not invited]
  • 屋久島における野生ニホンザルへの餌付け
    杉浦秀樹, 揚妻直樹, 田中俊明
    霊長類研究 9 225 - 233 1993 [Refereed][Not invited]
  • N AGETSUMA
    ECOLOGICAL RESEARCH 7 (3) 387 - 389 0912-3814 1992/12 [Refereed][Not invited]
     
    Age and spatial distribution of Abies firma saplings were analyzed in a mature mixed forest of A. firma and Fagus japonica. There were two major peaks in the age structure of Abies saplings at around 10 and 75 years of age. Distribution of these age classes of saplings was contagious, while that of all saplings was approximately random. These facts showed that most of the establishment of A. firma occurs just after a gap is formed, and the frequency at which such establishment occurs is about once every 60 years in a 1600 m2 area.
  • Leaf inclination of Abies firma Sieb.et Zucc, responding to light condition
    Agetsuma N
    Ecological Review 21 289 - 292 1989 [Not refereed][Not invited]

Books etc

  • ヤクシカの謎.
    揚妻直樹 (Single work)
    屋久島ヒトメクリ16: 27-29. 2018/04
  • ディア・アイランド「屋久島」
    揚妻直樹 (Single work)
    屋久島ヒトメクリ15: 18-19. 2016/11
  • どんな自然生態系をどうやって守るか考えよう.
    揚妻直樹 (Single work「自然と共生する地域社会を目指して」pp5-6.)
    第32回日本霊長類学会大会事務局 2016/07
  • 和歌山を科学するためのネタ本“オルタナティブ”な地域学を和大から(2016年度版)
    中島敦司, 湯崎真梨子, 揚妻直樹, 秋山演亮, 岩野清美, 尾久土正己, 木村亮介, 此松昌彦, 竹林浩志, 中島正博, 西村竜一, 原祐二, 藤永博 (Joint work)
    和歌山大学教育学生支援機構 2016
  • ねこさんから教えてもらったこと
    揚妻 直樹 (Contributorフィールドワーカーへの導師)
    菊池多賀夫先生追悼文集出版会 2012/08
  • Educational presentation material for use in university lectures: The Futurability of Biodiversity”.
    Satoshi Yamashita, Hiromitsu Samejima, Naoki Agetsuma, Mitsue Shibata, Yayoi Takeuchi, Masaaki Takyu, Kentaro Kanazawa, Aya Hatada, Stewart Wachs, Martin Piddington (ContributorHow can we conserve biodiversity? - Ecological methodologies -.)
    Research Institute for Human and Nature 2010/10
  • Educational presentation material for use in university lectures: The Futurability of Biodiversity.
    Naoki Agetsuma, Yuji Isagi, Atsushi Ushimaru, Shumpei Kitamura, Takuo Nagaike, Shoko Sakai, Zen-ichiro Kawabata, Wataru Fujita, Aya Hatada, Stewart Wachs, Martin Piddington (ContributorWhat will happen when biodiversity degrades?)
    Research Institute for Human and Nature 2010/10
  • 日本列島の野生生物と人
    揚妻直樹 (Contributor「シカの生態系破壊」から見る日本の動物と森と人.)
    世界思想社 2010
  • 「北方林業創立60周年誌 北の森づくりQ&A」
    揚妻直樹 (Contributorシカは森林の破壊者なのか?)
    北方林業会 2009
  • 大学講義のためのプレゼン教材 生物多様性の未来にむけて(CD-ROM)
    揚妻直樹, 井鷺裕司, 丑丸敦史, 北村俊平, 酒井章子, 長池卓男, 藤田渡, 畑田彩 (Contributor⑤生物多様性が減少すると何が起きるか?)
    昭和堂 2008
  • Sustainability and biodiversity assessment on forest utilization options
    Naoki Agetsuma (ContributorCrop raiding by wildlife induced by landscape modifications: Ecological function losses by forest developments on the island of Yakushima, southern Japan.)
    Nakanishi Printing Company 2008
  • Sustainability and diversity of forest ecosystems. An interdisciplinary approach
    Agetsuma, N (ContributorEcological function losses caused by monotonous land use induce crop raiding by wildlife on the island of Yakushima, southern Japan.)
    Springer 2007
  • 世界遺産 屋久島
    揚妻直樹, 揚妻-柳原芳美 (Contributorヤクシカの森林環境利用)
    朝倉書店 2006/10
  • やくしかノート6(神様編).
    揚妻直樹 (Single work)
    生命の島76: 80-85. 2006/10
  • やくしかノート5(杉林編).
    揚妻直樹 (Single work)
    生命の島75: 87-92. 2006/07
  • やくしかノート4(お仕事編).
    揚妻直樹 (Single work)
    生命の島74:59-63. 2006/04
  • フィールド科学への招待
    揚妻直樹 (Contributor野生動物の管理と保護.)
    三共出版 2006
  • やくしかノート3(あくび編).
    揚妻直樹 (Single work)
    生命の島73:33-37. 2006/01
  • やくしかノート2(遊動編).
    揚妻直樹 (Single work)
    生命の島72:42-46. 2005/10
  • やくしかノート1(食物編).
    揚妻直樹 (Single work)
    生命の島71:21-26. 2005/07
  • 森林の科学-森林生態系科学入門
    揚妻直樹 (Contributor食物網)
    朝倉書店 2005
  • 秋田県の絶滅のおそれのある野生生物2002.秋田県版レッドデータブック動物編
    揚妻直樹, 向山満 (Contributor哺乳類)
    秋田県 2002
  • 霊長類生態学-環境と行動のダイナミズム
    揚妻直樹 (Contributorひなたぼっこをするサル -温熱生態学のすすめ-)
    京都大学学術出版会 2000
  • 霊長類学を学ぶ人のために
    揚妻直樹 (Contributor野生生物の保護管理と霊長類学)
    世界思想社 1999
  • 東北のニホンザル
    斎藤千映美, 揚妻直樹, 岩月広太郎, 大井徹, 大谷達也, 大槻晃太, 松岡史郎, 三戸幸久 (Joint editor)
    東北ニホンザルの会 1999
  • 秋田の経済と社会-その構造と可能性
    揚妻 直樹 (Contributor白神山地と屋久島・世界自然遺産の保全)
    秋田経済法科大学 1997
  • 保護管理のためのデータベース、東北地方のニホンザル・ステータスレポート(1996年版)
    大井徹, 森治, 足澤貞成, 松岡史郎, 揚妻直樹, 中村民彦, 遠藤純二, 岩月広太郎, 大槻幸太, 伊沢紘生 (Joint work)
    東北ニホンザルの会 1997
  • 人工林にすむ動物たち.
    揚妻直樹 (Single work)
    WWF27:8. 1996
  • 矢作川の伝統漁業と人の暮らし-豊田市広瀬ヤナを中心に-
    揚妻直樹, 柳原芳美, 室山泰之, 田中蕃 (Contributor広瀬ヤナ周辺の植生)
    豊田市 1996
  • The Yakushima Wildlife Conservation Project: Assessing the influence of habitat disturbance on the ecology of macaques and deer.
    Hill D.A, Agetsuma, N (Joint work)
    Primate Eye 55: 17-18. 1995
  • 生命の島・太陽の森.
    揚妻直樹 (Single work)
    生命の島 31:98-99. 1994
  • 屋久島西部林道の緑のトンネル.
    揚妻直樹 (Single work)
    生命の島 32:69-73. 1994
  • The Yakushima Wildlife Conservation Project.
    Hill, D.A, Ohsawa, H, Agetsuma, N (Joint work)
    Asian Primates 4:5-6. 1994
  • 屋久島の自然について思うこと.
    揚妻直樹 (Single work)
    屋久杉自然館報 1:6. 1991

Conference Activities & Talks

  • シカ排除がチマダニ属の密度へ及ぼす影響-シカ密度操作実験による検証-  [Not invited]
    松山紘之, 土井寛大, 揚妻直樹, 鈴木牧
    第71回日本衛生動物学会大会  2019/04
  • Does high density of deer decrease tick density?; Interaction between an ecosystem engineer and an ectoparasite  [Not invited]
    Hiroyuki Matsuyama, Naoki Agetsuma, Ayumi Okada, Maki Suzuki
    The 66th Annual Meeting of the Ecological Society of Japan  2019/03
  • パネルディスカッション:和歌山の森里海.  [Invited]
    武内和彦, 揚妻直樹, 宇井晋介, 勝木俊雄
    和歌山県の人と自然をつなぐシンポジウム~学び生かそう自然の力~  2019/01
  • 「西川の獅子舞-古座流獅子舞の「保存」と「活用」をめぐって-」. 映像記録発表「西川の祭り 和歌山県古座川流域」  [Not invited]
    揚妻直樹, 揚妻-柳原芳美, 吉村旭輝, 藤田良治
    「西川の獅子舞-古座流獅子舞の「保存」と「活用」をめぐって-」. 映像記録発表「西川の祭り 和歌山県古座川流域」  2018/11
  • 神社合祀に反対する博物学者としての熊楠の視点  [Invited]
    揚妻直樹
    第4回南方熊楠研究会夏期例会・公開シンポジウム「紀伊半島の植生から考える南方熊楠の神社合祀反対運動」  2018/08
  • 長期観察による屋久島における野生ニホンザルの密度変化.  [Not invited]
    杉浦秀樹, 揚妻直樹, 揚妻-柳原芳美, 藤田志歩, 田中俊明ほか
    第34回日本霊長類学会大会  2018/07
  • The influence of deer exclusion on tick community  [Not invited]
    Hiroyuki Matsuyama, Ayumi Okada, Naoki Agetsuma, Maki Suzuki
    第70回日本衛生動物学会  2018/05
  • 非発情期におけるニホンジカ(Cervus nippon)オスの社会関係.  [Invited]
    日下部力, 揚妻直樹
    屋久島研究2018-京都大学野生動物研究センター共同利用研究会  2018/02
  • 人と自然の関わり合いから野生動物問題を読み解く  [Invited]
    揚妻直樹
    和歌山県の人と自然をつなぐシンポジウム~学び生かそう自然の力~  2018/01
  • ヤクシカは屋久島でどのように暮らしてきたのか?  [Invited]
    揚妻直樹
    「ヤクシカ問題と屋久島の生態系管理を考える」屋久島学ソサエティ第5回大会.  2017/12
  • Endocrinological characteristic of Yaku sika deer.  [Invited]
    Kozue Kinoshita, Yoshimi Agetsuma-Yanagihara, Naoki Agetsuma, Hideki Sugiura, Goro Hanya, Takashi Hayakawa, Yojiro Yanagawa
    The 7th International Seminar on Biodiversity and Evolution: Genetic and Hormonal Analyses on Wild Animals.  2017/11
  • Behavior and sex hormone concentrations of wild Yaku sika deer.  [Not invited]
    Zefang Xu, Sota Inoue, Maegan Fitzgerald, Li Weidong, Hao Jing, Evyen Wevan, Ekta Chaudhary, Yoshimi Yanagihara, Naoki Agetsuma, Mari Nishikawa, Kodzue Kinoshita
    The 7th International Seminar on Biodiversity and Evolution: Genetic and Hormonal Analyses on Wild Animals.  2017/11
  • ヤクシカにおける糞中性ステロイドホルモン濃度の季節変化―エゾシカと比較して―.  [Not invited]
    木下こづえ, 揚妻‐柳原芳美, 揚妻直樹, 杉浦秀樹, 半谷吾郎, 早川卓志, 栁川洋二郎
    第23回 日本野生動物医学会大会  2017/09
  • 屋久島における野生ニホンザルの人口変数の長期観察  [Not invited]
    杉浦秀樹, 揚妻直樹, 揚妻-柳原芳美, 藤田志歩, 田中俊明ほか
    第33回日本霊長類学会大会  2017/07
  • What nutrients do wild deer base on for food selection at natural feeding stations in a warm-temperate forest?  [Not invited]
    Naoki Agetsuma, Yoshimi Agetsuma-Yanagihara
    12th International Mammalogical Congress  2017/07
  • How do deer achieve foraging success under intraspecific competition for food dropped by foraging macaques?  [Not invited]
    Yoshimi Agetsuma-Yanagihara, Naoki Agetsuma
    12th International Mammalogical Congress  2017/07
  • パネルディスカッション「地域植物を活用した自然再生や緑化の波を和歌山から」  [Invited]
    中島敦司, 岡田和久, 吉原敬嗣, 山田守, 揚妻直樹
    地域植物を活用した自然再生や緑化のワークショップ(DPDS認定プログラム):みどりの地産地消“地域の自然を活用した和歌山緑化工”  2017/05
  • シカの嗜好性に関わる樹皮形質の季節及び成長段階に伴う変化パターン.  [Not invited]
    松本洋平, 饗庭正寛, 黒川紘子, 揚妻直樹, 日浦勉, 中静透
    第64回日本生態学会  2017/03
  • 照葉樹林の中のヤクシカはどんな栄養素をもとに食物の選択をしているのか?―行動観察と栄養分析を用いた解析―.  [Invited]
    揚妻直樹
    南紀生物同好会2016年秋の研究発表大会  2016/11
  • 和歌山県内におけるヤマネ(Glirulus japonicus)の生息状況と森林性大型哺乳類生息調査における巣箱自動撮影法の可能性.  [Not invited]
    芝田史仁, 細田徹治, 揚妻直樹, 鈴木慶太
    日本哺乳類学会2016年度大会  2016/09
  • どんな自然生態系をどうやって守るか考えよう  [Invited]
    揚妻直樹
    第32回日本霊長類学会大会公開シンポジウム「自然と共生する地域社会を目指して」  2016/07
  • パネルディスカッション「自然と共生する地域社会を目指して」  [Invited]
    湯本貴和, 山極寿一, 揚妻直樹, 興克樹, 河合渓, 長田啓
    第32回日本霊長類学会大会公開シンポジウム「自然と共生する地域社会を目指して」  2016/07
  • Behavior monitoring and genetic molecular analysis of wild sika deer.  [Not invited]
    Toge A, Kusakabe C, Valdevino G. Maciel, Liu J, Nomoto M, Asami M, Sharif N. A. Mohd, Otsuka R, Amaral R. S, Pokharel S. S, Nishikawa B.M, Agetsuma-Yanagihara Y, Murayama M, Agetsuma N
    The 5th International Seminar on Biodiversity and Evolution: Molecular Studies for Wildlife Science.  2016/06
  • 尾之間区の鳥獣害ハザードマップづくり.  [Not invited]
    揚妻直樹
    尾之間区果樹部会総会  2016/05
  • エゾシカによる樹皮食害の頻度は樹皮形質で計測可能か?  [Not invited]
    松本洋平, 饗庭正寛, 黒川紘子, 揚妻直樹, 日浦勉, 中静透
    第63回日本生態学会  2016/03
  • 屋久島西部地域におけるヤクシカ研究の発展性-長期調査&個体識別&行動観察-.  [Invited]
    揚妻直樹, 揚妻-柳原芳美
    野生動物研究センター・共同利用研究会2015  2015/10
  • Age and sex differences in the feeding strategies of sika deer under macaques foraging in trees.  [Not invited]
    Yoshimi Agetsuma-Yanagihara, Naoki Agetsuma
    Vth International Wildlife Management Congress  2015/07
  • Establishment and application of individual identification method of Yaku sika deer using polymorphisms of micro satellite DNA.  [Not invited]
    Tajima N, Ichiyama K, Ohkawa T, Koba H, Katale B. Z, Baking Esther L, Agetsuma Y, Agetsuma N, Sugiura H, Inoue E
    The 4th International Seminar on Biodiversity and Evolution: Molecular Studies for Wildlife Science.  2015/06
  • 地域貢献に関する和歌山研究林のとりくみ.  [Invited]
    揚妻直樹
    北大会館祭(12周年)「母校を知ろう」講演会  2015/05
  • シカ個体群の歴史から自然生態系保全を考える.  [Invited]
    揚妻直樹
    第18回紀伊半島研究会シンポジウム「森林とシカと人の暮らしを考える」  2015/02
  • パネルディスカッション  [Invited]
    前迫ゆり, 松井淳, 幸田良介, 揚妻直樹, 辻野亮, 手塚沙織, 渡邊三津子
    第18回紀伊半島研究会シンポジウム「森林とシカと人の暮らしを考える」  2015/02

Works

MISC

  • 神社合祀に反対する博物学者としての熊楠の視点
    揚妻直樹  熊楠ワークス  53-  31  -35  2019/04  [Not refereed][Invited]
  • ヤクシカは屋久島でどのように暮らしてきたのか?:その生態・進化・過去から生態系保全を考える.
    揚妻直樹  屋久島学  5-  45  -52  2018/12  [Not refereed][Invited]
  • Endocrinological characteristic of Yaku sika deer
    Kinoshita K, Agetsuma-Yanagihara Y, Agetsuma N, Sugiura H, Hanya G, Hayakawa T, Yanagawa Y  The 7th International Seminar on Biodiversity and Evolution: Genetic and Hormonal Analyses on Wild Animals  2017/11  [Not refereed][Not invited]
  • ヤクシカにおける糞中性ステロイドホルモン濃度の季節変化―エゾシカと比較して―
    木下こづえ, 揚妻‐柳原芳美, 揚妻直樹, 杉浦秀樹, 半谷吾郎, 早川卓志, 栁川洋二郎  第23回野生動物医学会大会  2017/09  [Refereed][Not invited]
  • 和歌山研究林に関する実習の現状と展望-技術職員の実習への関わり方-.
    金子潔, 揚妻直樹  北方森林保全技術  31-  17  -26  2014/02  [Not refereed][Not invited]
  • ユズの絞り滓を採食利用する野生動物の行動観察-自動デジタルカメラを用いた観察手法の有効性について-.
    浪花彰彦, 桝本浩志, 揚妻直樹, 芦谷大太郎, 野田真人  北方森林保全技術  27-  20  -26  2009  [Not refereed][Not invited]
  • 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  [Not refereed][Not invited]
     
    [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。
  • シカ大規模エンクロージャーを用いた野外実験の展開-エゾシカが森林生物群集の動態に果たす役割-.
    市川一, 石井正, 汲川正次, 佐藤智明, 三好等, 本前忠幸, 柳田智幸, 揚妻直樹, 日浦勉  北方森林保全技術  22-  37  -42  2004/10  [Not refereed][Not invited]
  • サルの時間割・ヒトの時間割.
    揚妻直樹  北方森林保全技術  19-  24  -25  2001  [Not refereed][Not invited]

Awards & Honors

  • 2005 Ecological Research Award
  • 1996 Daiwa Awards

Research Grants & Projects

  • 人為攪乱はシカの森林動態への影響を促進・抑制するか?-大規模長期操作実験での検証
    Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2020/04 -2023/03 
    Author : Hino Takafumi
  • 山間地など多様な条件不利地域を想定した森林エリアネットワーク実用化技術の確立
    Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2019/04 -2022/03 
    Author : 塚田 晃司, 中島 敦司, 湯崎 真梨子, 中村 誠宏, 揚妻 直樹
  • The impacts of artificial disturbances on wildlife ecology and physiology
    Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2018/04 -2022/03 
    Author : 揚妻 直樹, MacIntosh Andrew, 木下 こづえ, 和田 崇之, 井上 英治
     
    人間と野生動物の共存を実現するには、野生動物に対する人為的攪乱の実態を理解する必要がある。本研究の目的は、屋久島において生息地改変(農林業・道路交通など)や狩猟・駆除などの人為的攪乱が、野生のシカの体内(ストレス・寄生虫や腸内細菌感染など)および生態(生息密度・逃走距離・活動性など)に及ぼす影響を明らかにすることである。2018年度は、その準備期間に充てる予定となっていた。 そこで、まず人為的攪乱の大きい地域(攪乱地)と対照区となる攪乱の小さい地域(非攪乱地)の選定を行った。さらに、それらの地域で調査を行うための各種許可を行政各署に申請し、許可を取得した。 本研究ではシカから非侵襲的に得られる糞を用いてストレスホルモン、性ホルモン、腸内細菌叢、寄生虫、糞をしたシカの個体識別のためのDNAを分析することにしている。しかしながら、糞中のホルモン濃度や細菌叢は排泄後の経過時間とともに変化していくことが予測される。どのように変化するかを事前に把握しておく必要があった。そこで、非攪乱地においてシカを個体追跡し、排泄直後の糞を採集し、その糞を野外に放置して、時間経過とともにホルモン濃度や細菌叢の変化の様子を調べた。さらに、収集した糞の新鮮さを推定する手法も検討した。 また、試験的に各調査地に落ちている新鮮な糞の採集を行い、効率的な試料収集の手法を模索した。さらに各調査地におけるシカの生息密度・活動性などを調べるために、自動撮影カメラを設置した。
  • 気候変動に伴う温暖化と台風巨大化の複合効果が暖帯林の群集と生態系機能へ与える影響
    Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2018/04 -2021/03 
    Author : 中村 誠宏, 日浦 勉, 西岡 正恵, 揚妻 直樹
     
    気候変動は温暖化と同時に、突発的な撹乱の頻度と規模を増加させると予測されている。本研究の目的は、1)台風撹乱と温暖化の複合効果が紀伊半島の暖帯林(照葉樹林)の群集構造と垂直的な階層(空間)構造にどの様な影響を与えるのか?2)その複合効果に対して生物多様性(樹木、昆虫)と生態系機能はどのような応答(線形、非線形)をするのか?を林分レベルで実験的に解明することである。 平成30年度は研究分担者が和歌山研究林に集まり、研究林内において土壌温暖化と林冠ギャップの2要因を操作する実験のためにブロック・デザインの方形区(6m x 6m)を選定した。優占樹種(シキミ、サカキ、ヒサカキ)は同じになるよう処理区間で揃えた。操作実験前の初期状態の評価として、樹木の群集構造を評価するために、全樹木個体を対象にした毎木調査を行なった。研究林の中で自立した発電プラントを立てるために、太陽光発電装置を利用する予定にしている。和歌山大学が海南市で実施した自然再生エネルギーを利用した実験が昨年度終了したため、その太陽光発電装置を再利用させてもらうために、その資材を古座川町にある和歌山研究林にまで運搬した。 土壌温暖化処理のための太陽光発電装置を設置するには、研究林内に自動車による大量の資材の運搬および重機による設置箇所の整備をする必要がある。しかしながら、2018年8月23日に襲来した台風20号の豪雨により、研究林内の多数の林道や軌道線の崩壊・資材類の流失が引き起こされた。このため自動車や重機を使った研究林敷地内への侵入ができない状態になった。以上のことから、予定していた土壌温暖化と林冠ギャップの処理を実施することができなかった。
  • Sodium acquisition by herbivores in 'ordinary' ecosystems
    Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2018/04 -2021/03 
    Author : 半谷 吾郎, 大井 徹, 加藤 正吾, 揚妻 直樹, 太田 民久
     
    ナトリウム(Na)は、動物には必須だが植物組織には少ししか含まれておらず、その確保は植物食動物にとり大問題である。本研究では、植物食動物のNa獲得戦略を明らかにすることを目的とし、そのために日本列島スケールで海岸からの距離による森林のNa量をモデル化した上で、海岸というNaホットスポットが存在する場所(屋久島海岸部)と、それがない「普通」の生態系(屋久島上部域、白山)で、環境中のNa分布と、直接観察や糞のメタバーコーディングで調べた野生ニホンザル、ニホンジカ、ニホンカモシカの食性資料と組み合わせて野生動物のNa摂取量を推定することを目指す。これら野生動物の糞中のNa再吸収ホルモン(アルドステロン)濃度を調べ、Naが制限される野生下で、腎臓でのNaの回収や食物からの積極的なナトリウム吸収があるのかを調べる。これらを通じて、Naホットスポットがある場合とない場合に、野生の植物食動物は、生存に必要なNaをどう確保するのかという、動物生態学で見過ごされてきた大きな課題を解明する。 本年度は、本州でもっとも海から遠い位置にある、岐阜県の岐阜大学演習林で9月に、屋久島の海岸部と上部域で9月と2月に、環境を網羅するような樹木の生葉と落葉の採取を行い、そのうち9月採取分については、ナトリウムの測定を終えた。2月分については、試料の分析中である。 また、屋久島海岸部のニホンジカについて、排泄直後から、数時間の間に繰り返し何度も採取した糞を用いて、アルドステロン濃度を測定した。その結果、2時間程度で、アルドステロン濃度は変化することがわかり、アルドステロンの測定のためには、排泄直後の糞を用いる必要があることがわかった。 これを踏まえ、屋久島海岸部と上部域、白山でニホンザルとニホンジカの新鮮な糞の採取を行った。
  • Density of large and medium sized animals and its influence on vegetation in primary and secondary low-land forests in Yakushima Island.
    Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2017/04 -2020/03 
    Author : 杉浦 秀樹, 揚妻 直樹
     
    屋久島・西部地域は世界遺産にも指定され厳重に保護さている地域であるが、近年ニホンジカ(以下シカ)の高密度化が問題視されている。ただし、よく調査されているのは、かつて人がかなり伐採した海岸に近い二次林である。西部地域全体では、シカをはじめとする中・大型哺乳類がどれくらい生息しているかは、よく分かっていない。とりわけ人為的な攪乱のほとんどない一次林での生息状況を把握することが、この地域全体のモニタリングや、保全のためには不可欠である。中・大型哺乳類の密度の基礎的な情報を得るために、自動撮影カメラを西部地域の4カ所(一次林に2箇所、二次林に2箇所)に設置し、その撮影枚数から相対的な密度を推定した。 調査地は、県道に近い 標高約40~200mの二次林と、標高約340~580mカ所の一次林である。撮影は2017年7~11月、2018年7~11月に調査を行った。各地点約20台のカメラを140m間隔のグリッド状に配置し期間中連続して撮影した。ただし大量の写真が撮影されたため、まだ全ての分析は終了していない。 これまでに分析できた結果からは以下のことが示唆された。1)シカは二次林の2つの調査地で撮影頻度が非常に高く、一次林の2つの調査地ではこれに比べるとかなり低い。シカの生息密度が二次林と一次林でかなり異なる可能性が示唆される。また、当歳児の撮影率から、シカの出産率が二次林では低くなっている可能性も示唆された。 2)ニホンザル(以下サル)では、二次林の1箇所と一次林の1箇所で撮影頻度が高く、二次林の1箇所と一次林の1箇所で撮影頻度が低くなった。シカとは異なり、一次林、二次林という植生の違いでは、密度の違いが説明できない可能性がある。二次林の二箇所については、直接観察によるサルの密度推定の結果とも傾向は一致しており、二次林の中でも違いがあるとは言えそうである。
  • Forest-Area Networking as communication infrastructure suitable for the areas with poor geographical conditions such as hilly and mountainous areas
    Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2015/04 -2019/03 
    Author : Tsukada Koji
     
    In this study, we defined "Forest-Area Networking" as communication infrastructure suitable for the areas with poor geographical conditions such as hilly and mountainous areas. And we clarified difficulties which we are facing when building and operating communication infrastructure and electric power infrastructure in the area. Moreover, we conducted an interview and questionnaire survey to residents in the area to clarify the regional problems. And we verified whether the Forest-Area Networking could be used for a solution of the problems.
  • Potential of habitat management for preventing agricultural damages by wildlife
    Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2015/04 -2018/03 
    Author : AGETSUMA Naoki, MOCHIDA Koji, AGETSUMA Yoshimi, NISHIKAWA Mari
     
    We researched factors influencing intensities of crop damages by wildlife in two villages in Yakushima, southern Japan. The damage intensity by deer was positively influenced by area of the farm, and total area of broad leaved forests and negatively influenced by total length of stockade fences within 800m from the farm. The damage intensity by monkeys was negatively influenced by total farm areas within 200m from the farm, and that by Brown-eared Bulbul was positively influenced by total length of stockade fences within 200m from the farm. On the other hand, population densities of these wildlife species did not have significant positive effects on their damage intensities.
  • 自然エネルギー活用による農山漁村スマート化モデル開発-持続可能低炭素技術の発掘・開発と地域力の強化
    JST:我が国の未来を開く地域の実現に関する調査研究
    Date (from‐to) : 2014/11 -2015/02 
    Author : 湯崎 真梨子
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(B))
    Date (from‐to) : 2008/04 -2009/03 
    Author : Hirofumi HIRAKAWA, Yasuyuki ISHIBASHI, Naoki AGETSUMA
     
    The females of Ussurian tube-nosed bats use roosts in tree crowns during parturition and child-rearing period in June and July. In contrast, males use roosts below tree crowns in this period. In Autumn, both males and females use roosts close to the ground mostly less than 2 m from the ground. In late autumn, use of roosts in tree cavities were observed. During winter, it is highly likely that they hibernate within snow. PCR primers were newly designed and synthesized to amplify eight microsatellite DNA loci in the Ussurian tube-nosed bat. Of 12 primer pairs including the new primers and pr...
  • 屋久島世界遺産地域における自然環境の動態把握と保全管理手法に関する調査
    環境省:
    Date (from‐to) : 2006/04 -2009/03 
    Author : 日本自然保護協会
  • 持続的森林利用オプションの評価と将来像
    総合地球環境学研究所:研究プロジェクト
    Date (from‐to) : 2002/04 -2008/03 
    Author : 中静 透
  • Ecological functions of large herbivore for bio diversity under forest ecosystem : A large scale field experiment.
    Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2006 -2008 
    Author : AGETSUMA Naoki, HIURA Tsutomu, MIYAMOTO Toshizumi, HIURA Tsutomu, MIYAMOTO Toshizumi, MURAKAMI Masashi, HINO Takafumi, TOYOTA Ayu, ARAKI Natsuko, HIRONAGA Takuo, YAMAZAKI Akinobu, AGETSUMAYANAGIHARA Yoshimi
     
    森林環境においてシカ密度と林床植物の生産性(光条件・土壌栄養)を操作し、大型植食者の採食圧と林床植生、土壌動物の反応を調べた。3年間の実験で、シカ密度が林床植物の種数・種多様性・ミミズ密度に対し有意な影響を与えていないことが示された。また、シカが土壌微生物の多様性や活性に促進的な機能を持っていることが示唆された。なお、光条件向上のため択伐を行ったが、この択伐が林床植生・土壌動物ひいてはシカの採食行動に大きな影響を与えることが解った。
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(A))
    Date (from‐to) : 2004/04 -2007/03 
    Author : Kaichiro SASA, 中静 透, 小池 孝良, 日浦 勉, 柴田 英昭, 揚妻 直樹
     
    The purposes of this project were to clarify the mechanism of relationship between biodiversity and ecosystem functions at the boreal forests by the field experiments as forest cutting or fertilization, and to prepare some long term monitoring sites.In Uryu experimental forest, under the heavy snowfall climate, nine experimental basins were established and clear cutting and removal of undertory were carried out. (1)Increasing of current discharge and decline of water temperature were observed after clear cutting. (2)Concentration of NO3-N was not increased by clear cutting, but increased by...
  • ミズナラを取り巻く生物群集をモデル系とした生物多様性インヴェントリーと生態的分類
    文部科学省:科学研究補助金(基盤研究A)
    Date (from‐to) : 2003/04 -2006/03 
    Author : 戸田 正憲
  • 文部科学省:科学研究費補助金(若手研究(B))
    Date (from‐to) : 2004 -2005 
    Author : 揚妻 直樹
     
    本研究により以下のことが明らかとなった。全国各地でシカによる森林破壊が多く報告されており、密度が5から14頭/km^2を超えると植生への影響が顕著になると言われている。屋久島の照葉樹林では、シカ密度が60から80頭/km^2と報告されており、急激で著しい森林破壊が進行しているはずであった。しかし、ヤクシカが小型であることや照葉樹林の高い生産性を考慮しても、屋久島の照葉樹林ではシカの森林に対する悪影響は小さいものであることが示唆された。シカの森林に対する悪影響が少ないのは、彼らが安定した生息環境にあって、森林植生と安定的な相互作用を進化させてきた可能性がある。ヤクシカは食物の大半をリター(主に落葉)に依存し、植物が光合成を行う生産器官への採食が少なかった。また、サルが落とした食物も利用している。これらの他にも何らかのメカニズムによって森林への影響が緩和されていた可能性がある。シカを排除による植物種多様性の低下や土壌の栄養塩循環の減速も他研究により明らかになっていることから、もともと捕食者のいない屋久島では、その植物種の多様性の高さを、むしろシカが積極的に維持してきた可能性がある。一方、大規模伐採・人工植林で撹乱された場所ではシカの生息密度は著しく減少しており、その影響は植林から数十年経っている現在でも歴然と現れていた。さらに、シカ1頭当たりの植物への採食圧は自然林と比べ植林地で...
  • 文部科学省:科学研究費補助金(若手研究(A))
    Date (from‐to) : 2002 -2003 
    Author : 揚妻 直樹
     
    屋久島の照葉樹林において、オス・メス数頭のシカの採食行動を春・夏・秋・冬に観察した。その結果、彼らは木本落葉、落下した木本の繁殖器官(果実・種子・花)、草本(シダ植物を含む)をおもに採食していることが示された。一貫して木本落葉の割合がもっとも多く、全体の約半分を占めた。落下した植物繁殖器官の採食割合が次に高かった。落下した植物器官(木本落葉+落下繁殖器官)は各季節の採食割合の5〜9割に達した。なお、落下植物器官にはサルが落としたものが1割含まれていた。草本と木本生葉の採食割合は季節で大きく変化したが、草本は夏期に、木本生葉は冬期にそれぞれ3割を占めた。樹皮の採食割合は1%未満であった。以上から、この地域のシカは林床に落下した植物器官に食物の大半を依存していることが解った。シカの行動域を調査するため、春・夏・秋・冬に6〜8頭の行動域をラジオテレメトリー法によって調査した。その結果、オスの行動域面積はメスに比べ広いこと、メスの行動域は狭い地域に集中していたのに対し、オスの行動域は集中的に利用する場所が数キロずつ離れて複数存在することが解った。調査地のシカの生息密度を調査したところ約70頭/km^2と推定され、ニホンジカの生息地のなかでも非常に高いことが示された。調査地において胸高直径5cm以上の樹木5000本以上調査した結果、調査地の森林は小径木の割合が非常に多いL字構造となって...
  • 屋久島の哺乳類相の解明
    藤原ナチュラルヒストリー振興財団:
    Date (from‐to) : 2001/04 -2002/03 
    Author : 揚妻 直樹
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(A))
    Date (from‐to) : 1999 -2001 
    Author : Hideyuki OHSAWA, Njifoti Hanson, 中川 尚史, 濱田 穣, 揚妻 直樹
     
    Field researches both in a topical forest and an open land in Africa was conducted to clarify the feature of adaptation and process of dispersion of cercopiethecid monkeys in forests and into open lands.Research in a forest was conducted at the Nature Reserve of Ipassa-Mingouri in Gabon this year following the previous year. Hamada accompanied a research collaborator Okayasu (Howletts Institute, United Kingdom). In the vocal communication studies of colobus monkeys and cercopiethecid monkeys they collected vocal response of monkeys to vocal sounds of individuals in their own group and those...
  • ニホンザル生態調査業務
    秋田県八森町:
    Date (from‐to) : 1997/09 -1998/03 
    Author : 揚妻 直樹
  • ヤマネ調査
    秋田県:
    Date (from‐to) : 1997 -1998 
    Author : 揚妻 直樹
  • 「矢作川の伝統漁法と人の暮らし-豊田市広瀬ヤナを中心に-」(哺乳類・植生担当)
    豊田市:愛知県地方振興補助事業費
    Date (from‐to) : 1995/04 -1997/03 
    Author : 揚妻 直樹
  • 屋久島のサルと森林の保全に関する基礎研究
    日本生命財団:研究助成
    Date (from‐to) : 1990/10 -1991/09 
    Author : 加納 隆至

Educational Activities

Teaching Experience

  • Advanced Course in Forest Sphere Science III (Conservation Biology)
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 環境科学院
    キーワード : 脊椎動物,保全,野外調査,研究発表 Vertebrate Ecology, Conservation, Field Investigation, Presentation
  • Advanced Course in Animal Ecology II
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 環境科学院
    キーワード : 動物、個体群、群集、行動、保全、進化、種間相互作用 Animal, population, community, behavior, conservation, evolution, species interaction


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