| Project/Area Number |
13575006
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
生態
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| Research Institution | Research Institute for Humanity and Nature (2003-2004)
Kyoto University (2001-2002) |
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Principal Investigator |
YUMOTO Takakazu Research Institute for Humanity and Nature, Professor, 研究部, 教授 (70192804)
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| Co-Investigator(Kenkyū-buntansha) |
MARUHASHI Tamaki Musashi University, Faculty of Humanities, Professor, 人文学部, 教授 (20190564)
NOMA Naohiko University of Shiga Prefecture, Lecturer, 環境科学部, 講師 (80305557)
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| Project Period (FY) |
2001 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥8,500,000 (Direct Cost: ¥8,500,000)
Fiscal Year 2004: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2003: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2002: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2001: ¥3,700,000 (Direct Cost: ¥3,700,000)
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| Keywords | frugivory / fruit characteristics / hornbill / population fluctuation / seed dispersal / seed predation / small mammals / tropical forest / 熱帯雨林 / 分断化 / 哺乳類 / タイ / 種子撒布 / カオヤイ国立公園 / 一斉開花 / パソ森林保護区 / ネズミ / ゾウムシ / ブタオザル / カオヤイ / 熱帯季節林 |
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| Research Abstract |
1) Fruit consumption on the canopy by 4 species of hornbills, white-handed gibbons, pig-tail monkeys and other frugivores was observed to reveal the relationships between fruit consumers and fruit characteristics in Khao Yai National Park, Thailand, a moist tropical forest Among 259 plant species, plants having a large and lipid-rich fruit with 1-seed were observed to be consumed and be dispersed only by hornbills. So these plants can be called "hornbill dispersed plants". White-handed gibbons preferred sugar-rich fruits, and pig-tailed monkeys often ate unripen fruits and acted mainly as seed predators. 2) Seeds and seedlings dispersed around nest trees of hornbills were marked and monitored during 3 years. Most of seedlings near nest trees disappeared during 3 year, however, some seedlings of "hornbill dispersed plants" had survived. Seedling s were suffered by heavy seed predation, which caused by small mammals attracted by a high density of seeds and seedlings around nest trees. 3) Fruit consumption on the ground was studied by camera trapping, and population fluctuation of small mammals, Maxomys surifer and Niniventer bukit was monitored during 3 years by capture-recapture method. The biomass of two main seed predators, M. surifer and N. bukit (2150 g/ha) was twice and three times as high as rodents recorded in other tropical forests (e.g. 616 g/ha in Huai Kha Khaeng). These two species of rodents showed highest population density in the middle of dry period. But the breeding season of two rodents differed, which suggested some relationships of food fruit/seed of them. 4) In conclusion, the seeds and seedlings in the forests where hornbills are extinct will be suffered by heavier seed predation caused by heavier accumulation of seeds around mother trees, so that the regeneration of trees will become difficult at least for some tree species.
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