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Verification of top-down effects in the tropical forest ecosystems of South-eastern Asia

东南亚热带森林生态系统自上而下效应的验证

基本信息

批准号：
13575006
负责人：
YUMOTO Takakazu
金额：
$ 5.44万
依托单位：
Research Institute for Humanity and Nature (2003-2004)Kyoto University (2001-2002)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2004
项目状态：
已结题

项目摘要

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.

1)在泰国考艾国家公园的一个潮湿的热带森林中，观察了4种犀鸟、白手长臂猿、猪尾猴和其他食果动物在树冠上的水果消费，以揭示水果消费者与水果特性之间的关系。在259种植物中，观察到只有犀鸟消费和传播具有大的和富含脂质的单种子果实的植物。因此，这些植物可称为“犀鸟分散植物”。白掌长臂猿喜欢富含糖分的水果，而猪尾猴经常吃未成熟的水果，主要充当种子捕食者。2)在3年的时间里，对分散在犀鸟巢树周围的种子和幼苗进行了标记和监测。巢树附近的幼苗在3年内大部分消失，但仍有部分“犀鸟散生植物”的幼苗存活。种子被大量的种子和幼苗捕食，这是由于小型哺乳动物被巢树周围高密度的种子和幼苗所吸引。3)采用相机诱捕法研究了地面上的水果消费量，并采用捕获-再捕获法监测了3年来小兽、大腹鼠和白腹鼠的种群数量变动。两种主要种子捕食者M. surifer和N. bukit（2150克/公顷）是其他热带森林中记录的啮齿动物的两倍和三倍（例如Huai Kha Khaeng的616克/公顷）。这两种啮齿动物的种群密度在旱季中期最高。但两种啮齿动物的繁殖季节不同，提示了它们之间的食物果实/种子关系。4)总之，犀鸟灭绝的森林中的种子和幼苗将遭受更严重的种子捕食，这是由于母树周围的种子积累量更大，因此树木的更新将变得困难，至少对某些树种来说是如此。