1998 Fiscal Year Final Research Report Summary
Coevolution and Coexistece Mechanism of African Great Apes
| Project/Area Number |
08041146
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Field Research |
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| Research Field |
人類学(含生理人類学)
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| Research Institution | KYOTO UNIVESITY |
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Principal Investigator |
YAMAGIWA Juichi Kyoto Univ., Faculty of Science, Associate Professor, 大学院・理学研究科, 助教授 (60166600)
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| Co-Investigator(Kenkyū-buntansha) |
KANYUNYI Bas コンゴ民主共和国中央科学研究所, 室長
NGOWOU Joseph Ministry of Forest, Gabon, Dept.Fauna, Research Fellow, 動物管理局, 研究員
YUMOTO Takakazu Kyoto Univ., Center for Ecological Research, Associate Professor, 生態学研究センター, 助教授 (70192804)
KURODA Suehisa Shiga Prefecture Univ., Dept, Human & Culture Sciences, Professor, 人間文化学部, 教授 (80153419)
NISHIDA Toshisada Kyoto Univ., Faculty of Science, Professor, 大学院・理学研究科, 教授 (40011647)
BASABOSE Kanyunyi D.R.Congo, CRSN,Dept.Mammalogy, Head Researcher
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| Project Period (FY) |
1996 – 1998
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| Keywords | Govilla / chimpanzee / Tropical Forest / Coevolution / Diet / Ranging / Grouping / Nest |
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| Research Abstract |
This study aims to clarify the coexistence mechanism of gorillas and chimpanzees inhabiting tropical montane and lowland (coast and inland) forests sympatrically, by analyzing data on dietary composition, foraging patterns, group formation and interspecies relationships. Coevolution process of such apes with other fauna and flora of tropical forests is also analyzed and considered. This year field research was conducted in Gabon. Data on the fruit phenology were collected in the coastal forest of Petit Loango Reserve by the transect census. We found the positive correlation between chimpanzee ranging patterns and the fruit availability in the coastal forest. The different seasonality in fruit scarcity between the coastal and inland forests may influence movements and grouping patterns of chimpanzees. The lack of terrestrial herbaceous vegetation also stimulate chimpanzees to disperse in wide range. BASABOSE, K.was invited to Japan, and we analyzed data collected in the Kahuzi-Biega National Park, D.R.Congo with him.
The results show a positive correlation between fruit availability and the length of day range for gorillas, while it was negative for chimpanzees. The distribution of nests also shows chimpanzee's avoidance to nest in the same food trees as gorillas. These tendencies suggest that the shortage of high quality foods may promote niche separation between gorillas and chimpanzees. We are still analysing data on differences in socioccological features between sympatric gorillas and chimpanzees and will present new perspectives on their speciation and coevolution in the near future.
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