| Project/Area Number |
12640616
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
生態
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
IWASA Yoh Faculty of Sciences, KYUSHU UNIVERSITY, Professor, 大学院・理学研究院, 教授 (70176535)
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| Co-Investigator(Kenkyū-buntansha) |
MOCHIZUKI Atsushi Faculty of Sciences, KYUSHU UNIVERSITY, Ass. Prof., 大学院・理学研究院, 助手 (10304726)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2001: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2000: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | synchronized reproduction / masting / coupled chaos system / pollen coupling / spatio-temporal dynamics / spatial covariance / beech / 時空間動態 / 一斉開花 / 結実 / 熱帯多雨林 |
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| Research Abstract |
Trees in mature forests often show intermittent reproduction. Intensive flowering and seed production occur only once in several years, often synchronized over a long distance. We study a coupled map model for the dynamics of energy reserve of individuals, and show that trees become synchronized in reproduction when their fruit production is limited by the availability of outcross pollen. Without pollen limitation, the trees show independent chaotic fluctuation. With global pollen coupling, trees show various degree of reproductive synchronization. Lyapunov exponents are calculated analytic ally for perfectly synchronized forests, demonstrating that synchronized reproduction of trees can occur only if trees flower at low (but positive) levels in a significant fraction of years, resulting in small fruit sets due to the shortage of outcross pollen. We then study a coupled map lattice with local pollen exchange. Dynamic spatial covariance shows that a strong synchronization over the whole forest can develop from rather short range pollen exchange. We then examined the synchronization caused by common environmental fluctuation either in the annual productivity or the reproductive threshold level. Without pollen coupling, positive correlation between individuals are difficult to emerge even under environmental fluctuation correlated between individuals. Positive correlation can be maintained at high level only in the presence of both pollen coupling and correlated environmental fluctuation. We also discuss the reproductive synchronization between different species who share common pollinators, which is applicable to the synchronization in the tropical rain forest in Southeast-Asia. The first paper was printed in JTB, the second in now (in press) in Ecology, and another was submitted to J Ecology.
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