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Theoretical Study of Spatio-Temporal Dynamics of Synchronized Flowering and Reproduction of Trees in Forests

森林树木同步开花与繁殖的时空动态理论研究

基本信息

批准号：
12640616
负责人：
IWASA Yoh
金额：
$ 2.3万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

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.

成熟森林中的树木通常表现出间歇性繁殖。密集的开花和种子生产在几年中只发生一次，通常是远距离同步的。我们研究了个体能量储备动态的耦合映射模型，并表明当异交花粉的可获得性限制了树木的果实产量时，树木在繁殖过程中变得同步。在没有花粉限制的情况下，树木表现出独立的混沌波动。随着全球花粉的结合，树木表现出不同程度的生殖同步。对于完全同步的森林，李亚普诺夫指数被解析地计算出来，表明只有当树木在很大一部分年份以低(但正)的水平开花时，才能发生树木的同步繁殖，由于异交花粉的短缺而导致小结果。然后，我们研究了具有局部花粉交换的耦合映象格子。动态空间协方差表明，整个森林的强烈同步性可以从相当短的距离花粉交换中发展出来。然后，我们检验了共同环境波动导致的同步性，无论是在年生产力水平上还是在生殖阈值水平上。如果没有花粉耦合，即使在个体间环境波动相关的情况下，个体间也很难出现正相关。只有在花粉耦合和相关环境波动同时存在的情况下，才能保持高水平的正相关。我们还讨论了不同物种之间共享传粉者的生殖同步性，适用于东南亚热带雨林的同步化。第一篇论文发表在《JTB》杂志上，第二篇发表在《生态学》杂志上，另一篇论文提交给了《生态学》杂志。