Dispersal Limitation: Does it Limit the Distribution and Abundance of Pioneers in a Neotropical Forest?

小行星9509026 对巴拿马巴罗科罗拉多岛（BCI）新热带森林的50公顷永久性地块的长期研究表明，许多潜在的合适的林隙地点没有个别先锋物种。 虽然先锋物种在合适的地点很少的森林中并不常见，但它们似乎比偶然预期的要少。 这项研究将测试的假设，即分布和丰富的先驱物种在BCI森林主要是由扩散限制，而不是由发芽和建立的限制。 所有大于25平方米的林冠空隙都将在50公顷的地块上绘制。 在林隙中进行一系列的田间试验，以确定林隙和封闭林中的环境条件是否影响发芽和建立。 还将监测种子下落，作为传播限制的一种措施。 扩散限制的潜在重要性远远超出了对分布和丰度的解释。 最近的理论研究表明，强扩散限制可以通过大大减缓竞争排斥来促进树种丰富度。 此外，这项工作将提供重要的见解机制，保持物种多样性的新热带森林社区，正在迅速消失，由于砍伐森林。

9509026 HUBBELL A long-term study of a 50 ha permanent plot of neotropical forest on Barro Colorado Island (BCI) Panama, has revealed that individual pioneer species are absent from many potentially suitable gap sites. Although pioneer species are not expected to be common in a forest where suitable sites are rare, they appear to be less common than would be expected by chance. This research will test the hypothesis that distribution and abundance of pioneer species in the BCI forest are primarily controlled by dispersal limitation rather than by germination and establishment limitation. All canopy gaps greater than 25 m2 will be mapped on the 50 ha plot. A series of field experiments in gaps will be conducted to determine if the environmental conditions in gaps and closed forest affect germination and establishment. Seed fall will also be monitored as a measure of dispersal limitation. The potential importance of dispersal limitation goes far beyond finding explanations for distribution and abundance. Recent theoretical work has shown that strong dispersal limitation can promote tree species richness by greatly slowing competitive exclusion. In addition, this work will provide important insights into mechanisms that maintain species diversity in neotropical forest communities that are rapidly disappearing due to deforestation.