LTREB: Long-Term Studies of Seedling and Small Sapling Community Dynamics in a Neotropical Forest

这笔拨款支持对热带雨林及其如何应对气候变化的长期研究的继续。这片森林位于巴拿马运河上的巴罗科罗拉多岛（BCI），这是一个由史密森学会管理的生物保护区，也是世界上最著名的植物学和生态学热带森林之一。这笔拨款用于研究幼苗的发芽和存活，这是树木生命历史中对气候最敏感的阶段。由于大气中二氧化碳的增加，预计热带地区的季节性和年度降雨模式将发生巨大变化，这可能导致热带森林树种组成和周转率的重大变化。幼苗是早期预警系统，因为它们对干旱很敏感。该项目的结果在预测热带雨林如何应对气候变化方面应该具有实际意义。这项研究还增加了对热带雨林如何运作以及为什么有这么多树种的基本了解。主题研究地块有五个足球场那么大，其中的树木种类是墨西哥以北北美所有树木种类的两倍。这个项目将检验这样一种假设，即在普通物种无法繁殖的年份里，幼苗的波动会给稀有物种带来竞争优势，从而让更多的物种共存。先前的支持导致了许多美国学生在热带植物学和生态学方面的培训（自1980年以来，有200多名本科生和研究生接受培训，其中包括7名博士和4名硕士学生）。与这个项目相关的学生、同事和pi已经根据这个项目的数据发表了100多篇论文和3本书。

This grant supports a continuation of a long-term study of a tropical rain forest and how it is responding to climate change. The forest is in the Panama Canal on Barro Colorado Island (BCI), a biological reserve managed by the Smithsonian and one of the botanically and ecologically best known tropical forests in the world. The grant is to study germination and survival of seedlings, stages of tree life histories that are most sensitive to climate. Large changes in seasonal and annual rainfall patterns are predicted in the tropics due to increasing atmospheric CO2, which may cause major changes in the tree species composition and turnover rates of tropical forests. Seedlings are early warning systems because of their drought sensitivity. Results of this project should be practically beneficial in forecasting how tropical rain forests will respond to climate change. The study also adds to basic understanding of how tropical rain forests work and why they have so many tree species. The subject research plot, five football fields in size, has twice the tree species found in all of North America north of Mexico. This project will test the hypothesis that seedling fluctuations let more species coexist by giving rare species a competitive edge in years when common species fail to reproduce. Prior support has resulted in the training of many U.S. students in tropical botany and ecology (over 200 undergraduate and graduate trainees since 1980, including 7 Ph.D.'s and 4 Master's students). Students, colleagues, and PIs associated with this project have already published more than 100 papers and 3 books based on data from this project.