CAREER: Drivers of tropical tree seedling dynamics and species coexistence along environmental gradients

热带地区拥有地球上最丰富的植物多样性，成百上千的树种生活在一片森林中。如何在没有少数物种接管的情况下，在这些地区存在如此多样化的植物，仍然是生态学中的一个长期问题。作用于幼苗的过程对于确定在这些森林中发现的植物的数量和类型可能特别重要。本研究将研究光和水的可获得性以及邻近植物的类型和数量等因素如何影响幼苗存活并帮助维持植物多样性。了解如何维持多样性对于保护和管理森林以及保护森林提供的服务非常重要。该项目将把研究与教育活动结合起来，包括热带森林生态和保护的课堂和实地考察课程。还将开发针对环境决策者的在线培训项目的视频。该项目将利用巴拿马中部强烈的降雨梯度，调查不同苗木生长和存活驱动因素的相对重要性如何随着降雨量和旱季严重程度的变化而变化。此外，该项目还将研究树种特征--如木材密度和叶面积等特征--如何决定幼苗对当地环境的反应。在巴拿马实地收集的数据将用于开发新的计算机模型，模拟多个世代的森林动态，以评估苗木表现的非生物和生物驱动因素对树种共存的相对贡献。这种现场数据和新颖的森林模拟模型的整合将显著提高对热带树木群落形成的关键机制的理解，并将提供一个框架，以预测热带森林多样性和物种组成的变化，以应对气候的变化。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The tropics contain the highest diversity of plants on earth, with hundreds of tree species existing within a single forest. Understanding how such a diversity of plants can exist in these areas, without a handful of species taking over, remains a long-standing issue in ecology. Processes acting on seedlings may be particularly important for determining the number and types of plants found in these forests. The present study will examine how factors such as light and water availability, and the types and number of neighboring plants influence seedling survival and help maintain plant diversity. Understanding how diversity is maintained is important for conserving and managing forests and preserving the services they provide. This project will integrate research with educational activities, including classroom-based and field trip courses on tropical forest ecology and conservation. Videos for online training programs targeting environmental decision makers will also be developed.The project will take advantage of a strong rainfall gradient in central Panama to investigate how the relative importance of different drivers of seedling growth and survival shift with changes in rainfall and dry season severity. In addition, the project will examine how species characteristics -traits like wood density and leaf area- determine seedling responses to their local environment. Data collected at field sites in Panama will be used to develop new computer models that simulate forest dynamics over multiple generations in order to assess the relative contribution of abiotic and biotic drivers of seedling performance to tree species coexistence. This integration of field data and novel forest simulation models will significantly advance understanding of the key mechanisms shaping tropical tree communities and will provide a framework for predicting changes in tropical forest diversity and species composition in response to shifts in climate.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.