Collaborative Research: Intraspecific variation in drought responses of tropical tree seedlings - consequences for species distributions under climate change

充足的降雨是热带森林如此多样化和多产的原因之一。 据预测，气候变化将改变大多数热带森林所经历的旱季的长度和强度。因此，了解这些森林将如何应对气候变化，需要我们调查热带树木对干旱的反应。从温带森林，我们知道，干旱的反应各不相同，不仅在树种之间，而且在物种内部：来自不同地点的同一物种的种群对干旱的反应可能不同，从而增加了整个物种在气候变化时持续生存的能力。然而，我们对热带树种的干旱反应如何变化知之甚少。 该项目将测量巴拿马热带树种对干旱的反应变化，从太平洋到大西洋，巴拿马地峡各地的降雨量各不相同。 为了对比不同降雨量地点的树木种群的反应，研究人员将联合收割机结合生理测量和遗传分析，对不同地点之间移植的幼苗的生长和存活进行实地实验。 研究结果将显示变异是由遗传因素还是环境因素决定的，以及哪些植物性状是干旱反应的基础。这将提高我们预测热带森林将如何应对全球气候变化的能力。这个项目对社会很重要，因为热带森林拥有地球上大部分的陆地生物多样性，并为人们提供有价值的产品和生态系统服务。该项目产生的信息将有助于保护生物多样性和管理森林，以维持具有重要商业价值的木材品种的生产。 除了向科学界提供调查结果外，该项目还将在一次专题讨论会上向当地管理人员和利益攸关方传播调查结果。 此外，该项目还将通过培训青年生物学家来加强科学工作者队伍。

Abundant rainfall is one of the reasons that tropical forests are so diverse and productive. Climate change is predicted to shift the length and intensity of the dry seasons that most tropical forests experience. Understanding how these forests will respond to climate change therefore requires that we investigate the responses of tropical trees to drought. From temperate forests, we know that drought responses vary, not only among tree species, but also within species: populations of the same species from different sites can show different responses to drought, increasing the capacity of the species as a whole to persist when climate changes. However, we know very little how drought responses may vary within tropical tree species. This project will measure the variation in response to drought within tropical tree species in Panama, where current rainfall varies from site to site across the isthmus from the Pacific to the Atlantic. To contrast responses of trees in populations from sites with different amounts of rainfall, researchers will combine physiological measurements and genetic analyses with field experiments on the growth and survival of seedlings transplanted between sites. Results will show whether variation is determined by genetic or environmental factors, and which plant traits underlie drought response. This will improve our ability to predict how tropical forests will respond to global climate change. This project is important to society because tropical forests harbor the majority of the Earth's terrestrial biological diversity and provide people with valuable products and ecosystem services. The information generated by the project will be useful for conserving biodiversity and for managing forests to maintain production of commercially important timber species. Besides making findings available to the scientific community, the project will disseminate findings to local managers and stakeholders in a symposium. In addition, the project will strengthen the workforce for science by training young biologists.