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.
