RAPID: Growth, Mortality, and Competition of Tropical Tree and Liana Species During an Extended Drought

Marquette University, Milwaukee WI

Investigators

Abstract

A major goal in ecology is to understand why different types of plants and animals occur where they do. This question is particularly important for tropical forests because they are home to most of the world's species and are essential for global carbon and nutrient cycles; they help control the atmosphere of the entire planet. In a sense, tropical plants are the "lungs" of the planet. Scientists are starting to think that drought is critically important in determining how well tropical forests "breathe". However, the evidence for this is still unclear. In this project, researchers will test how different tropical plant species respond to an ongoing, multi-year drought in Panama. Undergraduate and graduate students from the U.S. will participate in the project and receive training in how to conduct scientific research. In the context of a large-scale, long-term competition experiment, the PI will examine the role of a multi-year drought to test two predictions: 1) The strength of plant-plant competition increases with drought and varies with species identity. 2) Plant species that capitalize on drought will share a suite of plant hydraulic functional traits. By testing these predictions, the PI can provide a functional-mechanistic explanation for how different species respond to drought, and determine whether plant-plant competition intensifies the effects of drought. By examining the responses of more than 100 plant species and by relating those responses to a suite of functional characteristics for each species, this project will identify the subset of species that will likely increase or decrease with future droughts, as well as the dual effects of drought and competition on tree species performance. Considering the importance of both drought and competition to tropical forest diversity and function, results will be fundamental to our understanding of tropical forest ecology and, more generally, ecosystem health. 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.