Long-Term Studies of Small-Sapling Community Dynamics in Relation to Light Gaps in a Neotropical Forest

University Of Georgia Research Foundation Inc, Athens GA

Investigators

Abstract

HUBBELL The objective of this research is to conduct an annual census of seedlings and saplings in a tropical rain forest in Panama, to monitor their annual growth, survival, and recruitment for 5 years. We will also record the location and dynamics of all treefall light gaps that open in the forest, because these are the main sites for forest regeneration, where seedling and small sapling dynamics are accelerated. The dynamics of this forest, located on Barro Colorado Island (BCI) in the Panama Canal, has been studied for the past two decades, but thus far seedlings and small saplings have not been included. These new data will enable us to test alternative hypotheses for how the more than 300 species of trees are maintained and coexist in the BCI forest. New evidence suggests that host-specific fungal pathogens that kill seeds and seedlings may be important agents regulating tree diversity in the BCI forest. We will test this hypothesis and test the strength of density-dependent regulation in the seedling and small sapling community. We will also test the hypothesis that treefall gaps, interacting with limited seed dispersal, limit the recruitment success of most tree species in the BCI forest. The work is likely to have broader significance for understanding how tropical forests in general maintain high tree species diversity.