PARENT SESSION
Poster Session #36: Seed Production, Recruitment, and Pollination.
Wednesday, August 7. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC
50
Maintenance of diversity in a neotropical tree community: New insights from the seedling layer.
Comita, Liza*,1, Hubbell, Stephen1,2, 1 University of Georgia, Athens, GA2 Smithsonian Tropical Research Institute, Balboa, Panama
ABSTRACT- For two decades the survival, growth, and spatial locations of all trees >1cm dbh have been monitored within a 50-ha plot on Barro Colorado Island (BCI), Panama. One of the main goals of the BCI Forest Dynamics Project has been to test several hypotheses to explain the high tree diversity of tropical moist forests. Many of the proposed mechanisms for maintaining diversity are thought to act most strongly at the seed and seedling stages. Recruitment limitation, Janzen-Connell effects, and light gaps are all thought to enhance local tropical tree diversity by altering the spatial distribution of surviving seedlings. In order to assess the relative importance of these factors in the maintenance of tropical tree diversity in the BCI forest, we have undertaken a large-scale community-level study of seedlings and small saplings in the 50-ha Forest Dynamics Plot (FDP). In the first year, we collected data on the abundance and spatial distribution of >60,000 seedlings and small saplings of 344 liana and tropical tree species in twenty thousand 1-m2 plots distributed uniformly over the 50-ha FDP. Using these data in conjunction with the spatial data on adult tree distributions and light gap locations, we evaluate the relative importance of recruitment limitation, adult density, and heterogeneous light levels in shaping the observed spatial distribution of seedlings and small saplings of tropical trees. Our results advance the current understanding of how diversity is maintained in species rich tropical forests.
KEY WORDS: diversity, density dependence, Janzen-Connell hypothesis, recruitment limitation