PARENT SESSION
Oral Session 63: Forest Ecology III: Communities; Diversity; Mycorrhizae.
Presiding: B Kerns and I Ashton
Wednesday, August 4, 8:00 AM to 11:30 AM, Meeting Room C 120.

The consistency and ecological importance of life history trade-offs in tropical trees and lianas.

Gilbert, Benjamin^*,1, Wright, S. Joseph², Kitajima, Kaoru³, Muller-Landau, Helene⁴, Hernandez, Andres², ¹ University of British Columbia, Vancouver, BC, Canada² Smithsonian Tropical Research Institute, Panama City, Panama³ University of Florida, Gainesville⁴ University of Minnesota, Twin Cities

ABSTRACT- Life-history trade-offs in growth and survival were quantified for 58 species of woody seedlings and augmented with existing data on tree saplings (10 mm < dbh < 39 mm) from Barro Colorado Island (BCI), Panama. We evaluated the general applicability of a rapid growth to low survival trade-off across two functional groups (lianas and trees) and for two life stages (seedlings and saplings, for trees only). A species' relative position on the trade-off gradient was correlated to two other traits in trees --wood density and fecundity-- and was likewise correlated to species' gap preferences. Lianas showed trade-offs similar to trees, with these groups demonstrating broadly overlapping ranges in survival and relative height growth as seedlings. Trees were tested for ontogenetic shifts in life history trade-offs; only two out of 15 species demonstrated shifts in their growth and survival trade-off patterns between seedling and sapling life stages. The relative positions of tree species on the trade-off gradient were correlated to their abundances in this community. In the case of the two species showing ontogenetic shifts, abundances were more strongly correlated to seedling trade-offs than sapling trade-offs. Our results indicate that life-history trade-offs are applicable across functional groups (lianas and trees), are mainly consistent across life-stages (within trees), and likely play an important role in determining plant species composition in forests.′

Key words: life history, lianas, trade-offs, tropical forests