PARENT SESSION
Oral Session # 8: Plant Ecology I: Physiology and Function I.
Presiding: E Hamerlynck
Monday, August 4. 8:00 AM to 11:30 AM, SITCC Meeting Room 200.

Linking plant physiological ecology to ecosystem science: Effects of life history traits on leaf decomposition.

Santiago, Louis¹, ¹ University of Florida, Gainesville, FL, USA

ABSTRACT- Plant life history traits such as wood density, photosynthesis and anti-herbivore defenses, were compared with leaf litter decomposition rates (2 years) on a broad selection of plant growth forms including palms, lianas, canopy trees and pioneer trees in Panamanian lowland wet forest. Leaf nitrogen had a strong positive effect on leaf decomposition rate, whereas anti-herbivore defenses had a strong negative effect on decomposition. Leaf nitrogen also had a strong positive effect on leaf photosynthetic rate and anti-herbivore defenses were negatively correlated with photosynthesis. Wood density appeared to constrain suites of traits. Species with low wood density exhibited high photosynthetic and decomposition rates. In contrast, species with low wood density exhibited leaves with lower photosynthetic rates that were relatively slow to decompose. In general, wood density is negatively correlated with plant growth rate and therefore reflects variation along an axis of life history traits. The observation that leaf photosynthesis and decomposition are driven by the same interdependent suite of characteristics suggests that the axis of plant life history traits can be extended to decomposition. Therefore, the effects of plant species on decomposition at the ecosystem scale can be understood in terms of specific allocation patterns that reflect plant strategies.

Key words: nitrogen, tropical, decomposition, photosynthesis