Functional convergence and trade-offs in functional and morphological traits of tropical tree species related to water uptake, transport and loss.

GOLDSTEIN GUILLERMO, MEINZER FREDERICK C., BUCCI SANDRA J., STRATTON LISA

Cairns, Australia

Conferencia; 3er International Canopy Conference; 2003

Here we examine the extent to which different tree species exhibit functional convergence in regulation of water economy at different scales from leaves to whole trees. Striking similarities in behavior in terms of water uptake, transport an d loss can be revealed when appropriate normalizing and scaling factors are identified. We will use information on canopy trees from different tropical ecosystem. For example, hydraulic efficiency to water transport is positively correlated to wood-saturated water content, a surrogate for relative water storage capacity in evergreen dry forest species. Despite large species-specific differences in leaf water relation characteristics, all species conform to the same functional relationship. The species with higher water storage capacity are more efficient in terms of long-distance water transport and consequently exhibit smaller seasonal variations in water potentials. Similarity, individuals and species of neotropical savannas share the same functional relationship between wood density, hydraulic conductance and several physiological properties of the leaves. In co-ocurring canopy species in a Panamanian forest the shared relationship between tree size and time of maximum sap flow at the base of the trees suggest that a common relationship between diurnal stem water storage capacity and tree size exists. These results are consistent with hypotheses that allometric scaling of plant vascular systems, and therefore water use, is universal.