Compositional Changes in Undisturbed Neotropical Forests and Their Implications for Carbon Dynamics
William
F.
Laurance, Smithsonian Tropical Research Institute, laurancew@tivoli.si.edu
(Presenting)
Richard
Condit, Smithsonian Tropical Research Institute, condit@ctfs.si.edu
Recent studies suggest that, since the early 1980s, undisturbed forests in a central Amazonian landscape have experienced pervasive changes in tree-community composition. Although the cause of these changes is uncertain, a leading explanation is that forest productivity is increasing in response to rising atmospheric CO2 levels. These changes are manifested by increased growth, mortality, and recruitment of most tree taxa and compositional shifts in tree communities, with faster-growing canopy and emergent genera increasing at the expense of smaller, slower-growing genera. However, the generality of these findings for other tropical forests is uncertain. We contrast results from central Amazonia with those from Barro Colorado Island (BCI) in Panama, where forest composition and dynamics have also been carefully monitored since the early 1980s. Preliminary results suggest that BCI forests are more strongly influenced by El Ni�o droughts than are those in central Amazonia, and that severe droughts have been the main cause of recent changes in BCI tree-community composition. These differences suggest that local climatic conditions can have a strong influence on forest dynamics and composition. The implications of these findings for forest carbon storage will be discussed.
Submetido por William F. Laurance em 15-MAR-2004
Tema Cient�fico do LBA: CD (Armazenamento e Trocas de Carbono)