HR: 16:40h
AN: B24C-03    [Abstracts]
TI: Dynamics of Amazon Forest photosynthetic increase during 2005 drought
AU: * Saleska, S R
EM: saleska@email.arizona.edu
AF: Ecology & Evolutionary Biology, University of Arizona 1041 E. Lowell Street, Tucson, AZ 85721, United States
AU: Didan, K
EM: kamel@Ag.arizona.edu
AF: Soil Water and Environmental Science, University of Arizona Shantz Room 429, Tucson, AZ 85721, United States
AU: Christoffersen, B
EM: bchristo@email.arizona.edu
AF: Ecology & Evolutionary Biology, University of Arizona 1041 E. Lowell Street, Tucson, AZ 85721, United States
AU: Huete, A R
EM: ahuete@Ag.arizona.edu
AF: Soil Water and Environmental Science, University of Arizona Shantz Room 429, Tucson, AZ 85721, United States
AU: Restrepo-Coupe, N
EM: ncoupe@email.arizona.edu
AF: Ecology & Evolutionary Biology, University of Arizona 1041 E. Lowell Street, Tucson, AZ 85721, United States
AU: Rocha, H
EM: humberto@model.iag.usp.br
AF: Institite of Astronomy, Geosciences and Atmospheric science, University of Sao Paulo, Sao Paulo, SP 05508-090, Brazil
AB: Coupled climate-carbon cycle modeling studies indicate that Amazon forests are vulnerable to drought, and some predict substantial carbon loss from tropical ecosystems, including the drought-induced collapse of the Amazon forest and conversion to savanna. The model-simulated future forest collapse is attributable, in part, to a forest physiological feedback mechanism which should be observable as reductions in transpiration and photosynthesis during drought years under current climates. A widespread drought occurred in the Amazon in 2005, the first such climatic anomaly since the launch of the Terra satellite's MODIS sensor in 1999, providing a unique opportunity to compare actual forest drought response to expectation on broad spatial scales. We recently reported that, contrary to expectation based on model simulations, satellite observations showed a large-scale green-up in intact evergreen forests of the Amazon in response to the 2005 drought. Here, we explore the temporal dynamics of this response, using a simple water-balance model to predict drought response. These findings suggest that Amazon forests, though threatened by human-caused deforestation and fire, may be more resilient to climate changes than many ecosystem models assume.
DE: 0428 Carbon cycling (4806)
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 0480 Remote sensing
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting