0 avis
Water uptake patterns in a tropical rainforest ecosystem and consequences on intra- and inter-annual variations in C flux and balance
Archive ouverte
Edité par CCSD -
International audience. Background/Question/Methods Tropical rainforest ecosystems are characterized by high annual rainfall. Nevertheless, rainfall regularly fluctuates during the year and seasonal soil droughts do occur. Over the past decades, a number of extreme droughts have hit tropical rainforests, not only in Amazonia but also in Asia and Africa. A great diversity and complexity of the response of tropical rainforest trees to drought has been found. We focus in this presentation on water uptake patterns in tropical rainforests and intra- and inter-annual variations in C flux and balance. Based on several studies conducted in a tropical rainforest ecosystem in French Guiana, we discuss the variability in depth of soil water uptake among trees and lianas during dry periods and the abiotic drivers (water limitation, radiation) of long-term variations in gross primary productivity (GPP), ecosystem respiration (RE) and net ecosystem exchange (NEE). Results/Conclusions A large variability in depth of water uptake among trees and lianas was found during dry seasons, which points to various ecological strategies in resistance and avoidance to drought. Global radiation was always the best predictor of annual and seasonal variations in GPP, RE and NEE, but soil water content did also influence carbon fluxes and balance. We conclude that the reduced precipitation expected in tropical rainforest areas under future climatic conditions will strongly influence carbon fluxes and carbon uptake. These results are essential to simulate the future of these ecosystems under diverse climate scenarios and to predict the future of the global earth carbon balance.
Consulter en ligne
Suggestions
Du même auteur
