Amazon forest responses to drought: scaling from individuals to ecosystems

OCTF seminar followed by drinks – all welcome

Scaling from individuals or species to ecosystems is a fundamental challenge of modern ecology and understanding tropical forest response to drought is a key challenge of predicting responses to global climate change. Scott will synthesize his developing understanding of these twin challenges by examining individual and ecosystem responses to the 2015 El Nino drought at two sites in the central Amazon of Brazil, near Manaus and Santarem, which span a precipitation gradient from moderate (Manaus) to long (Santarem) dry seasons. He will focus on how ecosystem water and carbon cycling, measured by eddy flux towers, emerges from individual trait-based responses, including photosynthetic responses of individual leaves, and water cycle responses in terms of stomal conductance and hydraulic xylem embolism resistance. Contrasting results were found to drought along the precipitation gradient: the highly seasonal forest responded strongly in terms of ecosystem water and carbon fluxes, with contrasting precipitation regimes (at seasonal and interannual timescales) apparently selecting for assemblies of traits and taxa manifest at the community level. These results suggest that we may be able to use community trait compositions, as selected by past climate conditions, to help predict ecosystem responses to future climate change.

Dr Scott Saleska investigates questions related to how the structure and function of terrestrial vegetation and microbial communities regulates large-scale biogeochemical processes. As a global change ecologist, he focuses in particular upon how ecological communities regulate land surface interactions with the atmosphere and with climate, from local to global scales. These topics collectively address one of the largest uncertainties in predicting the future of climate on earth, the response of living communities to climate change. Scott is a Professor of Ecology and Evolutionary Biology at the University of Arizona, where he is Agnese Nelms Haury Faculty Fellow in Environment and Social Justice, and an elected fellow of the Ecological Society of America.