Abstract:
The severity of seasonal dryness and increased frequency of strong interannual droughts in the Amazon have highlighted the need to better understand the rainforest vulnerability to heat- and drought-induced stresses. Increasingly recognized is the critical role of multiple tree hydraulic strategies that represent a spectrum of trade-offs ranging from drought avoidance to drought tolerance. We present evidence of such variations using ecohydrologic data on intrinsic xylem hydraulic traits, tree seasonal growth patterns, and leaf gas exchange and stem water dynamics collected in a seasonal rainforest in eastern Amazonia, the Tapajos National Forest. We find strategies among co-occurring trees, ranging from the tight control of canopy conductance guarding against xylem embolism and failure, to low regulation of the water flux. Our integrated view of hydraulic traits, growth strategies, and plant community structure provide new insights for mapping hydraulic traits to emergent forest function in the next generation of predictive models of tropical forest dynamics.
Bio:
Education: 1996 - Diploma in Hydrology obtained at Moscow State University, Russia; 2002 - M.S. and 2006 - Ph.D. obtained at the Massachusetts Institute of Technology, U.S.A. In 2006, he pursued Ziff Postdoctoral Fellowship at the Center for the Environment, Harvard University and, in 2007, he started faculty position at the University of Michigan. Dr. Ivanov’s research interests involve physical surface and subsurface hydrology, climate science and hydrologic impacts, plant water relations and ecohydraulics, and floods. Current research projects focus on Amazon rainforest ecohydrology; surface and subsurface impacts of tall vegetation encroachment in Arctic tundra; and the development of a framework for evaluation of flooding impacts in real-time at scales of “human action”.
