Anomalously high temperature, water deficit, and their interaction are predicted to be pervasive in global change scenarios. Because plants' responses to temperature and water stress typically involve decreased stomatal conductance and photosynthesis, these stressors fundamentally affect terrestrial carbon sequestration, energy balance, and ecosystem functioning. As drought continues, it may also significantly shift plant demography. Given the high and persistent uncertainty associated with terrestrial carbon, water, and energy fluxes under global change, diagnosis of plant stress and clarification of its consequences for fluxes and demography are research priorities.
This research combines remote sensing data associated with plant physiological responses to water and temperature stress with an individual-level terrestrial biosphere model (ED2) to: (1) assess our current mechanistic understanding of plant stress in functionally and structurally diverse Californian ecosystems and (2) improve our ability to predict plant demographic change and fluxes of carbon, water, and energy in the future.
This is dissertation research conducted by Miriam Johnston.