Pervasive Drought Legacy Effects in Forest Ecosystems and their Carbon Cycle Implications

Thursday, 17 December 2015
Poster Hall (Moscone South)
William Anderegg1, Christopher Schwalm2, Franco Biondi3, Jesus Julio Camarero4, George W Koch2, Marcy E Litvak5, Kiona Ogle6, John Shaw7, Elena Shevliakova8, Park Williams9, Adam Wolf1, Emanuele Ziaco3 and Stephen W Pacala10, (1)Princeton University, Princeton, NJ, United States, (2)Northern Arizona University, Flagstaff, AZ, United States, (3)University of Nevada Reno, Reno, NV, United States, (4)Instituto Pirenaico de Ecología, Zaragoza, Spain, (5)University of New Mexico Main Campus, Albuquerque, NM, United States, (6)Arizona State University, Tempe, AZ, United States, (7)US Forest Service, Logan, UT, United States, (8)GFDL-Princeton University Cooperative Institute for Climate Science, Princeton, NJ, United States, (9)Lamont -Doherty Earth Observatory, Palisades, NY, United States, (10)Princeton University, Ecology and Evolutionary Biology, Princeton, NJ, United States
The impacts of climate extremes on terrestrial ecosystems are poorly understood but central for predicting carbon cycle feedbacks to climate change. Coupled climate-carbon cycle models typically assume that vegetation recovery from extreme drought is immediate and complete, which conflicts with basic plant physiological understanding. We examine the recovery of tree stem growth after severe drought at 1,338 forest sites globally comprising 49,339 site-years and compare it to simulated recovery in climate-vegetation models. We find pervasive and substantial “legacy effects” of reduced growth and incomplete recovery for 1-4 years after severe drought, and that legacy effects are most prevalent in dry ecosystems, Pinaceae, and species with low hydraulic safety margins. In contrast, no or limited legacy effects are simulated in current climate-vegetation models after drought. Our results highlight hysteresis in ecosystem carbon cycling and delayed recovery from climate extremes.