Assessing Emerging Drought Threats to National Forests and Grasslands
The Water Supply Stress Index (WaSSI) model simulates water and carbon cycles in watersheds across the lower 48 United States and Mexico, enabling researchers to project likely impacts of future climate change on ecosystem productivity and water supply. Scientists with the Eastern Threat Center used WaSSI to estimate how water yield and carbon sequestration in the National Forest and Grassland System (NFs) were impacted by periodic droughts across the United States over the past 60 years. They then examined drought trends and chose five extreme drought years to estimate the ‘worst cases’ of drought impacts on water yield and ecosystem productivity in the future. This benchmark study provides a reference point to assess drought impacts for each of the 170 NFs and can help land managers better optimize limited resources during watershed restoration efforts in response to climate and land use changes. Ongoing study results highlight the importance of understanding drought stress on forest and grassland ecosystems and the need to better quantify stress under a changing climate.
Right: A map shows computer-simulated percentage decrease in ecosystem productivity (GEP) during the top five most severe drought years for 170 U.S. National Forest and Grasslands, 1961-2012. The study offers quantitative assessment of likely impacts of climate change-induced droughts. Click to enlarge.
References:
Sun, S.; Sun, G.; Caldwell, P.; McNulty, S.G.; Cohen, E.; Xiao, J.; Zhang, Y. 2015. Drought impacts on ecosystem functions of the U.S. National Forests and Grasslands: Part I evaluation of a water and carbon balance model. Forest Ecology and Management. 353: 260-268.
Sun, S.; Sun, G.; Caldwell, P.; McNulty, S.; Cohen, E.; Xiao, J.; Zhang, Y. 2015. Drought impacts on ecosystem functions of the U.S. National Forests and Grasslands: Part II assessment results and management implications. Forest Ecology and Management. 353: 269-279.
Forest Service Partners/Collaborators: Southern Research Station Coweeta Hydrologic Laboratory
External Partners/Collaborators: North Carolina State University; National Science Foundation
Contact: Ge Sun
