Vegetation Responses to Climate Change Mediates Streamflow Dynamics at Forested Watersheds

Forests are crucial for the production of high-quality freshwater resources. Complex interactions between climate change and forest processes can result in uncertainty in freshwater availability to downstream communities and the environment. In this talk, we will investigate how long-term hydrologic nonstationary and seasonal flow patterns have responded to greenup variability and long-term greening across the eastern United States over the last four decades. After removing a dominant precipitation control, one-day earlier greenup is associated with about one-day early spring flow peak at the deciduous catchments. In addition, we found that the divergent trends in precipitation versus runoff rates are significantly correlated to long-term increasing rates in NDVI and growing season length at the watershed scale, while climate variables cannot provide significant explanation. This indicates that the strong dependency of seasonal and long-term flow regimes on precipitation is mediated by warming-induced extended growing season and long-term greening due to CO2 fertilization. This study emphasizes the importance of understanding vegetation responses to climate change to predict future flow regimes in forested watersheds.
 
Bio: Taehee is a ecohydrologist who works at inter-disciplinary boundaries between hydrology, ecology, remote sensing science, and geomorphology. The overarching questions that drive much of his research is how coupled ecological and hydrological systems evolve and adjust to perturbations such as droughts, climate change, geomorphic settings, and human disturbances at multiple scales. His research has been focusing on how vegetation patterns in space and time imply important climate-ecosystem-hydrology feedback and long-term adjustments of soil-vegetation system given climatic, geomorphic, and hydrologic settings.