Revegetation Does Not Decrease Water Yield in the Loess Plateau of China

Abstract

AbstractVegetation restoration over degraded drylands has considerable climate, carbon and ecosystem benefits, yet its water impacts remain contentious. Previous studies suggest that extra vegetation in drylands could lead to decreased soil moisture and runoff caused by enhanced evapotranspiration. However, these studies ignore important vegetation‐climate feedbacks that can partially offset such negative consequences. Here, we examine how revegetation affects water budgets in China's Loess Plateau, where the world's largest revegetation occurs. Despite increased evapotranspiration, long‐term observations exhibit robust increasing trends (2.76 mm yr−2) of surface water yield over a large swath (82.3%) of the Plateau since revegetation starts. This is mainly caused by increased regional precipitation that outweighs increases in evapotranspiration. Numerical experiments further reveal that the increased precipitation is largely driven by revegetation‐induced enhancement in land‐atmosphere interactions that greatly accelerate local moisture recycling. Our findings highlight the importance of considering vegetation‐climate feedbacks in assessing hydrological responses to large‐scale vegetation changes.