A Global Review on the Effects of Land Cover and Climate Changes on Water Resources at Large Watersheds: Implications for Management

Abstract:

Water availability is of the utmost importance for now and future development and environmental protection. In spite of various factors, climate variability and vegetation cover change are commonly believed as two major drivers in influencing water resources. This study reviewed the published studies from 160 large watersheds (>500 km²) in the world. Based on the Budyko’s Curve, E₀/P (potential evapotranspiration/precipitation) is selected as the indicator for climate variability, while watershed area and vegetation cover change represent the watershed properties. Our meta-data analysis shows that the impacts of land cover change on water can be as important as the influence from climate change. In addition, hydrological sensitivity increases with E₀/P (dryness index), which is different from the commonly-held perception (i.e., the sensitivity at E₀/P = 1 is the highest). Large watersheds have the ability to buffer the effects of land cover change on water yield. The implications of our results for watershed management are discussed in the context of future climate and land cover changes.