Impacts of land use and climate change on hydrological processes and ecosystem productivity in Chinas Yellow River Basin

The Yellow River Basin (YRB) is an ecologically vulnerable region and is well known for its high soil erosion rates. To ensure food and water security and maintain environmental sustainability in YRB, the Chinese government has implemented a number of ecological restoration projects, which led to widespread land cover conversion in this region. In this study, we applied a highly integrated, process-based terrestrial ecosystem model, the DLEM (Dynamic Land Ecosystem Model, DLEM), to assess how land use/cover change and climate change have affected water and carbon cycling over the YRB from 1901 to 2018. Specifically, we examine changes in each component of water cycle and ecosystem productivity, and their driving factors. We implemented a set of the factorial simulation experiments to quantify the contribution of individual driving factors to the spatial and temporal characteristics of water cycle components (i.e. ET, runoff, soil moisture and discharge) and ecosystem productivity (GPP, NPP and NEP). Simulated results indicated that climate change and land use caused significant increases in both ecosystem productivity and ET in the past century, showing substantially spatial and temporal variations. This implies that increased ecosystem productivity was associated with high water consumption. Therefore, it has been a big challenge to maintain a high productivity in the water-limited ecosystems of the YRB.