Climate, land use/cover, and leaf area index (LAI) have changed notably in China since 1980, and these have had major impacts on river runoff and the terrestrial ecosystem water retention (TEWR) service in China. However, the mechanisms underlying the spatiotemporal changes of runoff and TEWR are not understood well. Here, meteorological, LAI, and land use/cover data were applied in a hydrological model (variable infiltration capacity) to quantify their contributions to runoff and TEWR changes during the 1980s, the 1990s, the 2000s, and 1982-2015, respectively. The results show that climate change, particularly precipitation change, was the dominant factor controlling runoff and TEWR changes. Between 1982 and 2015, climate change increased the runoff in large areas in northwestern and southwestern China and the Hai River (HR) basin and improved the TEWR in large areas in northwestern and northeastern China and the Huai River (HuR) basin. However, the magnitudes and signs of the climate change impact varied in different regions and time periods. The LAI increased extensively, which led to decreased runoff and increased TEWR in most of China from 1982 to 2015, especially in the Yellow River basin, HuR basin, and HR basin. The impacts of land use/cover change on runoff and TEWR were in general less than those of climate and LAI changes, nevertheless, they were important in some local areas. This study improves the understanding of the spatiotemporal patterns and the underlying mechanisms of runoff and TEWR changes across China between 1982 and 2015.
