Synergetic impact of climate and vegetation cover on runoff, sediment, and nitrogen and phosphorus losses in the Jialing River Basin, China

Abstract

Climate change has an important impact on water and material cycle in basin, and is closely related to the dynamic changes of vegetation cover on the underlying surface. It is therefore necessary to investigate how climate-induced changes in the vegetation influence the hydrology and environment in a basin. In this study, through the establishment of vegetation and meteorological factors of bivariate regression model, the responses of the Jialing River Basin to changes in climate and vegetation under different emission scenarios were simulated by a distributed hydrological model from data of precipitation and temperature generated by a climate change model , and the impacts of changes in vegetation on the basin were quantified. The outputs showed that the climate in the basin will be warmer and wetter, which would cause increases in the runoff and nitrogen losses, and decreases in the sediment discharge and phosphorus losses. The numerical relationship of runoff and sediment discharge will also change while keep the synchronization of runoff and sediment trend. The changes in climate were predicted to promote the increases in the vegetation coverage, resulting in a maximum changes in the runoff, sediment discharge, and nitrogen and phosphorus losses of approximately 7.5%, 5.1%, 16.7%, and 1%, respectively. Indicating that the vegetation change caused by climate has an important impact on the basin. The models were able to predict the trends in runoff, sediment, nitrogen, and phosphorus in the basin under future climate, and provide useful information to support the formulation of appropriate management measures. • A water–sediment–pollutant distribution model was set up for the Jialing Basin. • Climate change was predicted under RCP4.5 and RCP8.5 emission scenarios. • The effects of climate and vegetation cover on basin processes were simulated. • The runoff increased and the sediment flux decreased under the emission scenarios. • Vegetation cover changes drove changes in the basin processes.