Predicting water ecosystem services under prospective climate and land-use change scenarios in typical watersheds distributed across China

Water-related ecosystem services (WES) critical to anthropogenic-related water security are being severely degraded, primarily due to climate and land-use change. Clarifying future trends in WES (i.e., water yield and water purification services) will contribute to water resource sustainability. However, most existing studies are single case studies and rarely consider the combined impacts of climate change and land-use change on ecosystem services, resulting in patterns that cannot be adequately summarized. In this study, the “Annual Water Yield” module of the InVEST model was used to estimate water yield and the “Nutrient Delivery Ratio” module was used to analyze water purification services. In order to compare the impacts of different natural conditions and geographic locations on water ecosystem services, 17 typical watersheds throughout China were selected as study areas. Coupled scenarios were also considered when setting climate and land-use scenarios to predict prospective (2020–2100) evolutionary trends in WES. The response of WES under different scenarios was also assessed. Results show that climate change is more likely to affect water yield services than water purification services. The impact of land use on water purification services is more pronounced than its impact on water yield services. Climate change contributed > 90 % to water yields in 15 out of the 17 watersheds, contributed 79.4 % in the Hei River watershed, while only contributing 11.2 % in the Yarkant River watershed. The influence of climate change on total nitrogen (TN) output in eight of the watersheds was greater than that of land-use change, especially in the Min River and Mintuo River watersheds, for which the contribution was > 95 %. Furthermore, water purification services in nine of the watersheds were more affected by land-use change, especially in the Dongting Lake and Hei River watersheds, for which the contribution was > 95 %. The aim of this study is to assist in the planning of sound water resource measures while developing sustainable management strategies to help relevant water resource sectors cope with prospective risks and challenges.