MODELLING ECOSYSTEM WATER SUPPLY SERVICES UNDER VARIOUS LAND USE AND LAND COVER SCENARIOS IN THE LIAOHEYUAN WATERSHED, CHINA

Ecosystems provide a wide range of benefits to society. Ecosystem services related to water supply are now a hot topic in ecology and hydrology. Calculation and mapping of water supply services are of great importance to water resource planning and management as well as in hydropower station construction. Recent efforts have called for the integration of the values of these ecosystem services in order to improve decision making in social and economic issues, but so far few practical efforts have been demonstrated of such an approach. Quantifying levels and values of these services has proven difficult. In this study, we used a spatially explicit modelling tool, Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST), to predict changes in ecosystem water supply services under different land use and land cover scenarios in the past (year 2003, LULCO), present (year 2013, LULC1) and for a sustainable development scenario focusing on ecosystem protection and restoration (year 2013, LULC2) in Liaoheyuan watershed, China. The datasets used for this model include land use and land cover, average annual precipitation, annual reference evapotranspiration, depth to root restricting layer, the amount of available plant water, watersheds and sub-watersheds, a seasonality factor and other variables. The results show that total water yield in the watershed under LULCO, LULC1 and LULC2 was 36.6, 33.62, and 34.07million m(3).y(-1), respectively. The water supply ranged from 31.50million m(3).y(-1) for the LULC1 to 34.33million m(3).y(-1) for the LULCO. The total annual value of water supply services in the Liaoheyuan watershed was approximately 7.09E+05 RMB.y(-1) in LULCO, 6.51E+05 RMB.y(-1) in LULC1, and 6.60E+05 RMB.y(-1) in LULC2 (1 US$ = 6.3 RMB). Our study provides an example for understanding how ecosystem processes determine the provision of ecosystem services and benefits to society in the Liaoheyuan watershed. More broadly, quantifying ecosystem services in a spatially explicit manner can provide crucial scientific support for more effective, efficient and defensible water resources management.