Spatiotemporal Dynamics of Water Yield Service and Its Response to Urbanisation in the Beiyun River Basin, Beijing

Water-related ecosystem services are vitally important for growing mega-cities. However, accelerating urbanisation has brought many associated issues, such as rapid population growth, extensive land occupation and landscape pattern changes, which affect both the functions and services of regional ecosystems. To achieve sustainable urban ecological development, it is necessary to determine the impacts of urbanisation on water yield. In this study, the water yield ecosystem service of the Beiyun River Basin in Beijing was simulated by the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model and the Geographical Detector method (Geo-detector) was applied to obtain the contributions and temporal regularity of urbanisation impacts on water yield. The results indicated the following: (1) the water yield of the Beiyun River Basin increased from 9.52 x 10(8) m(3) in 2000 to 12.84 x 10(8) m(3) in 2010, with a growth rate of 34.9%; (2) the urbanisation level of the Beiyun River Basin increased from 2000 to 2010, and the selected five landscape indexes varied greatly with the continuously increasing patch density (PD), splitting index (SPLIT) and Shannon's diversity index (SHDI); (3) during this decade, patch richness density (PRD), SHDI, aggregation index (AI), portion of construction land (CL) and average annual precipitation (AP) were the influencing factors that continuously contributed more than 30% of the spatial variability of water yield in the Beiyun River Basin; and (4) the explanatory power of the interaction between any two driving forces was greater than any single factor. Our results could provide scientific references and constructive advice for city water resource operation from a landscape perspective.