Spatial imbalance and changes in supply and demand of ecosystem services in China.

Human activities and regional land development have caused intense interference to ecosystems. With rapid development of economy and urgent needs of life quality improvements in China, sustainable ecosystem management is crucial for national ecological civilization construction. However, few studies have focused on supply-demand patterns of ecosystem services on a national scale in China. The aim of this study was to analyze the spatial-temporal patterns and changes in the supply-demand of ecosystem services and to explore their interactive relationship in the context of economic development and urbanization drivers. The ecosystem services provision index (ESPI) and land development index (LDI) were proposed to indicate the supply and demand for ecosystem services. The results indicated that the Low supply-High demand (L-H) pattern accounted for 3.27% of the total land area in China and was mainly concentrated in developed regions and some capital cities, where 28.95% of the total population and 51.93% of the country's GDP was generated in 2015. The spatial imbalance in the supply-demand of ecosystem services was obvious. From 2000 to 2015, the imbalance was shrinking, and regions with negative changes in supply-demand patterns were declining. During 2000-2008, there was an obvious transformation from Low supply-Low demand (L-L) to High supply-Low demand (H-L), which accounted for 12.44% of the total land area due to Grain for Green and other ecological protection policies. The proportion of ecological land to total land area, vegetation cover and elevation were significantly correlated with the supply of ecosystem services. In the meantime, ESPI was negatively correlated with LDI in most regions in China. There were also regional differences in their relationships. The rapid economic growth and the intensive land development resulted in a more significant decrease in ESPI in the developed regions than that in the undeveloped North and Northeast China. The results of this study could contribute to sustainable ecosystem management and decision-making for Chinese ecological civilization construction.