Spatial and temporal changes in ecosystem service driven by ecological compensation in the Xin'an River Basin, China

Ecological compensation is an effective way to harmonize the conflict between exploitation and protection of ecosystem. Xin 'an River Basin, as the first pilot project in China to carry out horizontal ecological compensation for upstream and downstream river basins, has been continuously exploring the compensation path and mode in the past ten years. The significance of this study is to systematically evaluate the effectiveness of ecological compensation from the perspective of ecosystem service value. It is helpful to explore more effective refined implementation methods. It provides reference for further adjustment and development of ecological compensation. In this paper, we used the equivalence factor method to construct the ecosystem service equivalent factors applicable to the Xin'an River basin against the background of land use change from 2010 to 2020, evaluated the ecosystem service value(ESV) of the Xin'an River basin in 10 years, and analyzed the spatial and temporal distribution characteristics. It was found that (1) ESV showed an overall growth trend over the decade, increasing by 1.25 billion, with an increase of 2.84 %. The increase in the value of the hydrological regulation function was the most significant driver. The diminishing marginal effects are also shown on the time scale. This suggests that existing ecological conservation actions are becoming less effective in increasing ESV over time, and that there is a need for appropriate expansion of existing environmental actions, as well as more fine-grained policy implementation. (2) The trend of ESV showed obvious differences in spatial distribution. Four districts and counties in the west-central part of the study area showed increasing trends in ESV, while four districts and counties in the east-central part showed negative trends. The most significant increase was in the Huangshan District (+160,370.32 million yuan), mainly due to the significant increase in the watershed area in this region, which led to an increase in the value of the hydrological regulating function. The increase in the value of hydrological regulation function in the study area mainly came from Huangshan District. This is closely related to the water pollution control, water conservation and protection, and water ecology restoration in the Xin'an River Basin promoted by ecological compensation. (3) Ecological compensation in the Xin'an River Basin has effectively promoted the growth of ESVs in the region, especially watershed-related ecosystem services. It has played an obvious positive role in promoting the construction of ecological civilization and the coordinated ecological-social-economic development.. However, the growth of ESV is not comprehensive, and the ESV of some regions and ecosystem service types are in a declining trend, without achieving a synergistic and balanced development. We give relevant suggestions for this situation.