从"污染控制"到"协同共治":新安江横向生态补偿试点的生态质量改善效应评估OA

The Xin'an River horizontal ecological compensation pilot represents a typical case of China's first institutional exploration of establishing a horizontal ecological compensation mechanism for watershed governance.This practice breaks away from the traditional end-of-pipe governance paradigm centered on water quality compliance and shifts toward an institutional model that integrates overall ecosys-tem functionality with regional collaborative governance.While the policy initially aimed to improve watershed water quality,a key ques-tion remains whether it can further enhance the overall ecosystem service capacity and promote coordinated improvements in ecological quality across upstream and downstream regions—both of which are critical for evaluating its overall effectiveness.This study used panel data from 70 counties in Anhui and Zhejiang provinces between 2007 and 2023 and applied a difference-in-differences(DID)method to assess the effects of the Xin'an River horizontal ecological compensation on ecological quality at both the watershed and subregional lev-els.It also examined the cumulative effects across different pilot phases,the underlying mechanisms,and the heterogeneity of improve-ments across pilot counties.The results showed that:① Horizontal ecological compensation significantly improved the overall ecological quality of the watershed,a conclusion that remained robust under multiple verification tests.② Heterogeneity analysis indicated that the policy significantly promoted ecological quality improvement in upstream areas,but the effect was not statistically significant in down-stream regions.From a watershed-wide perspective,the cumulative policy effects intensified over time.Regionally,as the compensation mechanism was continuously optimized and assessment standards were gradually tightened,the policy's cumulative effects gradually spread from downstream to upstream,fostering more synchronized ecological improvements and facilitating a collaborative governance pat-tern across regions.③ Mechanism testing revealed that ecological improvements in upstream areas were mainly driven by green industrial transformation and increased agricultural infrastructure,while improvements in downstream areas stemmed from green industrial transfor-mation and enhanced ecological industrialization efficiency.④ The ecological impact of horizontal ecological compensation varied across different pilot counties.This study provides empirical evidence and policy insights for improving cross-regional ecological compensation systems,promoting collaborative watershed governance,and designing differentiated incentive mechanisms.