“Paying for water”: Does cross-provincial river ecological compensation enhance water ecological resilience in China?

Cooperative governance across different river basins has long faced the challenge of “intergovernmental bargaining.” As a significant institutional innovation, cross-provincial river basin ecological compensation (REC) plays a crucial role in improving water ecological environments. Existing research primarily focuses on the impact of cross-provincial REC policies on water quality or governance performance, lacking empirical evidence that characterizes water ecological resilience (WER) from an evolutionary resilience perspective to identify the effects of policies and their underlying mechanisms. The core research questions are: Can cross-provincial REC policies enhance provincial-level WER in China? What are the underlying mechanisms? Research objectives include: Establishing a provincial WER evaluation framework; Examining the independent impact of cross-provincial REC policies on WER; Revealing the policy implementation mechanisms. This study commenced by examining the institutional advantages of cross-provincial REC from the evolutionary game theory perspective. Based on the comprehensive capacity of water ecosystems to withstand external disturbances, self-regulate, restore from degraded states, and undergo innovative transformability, this research established a water ecological resilience (WER) evaluation framework encompassing “Resistance - Adaptation - Restoration - Transformability”. Subsequently, the CRITIC-TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) method was employed to measure the WER of 30 Chinese provinces from 2006 to 2021. A multi-period difference-in-differences (DID) model was used to empirically examine whether the cross-provincial REC policy effectively enhanced WER, with its impact mechanism explored through a mediation effect model. Finally, spatial analysis was employed to identify the spatiotemporal evolution patterns of WER. These results indicate that the cross-provincial REC policy has significantly boosted provincial WER. This policy primarily enhances WER through two pathways: promoting technological innovation (TI) and industrial upgrading (IU). Furthermore, China's WER level increased from 0.149 in 2006 to 0.364 in 2021 during the study period, demonstrating markedly strengthened spatial agglomeration. These findings provide empirical evidence for evaluating the effectiveness of the cross-provincial REC policy. • Developed a novel four-dimension framework for evaluating WER. • Cross-provincial REC policy robustly enhances WER. • Cross-provincial REC enhance WER through TI and IU pathways. • China's WER is rising and shows significant spatial agglomeration.