Revealing the coupling mechanism of Socio-Ecological networks and their collaborative governance pathways from complex network Insight

• This study investigates the socio-ecological coupling characteristics of the CDPUA and addresses the following core questions: • What spatial structural characteristics do the ecological network, policy transmission network, and the resulting socio-ecological composite network exhibit? How are core nodes and hierarchical structures distributed? • To what extent are the policy transmission network and ecological network aligned within the urban agglomeration? • How do different policy themes influence ecological connectivity strength, and which policy themes serve as key drivers of regional socio-ecological synergy? Socio-ecological networks capture the interactions between human activities and ecosystems, offering a scientific basis for environmental management and resource conservation. While policy documents play a central role in ecological governance through legal and institutional mechanisms, limited attention has been paid to how policy transmission linkages within urban agglomerations shape ecological outcomes. This study investigates the Chengdu Plain Urban Agglomeration from a complex network perspective, constructing ecological and policy transmission networks and integrating them into a socio-ecological framework. Social network analysis and QAP methods are applied to examine network structures, interrelationships, and coupling mechanisms between policy transmission and ecological conservation. The results reveal three key findings. First, the socio-ecological network presents a multi-level structure centered on the “Ya’an–Chengdu” axis, with a small number of core cities sustaining overall connectivity and information flow. Second, the system exhibits a “partial coupling” pattern. While Chengdu lacks core ecological attributes, it functions as a coupling hub that bridges institutional and ecological misalignments through centralized policy resources and information flows, highlighting the differentiated roles of core cities. Third, comprehensive service policies strongly enhance cross-domain and cross-level integration, serving as the primary driver of ecological governance. By contrast, geographic proximity exerts a significant adverse effect, indicating that functional complementarity and institutional coordination—rather than spatial closeness—are the primary drivers of inter-city linkages. Overall, this study elucidates the mechanisms by which policy transmission influences ecological connections, providing empirical insights for strengthening regional cooperation and promoting high-quality ecological governance in urban agglomerations.