New insights into intercity ecological synergy: revealing community structures and their drivers through the dynamics...

Given the dynamics and externalities of ecological processes, cross-regional governance is essential. However, previous research mostly characterized intercity ecological linkages by static indicators, ignoring the spatial dynamics of ecosystem service flows (ESFs). This research selected directional water yield flow (WYF) and omnidirectional carbon sequestration flow (CSF) to characterize ecological linkages within the Yangtze River Delta region (YRDR). Using complex network analysis and community detection methods, the overall network and community structures of intercity ecological linkages were analyzed. Besides, drivers of ESFs were compared across network and community scales through multiple regression analysis. The results indicated that the supply-demand patterns and flow characteristics of ESs shaped the intercity ecological linkage networks. Although CSFs and WYFs covered over 90 % of YRDR, some proximate cities lacked ecological linkages. The CS linkage network exhibited distinct core-periphery structure with 6 communities orienting north-south, while WY linkage network was relatively balanced with 5 communities orienting east-west. Both networks exhibited cross-boundary spillovers. Spatial heterogeneity in topography, land use, and precipitation shaped spatial gradients of ES supply and demand, thereby influencing CSFs and WYFs. Their effects differed across network and community scales, especially for topography and precipitation (e.g., every 1 % increase in ΔPRE resulting in 0.162 % CSF increase in YRDR, but a 0.199 % reduction in community CS3). Moreover, certain cities (i.e., geographic centers within surplus or deficit areas, and transmission cities linking them) and cross-community linkages, were critical for maintaining networks' transmission. This study proposed multi-scale differentiated spatial planning and management strategies for intercity ecological collaborative governance.