Network-Based Coupling Analysis Between Human Activity Intensity and Ecosystem Services: Evidence from the Pinglu Canal Economic Belt, China

As a strategic core of the Western Land–Sea New Corridor, the Pinglu Canal Economic Belt (PCEB) is undergoing unprecedented landscape restructuring due to canal construction. This mega-project serves as a critical case for understanding how intense human intervention reshapes regional ecosystem service (ES) patterns. Integrating complex network analysis with Generalized Additive Models (GAMs), this study examines the spatiotemporal evolution of human activity intensity (HAI) and ES networks (2000–2020) and their nonlinear responses. Research findings: the PCEB’s ES network evolution reflects a “policy–terrain coupling” mechanism. While HQ remains the structural anchor for regulating services, FP drives key trade-offs. The network has transitioned from coexisting trade-offs and synergies to synergy dominance, driven by ecological engineering and spatial zoning. We identified HAI 0.10–0.15 as a critical threshold where moderate disturbance promotes service integration. However, excessive intensification leads to functional simplification. Future governance should move beyond rigid zoning, employing dynamic spatial policies and adaptive agroforestry to mitigate FP’s pressure and activate the ecological potential of transition zones. This study provides a framework for understanding nonlinear socio-ecological responses to human–policy–terrain feedback. This study provides a scientific basis for optimizing land-use management and enhancing ecosystem sustainability in the PCEB.