Spatiotemporal patterns of cultural ecosystem service supply, demand, and flows in urban green–blue spaces: A case study of Hangzhou, China

Rapid urbanization has intensified spatial mismatches between the supply and demand of cultural ecosystem services (CES) in urban green–blue spaces. This study developed an indicator-based spatiotemporal framework to assess CES supply, demand, and service flows in Hangzhou, China, for 2014, 2019, and 2024. Spatial matching and spatial autocorrelation analyses were applied to examine supply–demand relationships and their temporal evolution. A raster-based service flow model was further used to simulate CES transmission pathways under spatial resistance constraints. Results show pronounced spatial heterogeneity and an increasing supply–demand mismatch. Spatial coupling between supply and demand weakens over time, shifting from a core–periphery structure to a fragmented, multi-center pattern. Service flow analysis further indicates that the effectiveness of CES delivery is constrained by the spatial configuration of transmission networks rather than by supply capacity alone. Despite improvements in urban transport infrastructure, service flows have become increasingly concentrated along several dominant corridors, with maximum flow intensity rising from 0.33 in 2014 to 0.59 in 2024. Meanwhile, the maximum potential satisfied CES declines from 0.91 to 0.80, and service cold spots expand toward newly urbanized districts. These findings highlight the structural nature of CES imbalance and provide indicators to support urban ecosystem service assessment.