Supply–Demand Mismatches in Built Environment and Water-Heat-Carbon Ecological Functions: Coupling Coordination and Nonlinear Mechanisms

As a sub-center of the Yangtze River Delta and a rapidly expanding metropolis, Hefei faces key regional low-carbon resilience challenges due to the incoordination between its built environment (BE) and water-heat-carbon (WHC) ecological functions. This study quantitatively evaluated the multidimensional BE characteristics of Hefei (2013, 2018, and 2023). By integrating ecosystem service models, land surface temperature, and energy consumption data, we systematically quantified the supply–demand matching of flood control, thermal regulation, and carbon sequestration. Furthermore, by combining coupling coordination degree (CCD) models, interpretable machine learning (LightGBM-SHAP), and dynamic-static integration evaluation, we revealed the spatiotemporal coupling, non-linear impact mechanisms, and ecological management zoning. Results show that Hefei’s BE exhibited “core polarization and multi-point expansion”, with its spatial center shifting southwestward, causing patch-like “deficit shifts” in ecological demand and compound supply–demand imbalances. Regionally, CCD was heterogeneous; traditional core and secondary growth poles showed high coordination alongside degradation risks under “low-level equilibrium”. Urban functional mix and nighttime lights positively dominated system synergy, whereas saturated impervious surfaces and population loads exhibited significant negative effects. Finally, a dynamic-static management framework was established to guide fine-grained governance and low-carbon resilience.