How does the mixed-functional land use pattern suppress the cooling capacity of urban green spaces? Evidence from China

Abstract

Urban green spaces are widely recognized for their role in mitigating urban heat through ecological processes such as evapotranspiration and shading. However, the intensification of compact and mixed-functional land use patterns may constrain their thermal regulatory performance. This study investigates the extent to which mixed-functional land use patterns modulate the cooling capacity of urban green spaces across 287 Chinese cities, employing a multi-method framework that integrates spatial regression models, multi-scale geographically weighted regression (MGWR), and interpretable machine learning (XGBoost with SHAP values). The results indicate that mixed-functional land use significantly suppresses green space cooling through three main pathways: (1) by increasing landscape fragmentation, it disrupts spatial continuity; (2) by intensifying competition with built-up areas, it diminishes marginal cooling gains; and (3) by interacting with green space morphology, it selectively impairs the thermal performance of planned urban green spaces (PDUGS), while natural urban green spaces (NAUGS) remain relatively resilient. Empirical evidence supports these mechanisms: the MIXD (degree of mixed-functional land use pattern) × PDUGS coverage interaction yields a significantly negative coefficient (β = −0.000865) in the cold island area model, and MGWR identifies stronger suppressive effects in high-density southern cities. SHAP-based threshold analysis identifies a suboptimal MIXD range (≈55–240) associated with markedly reduced cooling capacity, and a saturation point beyond ≈405 where additional functional mixing yields diminishing returns. These findings highlight the conditional role of urban form in shaping green infrastructure performance and underscore the importance of adopting type-specific and structure-sensitive planning strategies to optimize green space effectiveness under compact urban development.