Spatiotemporal Evolution and Influencing Factors of Multifunctional Territorial Spatial Utilization Efficiency: Evidence from the Yangtze River Delta, China

Analyzing the spatiotemporal evolution and drivers of multifunctional territorial spatial utilization efficiency (TSE) is essential for guiding the sustainable use of territorial space. This study develops an evaluation system integrating urban, agricultural, and ecological spatial utilization, and investigates the Yangtze River Delta (YRD) from 2000 to 2023 using kernel density estimation and the XGBoost–SHAP model. The main findings are as follows: (1) TSE in the YRD exhibits a sustained upward trajectory and a distinct east–west gradient. At the sub-dimensional scale, urban spatial utilization efficiency is clustered in southeastern core cities, agricultural spatial utilization efficiency is concentrated in the central transition zone, and ecological spatial utilization efficiency is highest in the northern areas. (2) The overall regional disparity in multifunctional TSE shows a fluctuating yet declining trend, indicating a gradual reduction in spatial inequality. The inter-provincial imbalance in development is identified as the primary cause of spatial differentiation in the YRD. (3) Topography, economic density, and population density are the leading determinants of TSE, while their interactions with socioeconomic variables generate nonlinear effects on efficiency improvement. These conclusions provide empirical support for spatial planning and efficiency-oriented territorial governance in the YRD.