Yongge Li, Wei Liu, Meng Zhu, Qi Feng, Xinwei Yin, Xiaomiao Li
Sustainable management of multiple ecosystem services (ESs) and human well-being (HWB) is essential in regions facing supply-demand imbalances or spatial mismatches. However, the nonlinear relationships and potential threshold effects among variables associated with ESs-HWB coupling remain underexplored, especially within ES supply-demand bundles. This study investigated the spatiotemporal dynamics of ESs, HWB, and their coupling coordination degree (CCD) in the mountainous and hilly regions of central-southern Shandong Province, China from 2000 to 2023, using self-organizing map (SOM) to classify ES supply-demand bundles, and the XGBoost-SHAP method to identify key variables and potential threshold effects on CCD. The results were as follows: (1) The ecosystem service supply-demand ratio (ESDR) exhibited relatively stable, but supply-demand mismatches persisted across regions over time. SOM analysis identified five ES supply-demand bundles. (2) Although HWB exhibited obvious spatial heterogeneity, featuring higher levels in urban centers and lower levels in mountainous and waterway-adjacent areas, regional disparities showed a gradual narrowing trend, especially health and security well-being. (3) High-level CCD areas expanded gradually during the study period, with their proportion increasing by 9.50% primarily through the conversion of intermediate- and low-level coordination areas. The ESDR of food production and carbon storage showed highly coordinated with HWB, with CCD values generally exceeding 0.69, whereas cultural services and soil retention showed weaker coordination. (4) Distinguishing system indicators and external factors improved the interpretation of CCD, with both groups exhibiting nonlinear associations and potential threshold effects across different bundles. These findings offer a refined basis for improving ESDR-HWB coordination and supporting targeted management strategies in mountainous and hilly landscapes.