Operationalizing SDGs through the Water-Energy-Food Nexus: multi-level assessment of ecosystem service supply-demand patterns in China

• Integrated Water-Energy-Food nexus reveals ecosystem service supply demand dynamics in China. • Revealed scale‑dependent Water-Energy-Food linkages and distinct regional patterns across multiple administrative levels. • Proposed a scheme structured around zonal control, classified strategy, and hierarchical management to achieve the SDGs. Global climate change and human society's development have escalated the imbalance between the supply and demand of Ecosystem services (ESs). Clarifying the relationship between the supply and demand of ecosystem service and elucidating its multi-scaled spatiotemporal evolution offers vital comprehensive supporting information for sustainable development. This study integrates the interactions between human-activities, natural-ecosystems, and socio-economics from a water-energy-food nexus perspective, covering multiple sustainable development dimensions, including SDG 2 (Zero Hunger), SDG 6 (Clean Water and Sanitation), SDG 7 (Affordable and Clean Energy), and SDG 11 (Sustainable Cities and Communities). The ESs from a water-energy-food nexus perspective were quantified by the water yield, carbon sequestration, and food production. The relationship among the supply–demand balance for water yield, carbon sequestration, and food production was analysed by the supply–demand index. We also investigated the spatial scale effects of each ecosystem service across various administrative levels (provincial, municipal, and county). The results shown that: (1) From 2000 to 2020, the supply of China's ESs in water-energy-food nexus exceeded demand overall, with limited spatial heterogeneity yet pronounced internal disparities. (2) The individual supply–demand ratio of China's ESs in water-energy-food nexus has shown a gradual improvement trend with notable spatial heterogeneity (2000–2020), but decline in carbon storage, and the integrated supply–demand ratio for the water-energy-food nexus fluctuates upwards. (3) Water-energy-food exhibit different interrelationships at various spatial scales, demonstrating regional characteristics. Furthermore, we proposed an integrated water-energy-food management scheme and policy recommendations in the principles of “zonal control, classified strategy, and hierarchical management”. Our study systematically incorporates ecosystem service supply–demand dynamics and their interdependencies into ecological conservation and restoration planning, providing innovative approaches for achieving sustainable human-environment system co-development and circular resource management.