Rethinking Pathways of Sustainable Development Goals: Insights from the Multidimensional Urbanization- Ecosystem Health Hierarchical Responses

Against the backdrop of accelerating global urbanization and mounting sustainability challenges, this study aims to quantify the nonlinear relationships between urbanization and ecosystem health, while integrating these relationships into an updated Sustainable Development Goal (SDGs) classification framework—essential needs, governance, and objectives. This approach provides a transformative understanding of hierarchical responses between ecosystems and SDGs during urbanization processes. This study developed a sustainable urban development-oriented multidimensional urbanization level (MUL)-ecosystem health index (EHI)-SDGs hierarchy framework in Yangtze River Economic Belt (YREB), identified the nonlinear relationships between MUL and EHI via Boosted Regression Tree (BRT) model, and revealed the divergent influence pathways of MUL and EHI on SDGs, along with their hierarchical interaction responses by employing factor analysis and structural equation modeling. Findings reveal three key insights: (1) From 1990–2020, high MUL values were concentrated in downstream cities with intensive construction and unused land. The EHI exhibited significant spatiotemporal heterogeneity with an upward trend, while upstream cities lagged in SDG progression compared to downstream regions. (2) Economic, social, demographic, and Spatial urbanization exerted nonlinear threshold effects on EHI via spatial interactions, and EHI demonstrated significant spatial spillover effects on SDGs. (3) EHI significantly moderates the linkage between MUL and SDGs, YREB should strategically concentrate on achieving SDGs 9, 11, and 12. Prioritizing these goals in YREB could enhance sustainable development. Notably, interactions among land use, ecosystems, and SDGs highlight the potential of systemic planning for megagglomerations to integrate resource management and sustainability, offering a novel theoretical framework and methodology for similar regions.