Context Current research on urban ecosystem services faces three major challenges: scale gap, disciplinary barriers, and knowledge fragmentation, necessitating a systematic assessment framework to support precise governance decisions. Objectives This study proposes a cascading "Typology-multifunctionality-supply and demand" framework to establish a full-chain research paradigm, enhancing information flow and feedback mechanisms from fundamental understanding to management implementation. Methods A practical case study in Changchun, Northeast China, applied multisource data and interdisciplinary tools to map urban green space (UGS) typologies, assess multifunctionality, and identify supply–demand mismatches. Results UGS ecological functions exhibit higher values at the edges and lower values in the center, contrasting with the spatial distribution of social functions. Significant synergies exist among ecological functions, while weak trade-offs are observed between ecological and social functions, with most UGS being ecology-dominant. The mismatches of supply–demand gradually transition from social to ecological aspects from the inner ring to the outer ring of the city. The multifunctional performance characteristics of different UGS types vary significantly. The "Three-Question Decision Toolkit" (Where-What-Which) enables the optimization of UGS management by tracing decision-making processes back to typological adjustments, integrating spatial prioritization, functional enhancement, and targeted type-specific interventions. Conclusions The cascading framework’s bidirectional coupling mechanism (forward analysis and feedback optimization) provide theoretical and practical tools for precision governance of high-density cities.

Rural communities in ecologically sensitive areas are confronted with environmental challenges and land waste. The hollowing out of villages because of the steady loss of young people has brought these problems to the fore. Research on the remediation of rural settlements in ecologically sensitive regions is scarce. This paper focuses on Tong Yu County, a region located in the agricultural and pastoral intertwined zones of western Jilin, which is known for its ecological sensitivity. On the basis of the results of the geographical assessment of the area via hierarchical analysis (AHP method) and soil and water conservation capacity evaluation via the revised universal soil loss equation model (RUSLE) and the net primary production quantitative index model (NPP model), we propose a rural development program that divides the study area into three different zones with different development orientations, namely, potential enhancement, agglomeration development, and expansion restrictions. Moreover, we conceived a rural settlement remediation scheme using the kernel density estimation method and provided remediation strategies for rural settlements of various density levels. The rural settlement development program and the rural settlement remediation scheme led to the optimization of rural settlements. Notably, with increasing kernel density, the area of rural settlements tends to increase and then decrease. Our research helps save 5.059 km² of land resources in the study area and offers guidance for improving the rural settlement layout in Tong Yu County.