Landscape ecological health assessment of coastal cities: a case study of Weihai

Landscape Ecological Health (LEH) assessment supports the coordination of ecological conservation, urban development, and resource use in rapidly changing coastal cities. However, existing studies often apply a uniform indicator system and weight vector across the entire study area. This approach does not adequately account for differences in the spatial applicability of terrestrial and marine indicators. Taking Weihai, China, as a case study, this study developed an integrated pressure–structure–process–function framework for citywide LEH assessment at eight observation dates from 1990 to 2025. A 23-indicator system, comprising 15 terrestrial indicators and 8 marine indicators, was established through qualitative screening and quantitative analysis. The marine indicators were applied within a 1.5 km landward coastal belt, whereas the terrestrial indicators were applied to the remaining area. The two domains shared a common normalization baseline but used separate domain-specific weight vectors, which are integrated to generate a continuous citywide LEH surface. The results indicate that: (1) Mean LEH increased from 0.3835 in 1990 to 0.4092 in 2025. The temporal pattern showed gradual improvement, a brief decline around 2010, and renewed growth after 2015. Over the same period, the proportion of the low-LEH class decreased from 59.19% to 45.28%, whereas that of the high-LEH class increased from 0.07% to 3.32%. (2) LEH exhibited persistent and significant positive spatial autocorrelation, with global Moran’s I remaining approximately 0.86–0.90. Higher-value areas gradually expanded in selected coastal sections and mountain–reservoir corridors. Lower-value areas remained concentrated in intensively used plains and urbanized belts. (3) Land use (q = 0.373) and elevation (q = 0.290) had the greatest single-factor explanatory power. Their interaction yielded the highest explanatory value (q = 0.47), indicating that human land use and topographic conditions jointly shaped the spatial differentiation of LEH. This study advances coastal-city LEH assessment from uniform citywide weighting to an explicit spatial integration rule, providing a transferable framework for long-term ecological monitoring and differentiated spatial management in coastal cities.