Urban blue–green space landscape ecological health assessment based on the integration of pattern, process, function and sustainability

Landscape ecological health (LEH) assessment of blue–green space is vital for the management and restoration of the urban environment. At present, existing LEH assessment research has mainly focused on the single measurement of landscape pattern or external ecological service function, ignoring the effect mechanism. Moreover, there is a lack of targeted assessment of urban blue–green space LEH. In this study, we constructed an urban blue–green space LEH assessment framework based on the integration of pattern, process, function and sustainability, and conducted an empirical analysis in Harbin, a megacity in Northeastern China. The results showed that the spatial changes in the four assessment units of landscape ecological pattern, process, function and sustainability were not coordinated in the study area. From 2011 to 2020, the overall condition of blue–green space LEH in the study area improved but still at an unhealthy level, and the spatial difference increased. Grassland, water and wetland suffered from the widespread degradation of LEH in the study area, and the LEH level improvement type had the largest area proportion, and the stabilization type had the smallest. Moreover, based on the spatial autocorrelation analysis, we clarified the LEH spatial correlation characteristics of the study area and proposed targeted optimization suggestions. Our assessment framework will extend the LEH assessment scope and methodology, and the research results can provide significant references for urban blue–green space protection and management.