Dynamic evaluation of waterfowl habitat quality based on an integrated multi-indicator framework and habitat function enhancement strategies in Xianghai Nature Reserve

Waterbird habitat quality in small inland wetlands is jointly influenced by hydrological processes and human regulation. Although previous studies have improved our understanding of waterbird habitats, most focus on large spatial scales and therefore fail to capture fine-scale habitat variation in small wetlands. In addition, while multiple environmental factors are often considered, existing indicator systems do not fully reflect the coupled interactions among hydrology, vegetation, and waterbird communities. To address this gap, this study selected the Xianghai Wetland Nature Reserve in the western Songnen Plain as the study area. By integrating remote sensing and field survey data, we developed a comprehensive Habitat Quality Index (HQI) for waterbirds. The index incorporates multidimensional hydrological connectivity (MNDWI), vegetation cover (NDVI), water depth, and waterbird diversity (Shannon-Wiener index). Using this framework, we systematically evaluated the spatiotemporal dynamics of habitat quality from 2014 to 2023The results show that from 2014 to 2019, reduced precipitation and shrinking water bodies weakened hydrological connectivity, resulting in an overall decline in habitat quality. Since 2020, ecological water replenishment and restoration projects have significantly improved hydrological connectivity, driving rapid recovery and continuous expansion of high-quality habitats. Spatially, high-quality habitats are consistently concentrated in the wetland core and along lake margins, with habitat quality decreasing from the center toward the periphery. Habitat quality changes are primarily constrained by hydrological connectivity, while water depth and vegetation regulate habitat conditions indirectly by influencing food availability and concealment. By integrating waterbird community metrics with hydrological processes, this study provides a methodological framework for dynamic assessment and refined management of waterbird habitat quality in small-scale inland wetlands.