Evaluation of effects of integrated ecological restoration technology on habitat and bird diversity improvement in the North Branch of Yangtze River Estuary

Aims: The restoration of estuarine wetlands and the assessment of how restoration techniques impact habitat and bird diversity are essential for urban biodiversity conservation and sustainable use. This aligns with the objectives of the China Biodiversity Conservation Strategy and Action Plan (2023–2030) and contributes to the implementation of the United Nations’ Kunming-Montreal Global Biodiversity Framework. By integrating machine learning with field surveys, this study evaluates the effects of various ecological restoration techniques on habitat conditions and bird diversity before and after restoration in the North Branch of the Yangtze River Estuary. Methods: By comparing and analyzing existing ecological and environmental problems in the study area, targeted restoration plans were developed, and integrated ecological restoration technologies were implemented. After project completion, we employed machine learning and field investigation methods to assess the restoration status of the Yangtze River Estuary habitat and bird diversity, comparing conditions before environmental degradation and after ecological restoration. Results: The findings indicate that Spartina alterniflora control, mudflat construction, tidal creek construction, and native salt marsh vegetation restoration are key methods for enhancing habitat heterogeneity and increasing avian diversity in estuarine wetlands. Specifically, Spartina alterniflora control and mudflat creation cover 12.97 ha. Reed (Phragmites australis) vegetation restoration covered 13.5 ha. Tidal creek measures extended 600 m in length. Bird diversity in reed planting areas showed the greatest recovery, with species richness, abundance, and diversity indices in winter and spring exceeding those recorded in 2018 before ecological degradation. The highest record included 18 species and 178 individuals. In tidal creek construction areas, spring bird species, abundance and Shannon-Wiener diversity index recovered to pre-degradation levels, with a maximum of 13 species and 68 individuals recorded. Spartina alterniflora control areas showed a slower recovery of bird diversity, with a maximum of 13 species and 68 individuals recorded, still lagging behind pre-degradation levels. Conclusion: This study compares and evaluates the effects of various restoration techniques on estuarine wetland habitat and bird diversity enhancement. By conducting a comparative analysis of domestic and international restoration projects, this study offers valuable experiences and references for future restoration efforts in China. Furthermore, it provides scientific support for the systematic biodiversity assessment, urban biodiversity conservation, and sustainable use of degraded estuarine wetlands following integrated ecological restoration.