Distribution and Key Impact Factors of Overwintering Waterbirds Diversity in Weihai

Exploring key factors influencing the distribution of overwintering waterbirds is crucial for their conservation and wetland management. Systematic surveys of overwintering waterbird resources were therefore conducted in January 2023 and January 2024 across various habitats in Weihai City, China, including coastal mudflats, bay estuaries, reservoirs, and lakes. A total of 63 703 overwintering waterbirds belonging to 48 species, 12 families, and 6 orders were recorded across 35 survey areas (80 sampling sites). Birds in the order Anseriformes accounted for 52.08% of all species and 69.08% of the total number of individuals, representing an absolute dominance of both species richness and abundance. Birds in the order Charadriiformes accounted for 22.92% of all species and 26.86% of individuals. Three species under first-class protection in China were recorded, including the scaly-sided merganser (Mergus squamatus), red-crowned crane (Grus japonensis), and saunders's gull (Saundersilarus saundersi), together with 8 species under second-class protection in China. Lagoon habitats were identified as the most important for overwintering waterbirds in Weihai. Yinghua Lake exhibited the highest Margalef richness and Shannon-Wiener diversity indices of overwintering waterbirds, while Yuehu Lake showed a highly similar community structure. Redundancy analysis reveal that habitat type, shape index of the survey area, and intensity of human disturbance were the three most significant factors influencing overwintering waterbird abundance, and their relative importance was quantified as 34.15%, 20.12%, and 8.98%, respectively, by variation partitioning and hierarchical segmentation analysis. Among the 35 survey areas, the abundance of 9 species of overwintering waterbirds exceeded the 1% criterion of their respective global populations. Six wetlands were identified as wintering sites for waterbirds that meet the criteria for internationally important wetlands under the Ramsar Convention. However, a conservation gap was identified in Rushan Bay wetland, which urgently needs to be included as a priority conservation area. It is recommended that a detailed assessment of overwintering waterbird resources be conducted in this region, accompanied by strengthened regulation of surrounding aquaculture activities to ensure effective and comprehensive protection of overwintering waterbirds and wetland resources.