Comparison of avian biodiversity and community similarity between Nansihu wetland and the Yellow River Delta wetland across different seasons.

Birds are widely recognized as important bioindicators, particularly in wetland ecosystems that support high biodiversity. This study investigated the structure and seasonal dynamics of bird communities in the Nansi Lake wetland and the Yellow River Delta wetland in Shandong Province, China. Bird surveys were conducted using the point count method, and species diversity, richness, evenness, and abundance were analyzed. A total of 220 bird species (347,599 individuals) were recorded across the two wetlands. The results revealed clear differences in community structure between the wetlands, with the Yellow River Delta consistently supporting higher species diversity, particularly in spring and summer, while the Nansi Lake wetland exhibited lower diversity during autumn and winter. Seasonal variation significantly influenced bird abundance and community composition, with stronger differences between the wetlands observed during the wet season. In addition, species similarity was generally higher in the Yellow River Delta wetland, indicating a more stable community structure across seasons. These findings suggest that habitat characteristics and seasonal environmental changes jointly shape bird community dynamics in coastal and inland wetlands. Overall, this study highlights the importance of seasonal processes in structuring wetland bird communities and provides a scientific basis for the conservation and management of wetland-dependent bird species in eastern China.