Abstract：Dongting Lake is the second largest freshwater lake in China and is one of the globally important wintering sites for migratory waterbirds in the East Asian–Australasian Flyway. Crucial sites and environmental variables for wintering migratory waterbirds are of great concern in the Dongting Lake wetlands. In this research, based on annual (2003/2004–2016/2017) waterbird and habitat census data, we recognized the crucial sites for waterbirds duringwintering seasons by comparing the difference ofwaterbird populations at the community, foraging guild and species levels in different natural wetlands within East Dongting Lake, and then identified the crucial
environmental variables affectingwaterbird distributions by analyzing the relationship between waterbird populations and the environmental variables, including vegetation area, mudflat area, water area with the depth of 0–20 cm, water area with the depth of 20–50 cm, water area with the depth of 50–100 cm, water area with the depth N100 cm, growth status of vegetation (Min,Mean and Max NDVI), and the human disturbance. Results indicated that five naturalwetlands, i.e., Daxiaoxi, Chunfeng, Baihu lakes, Dingzi dyke and Tanjiaweizi,were recognized as the crucial wintering sites for migratory waterbirds in the East Dongting Lake. Among the ten selected
environmental variables, water areas with the depth of 0–20 cm, 20–50 cm and N100 cm, human disturbance, Min and MeanNDVIswere identified as the crucial environmental variables overall.Waterbirds at different levels exhibited significant linear relationship with certain environmental variables, with the exception of Bean goose and LesserWhite-fronted goose at the species level, which showed Gaussian distribution with changes in mean NDVI. The crucial environmental variables appeared to be foraging guild- and species-specific. These findings provide significant information for managers to understand the differences of wetlands and waterbird populations within East Dongting Lake, and to make more targeted conservation efforts.