Evaluation of Lake Fragmentation and Its Effect on Wintering Waterbirds in Poyang Lake, China

This study was designed to determine the fragmentation of sub-lakes in winter and its effects on wintering waterbirds in Poyang Lake. Poyang Lake becomes fragmented in winter, which forms many seasonal sub-lakes every year, and have different environmental characteristics. These sub-lakes significantly impact winter bird habitats and result in susceptibility to various changes, because birds have different distribution responses. A total of 24 sub-lakes were surveyed from one to five vantage points using point count methods in each sub-lake with binoculars, monocular, and a spotting scope for four consecutive winter seasons. The multi-site dissimilarity Sorensen index measures overlapped between two populations, and the R software "iNEXT" package was used to evaluate the sample coverage test of the study area. We observed 58 wintering waterbird species belonging to 9 orders and 15 families from 2016 to 2020. Spearman correlation analysis showed that the species richness of wintering waterbirds was significantly positively correlated with the sub-lake areas and associated with the richness of habitat type. The WNODF analyses were considerably correlated for sites of waterbirds, mainly with the abundance of forage and conservation of habitat form. The outcomes of this study showed that Maying Lake has the highest local beta diversity, whereas Dacha Lake has the lowest local beta diversity contribution (0.007). This study's findings demonstrate Poyang Lake's role in waterbird the habitat suitability of waterbirds, especially for foraging and conservation.