Temporal and Spatial Evolution of Herbivorous Waterbird Habitat in Floodplain Wetland Driven by Hydrology

The hydrological rhythm of floodplain wetlands affected by natural climate variability and human activities is the driving factor affecting the distribution of herbivorous geese habitats. It has always been challenging to determine its long-term variation, due to the lack of data on species distribution and broad wetland observation. In this study, the key normalized difference vegetation index threshold range suitable for herbivorous geese, greater white-fronted geese (Anser albifrons, GWG) and bean geese (Anser fabalis, BG), was discovered by combining GPS tracking data with Landsat satellite data. The suitable habitat area and distribution variation characteristics of GWG and BG from 1982 to 2020 were extracted based on the threshold range. The results showed that the suitable habitat area had a declining trend after 2003, that the distribution had moved toward the lake's center, and that its average elevation had decreased by around 1 m, particularly during the arrival period. The change of herbivorous geese habitat is caused by the continuous drying of Poyang Lake. The study can offer a rational scientific foundation for wetland waterbird protection and watershed hydrological management.