Distribution dynamics of waterbirds in Dongting Lake and surrounding lakes

Abstract Dongting Lake and the lakes surrounding it are spatially relatively independent, yet they form an inseparable integrated system for waterbirds. Understanding the changes in waterbird distribution pattern in Dongting Lake and surrounding lakes is important for waterbird conservation and management. Based on six surveys during the winter period of waterbird and habitat data, we studied the changes in distribution pattern of different functional group of waterbirds between Dongting Lake and surrounding lakes and explored the effect of habitat area in Dongting Lake on waterbird distribution. The results revealed that the habitat areas within Dongting Lake are larger but less stable, whereas those in the surrounding lakes are much smaller but more stable. During regular hydrology periods, waterbirds were mainly distributed in Dongting Lake, whereas most of the diving ducks and vegetation gleaners occurred in surrounding lakes; during extreme dry periods, many waterbirds shifted to surrounding lakes (e.g., dabbling ducks and gulls). The Percentage Similarity Index (PSI) of these groups, which reflects waterbirds’ distribution dynamics, exhibited negative correlations with changes in water area within Dongting Lake. The percentages of these water-dependent groups and water area in Dongting Lake exhibited a positive correlation. Water area in Dongting Lake could reflect the distribution pattern of waterbirds between Dongting Lake and surrounding lakes. Our results emphasize the importance of the overall protection of wetlands in the Dongting Lake region.