Response of Landscape Types and Shorebird Diversity to Extreme Drought Climate in Poyang Lake, China During the Non-Breeding Period

Habitat use by shorebirds is described in Poyang Lake in the Nanji Wetland National Nature Reserve (“Nanji Wetland”) and the Wuxing reclamation region (“Wuxing”) during the non-breeding periods of 2022 (extreme drought year) and 2023 (normal water year), using the sample point method. The results indicated that the deep water area in the extreme drought year at Nanji Wetland and Wuxing was smaller than in the normal water year, while the mudflat area was larger. Grassland area during the early and middle parts of the extreme drought year was lower than in the normal water year, and fluctuations in shallow water area were relatively small in both regions. Landscape indices at Nanji Wetland exhibited greater variability, with most indices being lower in the extreme drought year. Most landscape indices in Wuxing were consistent across years. The number of species and individuals was higher in the extreme drought year than in the normal water year at Nanji Wetland, whereas the opposite trend was observed at Wuxing, suggesting that the large, protected area served as a refuge for many shorebirds. The mudflat area was found to be strongly and positively correlated with the total number of shorebirds, the number of species, and the populations of Vanellus vanellus and Tringa erythropus. The SHDI was found to exhibit a strong negative correlation with the number of shorebird species and the populations of Limosa limosa. The results indicate that the mudflat area is critical for maintaining shorebird diversity in Poyang Lake, and reducing the SHDI may enhance shorebird diversity. Our findings have to be further tested for long-term period in the future. These findings provide guidelines for shorebird population conservation and habitat management strategies.