Distribution of wintering waterbirds and assessment of their habitat in Dongting Lake, China.

The wintering waterbirds in Dongting Lake have features of rich species, abundant populations and high density. There are totally three wetlands in Dongting Lake listed as Ramsar sites due to their significance in conservation of migratory waterbirds. However, the habitats of the wintering waterbirds are threatened by hydrological projects such as the operation of the Three Gorges Dam. Understanding the current distribution and habitat quality are fundamental for conservation of wintering waterbirds. In this study, we divided the whole Dongting Lake wetland into three areas based on the boundary of the reserve: East Dongting Lake, South Dongting Lake and West Dongting Lake. Waterbirds richness (species, population size and population of rare and endangered species) in these three parts were calculated with synchronous bird survey data during the period of 20082012. Land cover of the study site at 30 m resolution for 2013 winter was mapped. Comparing waterbird richness and landscape pattern between these three areas, we found that the waterbird richness was the highest at the East Dongting Lake, which is consistent with its best preservation of habitats integrity. By contrast, habitat fragmentation caused by planting of poplar trees and reeds reduced the waterbird richness of the South and West Dongting Lake. The results indicated that only remaining well-preserved habitat in the Dongting Lake is the crucial refuge for wintering waterbirds and should be protected strictly. The wet meadows that were developed to plant poplar trees and reeds should be restored gradually. The results have direct conservation implications for future conservation and management of wintering waterbirds in the Dongting Lake.