Population Changes of Migratory Shorebirds at Yalu Jiang Estuary Wetland, a Critical Refuelling Sites along the East Asian-Australasian Flyway

Migratory birds require one or more stopover sites to refuel during their migration journeys between breeding and wintering sites. Many migratory birds have suffered population decline due to habitat loss and degradation at key stopover sites. This issue is particularly pronounced for migratory shorebirds in the East Asian-Australasian Flyway (EAAF). Loss of intertidal wetlands, the critical foraging habitats for shorebirds, in the Yellow Sea region has threatened population maintenance of many species along the EAAF. Detecting population dynamics at key stopover sites is the basis for making conservation and management actions. In this study, we conducted shorebird surveys and compared population changes over the past 20 years at Yalu Jiang estuarine wetland, a critical refueling sites in the Yellow Sea. While the number of species remained relatively constant throughout the years, peak count of shorebirds in late April declined by about 30-50%. Bar-tailed Godwits (Limosa lapponica), Great Knots (Calidris tenuirostris) and Dunlins (Calidris alpina) were the three most abundant species in the survey, comprising 88-95% of total birds recorded. The peak count of Bar-tailed Godwits declined by 44% since 2010, whereas Great Knots declined by 17%. Seven shorebird species attained 1% Ramsar criterion for wetlands of international importance in all the three years from 2022 to 2024, among which three were listed as threatened species in the IUCN Red List. This study confirmed that Yalu Jiang estuarine wetland is a critical staging site for migratory shorebirds. It is urgent to protect the coastal and estuarine wetlands of the Yellow Sea from further land reclamation and maintain a healthy habitat to stop or slow down the decline of shorebird populations.