Study area
The mudflats in Jiangsu Province support large and diverse and flocks of migratory shorebirds, including many rare and endangered species, and are crucial to global biodiversity conservation. The sampling sites Tiaozini (TZN) and Yongkou (YK) were areas of intertidal mudflats separated by 60 km (Fig. 1). In 2019, Tiaozini was selected as a Natural World Heritage site as the largest area of intertidal mudflats in the world. The mudflats have a pivotal role in the migrations of shorebirds and are key wintering, breeding, and staging sites on the EAAF. At least four hundred species and 50 million migratory birds are recorded in the study area, which is listed under Ramsar wetlands of international importance (Yang et al. 2017).