A biological bottleneck
The Yancheng Coastal Wetlands are the largest single patch of intertidal mudflats on the planet. This vast habitat is a refueling station on the East Asian-Australasian Flyway (EAAF), a migration corridor for tens of millions of birds. The wetlands annually host around 3 million migratory birds. For some species, the area is essential. More than half the world's population of the endangered Nordmann's Greenshank (Tringa guttifer) and the critically endangered Spoon-billed Sandpiper (Calidris pygmaea) depend on this specific site to rest and feed during their journeys.
The Spoon-billed Sandpiper, a bird smaller than a sparrow with a uniquely shaped bill, has a global adult population estimated at fewer than 1,000 individuals. These birds travel over 8,000 kilometers from their Arctic breeding grounds in Russia to wintering sites in Southeast Asia. They spend two to three months at Yancheng to molt and build up fat reserves for the next leg of their flight. Similarly, surveys have counted over 1,194 Nordmann's Greenshanks at Yancheng's Tiaozini mudflats, leading to an upward revision of the species' entire global population to between 1,500 and 2,000. The concentration of such a large percentage of these species' populations in one place makes the ecosystem's health a matter of global conservation importance.