Poyang Lake

Poyang Lake, the largest freshwater lake in China, provides critical wintering habitat for a variety of waterbirds. Poyang Lake stretches from the Yangtze River 173 km south through the middle of Jiangxi Province, serving as a catchment basin for five smaller tributaries including the Gan and the Xiu Rivers (Figure 1). During the summer rainy season, the lake expands to as much as 4,000 square km, and in the winter dry season, water level recedes dramatically, isolating sublakes and streams according to topography. This complex hydrology results in a heterogeneous landscape that provides a variety of ecological niches.

A large number and diversity of migratory waterbirds rely on this dynamic ecosystem for wintering refuge, including many threatened and important species. Approximately 98% of the world’s remaining population of critically endangered Siberian cranes and about 90% of the world’s endangered Oriental white storks winter at Poyang Lake. Other important species include white-naped cranes and swan geese, both of which are listed as vulnerable.

Roughly 50% of the world’s populations of both of these birds migrate to Poyang Lake each year. Over 300 other species of birds, hundreds of species of fish, a few dozen species of mammals, and over 200 species of insects also live in Poyang Lake for at least some of the year.

This impressive range of wildlife has given Poyang Lake global significance. Over 20 nature reserves are scattered across the lake, including Poyang Lake Nature Reserve (PLNR). PLNR was established in 1984, and in 1992 was selected as a Wetland of International Importance by the Ramsar Convention.

Hydrology is the main driving force within the Poyang ecosystem. In an effort toJiangxi people have dealt with the dramatic seasonal fluctuations by manipulating water levels protect for local livelihoods, – particularly agriculture aquaculture– from Poyang’s dramatic seasonal fluctuations, people have manipulated the region’s hydrology to a great extent and continue to plan new hydrological-engineering projects. These projects exist at a fine scalelocally (individual levees and dams to protect rice paddies and spatially manipulate fisheries) and at a coarse scalebasin-wide (extensive sand dredging and the proposed Yangtze outlet dam). It is estimated that over 9,000 dams have been constructed in the greater Poyang watershed. Because the ecological health of Poyang’s wetlands depends on itsare connectedion with the Yangtze River, there is also enormous potential for large projects, to have an impact on Poyang, even when these projects are thousands of kilometers upstream, to affect dynamics in the Poyang basin. The Three Gorges Dam, for example, has already been shown to have an impact on Poyang, and further studies are being done to better understand this relationship.