HONG KONG — Long celebrated as China’s largest freshwater lake, Poyang reaches more than three times the expanse of Los Angeles in the summer wet season. It is home to the rare Yangtze finless porpoise, and its mud flats are the primary winter feeding grounds for thousands of birds that fly south each autumn to escape Siberia’s chill, including the critically endangered Siberian crane.

Now it is Poyang itself that is at risk.

In recent years, the average expanse of the lake, in the southeastern province of Jiangxi, has been shrinking, and winter water levels have declined sharply.

The local government has a proposed solution, but it faces a chorus of opposition from scientists and environmental groups in China and beyond who argue that it could have disastrous effects on the lake’s fragile ecosystem and drive the Siberian crane and other migratory birds further toward extinction.



Water levels in the lake have always fluctuated radically between the summer rains and winter dryness, but there is now concern that the levels are off balance. Culprits include the Three Gorges Dam, which stores water upstream on the Yangtze for winter electricity generation, lowering a nearby river channel and sucking water from the lake. Dredging to collect sand for construction projects has also lowered the lake’s bed and caused more runoff. This year, drought turned much of the lake into grassy plains.