Following your News story 'Putting China's wetlands on the map' (Nature 458, 134; 2009) and the related Correspondence 'Time for China to restore its natural wetlands' (Nature 459, 321; 2009), we also wish to stress the need to manage and protect China's existing wetlands, and to remind delegates to the International Congress for Conservation Biology, starting in Beijing on 11 July, of these globally important issues.

Eastern China supports over two million migratory waterbirds outside the breeding season, of which more than one million live in the Yangtze River floodplain. These include concentrations of eight globally threatened species, including the Siberian crane (Grus leucogeranus) and the oriental stork (Ciconia boyciana), and more than three-quarters of the east Asian populations of seven waterfowl species (L. Cao, M. Barter and G. Lei Biological Conservation 141, 2301–2309; 2008). The wetlands also supply tens of millions of people with food and raw materials, and help to prevent floods and improve water quality.

The influx of water, sediment and nutrients brought by the annual monsoon has maintained these wetlands until now, enabling humans to exploit them without disrupting their spectacular biodiversity. But hydrological changes, especially from hydroelectric and water diversion projects, and the move from low-intensity use by local people to unsustainable exploitation, have severely compromised this long-standing balance.

Safeguarding China's wetland riches requires strategic regional planning, strengthening the nature-reserve network and, most of all, a sound scientific understanding of the processes that support its biological diversity and its productivity.