Ten percent of China's wetlands have vanished over the past decade as urban development has advanced, a forestry official said at the launch of a national wetlands conservation project on Wednesday.

Bao Daming, of the State Forestry Administration, said more than 3.3 million hectares of wetlands have disappeared since the first national survey 10 years ago, even though more wetlands are protected by regulations today. Protection has expanded from 30 percent of the country's total wetlands to 43 percent.

The first survey, from 1996 to 2003, showed China's wetlands at 38.5 million hectares, of which natural wetlands made up 36.2 million hectares, nearly 4 percent of the national territory.

"Of all the disappearing land, 99 percent is natural wetland," Bao said. "Threats that lead to its loss are increasing."