China's wetland change (1990-2000) determined by remote sensing

Two wetland maps for the entire China have been produced based on Landsat data acquired around 1990 and 2000. Wetlands in China have been divided into 3 broad categories with 15 sub-categories except rice fields. In 1990, the total wetland area in China was 355208 km(2) whereas in 2000 it dropped to 304849 km(2) with a net loss of 50360 km(2). During an approximate 10-year period, inland wetland reduced from 318326 to 257922 km(2), coastal wetland dropped from 14335 to 12015 km(2), while artificial wetland increased from 22546 to 34911 km(2). The greatest natural wetland loss occurred in Heilongjiang, Inner Mongolia, and Jilin with a total loss of over 57000 km(2) of wetland. In western China, over 13000 km(2) of wetlands were newly formed in Xinjiang, Tibet, and Qinghai. About 12000 km(2) of artificial wetlands were also added for fish farm and reservoir constructions. The newly formed wetlands in western China were caused primarily by climate warming over that region whereas the newly created artificial wetlands were caused by economic developments. China's wetland loss is caused mainly by human activities.