The variety of wetland environment in Sanjiang Plain

Wetland is one of the most important ecological systems on the earth with high biology-function. Sanjiang Plain is not only the largest concentrated distribution area of freshwater swamp in China, but also the most significant commodity grain production area. Whether the wetland environment healthy or not will have a great impact on food supply security. By use of RS and GIS technology TM, ETM, and CBERS data, author interpreted wetland on the RS data, calculated dynamic degree and transfer matrix of wetland, determined the distribution and transfer status of different wetland subtypes, then analyzed the mechanism of wetland changes. The research result shows that the variety of lake and river is less, swamp area reduces significantly, and constructed wetland area increases seriously. The changes among swamp, constructed wetland and non-wetland are significantly.