Research on dynamic changes of Zoige plateau landscape

Zoige wetland is the source of Yangtse River and Yellow River. Its dynamic changes are studied mostly before year of 2000 based on MSS and TM images. This study selects TM and CBERS images to obtain the landscape structure of typic region of Zoige plateau. The results show that: (1) the grassland is the primary landscape of study area. The next are bared soil, woodland and farmland. (2) Wetland area decrease from 1316.37km² to 303.22km² with decrease rate of about 72.36km²/a since 1994. (3) Farmland area increased between 1994 and 2001, but decreased since 2001. High coverage grassland area decreased, middle coverage grassland area increased, low coverage grassland area increase, snow and bared soil area decreased since 1994. (4) The wetland spectral characteristics are distinctive in bands of the fourth, fifth and seventh with lowest pixel values. (5) The wetland is converted into grassland, bared land primarily. (6) The landscape indexes of wetland show that the wetland patches are getting smaller and fragmentized in shape, and more disperse in distribution since 1994. Therefore, the degradation of wetland in Zoige plateau is much more severe and should be attach importance to for protection and management.