REMOTE SENSING RESEARCH OF WETLAND CURRENT STATUS AND CHANGE IN THE YANGZE RIVER BASIN

Wetland and wetland environment problems attract a great attention from the international and national levels.It is an ideal techniques to research wetland on a large regional scale using the remote sensing macro,for its efficient,timeliness and multi-temporal advantages.Based on multi-temporal satellite remote sensing data(MSS,TM/ETM,CBERS-02and so on)and software platform(ERDAS,ARCGIS,MAPGIS and so on),from the different phases 1975,2000and 2007,the paper carried out the remote sensing information extraction of wetland,the mapping results and the statistical analysis work according to sub watersheds unit systematically.It has predominated fully in the type,the area,the structure,the current distribution status and change rule of the wetland for 30years in the Yangtze River Basin.This paper analyzed the natural and human geological force mechanism and predicted its evolution tendency.And the results provids the basic data of large regional wetland research for the rational development and utilization of land resources.The results show that the total area of wetland current status in the Yangtze River Basin was 7.931 9×104 km2,in which the river wetland accounted for 42.33%,the lake wetland accounted for 20.93%,the marshland accounted for 18.53%,and the artificial wetland accounted for18.21%.The wetland type developed fully,and its spatial distribution was wide,but sub basin or local wetland distribution was seriously uneven and its type structure was incomplete;In the 30years from 1975to 2007,the total of lake wetland and marshland reduced 8.89×102 km2 and 5.91×102 km2 respectively,the total of river wetland and artificial wetland increased 3.50×102 km2 and 6.302×103 km2 respectively,so the total increase of wetland was 5.172×103 km2.The main way of wetland change was increase or decrease of area and type conversion,and its change was subject to the natural and human activities of geological force.The wetland change displayed the stage characteristics,before 2000,the wetland was in the adverse change period,however,after 2000,it was in the benign change period.After 2000,the overall performance of wetland environment was getting better and better in the Yangtze River Basin,but the local situation had more problems.