Study on the land use dynamic change in high-frigidecological vulnerable region——Source region of the Yangtze and Yellow River as a example

Based on land classification in the source region of the Yangtze and Yellow River,the two phases of TM/ETM remote sensing data obtained in 1986 and 2000 are compared. From spatial distribution pattern variations and type transformation trend,the land use dynamics changes are analyzed using GIS method. Results show that:From 1985 to 2000, construction land,unused land and cultivated land area increased rapidly. Grassland reduced and increasingly changed into unused land. Wetland and the forestland decreased obviously, and the comprehensive land use index reduced 0.36.As to the form of changes,the swapping area is less than its quantitative change for construction land and wetland while the quantity change is greater.As a whole,the quantity change is less than its swap. The analysis of land use dynamics shows that the speed of individual land use changes is in order of cultivated landwetlandunused landwater bodyconstruction landgrasslandforestland. Abnormal climate and irrational human activities are the major reasons for the change.