Research On Monitoring Dynamic Transformation And Driving Force In The Source Of Heihe

Wetland has a very important ecological, economic benefits. This paper discusses the importance of wetland taking the wetland in the source of Heihe as subjeces and general situation of wetland transformation in recently 20 years. It obtain 10 categories of landscape types in the area by combining 1987, 1999and 2006 Landsat-5 TM data, 1 / 25 million digital topographic map,and 1 / 100 million land-use maps , etc. It analyse the dynamic process and driving force of wetland in Heihe since 1987 by using transfer matrix made through the use of ENVI software. It shows that:â‘ The area of wetland shows obvious of reducing trend. In 1987 it was 987.9295km~2 which occapied 17.787% in the whole research region;and in 1999 it turned into 983.2871km2 which took up 11.7345%;as to 2006,it was 963.0655km~2 that its percentage reduced to 11.4932%.â‘¡Through the analysis,we can see that the increasing temperature and the decreasing precipitation make the wetland area tend to reduce in the natural driving force. And,in the society driving force, the pressure of population growth and economic development was the main driving force which leads to the area of wetlands to reduce.â‘¢By principal component analysis, the selected 9 initial variables extract into three components. The three principal components are economic factors, agriculture factors and population factors.Where the first principal component of economic factors, wetlands on the dynamic changes of the greatest impact. Therefore we can say that economic factors is the cause of wetland degradation major driving force.