The dynamic change research of ecological environment in Longbao region of Yushu state in Qinghai

The study selected the areas of 9 252 km2 in Longbao region of Yushu state in Qinghai and 15 years remote sensing image data from 1990 to 2004. The correlation between changes of ecological environment in Longbao region under the scale of climate change and climate factors was analyzed by means of evidence analysis and gray correlation analysis. The results showed that the ecological environment of Longbao region was in an obvious instable condition, the transformation of ecological types was remarkable, the area of lake and marsh which were the most representative factors of the wetland ecotype had been reduced, and the reducing rate of marsh was 487.3 hm2/a. The area changes of different ecological types such as rivers, marshes, transit area of shrub grassland and unsuitable forest grassland were more correlative with temperature, and lakes were more correlative with temperature and frozen earth, other waters were more correlative with temperature and evaporation, grassland and uncovered rock were more correlative with temperature and precipitation, permanent snow or glaciers were more correlative with temperature, evaporation and frozen earth. The grassland suitable for forestry and shoal were all associated with precipitation, evaporation and the frozen earth. The shrubbery ecotype was only correlative with frozen earth.