Study on the dynamic variation of landscape pattern in the middle and lower reaches of the Shule River Basin

Based on the data of TM images, land-use maps and topographic maps, the temporal and spatial patterns of landscape in the Shule River Basin from 1990 to 1999 were investigated. The results showed that the variations in landscape indices were fluctuating: The landscape diversity index and evenness index in the study area increased from 2.934 and 0.883 to 2.973 and 0.895 respectively but decreased to 2.994 and 0.886 from 1994 to 1999 and the variation tendency of dominance was in inversion with them. In the recent 10 years, the transitions of landscape types resulted in variations of landscape pattern in two aspects in the region. On one hand, intensive farmland landscape with a well-equipped irrigation system has been formed near the water resources in the middle and upper reaches of the river basin. On the other hand, with the increase of exploitation intensity of water resources, the natural ecological system had been gradually destroyed and he landscape pattern had changed from highly fragmented a natural vegetation landscape into desertified regions far away from water resources or the lower river basin.