干旱区生态环境知识资源中心

In this study, the land-use change characteristics in the past 30 years of an alpine-cold desertified area in the Qinhai-Tibetan Plateau were assessed by interpreting remote sensing satellite imagery during three key periods (1976, 1996, 2006) as well as by applying a geographical information system (GIS). The assessed results were summarized from three positions. First, grassland was the basic landscape background of study region, while, at the same time, many desert landscape elements (such as sandy land and drying ravines) were distributed among grasslands. Second, the disturbance derived from humans to the landscape was not intensive in the 1970s, but after 1996, such disturbance was greatly increased. Significant differences in dominance index were found among different patch types, and landscape fragmentation degree and simple landscape diversification were low in 1976. After 1996, there was an obvious change in the pattern of patches and the landscape became more fragmented. Third, in the last 30 years, transformation speeds among different lands-use types accelerated. During 1976-1996, great changes in land-use area occurred, but the speed of change was slow. During 1996-2006, the land-use area change was less than that for 1976-1996, but the speed of change was rapid. The main driving force contributing to the dynamic changes of land use was human activities.