Analysis of land cover change and its driving forces in a desert oasis landscape of Xinjiang, northwest China

摘要

The combined effects of drought, warming and the changes in land cover havecaused severe land degradation for several decades in the extremely ariddesert oases of southern Xinjiang, northwest China. Land coverclassifications of Landsat images in 1990, 2000 and 2008 were performed basedon the multistage supervised classification scheme using the maximum likelihoodclassifier integrated with conventional vegetation and soil indexes, whichimproved overall accuracies by 4–5% compared to the standard classificationmethod. Based on the detection of changes in land cover during 1990–2008using remote sensing (RS) and a geographic information system (GIS), it can befound that the oasis significantly (+35%) increased, while the area ofecotone decreased (?43%). The major trends of the land cover changeswere the notable growth of the oasis and the reduction of the desert–oasisecotone. These changes were mainly a result of the intensified humanactivities such as land and water exploitation as well as overgrazing. Theresults of this study indicate that the oasis environment will bedeteriorated by increase in potential areas of land degradation if the trendof desert moving further inward and the shrinking of the ecotone continuesover the next decades.