Aeolian desertification, one of the most serious eco-environmental issues, has hampered alpine ecosystem development in Qinghai-Tibet Plateau (QTP). However, the research of aeolian desertification in this region was very limited. To develop a set of science-based preventive measures to mitigate desertification, it is necessary to understand the dynamics of aeolian desertification and its driving factors. In this study, we established the aeolian desertification classification and grading system for QTP based on fieldwork and expert review. Using this system, we obtained the distribution of aeolian desertified land (ADL) through visual interpretation of the Landsat images during the four years of 1977, 1990, 2000, and 2010. Finally, we revealed the spatial and temporal distribution patterns of ADL since 1977 and discussed its possible causes.
ADL in the QTP covered 394,785 km2 in 2010, accounting for 15.2% of the total area of the Plateau. Gravel type accounted for 79.0% of the total ADL. The extremely severely, severely, moderately and slightly desertified land accounted for 8.1%、4.1%、58.3% and 29.5%, respectively. The area and degree of ADL increased from the southeast to northwest. ADL in QTP expanded from 1977 to 2010 at a rate of 246.2 km2 yr-1 as a whole. However, the development trends of ADL in different periods of QTP varied greatly. ADL expanded quickly from 1977 to 1990 at a rate of 775.5 km2 yr-1. The expansion rate slowed down from 1990 to 2000 with a value of 486.7 km2 yr-1. From 2000 and 2010, ADL reduced with a rate of 682.2 km2 yr-1. We found that irrational human activity was the dominant cause for the expansion of desertification, whereas climate change and ecological restoration projects caused the reversal of land desertification.