Abstract: The Badain Juran and Tengger deserts are ones of the three main sources of sandstorm in China. With the increasing frequency and intensity of sandstorm occurrence in China, more and more attention has been paid to the merging status of deserts in the duneactivation region (DAR for short) between the Badain Juran and Tengger deserts. Based on Landsat TM/ETM+ images in 1989, 1999 and 2007 respectively, the desertification process in the DAR was investigated using the methods of dynamic change, transferred matrix and landscape pattern indexes. Its driving forces including natural factors and human activities were explored as well. The main conclusions are as follows: (1) During the period of 1989-2007, the areas of sandy land and cropland were expanded, while those of grasslands, saline land and wetland were shrunk. The dynamic change of grasslands, wetland, sandy land and saline land was higher than that of other land use types in the DAR. The transition among the land use types was remarkable, particularly between sandy land and grasslands. The landscape pattern indexes in the DAR demonstrated an obvious tendency of intensified fragmentation. The patch centroid of sandy land was moved northwestward, which could be regarded as a merging direction of deserts in the DAR from the northwest marginal zone of the Tengger Desert to the southeast marginal zone of the Badain Juran Desert. The analysis revealed that the land desertification, soil salinization, the degradation of grasslands and shrinkage of wetland were aggravated during the period of 1989-2007. Consequently, the Badain Juran Desert and the Tengger Desert tended to merge; (2) The expansion of sandy land, degradation of grasslands and the shrinkage of wetland were driven by both the natural factors and human activities, which resulted in the merging of deserts in the DAR between the Badain Juran and Tengger deserts. Thereinto, the warmingdrying trend was the precondition of desertification. Population growth and overgrazing sped up the desertification process. Although the related national policy and measures, e.g., the project of returning the grain plots to forests or grasslands, have been implemented to prevent land desertification and regenerate grasslands in the arid and semiarid regions of China, the desertification situation in the DAR between the Badain Juran and Tengger deserts is still serious. It is suggested to stabilize and sustain the policy support, ecological projects and longterm field observation and monitoring so as to guarantee the environmental protection and the ecological regeneration in the DAR between the Badain Juran and Tengger deserts.

Key words: dune activation region, desertification, development progress, driving force, policy measures, Badain Juran Desert, Tengger Desert