The Contraction And Expansion Of The Southern Region Of The Tengger Desert And The Causes From 1973 To 2009

The sandy land in the southern region of the Tengger Desert is adjacent to cities and towns, and land desertification poses a threat to the livelihood and production of local residents. To determine dynamic changes in local desertification, five periods (1973,1987,1992,2001 and 2009) of remote sensing data are studied by Remote Sensing (RS) and Geographic Information System (GIS). Through analysis, we find that the desert contraction area is primarily centered around three units (Wuwei, Gulang, and Jingtai) and nearby regions of Zhongwei city. The primary desert expansion areas include the west side of Helan Mountain (WSHM), the central mountainous area (CMA) and the eastern and western Zhongwei unit far from towns. From 1973 to 2009, the degree of change in the contracting part of the primary desert expansion unit showed an increasing trend; in brief, most of the desert (especially after 2001) has been developing in a direction in which desertification has been gradually controlled. Through a comparative analysis of natural factors, human activity index data and desertification in the study area, we believe that the desertification in this area is affected by both natural factors and human activity, but they have different impacts in different regions. The primary desert expansion areas are less affected by human activity, but they are primarily controlled by natural factors (especially wind and terrain). The desert contraction areas occur around the towns and nearby regions with frequent human activity; desertification is primarily controlled by human factors. With rapid economic development (especially after 2000), the scale of the cultivated area, town and ecological protection engineering has gradually expanded, and the latter two are primarily built on a previous desert, which is the root cause of the reduction in the desert areas around the towns and the shrinkage towards north of border. Therefore, reasonable and effective human activity in the southern region of the Tengger Desert is playing a crucial role in preventing desertification.