巴丹吉林-腾格里沙漠间沙丘活化带发展过程及其驱动力分析

Desertification Process and Its Driving Forces in the Dune-activation Region between the Badain Juran and Tengger Deserts

基于1989,1999年和2007年TM/ETM+影像,从土地利用变化的视角分析巴丹吉林-腾格里沙漠间沙丘活化带的发展过程,并探讨沙丘活化带发展的驱动因素。分析表明:①1989-2007年,研究区沙地和耕地面积增加,草地、盐碱地和沼泽地面积减少,景观破碎化程度加剧,沙地斑块质心向西北偏移,即腾格里沙漠西北缘向巴丹吉林沙漠东南缘推进,巴丹吉林-腾格里沙漠间沙丘活化带合并趋势显著。②气候暖干是该区土地沙漠化的前提,国家政策措施对沙漠化防治和草地恢复起到一定作用,但人口增长和超载过牧加剧了沙丘活化带的合并。建议在巴丹吉林-腾格里沙漠间沙丘活化带继续加强政策调控与生态工程建设,以及长期野外定位观测和监测。

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.