Advances and Problems in the Understanding of Desertification in the Hunshandake Sandy Land during the Last 30 Years

Located in the northern margin of East Asian summer monsoon,Hunshandake Sandy Land is well-known for its ecologically vulnerable characteristics,and its desertification processes are concerned by both public and scientific communities.In this paper,we reviewed studies of the desertification in Hunshandake Sandy Land during the last 30 years.The current inconsistencies of understanding the desertification in this region were discussed in detail,regarding processes,causes and future trends.It shows that investigations on desertification processes are not thorough yet although a large number of publications are available.Different perspectives on the concept of desertification and differences in the selections of research materials and assessment indexes cause the discrepancies about the view on desertification degree and rate in Hunshandake Sandy Land.Combination of high resolution remote sensing and comprehensive field investigations is needed to unveil the complex ecological processes of sandy land.The system for monitoring desertification processes should be developed from these studies.Desertification in the Hunshandake Sandy Land is originated from interactions between human activity and climate changes,and uncertainties in desertification processes studies lead to the confusion about the causes of desertification.To distinguish between climate and human-induced desertification,a clear understanding of desertification processes,especially further investigations on feedback,coupling effects and threshold of sandy land system and effects of extreme events on desertification,are required.Desertification is likely to proceed in Hunshandake Sandy Land as a consequence of global warming.And improving the spatio-temporal accuracy of assessing dune activity in the future is not only a significant but also a challenging work for scientists to accomplish.