干旱区生态环境知识资源中心

Desertification of arid and semiarid land is a severe environmental problem. Better understanding of the desertification process, in the context of changing climate and growing human activities, is essential for policy-making on desertification control strategies and land-use management in these environmentally sensitive areas. In this study, we analyze vegetation change and dune activity over the years 1981-2013 in Mu Us, a semiarid dune field in north-central China, using remote sensing techniques and geomorphic analysis. During this period, we have observed an increasing trend in vegetation greenness, indicated by the Normalized Difference Vegetation Index, which is consistent with the decreasing trend of the dune mobility index. Changes in dune morphologies in the study area indicate that dunes are being stabilized under vegetation growth, and this morphological change could potentially be used to detect the long-term trend in desertification. Based on a detailed analysis of both climatic and socioeconomic data, we found that the decadal changes in wind strength have significant impact on the long-term vegetation rehabilitation in the study area and that the short-term variations in vegetation growth are associated with interannual fluctuations in precipitation. Policy-driven, large ecological restoration projects implemented in recent decades can exert a positive impact on vegetation restoration, especially under favourable climatic conditions. This study implies that such climatic conditions may offer a window of opportunity for land regeneration in semiarid northern China.