Author(s): Yanfu Li; Zhaoyin Wang; Lujie Han; Le Liu
Linked Author(s): Zhaoyin Wang
Keywords: Sanjiangyuan; Eolian sand erosion; Vegetation development; Ecological stresses; Vegetation-eolian sand erosion dynamics
Abstract: Moving sand dunes destroy vegetation and aggravate desertification. Whereas, vegetation fix moving sand dunes and prevent desertification. Vegetation and eolian sand erosion are a pair of competing and interactive factors that affect the geomorphic tendency of desertification area. Currently, Sanjiangyuan has been partly desertified and the vegetation has been scarred with sand dunes. Vegetation and moving sand dunes struggle drastically in the fringe area of desert. When the moving sand dunes are controlled by vegetation, the desert expansion will stop. Therefore, it is necessary to evaluate and predict the tendencies of vegetation development and the eolian sand movement for desert management and ecological restoration in Sanjiangyuan. In this study, taking the fringe area of desert as the research area, the vegetation-erosion dynamics was developed and applied to the desertification area. Considering certain stresses including planting trees, cutting trees and erosion reduction measures, a coupling equation of vegetation coverage and eolian sand erosion dynamic were developed. This model can be used to simulate and predict the tendencies of vegetation development and eolian sand dunes movement in fringe area of the desertification area. Based on remote sensing images of 10 years since 1977, ground-object identification of 43 spots, eolian sand erosion depths of 10 field spots and meteorological data of 30 years, the vegetation-eolian sand erosion dynamics was applied in the fringe area of Mugetan desertification area in the source region of Yellow River. The vegetation-eolian sand erosion chart of Mugetan desertification area was worked out. The vegetation-eolian sand erosion chart of the source region of Yellow River has a relatively large C-Zone. It is showed that once the vegetation coverage reaches a certain value, the vegetation in the source region of Yellow River will have a strong ability to self-improve, whether through natural vegetation development process or through artificial vegetation succession process. As long as the vegetation does not suffer severely damage, the vegetation will stably fix the sand dunes.