The Characteristics of Biological Crust and Its Environmental Significance in Shapotou Region
Chen Hesheng (Institute of Desert Research,Academia Sinica,Lanzhou)
The large-scale biologic protective system along Zhongwei-Gantang section of Baotou-Lanzhou railway have achieved substantial eco-environmental benefit. However, as time went on, the environmental condition had been changed, especially the formation of biologic crust exerted an influence on the development of the protective system.Biologic crust is a complex outcome under the actions of dynamically deposited dust, annual vegetation invasion, rotten fallings of plant, micoorganism and other elements after the artificial ecologic protective system has been established.Biologic crust as a new environmental factor entered into the atificial protective ecosystem and strengthened the ability of wind-erosion resistance as well as sand surface stability. On the other hand, the development of biolgic crust increased the ineffective evaporation of rainfall, decreased the infiltration depth of precipitation, deteriorated moisture ondition of sandy land, and led to the degeneration of deep-root plants and finally caused the succession of artificial protective system.