Studies On Indicator System Of Rangeland Desertification Assessment And Driving Force Of Desertification In Mu Us Desert

Desertification, land degradation in arid, semi-arid and dry sub-humid areas, is one of the environmental problems concerned by human society. It has a direct relationship with the existence and development of mankind. The theory and indicator system of desertification assessment, the driving forces of desertification development are main problems in recent study and prevention of desertification. These problems are very important for the determining the direction of the regional economic development, the evaluation of the environmental quality, the macro-policy-making and measure-selection of desertification-control. These topics were studied in the thesis. The theoretic framework of desertification assessment and the indicator system of rangeland desertification assessment in Mu Us Desert were put forward. By in depth analysis on the varies driving forces of desertification, some quantitative and qualitative conclusions were reached. The policies for desertification prevention were discussed.With in depth investigation and studies on the desertification and desertification assessment, and reference to the research results at home and abroad, the author put forward the theoretic framework of the desertification assessment. The framework include the principles and tasks of the desertification assessment, the types of the desertification and the assessment, the evaluation criterion of the developmental extent of the desertification, the scale and technology of assessment, the basis and methods on the construction of the indicator system.In the theoretic basis of the desertification, the causes and processes of the rangeland desertification in Mu Us Desert were studied. The indicator systems of the rangeland desertification on community level and landscape level were constructed by vegetation classification, ordination and gradient analysis. The sandy rangeland, the ridge rangeland, the salix rangeland and the shoal rangeland are the main types of rangeland.(1)The sandy rangeland in the community level is degraded from fixed sandy land or sandy flats to drift sandy land or flats. The indicators are the community type, the humus content and texture of the soil and the extent of the surface fixation.The indicators of the sandy rangeland desertification in the landscape scale are the variation of the area ratio of the drift sand, the mean coverage and main type of the vegetation, the changes of the landforms. (2)The ridge rangeland degradation are caused by over-grazing and cultivation. The expression are desertification process and erosion. The assessment indicators are the depth of the erosion and drifting sandy soil, the humus content and texture of the soil. In the scale of the landscape, the main expression are the mean coverage of the vegetation, the...