Long-Term Effect Of Ecosystem Evolution In Arid Regions, NW China

In the last 50 years, the ecological deterioration developed in the faster and faster speed, and became more and more serious in arid regions, NW China. Ecological deterioration in the regions not only restricts the harmonious development between economy and society, threatens the survival of the people, but also blights the stabilization of the society and the solidification of different nations, and even threatens the whole environment in Northern China. Therefore, there has been no time to delay for the ecological protection and restoration in the arid regions, NW China. To avoid wasting of resources, the ecological protection and restoration must be based on the good understanding of evolution trend of ecosystem and its causes.The traditional method to analyze the long-term evolution trend of ecosystem, e.g. extrapolation method, need long time series data of ecosystem history. However, in the areas, only few discontinuous data about ecosystem history are securable, and the data are mostly about the very recent history, no longer than several decades. An alternative method, namely ecological model, is very inaccurately for randomicity of environmental disturbance and non-linear mechanism exiting in ecosystem. It is necessary to develop a new method to analyze the long-term evolution of ecosystem and its causes according to the shot-term data about ecosystem history.Based on the research results in the past, this paper discussed the method how to get the information about the long-term evolution of ecosystem according to the shot-term dynamics of vegetation pattern. As a case in Ejina basin, the long-term and short-medium term evolution of ecosystem, its morphologic effect, and its driving forces were analyzed. The positive feedback mechanism in short-medium evolution of ecosystem was then discussed according to the fluctuation characteristics of environmental element at micro-scale. Employing spatial-temporal scales symmetry of ecosystem as theoretical basis, this paper predicted the long-term evolution trend of ecosystem in the area. At last, the object, principles, and measures of ecologic protection and restoration for the area were put up.1. The separation of long-term effect and short-medium term effect of ecosystem evolution...