The Spatial-temporal Analysis Of Landscape Ecological Risk In Yulin

With the development of economy, the increasing seriousness of the environmental issue makes it important for us to protect ecological environment. In order to protect and construct a good ecological environment and to fulfill its sustainable development, our country has taken a series of measures, such as combating desertification, controlling soil and water loss,planting trees and growing grass, constructing ecological agriculture and so on. Especially in the western, where ecological environment is relatively fragile, the ecological environment construction has become the basis for implementing the strategy of the Western Development.Yulin is located in the bordering area between loess plateau in northern shaanxi and sandy land in Maowusu, its ecological environment is relatively fragile. Furthermore, because of the rich mineral resources, the environment issue of this region caused by exploiting mineral resources becomes more severe. This paper explains the three phase remote sensing images of Yulin in 2000, 2005 and 2010. According to the changes of landscape type, it analyses the succession of landscape by making use of spatial analysis function of the Arc GIS. Dividing the three phase images into 527 pieces of sample plot, from the perspective of landscape ecological integrity, this paper selects index of landscape fragmentation degree, landscape connection degree, ecological sensitivity, landscape diversity and vegetation as the impact factors of landscape ecological integrity. Software of Fragstats is used to calculate the landscape index, combining with the experts grading method and the analytic hierarchy process, Idrisi is used to calculate weight of index, and finally constitutes index system to calculate the landscape ecological integrity index of each sample plot. Then Arc GIS is applied to Kriging interpolation, reflecting the space-time differentiation status of landscape ecological integrity. The space-time differentiation status of landscape ecological risk is discussed on the basis of this. The comparative results exhibit that the risk of landscape ecological in Yulin is gradually weakened, most strong risk areas and strong risk areas tend to become medium risk areas, but the landscape ecological risk has a tendency to increase in some areas. The ecological environment protection in Yulin has achieved a certain progress,but the attention to environmental change still should be paid.