Landscape Ecological Risk Assessment of the Shiyang River Basin

Abstract

It is significant to make a reasonable assessment of ecological risk to optimize the landscape pattern, establish the ecological risk alarm mechanisms, minimize the risk of ecological environment and maintain the ecological function in river basin. The study, based on the remote sensing data of 1987, 2000 and 2010, the study chooses the typical arid inland river basin – the Shiyang river basin as the subject to analyze the temporal-spatial distribution pattern of the ecological risk by constructing the ecological risk index with the help of the spatial analysis function of GIS. The results show that: (1)The main landscape types of the river basin are the grassland and unused land,but the predominance of the arable land, woodland and grassland decrease little by little during the study periods while the predominance of water and construction land increase gradually. (2)At the early stage of the study periods, the main ecological risk grades are extremely low and high. With the time going, three ecological risk models, extremely low, low, and extremely high, coexist in the study area, which mean that the threatens of the ecosystem is increasing. (3)The tendency of environmental deterioration is clear, which embodies in the space that extremely low ecological risk areas shrink to upstream, the low ecological risk areas spread to the upper and middle stream and the extremely high ecological risk areas expand to the downstream.