Sensitivity Changes Of Wuding River Basin In The North Of Shaanxi Province In The Past10Years

The research chooses Wuding River Basin as research object which is located in the northern ecotone in northern Shaanxi and we make a ecological sensitivity comprehensive evaluation of the watershed environmental systems in multiple time periods. First, we conduct the multiple-time watershed environmental state indicators based on the period features and the geographical features of ecological sensitivity evaluation combining with the actual situation of Wuding River Basin Environmental Systems. Then we carries on evaluation of the different periods of single factor sensitivity by the comprehensive index evaluation rms method and analyzes last two periods integrated watershed sensitivity in maximum method.The results show that:(1)the Wuding River basin soil erosion sensitivity was mainly mild and moderate sensitivity in2000and2010.Soil Erosion Sensitivity level distribution presents some regularity. Soil erosion sensitivity changes from insensitive to moderate and highly sensitive with the humidity and terrain features change from northwest to southeast in this basin.(2) The Watershed Health Mirror sensitivity was mild in2000and becomes moderately sensitive in2010. Watershed Central Health Mirror sensitivity has significantly increased from2000to2010, the highly sensitive and extremely sensitive area clearly change from scattered punctate to sheet development and aggregation characteristics.(3)Watershed desertification sensitivity significantly decreased from2000to2010, moderately sensitive areas disappear and mainly convert to mildly sensitive areas. The conversion occurs mainly in the sand beach area of the northwest of basin.(4) The area of Watershed moderately sensitive has decreased from2000to2010, highly sensitive area and extremely sensitive areas have increased slightly. The ecological sensitivity of the wind beach area in north of basin has declined, but highly sensitive and extremely sensitive areas have increased. The sensitivity of counties in south of basin loess gully have totally increased, including most of moderately sensitive areas, highly sensitive areas and extremely sensitive areas. The areas whose comprehensive sensitivity are always changing are located in the northwest sand beach area and transition belt of loess gully region and there is positive relation between drier areas and the change of comprehensive ecological sensitivity and vice versa. The basin-wide ecological sensitivity mainly changes from low sensitivity to high sensitivity. Change from low sensitive to highly sensitive is mainly in the high humidity of loess gully region and the reverse transition is mainly in the dry sand and wind zone.The research clearly conducts aggravating area and alleviating area about the sensitivity of watershed eco-sensitive though the comprehensive assessment.It helps to know more about the succession trend of watershed ecological environment. and provides scientific reference to ecological environment construction and social production to improve the development of the basin and society.