Study On Evaluation Method Of Ecological Sensitivity In Lanzhou Section Of Yellow River Basin

In recent years,serious soil erosion and frequent geological disasters have caused a series of ecological problems in Lanzhou section of Yellow River Basin.The stability of ecological environment is the premise of human economic development,but the deterioration of watershed ecology not only destroys the ecosystem,but also hinders the development of human economy.The sensitivity of watershed ecology is analyzed from the ecological point of view,which is the self-bearing capacity and sensitivity degree of ecology under external disturbance.The study of ecological sensitivity by using fixed model and various factors is not comprehensive and accurate,so it is necessary to select an evaluation model based on local conditions and a multi-factor perspective to jointly determine the sensitivity degree of ecological environment in different study areas,so as to make strategic suggestions for the construction of ecological civilization.Lanzhou section in the Yellow River basin as the upstream river must pass through,not only related to the economic and survival of the people,but also related to the national ecological security and social stability.The main contents of the thesis are as follows:The improved RUSLE model was proposed based on vegetation coverage,soil erodibility,slope length,rainfall erosivity,soil and water conservation measures and slope,and the evaluation index system of soil erosion sensitivity was constructed by using Geographic Information System(GIS)and Remote Sensing(RS)technology.Using ArcGIS technology and SPSS tools,based on the slope,elevation,soil type,normalized difference vegetation index,stratum lithology,geological Zai Hai Dian years of average rainfall,distance from the road,such as impact factor,put forward on the basis of spatial principal component analysis(pca)of geological disaster sensitivity comprehensive index model and based on the deterministic coefficient method of logistic regression models,The sensitivity evaluation system of geological disaster was constructed by comparing the two models with analytic hierarchy process.Combined with the sensitivity evaluation of soil erosion and geological disaster,the ecological sensitivity evaluation system was established by using the comprehensive index model of ecological environment sensitivity.The aim is to provide technical support for ecological protection and sustainable development and promote the balanced and coordinated development of regional ecological protection and economic construction in the Yellow River Basin.Based on the above work plan,this paper explores the sensitivity degree of ecological environment in Lanzhou section of Yellow River Basin with the help of ArcGIS,ENVI,SPSS and YAAHP platforms.conclusion(1)The extremely sensitive and severely sensitive areas accounted for 42.73%of the total area,the moderately sensitive and mildly sensitive areas accounted for 45.60%of the total area,and the mildly sensitive and insensitive areas accounted for 11.67%of the total area.Among them,the most sensitive area is located in Lanzhou City Yuzhong County.The results can provide decision support for rational planning of water and soil resources,ecological environment protection and control and early warning in Lanzhou section of Yellow River Basin.(2)The total area of insensitive and mildly sensitive areas obtained by the two sets of geological hazard sensitivity models in Lanzhou section of the Yellow River Basin is the same,but the area proportion of medium,heavy and extremely sensitive areas is different.Compared with the SSI model using SPCA method,the total area of heavy and extremely sensitive areas accounted for 43.24 km~2 more by Logistic regression model.The number of geological disasters increased by about 1.23%.The Kappa values of the two models were 0.62 and 0.6,the AUC values of ROC test were 0.810 and 0.800,respectively,and the progressive sig.b values were less than 0.05,indicating that the two models could reasonably evaluate the sensitivity of geological hazards in the study area.Both Kappa value and ROC curve showed that SPCA SSI model had higher accuracy,and the evaluation results were more consistent with the status quo of the study area.The results can provide technical support for the sensitivity assessment and disaster prevention and mitigation of geological hazards in Lanzhou section of Yellow River Basin.(3)The results show that most of the ecological sensitivity in Lanzhou section of Yellow River Basin is moderate,accounting for 29%of the total area.Severe sensitivity and extreme sensitivity were mainly distributed in the mountainous areas of southeast and northwest,accounting for 36%of the total area,15%of the total area,and 35%of the total area.Soil erosion and geological disasters are caused by human activities and natural environment.According to the study area,the ecological protection watershed needs zoning management,ecological management is carried out from three dimensions of macro,medium and micro,and reasonable ecological protection strategies are put forward.To solve the livelihood of the Yellow River basin,the restoration of ecological environment.