Study On Combination Weighting For Ecological Sensitivity Evaluation Index Of Ecological Land In Karst Region

Karst region is a special type of region formed by the development of soluble rock such as carbonate,the ecological environment in this region is fragile,and worsende under the role of population pressure and irrational economic activity,it appers many serious promblems of ecological environment,which seriously affect the production and life of human beings.Ecological sensitivity evaluation of ecological land can identify the possibility of the emergence of ecological environment problems of ecological land,and put it into specific space areas to provide a scientific basis for the protection of regional ecological environment.This study attempts to introduce the combination weighting method into the evaluation index of ecological sensitivity.Taking Huanjiang Maonan Autonomous County of typical Karst region as the study area,take ecological land as the evaluation object,by constructing evaluation index system and using GIS as technical support method,evaluated the ecological sensitivity level of ecological land in Huanjiang County.The main conclusions are as follows:(1)The existing ecological sensitivity index weighting method is mainly based on Delphi method,analytic hierarchy process and variation coefficient method,and there are some defects and shortcomings,which affect the scientificity of the comprehensive evaluation results.The combination of weighting method can combine the subjective weighting method and the objective weighting method.It can reflect the two aspects of the subjective and objective information in a more comprehensive way.(2)By analyzing the ecological environment of the area,setting up an evaluation index system based on natural factors for the specific geographical background.Relief degree,average annual precipitation,soil type,soil texture,vegetation types,lithology and geological hazard were selected as ecological sensitivity evaluation indexs of ecological land in Huanjiang County.Using the traditional ecological sensitivity evaluation index confirmation method:the Delphi method,the analytic hierarchy process and the variation coefficient method,to calculate the weight value respectively.Through the pre-inspection and post-mortem examination of the combined weighting method,the analytic hierarchy process and the variation coefficient method were selected for combination weighting method,the distance function is used to determine the distribution coefficient in linear weighted combination.The evaluation index weight value ranking determined by the combination weighting method is:lithology?Relief degree?geological hazard?soil type?soil texture>vegetation types ?average annual precipitation.(3)The comprehensive evaluation of ecological sensitivity of ecological land was carried out by Weighted superposition model,and the comprehensive evaluation results of ecological sensitivity of ecological land in Huanjiang county were obtained.By comparing the evaluation results of combination weighting method and the single weighting method,the combination weighting method is effective for ecological sensitivity evaluation of ecological land.