Multi-scale Landscape Ecological Risk Assessment Under Different Models In Ecologically Fragile Regions

As one of the core concepts of landscape ecology,the multi-scale synthesis has become an essential part in landscape ecological risk assessment,it has important theoretical and practical value for understanding multi-scale landscape ecological risk and improving the evaluation accuracy of landscape ecological risk.This paper takes Gaoqu Township,Mizhi County,Shaanxi Province as the study area.Firstly,eight landscape pattern indices were selected to analyze the trend of landscape ecological risk under different spatial grains of 30 m,60m,90 m,120m,150 m and 180 m,and the most appropriate spatial grains was determined.Secondly,the study area is divided into three scales,quadrat scales,administrative scales and ecological scales,the two models are used to calculate the landscape ecological risk values of the study areas at different scales.Thirdly,using the geostatistical method to complete the spatial distribution mapping of landscape ecological risk;The superposition analysis and spatial autocorrelation analysis of the landscape ecological risk distribution results at three different scales under the two models are carried out,and the most suitable research scale is selected on this basis.Finally,By analyzing the matching degree between the landscape ecological risk results of the two models at the appropriate scale and the actual landscape ecological environment in the study area,select the optimal model and test it with a typical village.Conclusion as below:(1)The spatial grain effect of landscape index.Analyzed the variation trend of the8 landscape index under the spatial grain of 30 m,60m,90 m,120m,150 m and180m,it is determined that the most suitable spatial grain of the study area is120 m.(2)Select the most appropriate spatial scale.This study based on the multi-model multi-scale landscape ecological risk difference analysis,and uses the results of landscape ecological risk overlay analysis and spatial autocorrelation analysis,based on the method of high coupling and maintaining ecological integrit to select the ecological scale as the most appropriate spatial scale for the study.(3)Select the most appropriate model.On the basis of suitable spatial scale,the paper analyzes the differences of the spatial distribution results of landscape ecological risk under the two models,and compares them with the field situation of the study area,analyzes the accuracy of the two models to selects the optimal model,and test it with a typical village.The landscape ecological risk assessment model based on landscape pattern and soil erosion process is finally determined as the optimal model for this study.