Changes Of Vegetation Landscape Pattern And Ecological Risk Assessment In Fen River Basin

The Fen River is the second largest tributary of the Yellow River,pass through Shanxi from north to south,its vegetation changes have a great influence on the ecological environment of the basin and Shanxi Province.This study takes Fen River basin as the research area.Based on NDVI data,the change of vegetation coverage and vegetation landscape pattern in Fen River basin from 2000 to 2018 are analyzed by using pixel binary model method and landscape index analysis.The index and different coverage levels assessment of ecological risk.The purpose is to reveal the vegetation distribution pattern and change rule of Fen River Basin,and grasp the current situation and changes of the basin ecological environment.In order to provide reference for watershed soil erosion control and ecological construction.The research results are as follows:(1)On the distribution of vegetation coverage,the northern area of Fen River Basin is superior to the southern part,and the vegetation coverage increases along The Fen River to both sides.The overall spatial change is that the coverage level of the central and southern regions gradually increases.During the transformation of each grade,the vegetation coverage mainly evolved from low to higher.The area of Class IV and V coverage increased,the area of Class II and III coverage decreased,and the area of Class I coverage changed less.(2)In the vegetation landscape pattern,the degree of landscape fragmentation of each grade increases and the landscape heterogeneity increases.The landscape index changed greatly during 2010-2015,this indicates that the vegetation landscape pattern of Fen River Basin has changed obviously during this period.(3)At the level of patch type,the patch fragmentation changes of vegetation coverage levels II and III among the five coverage levels changes most obviously,and plaque dominance of V-level vegetation coverage increased,showing an optimization trend.(4)On the ecological risk assessment,the ecological risks in the IV and V elevation levels and vegetation coverage levels are relatively low,the ecological stability in the II and III elevation levels and vegetation coverage levels are poor and the ecological risks are high.Generally speaking,the vegetation coverage in Fen River Basin is optimized,the area of higher ecological risk areas is reduced,and the ecological risk is reduced to a certain extent.