| With the acceleration of urbanization in China,human social activities have caused serious damage to the ecological environment.The resulting ecological environment problems have become increasingly prominent,and have a huge impact on human life.Therefore,how to analyze the dynamic change trend of ecological environment quality in the region quantitatively and qualitatively,and evaluate the ecological environment quality scientifically,has gradually become one of the hot topics of current research.In this paper,the Chahannaoer Basin in Inner Mongolia is taken as the research object.Four Landsat series remote sensing images in 1992,2000,2008 and 2020 are selected ENVI5.3 and ARCGIS10.7 software platforms as support to carry out data processing,data analysis and thematic map production.The Normalized Difference Vegetation Index,Humidity Index,Land Surface Temperature,Normalized Difference Build and Soil Index and Salinity Index were extracted from remote sensing image data,and the Modified Remote Sensing Ecological Index evaluation model was constructed based on principal component analysis.Combined with a variety of analytical methods,the ecological environment quality of Chahannaoer Basin from 1992 to 2020 was comprehensively evaluated,and the driving factors for the change of ecological environment quality were analyzed.A series of ecological protection and restoration policies and suggestions were put forward from the research results.The main conclusions are as follows:(1)According to the five ecological indicators extracted from remote sensing images and principal component analysis results,NDVI and WET trends are roughly the same,showing a trend of increasing first and then decreasing gradually,and the increase is less than the decrease,which plays a positive role in the balance of the ecological environment.LST,NDBSI and SI trends are roughly the same,showing a trend of decreasing first and then increasing,and the decrease is less than the increase,which inhibits the quality of the ecological environment.(2)The average MRSEI indexes of Chahannaoer Basin in 1992,2000,2008 and 2020 were 0.44,0.54,0.49 and 0.33,respectively.The study showed that the average MRSEI increased from 0.44 to 0.54 in 1992-2020 and then declined to 0.33 in 2020.The ecological environment quality showed a trend of first increase and then decrease,and the ecological quality generally developed in the direction of deterioration.(3)The results of MRSEI index classification and difference detection show that the areas with poor and poor ecological quality in Chahannaoer Basin increased significantly after 2000 from 1992 to 2020,and the areas with good and excellen ecological quality decreased gradually.During the study period,the change of ecological grade was dominated by one grade.By 2020,the area of ecological environment quality improvement accounted for a small proportion of the total area,while the area of ecological quality degradation accounted for a large proportion of the total area,up to 61.7%.The areas with obvious deterioration of ecological quality were mainly located in the hilly and gully areas in the northwest of the basin and the center of the southern urban area.The main reason was that the urbanization process was accelerated,the planting area and irrigation area of high water consumption crops in the basin increased significantly,the wetland area was seriously shrinking,and the soil erosion was serious,which led to the sharp deterioration of the ecological environment.(4)From the analysis results of gravity center transfer among different ecological grades and years,it can be concluded that the moving direction of the middle grade gravity center moves towards the southeast after 2000 and the amplitude is relatively small.These moving amplitudes of other grades are relatively large and chaotic.Among them,the gravity center of the superior grade shifts 17.71 km to the southeast from 1992 to 2000,the gravity center of the inferior grade shifts 21.02 km to the southwest from 2000 to 2008,and the gravity center of the good grade shifts 14.08 km to the southwest from 2008 to 2020,that is,the moving range is large and the regional change is obvious.(5)It can be seen from the distribution of ecological environment quality grades under four different terrain conditions that when the elevation value is above 1600 m and the slope is greater than 25°,the area of different ecological grades in each year is small,and there is no obvious change rule.However,under different slope directions,the area distribution of different slope directions in each year of Chahannaoer Basin is mainly poor,medium and good grades.Figure[18]Table[14]Reference[89]... |
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