Abstract:

A comprehensive evaluation of the characteristics of land ecological fragility in the Yarkant River Basin,Xinjiang,China provides a decisionmaking basis and theoretical support for river basin key management and the restoration of oasis vitality.In this study,the Yarkant River Basin is the research area.By obtaining the relevant data of different index layers in each period  from 2008 to 2018,we used the grid computing function of ArcGIS 10.5 and the natural discontinuous classification method to comprehensively calculate the ecological vulnerability index of the study area.We divided the vulnerability into five levels and presented its spatiotemporal distribution.Results show that in the spatial distribution,the study area is dominated by micro and lightly vulnerable areas,with an area ratio of 35.67% and 33.63%,respectively,distributed in the alluvial fan plain in the middle and lower reaches of the Yarkant River.The proportion of moderately and severely vulnerable areas was secondary,accounting for 14.89% and 12.93%,respectively,distributed in the hilly areas of the upper reaches of the Yarkant River.Although the proportion of extremely vulnerable areas is only 2.89%,which is 3 000 km²,distributed in densely populated areas in the middle and lower reaches of the Yarkant River,it plays a role of the cask effect on the overall ecological environment of the basin.The local ecological environment continues to deteriorate,resulting in a balance between the overall ecological pressure of the basin and the ecological threshold.Regarding the time distribution,the overall evaluation index decreased by 0.043 24 from 2008 to 2011,and the overall evaluation index decreased by 0.005 41 from 2001 to 2014.The overall evaluation index decreased by 0.056 86 from 2014 to 2018.Although the ecological vulnerability index of each period decreased to varying degrees,the overall ecological environment of the basin improved.However,the moderately,heavily,and extremely vulnerable areas are still widely distributed.Based on the representative SRP model and field survey,this study proposed some methods.In the micro and lightly vulnerable areas,basic pollution control is needed.In moderately and severely vulnerable areas,ecotourism should be developed,and food crops should be converted to export-oriented forestry and fruit growing.The sustainable development of orchards,farmhouses,and other rural plain ecotourism resources should be promoted.In extremely vulnerable areas,strict control of space use and ecological immigration should be implemented.

Key words: land ecological vulnerability')">

land ecological vulnerability, SRP model,
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