Ecological sensitivity assessment at county scale based on GIS: A case study of Aksai County and Subei County in Gansu Province

Aksai County and Subei County are located in the arid inland region of Northwest China, characterized by relatively harsh climatic conditions, with desertification, sandification, and salinization as the critical ecological environmental problems in the area. Based on the field verification and relevant data sources, four index layers of geology, vegetation, human activities and meteorology with 10 single factors are selected to construct an ecological sensitivity evaluation system at county scale by analytic hierarchy process(AHP). Supported by GIS spatial analysis function, the paper assesses the ecological sensitivity in the study area. The evaluation results are classified into five levels according to the Natural Breaks method, i.e. extremely low sensitivity, low sensitivity, moderate sensitivity, high sensitivity, and extremely high sensitivity. The moderate sensitivity dominates the study area, accounting for 29.12% of the total area; while low sensitivity areas 24.98%, high and extremely high sensitivity areas 19.59% and 16% respectively, and extremely low sensitivity areas only 10.31%. The Moran's I index value for ecological sensitivity in the area is 0.942, indicating an extremely high degree of spatial clustering.