Evolution of Ecological Damage Probability in the Arid Area Based on SPCA: A Case Study of Yinchuan City

Abstract

The cities in the arid area of northwest China are restricted by climate, and their economic development is affected to varying degrees. The oasis cities are located in an ecological fragile region, which is stressed by natural conditions and human activities, and has a high ecological risk. Based on Geographic Information System (GIS) and Remote Sensing (RS) technology, this paper selected human stress and landscape vulnerability as two types of evaluation indices from multiple perspectives. The random forest method was used for supervised classification to obtain land use data and the Kappa value was greater than 0.85. Each landscape index was calculated by Fragstats. Spatial principal component analysis (SPCA) was used to objectively determine weights. Finally, weighted superposition was used to calculate the ecological damage probability of the urban built-up areas in Yinchuan from 2000 to 2020. The results show that: (1) From 2000 to 2020, the high-value area of ecological damage probability of urban built-up areas in Yinchuan continued to increase, and the area of each grade changed from the dominant position of the low-value area to the equilibrium of each grade. (2) The spatial distribution of ecological damage probability is high in the central urban areas and low in the surrounding suburbs, and the medium value area as the transition area shrinks significantly. The ecological damage probability of the Yellow River and its banks decreases partly but still increases overall. (3) Human stress is the main factor in the ecological damage probability. (4) The risk of local areas in the central urban areas is reduced, and the ecological restoration projects achieve obvious results. Therefore, reducing man-made damage and implementing effective ecological restoration are the key points to protect the ecological environment, and also the key to scientifically preventing future ecological risks in the ecological fragile region.