The evolution process of ecological vulnerability and its quantitative analysis of influencing factors: a case study of Longdong area

Ecological vulnerability is the main index to evaluate areal environmental stability and monitor the development of ecological environment. Longdong area is a typical Loess Plateau area with complex terrain, serious soil erosion, mineral resource development, and other human activities leading to the ecological vulnerability evolution of the area, but the monitoring of its ecological status and the determination of its factors are still lacking. Based on the ecological characteristics of Longdong area, this study constructed an ecological vulnerability system including natural, social, and economic data and used the fuzzy analytic hierarchy process (FAHP) to study the temporal and spatial evolution of ecological vulnerability from 2006 to 2018. A model for quantitative analysis of the evolution of ecological vulnerability and correlation of influencing factors was ultimately developed. The results showed that (1) from 2006 to 2018, the ecological vulnerability index (EVI) had a minimum value of 0.232 and a maximum value of 0.695. EVI was high in the northeast and southwest of Longdong area and low in the central region. (2) At the same time, the areas of potential vulnerability and mild vulnerability increased, and the areas of slight vulnerability, moderate vulnerability, and severe vulnerability decreased. (3) The correlation coefficient between average annual temperature and EVI exceeded 0.5 in four years, and the correlation coefficient between population density and per capita arable land area and EVI exceeded 0.5 in two years showed significant correlation. The results reflect the spatial pattern and influencing factors of ecological vulnerability in typical arid areas of northern China. Additionally, it served as a resource for researching the interrelationships of the variables affecting ecological vulnerability.