Study on the spatial-temporal differences and evolution of ecological security in the typical area of the Loess Plateau.

The development and utilization of energy in the Loess Plateau has caused a wide range of ecological security issues, and Yan'an has become a typical area for ecological security research on the Loess Plateau. Ecological security evaluation research can provide data support and scientific reference value for the sustainable development, which is of great significance to the overall social and economic development of the region. In this study, the pressure-state-response (PSR) model was used to establish the evaluation index system in the evaluation of ecological security in Yan'an region (YAR), then the fuzzy analytic hierarchy process (FAHP) was used to determine the internal index weight of each element, and finally the ecological security index value (ESI) was calculated. The GIS technology was used to simulate the distribution map of ecological security in YAR and then analyzed the temporal and spatial changes and evolution of ecological security in YAR. The results showed that from 1997 to 2016, the ecological security in the western part of Luochuan County and the eastern part of Yanchuan County was still very high, while the ecological security index was relatively low in the southern part of Huanglong County. The ecological security index of Baota District had increased significantly, from 1.85 in 1997 to 2.76 in 2016. The proportion of III and IV ecological security regions had increased significantly, and the ecological security of the entire YAR was generally in a good situation. This study could clarify the temporal and spatial characteristics of ecological security and provided some reference for the study of ecological security evolution in typical regions of the Loess Plateau.