Landscape ecological risk analysis of subtropical vulnerable mountainous areas from a spatiotemporal perspective: Insights from the Nanling Mountains of China

Although mountains provide various important ecological services for human beings, the need remains to be stressed for further research on conducting ecological risk analysis in vulnerable mountainous regions characterized by a relatively high population density. In this study, the Nanling Mountains, which are recognized as a significant mountainous region in southern China, were selected as a case. Using the Globe Land30 dataset and landscape metrics, we calculated landscape ecological risk indices from 2000 to 2020. Our objective was to investigate the distribution and changes in landscape ecological risks within mountainous areas and their associated implication, to support the protection and development of the Nanling Mountains, and to provide a valuable reference case for risk management in other mountainous regions. The results showed that the land cover transformation in Nanling was predominantly driven by the expansion of artificial surfaces and open water, accompanied by a decline in woodland, cultivated land, grassland, wetland, and shrubland areas. The overall landscape metrics exhibited minimal changes, with the majority of modifications observed between 2000 and 2010. During this period, there was a noticeable shift in patch shape from complex to simple, a decrease in landscape continuity, an increase in landscape separation, and an overall increase in landscape heterogeneity. The landscape ecological risk index displayed substantial spatial heterogeneity within the study area. High-risk and medium–high-risk areas were primarily concentrated in the central and eastern regions, surrounded by medium-risk areas. Low-risk and medium–low-risk areas were widely dispersed across the entire study area. Between 2000 and 2020, there was an observed rise in the percentage of low and medium–low-risk areas from 61.74% to 64.05%. This indicates an overall enhancement in the ecological environment of the study area. The transfer of landscape ecological risk primarily involved artificial surfaces and high-altitude grasslands. The correlation analysis between the total regional GDP and LERI showed that there was a smooth inverse “U” linear relationship between them. To conclude, there exists a definite correlation between the landscape ecological risk and human activities, particularly environmental policies. Additionally, the relationship between the landscape ecological risk index and the total regional GDP aligns with the Environmental Kuznets Curve. It is crucial to approach major decisions concerning densely populated and fragile mountainous areas with careful consideration and caution. In promoting land optimization and integration, priority should be given to the area around the artificial surface.