Spatiotemporal Evolution of Landscape Ecological Risk Based on Geomorphological Regionalization during 1980–2017: A Case Study of Shaanxi Province, China

Abstract

Land surface elements, such as land use, are in constant change and dynamically balanced, driving changes in global ecological processes and forming the regional differentiation of surface landscapes, which causes many ecological risks under multiple sources of stress. The landscape pattern index can quickly identify the disturbance caused by the vulnerability of the ecosystem itself, thus providing an effective method to support the spatial heterogeneity of landscape ecological risk. A landscape ecological risk model based on the degree of interference and fragility was constructed and spatiotemporal differentiation of risk between 1980 and 2017 in Shaanxi Province was analyzed. The spatiotemporal migration of risk was demonstrated from the perspective of geomorphological regionalization and risk gravity. Several conclusions were drawn: The risk of Shaanxi Province first increased and then decreased, at the same time, the spatial differentiation of landscape ecological risk was very significant. The ecological risk presented a significant positive correlation but the degree of autocorrelation decreased. The risk of the Qinba Mountains was low and the risk of the Guanzhong Plain and Han River basin was high. The risk of Loess Plateau and sandstorm transition zone decreased greatly and their risk gravities shifted to the southwest. The gravity of the Guanzhong Plain and Qinling Mountains had a northward trend, while the gravity of the Han River basin and Daba Mountains shifted to the southeast. In the analysis of typical regions, there were different relationships between morphological indicators and risk indexes under different geomorphological features. The appropriate engineering measures and landscape management for different geomorphological regionalization were suggested for effective reduction of ecological risks.

Spatiotemporal Variations of Landscape Ecological Risks in a Resource-Based City under Transformation

“…However, in contrast to other studies [32,33], the research cycle in this study was mainly based on three time periods: before the closure of the Xuzhou mine, immediately prior to rapid expansion, and at the beginning of ecological restoration. Among these periods, 2010 was selected as the research object because it was just before the rapid expansion of Xuzhou.…”

“…This caused a sharp increase in the area of Xuzhou's extremely high-risk areas by a factor of two in 2010, reflecting the significant impact of urban expansion. Moreover, in contrast to other studies [33,36], this study selected five landscape pattern indices to construct the landscape ecological risk index and used the entropy weight method and AHP to determine their weightings. The calculated results were consistent with the actual development of Xuzhou and, significantly, revealed the characteristics of ecological risks as follows.…”

“…This method is usually used to evaluate the ecological risk of a specific pressure or interference source. The second takes a deviation from the optimal pattern as the risk source and evaluates the ecological effects [31][32][33]. In this method, the whole system is viewed as the receptor, and the ecological risk is usually evaluated in terms of ecological variation within the entire region, and then using landscape pattern indices to portray the research object landscape [34,35].…”

“…Using these indices, the threat posed to various landscape elements in the study areas is determined. Moreover, the ecological risk in the study area is assessed by the composition of and threat to various landscape elements [32,33]. Various landscape pattern indices and weighting methods are chosen to consider different research objects.…”

“…Finally, the ecological risk diagram is developed through the Kriging interpolation [39]. Meanwhile, the variation in spatiotemporal relationships between land-use changes and ecological risks are statistically analyzed to determine areas of different ecological risk levels [32,33]. The second method was chosen in the present study based on previous studies, according to the research objective and the ecological characteristics of the research object.…”