Spatiotemporal evolution of rocky desertification and soil erosion in karst area of Chongqing and its driving factors

The karst area is a prototypical ecologically fragile region, characterized by severe soil erosion and rocky desertification, which hinders sustainable development in these areas. To ensure effective and informed management, it is crucial to comprehensively analyze the long-term series of soil erosion and rocky desertification in terms of their changing characteristics and underlying driving factors. In this study, the Sen slope estimation and Mann-Kendall test were used to carefully examine the changes within the karst region of Chongqing, China, during the period of 2000–2020. Our findings revealed a deterioration followed by an improvement in the degree of rocky desertification in the study area. However, soil erosion exhibited a fluctuating downward trend due to the effective control measures implemented to address both rocky desertification and soil erosion. The driving factors behind these mentioned changes were studied using the Geographical Weighted Regression and Geodetector. Our results highlighted those natural, anthropogenic, and comprehensive factors all influenced the changes during the study period. Notably, each driving factor exhibited significant spatial heterogeneity. The combination of surface exposure rate and vegetation coverage emerged as the primary driver of rocky desertification evolution, while the combination of rainfall and vegetation coverage played a pivotal role in soil erosion evolution. Considering the geological characteristics of karst areas, our study revealed that the degree of rocky desertification and soil erosion in semi-karst areas was comparatively lower than that observed in pure-karst areas. However, in nearly 20 years of ecological restoration, the effectiveness of improvements in semi-karst areas is not as significant as in pure-karst areas. Therefore, more attention should be given to these areas in the future. The implications of this study are valuable for developing comprehensive strategies to combat rocky desertification and soil erosion customized to local conditions.