RESUMEN
Due to its vulnerability and anthropogenic disturbance, ecological problems in karst areas are prominent, such as vegetation destruction, soil erosion, and rocky desertification. Comprehensive analysis of ecological vulnerability and influencing factors in karst areas can provide scientific support for regional ecological restoration and environmental governance. With Guangnan County, a typical karst region in southeastern Yunnan, as an example, we constructed a karst regional eco-environmental vulnerability assessment index system from the perspective of natural and factitious factors. We used SPCA to assess the ecological vulnerability in 2000, 2010 and 2018. We further analyzed the temporal and spatial variations and explored its influencing factors by using geographic detectors. From 2000 to 2018, the changes of overall fragility were small, but the degree of fragility had been intensifying. The grade of ecological vulnerability was mainly slight fragile. The area with mild, moderate and severe fragility was increasing, while the area of extremely fragile showed no change. Guangnan County had a higher ecological vulnerability in the south of "Zhetu-Liancheng-Yangliujing-Banbang", and lower in the north. The spatial agglomeration effect of vulnerability was strong in this county. The north part of Guangnan was vulnerable low-low agglomeration areas, while the southwest and southeast parts were in high-fragility-high agglomeration areas. The implementation of ecological engineering was conducive to the improvement of regional ecological fragility, while the disturbance of human activities further deteriorated ecological fragility. The area proportion of rocky desertification and stratum lithology had stronger influence on ecological fragility of the karst area. The most important influencing factor of the karst ecological fragility was the development of karst carbonate rocks.