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.
由于自身的脆弱性和人类活动的扰动,喀斯特区域植被破坏、水土流失和石漠化等生态问题突出。综合分析喀斯特区域的生态脆弱性及其影响因素,可为区域生态修复、环境治理提供科学支持。本研究以滇东南典型喀斯特区域广南县为例,从自然和人为因素角度构建喀斯特区域生态脆弱性评价指标体系,运用SPCA对2000、2010和2018年的生态脆弱性进行反演,分析其时空演变特征,并利用地理探测器探究其影响因素。结果表明: 2000—2018年,广南县整体脆弱性变化较小,但脆弱程度在不断加剧。在脆弱等级方面,该县以微度脆弱为主,但轻度、中度和重度脆弱在逐渐增加。广南县沿“者兔-莲城-杨柳井-板蚌”以南地区的生态脆弱性较高,以北地区的脆弱性较低;脆弱性空间集聚效应强烈,北部处于脆弱性低-低集聚区,而西南部和东南部处于脆弱性高-高集聚区;生态工程的实施有利于区域生态脆弱性的改善,而人类活动的干扰使生态脆弱性进一步恶化。岩性和石漠化面积比重对喀斯特区域生态脆弱性的影响较为显著,导致喀斯特生态脆弱的基础是喀斯特碳酸盐岩的发育。.
Keywords: Guangnan County; eco-environment vulnerability; influencing factor; karst area; spatial and temporal evolution.