Spatial-temporal shifts of ecological vulnerability of Karst Mountain ecosystem-impacts of global change and anthropogenic interference

Under the background of global climate change, the natural environment of the southwest karst mountain region is undergoing profound changes. Considering the differences in the relative importance of each index in the vulnerability evaluation system in different periods, this study presents the dynamic weight determination method and then establishes the dynamic weight table of the ecological vulnerability evaluation index in the southwest karst mountain region. At the same time, net primary productivity (NPP) is introduced to help determine the ecological vulnerability classification threshold in different periods, and then the spatial-temporal change pattern and driving mechanism of ecological vulnerability in the past 15 years are analyzed. Results show the following: (1) Dynamic weight determination method has good application in the study of ecological vulnerability in long-term series, and the threshold of vulnerability classification based on NPP can ensure the comparability of ecological vulnerability evaluation results in different periods; (2) From 2000 to 2015, the southwest karst mountain region generally belonged to the moderate vulnerability category, and a decreasing trend is observed from the Sichuan-Yunnan-Guizhou border area to its surrounding region in a spatial distribution pattern; (3) In the past 15 years, the ecological vulnerability of the southwest karst mountain region increased first and then decreased; (4) The spatial-temporal change pattern of ecological vulnerability in the southwest karst mountain region is significantly affected by GDP of different industries, precipitation, soil erosion, rocky desertification. These results would be in particular useful for planning the conservation strategies or assessments of the conservation priorities. In addition, the method employed could provide a technical support and references for the ecological assessment and restoration of other similar karst mountain ecosystem zones in China or worldwide.