Evolution of ecological carrying capacity in typical karst counties: A case study of Luxi county, Yunnan Province

Luxi county is located in the southeast of Yunnan Province, where karst accounts for 79% of the total area. The vulnerable ecosystem overlapping with unreasonable human activities in the county has caused serious water and soil erosion and rocky desertification, thus the contradiction between human and land is prominent. Besides, there are many poor people in the county, and the deterioration of the ecological environment and poverty seriously limit the sustainable development of Luxi county. The purpose of this work is to understand ecological carrying capacity, analyze sustainable development capacity and the bottleneck factors restricting the development of Luxi county from the structure of ecological carrying capacity, thus to provide a scientific theoretical basis for promoting the coordinated sustainable development of ecology, economy and society as well as poverty alleviation in this area. We use the multi-index comprehensive evaluation method from three dimensions of ecological resilience, ecological support and ecological pressure to stratify the ecological carrying capacity, combining with the characteristics of the study area to construct an evaluation index system suitable for the karst rocky desertification area. In terms of the entropy method and the Analytic Hierarchy Process (AHP) method, combining subjective and objective weighting methods, we analyze the evolution of ecological carrying capacity of Luxi county from 2008 to 2017. Results show that the ecological resilience index has an upward trend, while the intermediate process fluctuates sharply, indicating that the karst ecosystem is less stable and has obvious fragile characteristics. As the rapid economic growth has given supports to the management and utilization of environmental resources, residents’income and other aspects, the ecological support index has increased year by year, from 0.133，2 to 0.896，3. With the improvement of the ecological environment and the promotion of ecological civilization in recent years, the ecological pressure index is in a stable state and has been decreasing slowly in recent years, and the pressure on the ecosystem is also decreasing gradually. Except for the severe natural disasters in 2012, the index of ecological carrying capacity has been steadily increasing year by year, from 0.269，2 to 0.759，0. The carrying capacity has changed from low to high state. The structure of the ecosystem turns gradually stable and reasonable, and the capacity for sustainable development has been improved. The overall development trend in the past ten years is fairly good. Although the ecological carrying situation exhibits a good development trend, due to the steep karst slope in the fault basin, the restriction of natural environment, such as serious soil erosion and rocky desertification, superposition of original extensive farming, the development of the secondary and tertiary industries in Luxi country remains slow, limiting its economic development. So there is still a long way to the national well-off society.