Assessment Of Eco-environmental Vulnerability In Karst Mountain Basin

With the rapid development of the economy and the continuous growth of the population,the more serious man-made activities are destroying the ecosystem,leading to the emergence of a large number of ecological fragility problems in the basin,attracting the attention of scholars at home and abroad.Research on ecological vulnerability has become a hot topic and focus in the research of global change and sustainable development.The Guizhou Wujiang River Basin is located at the core of the karst area in southwestern China and is a typical type of mountainous basin.It is also the key golden waterway linking the hinterland of Guizhou's central resources with the economic corridor of the middle and lower reaches of the Yangtze River.The long-term development and utilization of resources has led to a decline in the quality of the water environment,an increase in the area of soil contamination,serious ecological damage,large amounts of water and soil erosion,an increasing area of rocky desertification,increasing pollution of wetlands,and reduction of biodiversity,and other ecological environmental problems.Therefore,it is of great practical significance to carry out research on the evaluation of the ecological environment vulnerability of Guizhou Wujiang River Basin for the construction of a national ecological civilization pilot area in Guizhou Province.Based on the VSD model of exposure sensitivity adaptability,this study selected 16 eco-environmental vulnerability assessment indicators and constructed an evaluation index system for ecological environmental vulnerability of Guizhou Wujiang River Basin.Using remote sensing(RS)and geographic information system(GIS)technologies,the two types of weights,the Analytic Hierarchy Process(AHP)and Spatial Principal Component Analysis(SPCA)models,were adopted to conduct ecological vulnerability in the Wujiang River Basin in Guizhou in 2000 and2015.Comprehensive quantitative evaluation was performed to calculate the Ecological Vulnerability Index(EVI).The actual performance characteristics of the ecological vulnerability of the joint research area and the adoption of the natural breakpoint classification method divide the ecological environment vulnerability of the study area into five levels:slightly vulnerable,slightly vulnerable,moderately fragile,weak in intensity,and extremely weak in intensity.Through statistics of different vulnerability level areas,using the formula to calculate the Ecological Vulnerability Index(EVSI),the temporal and spatial distribution characteristics of the ecological vulnerability of Guizhou Wujiang River Basin in 2000 and 2015 were discussed,and suggestions were made for how to improve the geographical environment.The resulting conclusions are as follows:(1)Based on the spatial principal component analysis,minor vulnerability was dominant in the Wujiang River Basin in Guizhou from 2000 to 2015,followed by the weakest intensity.The intensity of vulnerable areas decreased from 2000 to 2015,and the moderately vulnerable area decreased.However,based on tomographic analysis,from 2000 to 2015,the same is mainly based on mild vulnerability,and the area has increased.The area of extremely weak and fragile is very small,accounting for less than 1%of the area of the watershed,and the intensity is weak.The 9.5%of the basin area dropped to 3.8%,the largest drop,the same moderate vulnerability is also declining,and the slightly vulnerable area increased slightly.(2)The fragility of the ecological environment in the Wujiang River Basin in Guizhou presents a relatively fragile ecological environment in the upper and lower reaches.The EVSI value of the comprehensive index of ecological environmental vulnerability in the Wujiang River Basin in Guizhou Province shows that the overall situation of the ecological environment in the study area has slightly improved over the past 15 years.The government departments attach great importance.(3)This study compares and analyzes the ecological vulnerability assessment results of the two weighted models and finds that there are certain differences between the evaluation results of the analytic hierarchy process model and the spatial principal component analysis model on the ecological vulnerability of the Wujiang River Basin in Guizhou;The weight values calculated by the model are all focused on natural conditions such as soil erosion intensity and rocky desertification degree.(4)The karst area in the study area has a relatively large area of mild fragility and strength,accounting for 56.03%of the karst area.The semi-karst and non-karst areas are mainly fragile and have an area of 6,425.56 km~2 and 5,378.15 km~2 respectively.(5)In 2015,the micro and vulnerable areas are mainly concentrated in the middle reaches of the river basin.The main method of protection is to continue to close mountains and forests and pay attention to the construction of protected areas,make rational use of land resources,use more new energy,and prevent further deterioration of the ecological environment.To maintain the balance of the ecosystem.In the middle and lower reaches of the moderately vulnerable areas in 2015,the main measures are to strengthen the basic construction of farmland,increase the coverage of vegetation,and increase afforestation.As for the mineral resources in the region,measures must be taken to protect the environment of the mine and the entire plant,and avoid Or reduce the adverse impact on the mine environment.In 2015,the fragile areas of extreme intensity and intensity were mainly in the upstream and downstream areas of the river basin.The ecological system in the region is already at the edge of collapse.It is the area where priority is given to the priority treatment of the region.The main method is to strictly control the blindness of the population in the region.Growth requires adjustment of land use results,prohibition of steep slope reclamation,and a substantial increase in the proportion of land used for forestry and animal husbandry;increase vegetation coverage,actively return farmland to forests,and retreat grass to forests,and can develop economic forests.