Research On Ecological Vulnerability Assessment And Spatial Evolution In Danjiang River Basin (Henan Section)

The Danjiang River Basin(Henan Section)is an important water source for the middle route of the South-to-North Water Diversion Project.Combined with the actual situation of the study area and the existing problems in the ecological environment,the ecological vulnerability assessment and spatial evolution law of Danjiangkou Reservoir and its surrounding land were studied.It can provide quantitative and effective technical support and reference for the sustainable utilization and development of water sources,water resources protection and management,ecological environmental protection policies,and water transfer safety in the middle route of the South-to-North Water Diversion Project.This paper takes the Danjiang River Basin(Henan section)as the research object.Comprehensively use a variety of scientific research methods and methods such as field survey and observation,indoor analysis,mathematical simulation,geostatistics,remote sensing technology,GIS spatial analysis,etc.Taking Landsat TM/OLI remote sensing images as the main data source,the land use change from 2000 to 2020 was analyzed.On this basis,taking the ecological sensitivity-ecological resilience-ecological pressure degree(SRP)model as the framework,an ecological vulnerability evaluation model based on the fuzzy synthesis-catastrophic series method was constructed.The established evaluation model is used to evaluate the ecological vulnerability of the study area,and then the quantitative analysis method is used to analyze the temporal and spatial evolution of the ecological vulnerability of the study area,and the driving factors are analyzed by geographic detectors.The research contents mainly include:(1)Construction of ecological vulnerability evaluation index system in the study areaBased on the land use data obtained from the remote sensing images of the study area in 2000,2010 and 2020,a total of 18 indicators including terrain,surface,meteorology,hydrology,vegetation,population pressure and economic pressure were selected.The value-grey correlation analysis method is used to determine the weights,and an ecological vulnerability evaluation model based on the fuzzy synthesis-catastrophic series method is constructed to quantitatively evaluate and analyze the ecological vulnerability of the study area.The results show that the ecological vulnerability of the Danjiang River Basin(Henan section)is mainly moderate and mild.By 2020,the areas will be 2535.26km~2 and 2717.33km~2 respectively,accounting for30.14%and 32.30%of the total basin area.The overall vulnerability distribution characteristic is"low in the north and high in the south".Among them,the ecological vulnerability of construction land and bare land is relatively high,and the ecological vulnerability of forest land is relatively low.Therefore,it is necessary to strengthen the management of the ecological environment of construction land.(2)Spatial and temporal evolution analysis of ecological vulnerability in the study areaAccording to the evaluation results of ecological vulnerability in the study area,an analysis method for the evolution of ecological vulnerability is established to quantitatively analyze the temporal and spatial evolution of ecological vulnerability in the study area.The results show that in 2000,2010 and 2020,the distribution of the comprehensive index of ecological vulnerability in the Danjiang River Basin(Henan section)was 0.56,0.61 and 0.58.It showed a trend of first decreasing and then increasing,and the ecological quality first decreased and then increased;The areas with increased ecological vulnerability are mainly distributed in the southern plain area of the study area,mainly in Xichuan County,Neixiang County,and part of Dengzhou City;The areas where the degree of ecological vulnerability decreased were mainly distributed in the northern part of the study area,that is,most of Xixia County,Luanchuan County and part of Lushi County.(3)Analysis on the driving factors of ecological vulnerability evolution in the study areaAccording to the evaluation results of ecological vulnerability and the research results of spatial and temporal evolution law in the study area,the driving factors of ecological vulnerability in the study area were analyzed by using geographic detectors.The results show that the resilience index,namely the vegetation factor,has a greater impact on ecological vulnerability,and the explanatory power is above 4%.However,the influence of economic pressure and surface factors on ecological vulnerability has gradually increased,which is mainly reflected in per capita GDP,land use type,total primary productivity,and vegetation coverage.With the passage of time,the degree of human disturbance gradually increased,and the explanatory power was greater than 2%.