Spatial And Temporal Evolutionary Characteristics Of Ecosystem Health In The Hexi Corridor

Ecosystem health status evaluation is very important to ensure the sustainable development of human society and is the main goal of environmental protection and governance,especially for areas with relatively fragile ecological environments.Scientific evaluation of ecosystem health can improve decision-making ability and provide a basis for sustainable development.This paper takes the Hexi Corridor region in northwestern China as the study area,based on a comprehensive evaluation index system of ecosystem vitality,ecosystem organization,ecosystem restoration,and ecosystem service supply/demand ratio from the perspective of ecological integrity and human demand for ecosystem services,considering the influence of natural environment and human social environment comprehensively to better reflect the characteristics of ecosystem health status.Apply the full alignment polygon composite index method and the ratio model method to calculate the ecosystem health index,and evaluate the ecosystem health of the Hexi Corridor from 2000 to2020 through GIS spatial analysis and statistical methods,explore and study the spatial and temporal variation features of long-time sequences,and finally propose corresponding zoning planning and management measures.The results of this study show that:(1)The overall spatial distribution of ecosystem vitality shows a high distribution in the southeast and a low distribution in the northwest,and the high values of vitality are mainly concentrated in the Qilian Mountains and other areas with high vegetation cover.The overall distribution trend of ecosystem organization and resilience from 2000 to 2020 is spatially consistent.The higher values are mainly distributed in areas less disturbed by human activities,while in densely populated areas with frequent human activities,ecosystem organization,and resilience are significantly lower.The distribution of ecosystem service supply,ecosystem service demand,and the ratio of supply and demand are basically the same,and both show an overall increasing trend in time.The overall pattern of eco-system service provision and demand shows a glut of eco-system services in the southeast and a weakness in the northwest,with an imbalance between supply and demand,while most regions show a balanced pattern of high supply-high demand and low supplylow demand.(2)From the spatial and temporal change pattern of ecosystem health status,the overall distribution pattern of ecosystem health status from 2000 to 2020 was consistent,showing a distribution pattern of high in the northwest and central part of the study area and low in the southwest,dominated by medium health level.The temporal change in the ecosystem health index first decreases and then increases,with an overall upward trend and improved ecosystem health.In terms of spatial distribution,the interannual ecosystem health conversion is small and no large conversion occurs,and the area of change is to the type of better ecosystem health.The overall ecosystem health status showed a continuous and stable change pattern,with fluctuating growth type area accounting for a larger proportion than fluctuating decrease type,and other change patterns accounting for a small proportion.(3)In terms of the spatial scale effect of ecosystem health,the spatial distribution of ecosystem health at different administrative scales has a certain directionality,mainly in the direction of gradual improvement from east to west.From the change of ecosystem health at the administrative scale,the number of administrative units with better ecosystem health increases from the city scale to the county scale,and the change becomes more and more significant.In terms of the dynamics of changes in the ecosystem health index,the area of areas where the frequency of changes in the ecosystem health index increased significantly accounted for a smaller percentage,mainly in the urban areas of the five cities in the Hexi Corridor,indicating that the impact of human activities and the natural environment on the health of the ecosystem became greater and the health of the ecosystem fluctuated more;the area of areas where the frequency of changes in the ecosystem health index decreased significantly accounted for 66.67% and was mainly distributed outside the main urban areas.(4)In terms of spatial correlation of ecosystem health,the change of global Moran’s I value from 2000 to 2020 shows a trend of gradual increase,indicating that the spatial autocorrelation is in a trend of increasing.The local Moran’s I indicate the local aggregation of ecosystem health in the Hexi Corridor region is obvious,and the overall distribution is dominated by high values of high aggregation and low values of aggregation.The area distribution of high and low areas and low areas of high areas in each study year from 2000 to 2020 is less,showing a fragmented spatial distribution characteristic.