Comprehensive Evaluation Of Ecological Vulnerability Of Resource-Based Cities

Focusing on the ecological vulnerability of resource-based cities,the author used 3S technology,moving split-window techniques（MSWT）,fuzzy ranking,membership function and Geo Detector to analyze the multi-source data such as terrain data,meteorological data,LUCC data,landscape pattern data and socio-economic statistical data.According to the analysis,the author improved and localized model parameters on the basis of"Press-Situation-Response"（PSR）and"exposure-sensitivity-adaptation"vulnerability scoping diagram（VSD）assessment systems,and proposed a PSSR evaluation framework suitable for ecological vulnerability assessment of resource-based cities.The ecological vulnerability of the study area was comprehensively evaluated from the scale of spatial-temporal differentiation to quantify and visually express the classification of ecological vulnerability in the study area.A preliminary exploration was made by using Geo Detector to diagnose the intensity of interaction between ecosystem vulnerability and socio-economic system vulnerability.Based on the qualitative research and the coupling law of self-organization evolution of socio-economic and eco-environmental subsystems,the evolution process and mechanism of resource-based cities are explored in order to provide scientific basis for ecological protection and restoration,for sustainable development and economic transformation,and for recovery of resource-based cities.The research results are as follows:（1）Handan is not a completely resource-based city,and its mining areas are mainly located in the western Taihang Mountains,so the eco-environmental vulnerability of the eastern plain counties is lower than that of the western area.In recent years,with the trend of aggravating drought in North China,Handan’s annual average temperature was increasing,annual average precipitation decreasing,relative humidity decreasing,and PM_2.5concentration increasing.The comprehensive effect of meteorological environmental factors reflects the decline of habitat quality in the study area,and the inherent natural attributes lead to potential crisis of Handan’s ecosystem vulnerability.The ecological sensitivity and ecological resilience indicators obtained in the study area by landscape pattern software show that Handan’s ecological sensitivity and ecological resilience are deteriorating.The highly sensitive areas are mainly concentrated in the mining areas in the western Taihang Mountains,while the low sensitive areas and non-sensitive areas are distributed in the eastern plain counties.The ecological resilience shows a downward trend,and the areas with weak resilience（level IV）and very weak resilience（level V）are extending significantly.（2）Based on the ranking of the four evaluation factors of PSSR evaluation system by fuzzy analytic hierarchy process,together with the comprehensive evaluation of eco-environmental vulnerability in the study area by membership function,Handan’s eco-environmental vulnerability is divided into five levels,which are slight vulnerability,light vulnerability,moderate vulnerability,severe vulnerability and extreme vulnerability.The results show that from 2000 to 2015,the ecological environment in Handan city was improved obviously,which is reflected by the continuous increase areas with slight vulnerability and light vulnerability at annual change rates of 32.06 km²/a and 13.99km₂/a respectively,as well as the continuous decrease areas with extreme vulnerability at an annual change rate of 68.48 km²/a.The change rates of eco-environmentally vulnerable areas are in the order of extremely vulnerable area>slightly vulnerable area>severely vulnerable area>light vulnerable area>moderately vulnerable area.（3）The spatial distribution of ecological vulnerability in Handan City shows that the level of vulnerability is increasing from the eastern plain areas to the western mountainous areas,with some vertical zonality characteristics.From 2000 to 2015,the vulnerability levels in the western mountainous areas and Handan urban areas showed a significant decreasing trend,indicating a significant effect of ecological restoration.The vulnerability of the southeast areas showed a slightly increasing trend,while that of the northeast plain areas showed a slightly decreasing trend.The analysis of the transformation relationship of ecological vulnerability levels found the transformation from severe level to moderate,light and slight levels,and also found the transformation from slight and light levels to severe and extreme levels.The transformation relationship between vulnerability levels,either ameliorating or deteriorating,is very complicated,and the overall data show that the positive function of the ecological remediation is greater than the negative function.The typical feature of the spatial distribution of the ecological vulnerability levels from 2000 to 2015 is that the latitude weighted value of main parts of each level of vulnerability is getting higher and higher,while the longitude weighted value is getting lower and lower,indicating the migration path from southeast to northwest.If ecological protection measures for corresponding levels are taken along that path,it will help to improve the ecological environment of the study area as a whole.（4）Based on the result of Geo Detector,the indicator of ecological vulnerability is linked with 16 socio-economic indicator to analyze the explanatory relation between the spatial heterogeneity of ecological vulnerability and the economic growth,industrial structure,human development needs,scientific and technological progress,agricultural production in the resource-based city from 2000 to 2015.In the past 15 years,the explanatory power of the q value on the impact of ecological vulnerability was developing towards equalization,and the difference of the six factors with the strongest explanatory power showed a significant decreasing trend.The factors with the stronger explanatory power were not limited to industrial factors;instead,other factors such as the gross output of the primary industry,the gross output of the tertiary industry,the urbanization rate and the expenditure of science and technology funds showed an increasing explanatory power to the ecological vulnerability of Handan city.The factors are tending to be diversified.（5）The risk detector model was used to explain the evolution mechanism of Handan’s ecological vulnerability.The detection results show that the transformation of the resource-based city Handan was effective in the past 15 years.However,its economic development still depends on the secondary industry,and the industrial structure is unreasonable,so accelerating the optimization and upgrading of its advantageous industries,developing high-tech enterprises and environment-friendly enterprises are the key to improving Handan’s ecological vulnerability.The gross output value of its tertiary industry has a positive relationship with ecological vulnerability,indicating that Handan has not found an ecological niche for developing its tertiary industry in the process of transformation.Developing high-quality tertiary industry based on advantageous cultural resources is an important way to promote economic transformation and improve ecological environment for resource-based cities.The positive relationship of“science and technology funding and talent”indicator versus ecological vulnerability shows that the city transformation is facing difficulties due to lack of science and technology innovation,lack of talents,and lack of guarantee mechanism for science and technology funding.The reverse relationship between the agricultural production indicator and the ecosystem vulnerability of Handan shows that agriculture has a positive effect on improving its ecological vulnerability.The distribution of agricultural industries according to local conditions has promoted the transformation and upgrading of modern agriculture in the resource-based city in all directions.（6）The level of coupling coordination between the socio-economic subsystem and the eco-environmental subsystem in Handan City is on the low side as a whole,and it was in a barely coordinated development stage in the past 15 years.On spatial pattern,Handan presents a basically coordinated development in the central and western areas and a slightly unbalanced development in the western areas,reflecting that the regional development resources are concentrated too much in the western mining areas and the eastern regions is lack of resources output and policy inclination.Through depicting the evolution path and history of Handan’s urban development,it is found that the evolution of the city has gone through three stages,which are the stage of low-level coordinated development of dual subsystems,the stage of economy priority development,and the stage of socio-economic system improvement and eco-environmental treatment.Currently,the social and eco-environmental vulnerability is evolving in the direction of improvement and optimization under the joint drive of the transformation and upgrading of resource-based industries,the state policy intervention and the positive response of farmers’behaviors.At the end of this research,according to the needs of Handan’s industrial transformation and upgrading,specific suggestions are put forward from five aspects:transforming and upgrading the industrial structure,undertaking Beijing-Tianjin industrial transfer,optimizing the tertiary industry,further developing the industrial chain of agriculture,rural areas and farmers,and strengthening ecological restoration and eco-environmental protection.Focusing on the assessment of the correlation and coupling of ecological vulnerability,ecological effects,natural environment factors and socio-economic factors,this study reveals the evolution mechanism of eco-environmental response in the resource-based city,systematically analyzes the contradiction and constraint relationship among human,land and ecological environment in the resource-based city,and provides research ideas and practical experience for the transformation and development planning of resource-based cities.