Study On Carbon Sink Benefits Evaluation Of Coal-mining Subsided Wetlands

As a large coal resource country,China’s long-term coal mining activities have led to the emergence of a large number of coal mining subsidence areas,which have caused certain damage to regional water and soil resources and social environment.The transformation of coal mining subsidence areas has always been a difficult point for ecological restoration and resource reuse in mining areas,and coal mining subsidence wetlands as a common restoration pathway have made great contributions to regional ecological environment enhancement and carbon sequestration and sink increase.Especially in the context of the dual pressure of "carbon peak" and "carbon neutrality" both domestically and internationally,how to better utilize the carbon sequestration function of coal mining wetlands and explore the value of carbon sink resources in wetland ecosystems is a new research trend in the field of ecological restoration in mining areas in the future.Based on these,this theis firstly investigates the relationship between land use changes of coal mining sink wetlands and carbon density and carbon storage,secondly constructs the evaluation system of carbon sink benefits of coal mining sink wetlands through DEMTAEL-ANP combined weighting method and gray clustering evaluation model,and carries out empirical analysis with Pan’an lake coal-mining sink wetland park in Xuzhou city to determine the evaluation level of carbon sink benefits of Panan Lake Wetland,and finally proposes measures to optimize the carbon sink benefits of coal mining sink wetlands and suggestions to promote regional wetland carbon sink trading.The main results of the study are as follows:(1)Study on the effect of land use change on the change of carbon density and carbon storage in the coal mining subsidence wetland of Pan’an Lake.The results show that between 2000 and 2020,the land use change of Pan’an Lake is mainly reflected in the decrease of arable land,construction land and the increase of forest land and water land,and this trend is also consistent with the main objective of ecological restoration.The changes of carbon stock in Pan’an Lake during 20 years are small and show an overall increasing trend.The spatial distribution of organic carbon density is basically in the zone of constant density,followed by the zone of decreasing low value of carbon density.When the land use type changes,the carbon density and carbon stock also increase or decrease,and when other land use type changes to forest land use type,the carbon density and carbon stock increase,and when other land use changes to water land,the carbon density and carbon stock decrease.(2)Constructed a coal mining subsidence wetland carbon sink evaluation index system and evaluation model.According to the own characteristics of coal mining sink wetlands,ecological carbon sink benefit evaluation indexes were selected and the corresponding index weights were determined.Firstly,the carbon sink storage of Pan’an Lake ecological wetland was taken as the research object,and an evaluation index system containing three criteria layers,such as wetland soil carbon sink benefits,wetland vegetation carbon sink benefits and wetland water carbon sink benefits,and10 index layers,such as soil organic carbon density,soil organic carbon storage and soil carbon sink value,was constructed.Secondly,the combined DEMATEL-ANP method was applied to determine the weights of the evaluation indexes of wetland carbon sink benefits.The research results show that the influence of the criterion layer species water carbon sink benefit on the evaluation object is the largest at 0.3596,vegetation carbon sink benefit is the second largest at 0.3241,and soil carbon sink benefit is the smallest at 0.3163.The degree of influence among the indicators in the criterion layer is comparable with little difference,indicating that all three play an important role in the evaluation of wetland carbon sink benefit.Finally,the gray clustering evaluation method was used to construct four evaluation levels of poor,fair,good and excellent,and the white-weighting function was derived by standardizing the indicator data,and the values of the white-weighting function were combined with the indicator weights to obtain the final comprehensive vector evaluation as well as the evaluation levels of each individual benefit.(3)Determine the evaluation level of carbon sink benefit of Pan’an Lake coal mining sink ecological wetland as "good".Firstly,according to the evaluation system and weights of ecological carbon sink benefit indicators of coal mining subsidence wetland,combined with the value of white-weighting function,the comprehensive vector evaluation matrix was obtained,and the evaluation interval was determined by the maximum coefficient method,the comprehensive benefit evaluation grade of Pan’an Lake coal mining subsidence wetland was "good",among which the evaluation grade of carbon sink benefit of soil was The evaluation grade of soil carbon sink benefit is "good",the evaluation grade of vegetation carbon sink benefit is "good",and the evaluation result of water body carbon sink benefit is "average".Secondly,combining with the evaluation results of carbon sink benefits,we propose countermeasures from the perspective of optimizing the ecological spatial planning of coal mining sink wetlands,so as to improve the carbon sink benefits of coal mining sink wetlands.Finally,the results of carbon sink benefit evaluation are used as a guide to explore the innovative products of ecological carbon sinks into the wetland carbon sink trading,which provides the basic conditions for the later carbon trading,and on this basis,suggestions are made for the development and improvement of the carbon sink trading market in coal mining sink wetlands based on the successful experience of wetland carbon sink trading.In summary,after the ecological restoration of coal mining subsidence areas,the carbon stock gradually increases,and the carbon sink benefits are subsequently improved.By constructing the evaluation system for the carbon sink benefits of coal mining subsidence wetlands,the final evaluation results are conducive to the improvement of the ecological restoration planning scheme of high diving coal mining subsidence areas,the optimization of wetland ecological space and the improvement of the carbon sink benefits of coal mining subsidence ecological wetlands.There are 30 figures,28 tables,and 157 references in the thesis.