Evaluation And Planning Strategy Of Ecological Restoration In Key Coal Mining Areas Of China

As China vigorously carried out the construction of ecological civilization,a large number of coal mines in China have been remedied,withdrawn with the causes of resource exhaustion and low production capacity.The number of closed mines will continue to increase.Besides,the coal mining areas also need to meet stricter standards of safety,output,reclamation and so on.Coal mines continue to pose a threat to the surrounding environment,including ecological stresses such as ground subsidence,groundwater contamination and coal gangue pollution,but ecological recovery under natural conditions is long in cycle and slow in effect.Therefore,ecological restoration planning is needed for coal mining areas to restore their natural conditions.However,the current planning scale for coal mining areas is limited to single and multiple mines,which cannot meet the requirements of the whole-area and whole-factor ecological restoration planning for the national space.Therefore,to solve the scale problem,this thesis evaluated the ecological status,land use status,and economic and social status of 16 key coal mining provinces at the national scale and conduct model validation.Then,based on the above,we carried out ecological restoration planning at five levels:vegetation-regulation-region-time-sequence-land,and finally formed a multi-faceted ecological restoration strategy at the regional level and its cases,subject level and concept and practice level.Firstly,this study analyzed the current situation of key coal mining areas nationwide,The number of key coal mine areas with comprehensive ecological sensitivity of mild and insensitive was the largest,accounting for 64.0%;coal mine areas with extreme ecological sensitivity were mainly located in the Yunnan,Guizhou and Sichuan regions and Hebei Province.Then we identified ecological source areas through spatial morphological analysis methods.After that,we analyzed how the coal mining areas affecting source areas and formed the level of ecological safety level in key coal mining areas based on the ecological source areas.Thus,the ecological status was formed by the synthesis of the above situations.From results,Shaanxi,Henan and Shanxi had a higher impact on ecological source areas than other provinces.The areas with ecological safety level at higher and above accounted for 73.5%of the key mining provinces,mainly in Shandong,Henan,Anhui,Ningxia and Inner Mongolia regions.By comparing the land use area and its changes in the screened coal mine areas from2015 to 2020,the current land use status of the coal mine areas and the evaluation effect of ecological restoration of land use during the five-year period were derived.43.2%of the selected coal mine areas had a significant decrease in the area of green land around the coal mine areas between 2015 and 2020,and more than 70%of the selected coal mine areas had water bodies,bare land and wetland areas around the coal mine areas remained basically intact.67.3%of the town construction land around the selected coal mine areas increased significantly.The proportion of green areas,water bodies,bare land and wetlands restored to a better level and above were 35.5%,4.3%,7.4%and11.4%,respectively.After synthesizing various types of restoration effects thourgh AHP hierarchical analysis,more than half of the comprehensive ecological restoration evaluation levels of the screened coal mine areas need to be improved.Through the buffer zone analysis method,the number of population affected around the coal mine area was statistically analyzed,and the number of population affected within 5km of the mine area was higher around the northwest towns as well as in Yunnan,Guizhou and Sichuan than in other areas.By using ridge regression anylysis,stepwise regression analysis,stepwise regression anylysis,curve estimation method and multiple covariance analysis,the ecological security level model and land ues evaluation model were validated.Then,based on the above situation analysis,we combined vegetation distribution and national comprehensive ecological sensitivity data.By using the combination and moran index spatial autocorrelation method,superposition analysis and hierarchical analysis,the ecological restoration planning of coal mining areas were formed including vegetation restoration planning,ecological spatial control,homogeneous regional planning,timing planning and land use target planning.Based on the five levels of"vegetation,control,coordination,timing,and land",the ecological restoration plan for coal mining areas was developed.In terms of vegetation,the dynamic restoration plan,flexible restoration plan and qualitative restoration plan for different areas were developed;in terms of control,the ecologically prohibited development zones,ecologically restricted development zones and ecologically suitable development zones in coal mining areas were divided,among which the ecologically restricted development zones had the largest area of 4,175,000 km~2 and the ecologically prohibited development zones had the smallest area of 183,000 km~2;in terms of coordination and timing,four areas where homogeneous restoration can be carried out are the Yunnan-Guizhou-Sichuan region,the Hebei,Shandong and Anhui regions,the junction of Ningxia,Inner Mongolia and Shaanxi,and the Shaanxi-Shanxi-Henan region.The first three were mainly near-term ecological restoration planning areas,while Shaanxi,Shanxi and Hebei were mainly medium-term and long-term ecological restoration planning areas.In terms of land,the northeast,northwest and southwest regions of China mainly focus on comprehensive greenland and bareland enhancement and management,the Shaanxi-Shanxi-Henan regions mainly focus on greenland enhancement and greenland conservation.Hebei and Shandong provinces mainly focused on greenland conservation and maintenance.The correlation anylysis and curve estimation methods showed that there was a significant positive correlation between the level of land use ecological restoration effectiveness and the level of ecological development.Finally,based on the analysis of the evaluation of the current situation of key coal mining areas and ecological restoration planning,ecological restoration strategies for key coal mining areas at the regional level were derived,including the main level the concept and practice level.At the regional level,restoration strategies were developed from the protection of pioneer vegetation and different sites in the southwest,northeast,northwest,Shaanxi-Shanxi-Henan and Hebei-Anhui-Shandong regions of the restoration.At the subject level,the guiding ideology and basic principles of ecological restoration of the government,ecological restoration planning work,and ecological restoration implementation guarantee were summarized,and strategies at the enterprise and citizen levels were elaborated.At the conceptual and practical levels,strategies were elaborated on the conjunctive concept and practical application scope of reclamation-while-rehabilitating and ecosystem restoration.