黄河流域上游煤矿区土地利用类型变化及其对固碳服务的影响

Analysis of Effect of Land Use Changes on Carbon Sequestration Services in Coal Mining Areas in Upper Yellow River Basin

明晰矿区土地利用变化及其对区域碳储量的影响,是“双碳”目标背景下推进矿区低碳减排和绿色高质量发展的重要手段.基于多源数据集,使用InVEST模型、土地利用动态度、转移矩阵、缓冲区分析和灰色关联度等方法,识别了1990-2020年黄河流域上游13个大中型煤矿区的土地利用类型时空变化,评估了不同矿区及其周边不同距离缓冲区的固碳服务能力,并对二者的关联度进行分析,旨在厘清矿区土地利用变化对固碳服务的影响.结果表明:(1)1990-2020年煤矿区土地利用类型主要以草地、未利用地、林地和耕地向城乡工矿居民用地转移为主,城乡工矿居民用地面积以288.8 hm^(2)/a的速度持续扩张.(2)1990-2020年不同时段城乡工矿居民用地的单一动态度均为正值,草地和未利用地则均为负值,其中2010-2015年各土地利用类型的综合动态度均较高,2015-2020年则均相对较低,并且露天开采方式矿区土地利用强度远高于井工开采方式.(3)1990-2020年各矿区内单位面积年固碳量在0.7~4.1 Mg/hm^(2)之间,在时间上呈先下降后升高再下降的趋势,并且在距离矿区50 km范围内,距离越远,平均单位面积年固碳量越高,影响程度逐渐下降.(4)不同土地利用类型与单位面积年固碳量的平均关联度从高到低表现为未利用地>耕地>草地>林地>水体.研究显示,黄河流域上游煤矿区开发过程中未利用地和耕地面积的变化是矿区生态系统固碳服务变化的重要原因.

Clarifying the land use change characteristics in coal mining areas and their effect on carbon sequestration is an effective means to promote carbon emission reduction and high-quality development in mining areas under the background of the goals of carbon peak and carbon neutral proposed by the Chinese government.This study took 13 large and medium-sized coal mining areas in the upper Yellow River Basin,analyzed their land use changes from 1990 to 2020 based on multi-source data sets,using the InVEST model,land use dynamic degree,transfer matrix,buffer zone and grey correlation degree analyses.The carbon sequestration services in different mining areas and their surrounding areas were evaluated,their correlations with land use changes and the influences of mining activities on carbon sequestration services in buffer zones at different distances from the mining areas were analyzed.The results showed that:(1)The land use changes in the mining areas mainly included the conversions from grassland,unused land,forest and cultivated land to construction lands(urban,rural,industrial and mining lands).The area of construction lands expanded at a rate of 288.8 hm^(2)/a and the areas of grassland,unused land,forest and cultivated land decreased by 156.0,68.1,47.4 and 26.4 hm^(2)per year,respectively.Furthermore,there were obvious differences in land use change in different mining areas.(2)During 1990-2020,the single land use dynamics of construction land were positive in different periods,while that of grassland and unused land were negative.The comprehensive dynamic degree of all land use type was the highest during 2010-2015,and was relatively small during 2015-2020.It should be noted that the intensity of land use change in open-pit mining areas was much higher than that in well mining areas.(3)The annual carbon sequestration per hectare ranged 2 from 0.7 to 4.1 Mg/hm in all mining areas,and showed a change trend of decreasing-increasing-decreasing.Within 50 km away from the mining area,the annual carbon sequestration increased with the increase of distance,but the influence degree decreased gradually.The carbon sequestration per hectare in open-pit mining areas was much lower than that of well mining areas.(4)The land use types with the average correlation degree between them and annual carbon sequestration services during 1990-2020 from high to low were:unused land>cultivated land>grassland>forest land>water body.The results show that the transfer of unused land and cultivated land to construction land during the development of coal mining areas in the upper reaches of the Yellow River Basin was an important reason for the decline in the carbon sequestration service function of the mining ecosystems.In the future studies,more field observation experiments should be carried out to clearly quantify carbon sequestration services of different vegetation types in the coal mining area to further verify the estimation results of carbon sequestration and improve the accuracy of the carbon sequestration research.