1990~2020年塔里木河流域土地利用变化及其对碳储量的影响

Land use Change and Its Impact on Carbon Stock in the Tarim River Basin from 1990 to 2020

土地利用是引起生态系统碳储量变化的重要因素之一.研究土地利用变化驱动下碳储量时空演变特征,对于增强陆地生态系统固碳能力、减缓气候变暖效应、助力“双碳”目标实现具有重要意义.以塔河流域为研究对象,基于1990~2020年4期土地利用数据,运用InVEST模型Carbon模块估算并分析流域碳储量时空演变特征,探讨土地利用变化对流域生态系统固碳能力的影响及碳储量空间分异驱动规律.结果表明:①草地和未利用地是塔河流域主要的土地利用类型,占土地类型总面积的90%以上,其次为耕地、林地、水域和建设用地.1990~2020年间耕地、建设用地和未利用地呈增加趋势,草地、林地和水域面积呈减小趋势;1990~2020年流域土地利用类型总转移面积2.19×10^(5) km^(2),草地为主要转出类型(占总转出面积的44.22%),主要转换为未利用地与耕地;②塔河流域碳储量空间分布整体特征表现为中部偏低,四周偏高,碳储量高-高聚类、高-低聚类主要位于林地与草地等分布区域,碳储量低值地区主要分布在塔河流域中部未利用地类型区.1990~2020年塔河流域碳储量呈持续下降趋势,近30 a间累计损失9×10^(7) Mg,碳储量变化重心向东南方向偏移,碳储量减少区域大部分为耕地与未利用地向周围扩张,侵占了碳密度更高的草地与林地;③不同土地利用类型对碳储量贡献大小依次为草地、林地、耕地、未利用地、建设用地、水域;④塔河流域碳储量的空间分异性受地形、气候、环境及人口等多种驱动因子及其之间协同作用的影响.

Land use is one of the important factors causing the change in ecosystem carbon storage.Studying the spatio-temporal evolution characteristics of carbon storage driven by land use change is of great significance for enhancing the carbon sequestration capacity of terrestrial ecosystems,slowing down the effect of climate warming,and helping to achieve the goal of“dual carbon.”Taking the Tarim River Basin as the research object,based on four periods of land use data from 1990 to 2020,the InVEST model carbon module was applied to estimate and analyze the temporal and spatial evolution characteristics of carbon storage in the basin,and the impact of land use change on the carbon sequestration capacity of the basin ecosystem and the spatial differentiation driving law of carbon storage were discussed.The results showed as follows:①Grassland and unused land were the main land use types in the Tarim River Basin,accounting for more than 90%of the total land types,followed by cultivated land,forest land,water area,and construction land.From 1990 to 2020,the area of cultivated land,construction land,and unused land increased,while the area of grassland,forest land,and water area decreased.The total transfer area of land use type in the basin from 1990 to 2020 was 2.19×10^(5) km^(2),and grassland was the main transfer type(accounting for 44.22%of the total transfer area),which was mainly converted into unused land and cultivated land.②The overall spatial distribution of carbon stocks in the Tarim River Basin was lower in the middle and higher in the surrounding areas.The high-to-highcluster and high-to-low-cluster carbon stocks were mainly located in the distribution areas of woodland and grassland,and the low-value carbon stocks were mainly distributed in the unused land type areas in the middle of the Tarim River Basin.Over the past 30 years,an accumulative loss of 9×10^(7) Mg was observed.The center of gravity of carbon storage change shifted to the southeast,and most of the areas of carbon storage reduction were cultivated land and unused land expanding to the surrounding areas,encroaching on grassland and forest land with higher carbon density.③The contribution of different land use types to carbon storage was grassland,forest land,cultivated land,unused land,construction land,and water area.④The spatial differentiation of carbon stocks in the Tarim River Basin was influenced by various driving factors such as terrain,climate,environment,and population and their synergies.