Identification Of Carbon Sources/Sinks In The Changsha-Zhuzhou-Xiangtan Urban Agglomeration

The issue of carbon sources/sinks has always been a hot topic of research.Urban agglomerations are an important component of carbon sources and the main bearing space for carbon sinks,with the potential for reducing sources and increasing sinks coexisting.In the context of the "dual carbon" goals and national spatial planning,this article selects the fourth phase of land use in the Changzhutan urban agglomeration as the research node,calculates carbon sources/sinks based on the emission factor method combined with the IPCC inventory,identifies the distribution areas of carbon sources/sinks,and identifies and explores the spatial differentiation characteristics of carbon sources/sinks through nuclear density analysis,spatial autocorrelation analysis,and cold and hot spot analysis,Utilize geographic detectors to identify the main driving factors affecting carbon source/sink changes,evaluate the suitability of carbon sink functions,and propose ecological protection and restoration strategies for reducing sources and increasing sinks,as well as low-carbon landscape strategies.The main results are as follows:(1)From 2005 to 2020,construction land was the most rapidly changing land use type in the Changsha Zhuzhou Xiangtan urban agglomeration,with an increase of 842.11 km2.The transfer between different land use types was relatively complex,with the largest and more frequent changes between cultivated land,forest land,and construction land,while the transfer between grassland,water,and unused land was relatively small.(2)The construction land carries the main carbon source,with the carbon source amount increasing from 9826.34 in 2005×104 tCO2 increased to 13029.34 by 2020×104 tCO2,showing a fluctuating trend overall;Carbon sequestration is mainly generated by forest land,from 4275.49 in 2005×104 tCO2 reduced to 4165.38 by 2020×104 tCO2,showing an overall downward trend.High carbon sink areas are mainly concentrated in forest land,distributed in the northeast,west,and southern regions of the Changzhutan urban agglomeration,while low carbon sink areas are scattered;High carbon source areas are mainly concentrated in the central part of the three urban areas and expand towards the surrounding areas;Low carbon source areas are mainly concentrated next to high carbon source areas and radiate towards the surrounding areas.(3)In terms of spatial differentiation characteristics,the overall carbon source/sink core density exhibits a spatial pattern of "small aggregation and large dispersion",with the highest values mainly concentrated in Furong District,Tianxin District,Kaifu District,Yuelu District,Yuhua District,Yuetang District,Yuhu District,and Shifeng District;The low nuclear density values are mainly distributed in Ningxiang City,Liuyang City,Shaoshan City,Xiangtan County,Xiangxiang City,Lukou District,Lusong District,Liling City,You County,Chaling County,and Yanling County.(4)From 2005 to 2020,the carbon source/sink of the Changzhutan urban agglomeration showed a significant spatial agglomeration distribution feature,with a fluctuating and stable degree of agglomeration.High altitude agglomeration areas were mainly distributed in the central urban area of the Changzhutan region;Low and high clustering mostly occurs around the central urban area;Low and low concentrations are scattered and mainly distributed in Chaling County and You County.(5)The single factor detection results show that the proportion of forest land,construction land,and arable land are the main factors affecting the spatial differentiation characteristics of carbon source/carbon sink.The interaction between any two factors results in a double factor enhancement,with the interaction between forest land and arable land having the strongest explanatory power for the spatial differentiation characteristics of carbon source/carbon sink in the study area.(6)Starting from reducing sources and increasing sinks,corresponding measures are proposed from the perspectives of ecological protection and restoration,as well as low-carbon landscapes.Based on the suitability evaluation results of carbon sink functions,it is extremely suitable,relatively suitable,and generally suitable to be divided into ecological key protection areas,ecological key protection areas,and ecological auxiliary restoration areas,and corresponding protection and restoration strategies are proposed.In summary,further optimization strategies have been proposed through the accounting and identification of carbon sources/sinks in Changzhutan,providing reference and value for the ecological protection and restoration of the land space planning and low-carbon sustainable development of the Changzhutan urban agglomeration.