Construction Of Green Infrastructure Pattern Of Carbon Sink In Beibu Gulf Urban Cluster And Measures For Optimization

Carbon sink green infrastructure is both a network of blue-green space carbon sinks and a strategic land conservation approach to help achieve the goal of"carbon peaking and carbon neutrality".As an important development concept and planning tool,it can effectively address the various"urban diseases"that arise in the course of uncontrolled urban growth,fundamentally address the environmental and ecological problems caused by greenhouse gases,and is an important measure to address the risks of climate change.Carbon sink green infrastructure mainly provides carbon sink ecosystem services,with multiple functions such as rainwater reduction,heat island effect mitigation,biodiversity protection,flood prevention and flood control,earthquake and disaster mitigation,and recreation.It focuses on the coordination of ecological,aesthetic,cultural and social benefits in many aspects.The Beibu Gulf Urban Cluster contains land,sea,blue and green spaces with huge carbon sink potential,and as a national city cluster entering a new stage of development and growth,it has a prominent strategic position and geographical advantages.In the context of carbon peaking and carbon neutral policies,the construction of a green infrastructure pattern for carbon sinks and the formulation of countermeasures to optimise sinks will greatly contribute to the green development of the Bay Area city cluster and generate positive effects on the large-scale regional carbon cycle.By constructing a carbon sink green infrastructure pattern,the study aims to expand the connotation of traditional green infrastructure ecosystem services,quantify the carbon sink potential of blue-green space,and provide universal methodological ideas for the construction of low carbon patterns in territorial spatial planning.The year 2000,2010 and 2020 are selected as the time points for the study,and the carbon sink green infrastructure elements are further extracted by accounting for the amount of carbon sinks in blue-green space,and then MSPA and landscape connectivity assessment are applied to identify and classify the carbon sink sources,and ecological corridors are extracted and pinch points and obstacle points are identified based on circuit theory.The results show that:（1）The total carbon sinks in blue-green space in 2000,2010 and 2020 are451.47 million t C·a^-1,448.99 million t C·a^-1and 452.33 million t C·a^-1respectively,and the overall carbon sinks fluctuate in a downward and then upward trend.The amount of carbon sink per unit area is higher in"blue"than in"green".Total carbon sink roughly shows the pattern of"high on both sides and middle,low on north and south",and the carbon sink potential of Beibu Gulf（Guangxi）>Beibu Gulf（Guangdong）>Beibu Gulf（Hainan）.（2）Fifteen core source patches were extracted based on connectivity evaluation in 2000,2010 and 2020,with a total area of 44030.56km²,44178.48km²and 44900.22km²of blue-green space core source patches,respectively,concentrated in the east and west and central parts of the study area,with stable changes in the overall pattern.In 2000 and 2010,20ecological corridors were extracted respectively,and in 2020,19 ecological corridors were extracted,with the most dense and circular distribution of corridors in the northwest and strong connectivity,and relatively long distances in the south-central corridors.（3）Based on circuit theory to identify pinch points and obstacle points,propose corresponding optimization countermeasures for carbon sink green infrastructure pattern,apply spatial planning related theories to respond to the demand for carbon sequestration and sink increase in blue-green carbon sink space,and focus on the coordinated development of three parts:carbon sink source,ecological corridor and important nodes.