皖南重点生态功能区城镇化对碳收支的影响

[Objective] In the context of population shrinkage, investigating the impact of urbanization on carbon budget in key ecological function zones is of great theoretical value and practical significance for regulating and promoting regional carbon budget balance. [Methods] A theoretical framework for the impact of urbanization on regional carbon budget was constructed from the perspectives of scale effects, agglomeration effects, and ecological disturbance effects. Based on the machine learning model, the impact of urbanization on the carbon budget and its mechanism in the key ecological function zones of southern Anhui Province were analyzed. [Results] (1) From 2010 to 2022, the carbon emissions in the key ecological function zones of southern Anhui Province showed a significant upward trend, increasing from 5.5967 million tons to 7.5138 million tons. The carbon sink increased slowly from 102.4 thousand tons to 113.5 thousand tons. The proportion of carbon emissions offset by carbon sinks showed an overall downward trend, indicating an intensified risk of regional carbon budget imbalance. (2) At the county scale, the carbon budget showed a spatial distribution pattern of being high in the north and south and low in the center. Ningguo City, She County, and Qingyang County were areas with relatively severe carbon budget imbalance, while Shitai County, Yi County, and Jingde County had a relatively low degree of imbalance. (3) Urbanization had a nonlinear relationship with the carbon budget. When the urbanization rate exceeded 49.5%, it exacerbated regional carbon imbalance. The impact of urbanization on the regional carbon budget exhibited scale effects, agglomeration effects, and ecological disturbance effects. Specifically, the scale expansion of construction land increased carbon emissions, while the expansion of cultivated land, forest, and grassland significantly enhanced carbon sink. The agglomeration of construction land exhibited stage-specific characteristics in emission reduction, while the agglomeration of cultivated land, forest, and grassland significantly enhanced carbon sink. The ecological disturbance effects suppressed carbon budget imbalance at low levels but exacerbated it at high levels. [Conclusion] Overall, urbanization in the key ecological function zones of southern Anhui Province plays a dominant role in increasing carbon emissions, thereby exacerbating the regional carbon budget imbalance.