耕地占补面积时空变化对碳储量的影响测度——以湖北省为例

基于InVEST模型定量评估湖北省2000-2020年耕地占补面积时空变化对陆地生态系统碳储量的影响,在县级行政单元尺度探究由耕地占补导致的碳储量变化量在空间上的集聚程度,并运用PLUS模型模拟区域未来四种发展情景下的土地利用格局及碳储量变化趋势。结果表明：（1）2000年至2020年,湖北省耕地面积净变化率为-3.89%,耕地面积略微下降,基本实现耕地占补数量平衡。（2）2000-2005年、2005-2010年、2010-2015年、2015-2020年耕地占用和补偿导致的碳储量变化值占该时段碳储量变化值的比例分别为68.45%、59.45%、57.86%、55.46%,二十年整体占比为61.38%。耕地碳储量的变化对陆地生态系统碳储量的影响巨大。碳固持的地块面积为1.29×10⁵ hm²,碳损失的地块面积为3.88×10⁵ hm²。（3）2000-2020年,湖北省耕地占补导致的碳储量变化值具有明显的空间集聚性,"高高聚集"区主要分布在西部和西南部山区,"低低聚集"区分布在中南部的江汉平原。（4）2020-2030年,湖北省陆地生态系统碳储量在自然发展情景下减少5.50×10⁶ t,在耕地保护情景下减少1.22×10⁶ t,在城镇开发情景下减少8.89×10⁶ t,在生态保护情景下增加2.43×10⁶ t。与其他三种情景相比,生态保护情景是未来发展的最优情景。研究通过定量评估耕地占补平衡背景下湖北省耕地面积时空变化对区域碳储量的影响为未来的国土空间规划以及增汇政策的制定提供决策依据和科学参考,对于实现土地资源的可持续利用和生态环境保护具有重要意义。

Measuring impacts of temporal and spatial changes of cultivated land on carbon storage: A case study of Hubei Province

Based on InVEST model, the quantitative evaluation was conducted for the impact of cultivated land occupancy and compensation area temporal and spatial changes on the terrestrial ecosystem carbon storage in Hubei Province from 2000 to 2020. The degree of spatial agglomeration of carbon storage changes caused by the cultivated land occupancy and compensation was explored at the level of county administrative units. PLUS model was used to simulate the change of land use pattern and carbon storage under four future development scenarios. Based on the research, the following results were obtained:(1) from 2000 to 2020, the net change rate of cultivated land area in Hubei Province was -3.89%, indicating a slight decrease in cultivated land area. It basically achieved a balance between the number of cultivated land occupation and compensation. (2) From 2000 to 2005, 2005 to 2010, 2010 to 2015, and 2015 to 2020, the proportions of carbon storage changes caused by the cultivated land occupancy and compensation accounted for 68.45%, 59.45%, 57.86%, 55.46%, respectively. The overall proportion in the past 20 years was 61.38%. The changes in carbon storage of cultivated land had a huge impact on the carbon storage of terrestrial ecosystem. The plot area of carbon sequestration was 1.29×10⁵ hm², while the plot area of carbon loss was 3.88×10⁵ hm². (3) From 2000 to 2020, the changes in carbon storage caused by cultivated land occupation and compensation in Hubei Province had obvious spatial aggregation. The "high and high aggregation" areas were mainly distributed in the western and southwestern mountainous areas, while the "low and low aggregation" areas were located in the Jianghan Plain in the central and southern parts of the province. (4) From 2020 to 2030, the carbon storage of terrestrial ecosystem in Hubei Province will decrease by 5.50×10⁶ t under natural development scenario, 1.22×10⁶ t under cultivated land protection scenario, 8.89×10⁶ t under urban development scenario, and increase by 2.43×10⁶ t under ecological protection scenario. Compared with the other three scenarios, the ecological protection scenario is the optimal scenario for future development. Through quantitatively assessing the impact of temporal and spatial changes in the cultivated land area on regional carbon storage in Hubei Province under the background of the cropland balance policy, the study provides decision-making basis and scientific reference for future territorial spatial planning and the formulation of carbon sink increase policy, which is of great significance for realizing the sustainable utilization of land resources and ecological environmental protection.