中国南北过渡带生态系统碳储量时空变化及动态模拟

山地是全球变化的敏感地带,对生态安全与发展具有重要作用,山地生态系统服务变化和生态环境承载力是地理学与生态学的研究热点。以中国南北过渡带的主体秦巴山地为研究对象,采用CA-Markov模型与InVEST模型模拟和预测（2000—2040年）不同土地利用情景下秦巴山地生态系统碳储量变化,运用热点分析（Getis-Ord G_i^*）探讨秦巴山地生态系统碳储量的空间分布差异。结果表明：（1）2000—2040年,研究区土地利用/土地覆被变化主要是耕地、林地、草地和建设用地。（2）2000—2020年,碳储量增加1.12×10⁷ t;2020—2040年自然增长情景下,碳储量损失剧烈,减少50.24×10⁷ t;生态保护情景下,碳损失幅度明显变弱,减少29.52×10⁷ t,说明采取生态环境保护政策,能够有效控制碳储量减少。（3）土地利用/土地覆被与生态系统碳储量的变化呈现显著的一致性,土地利用数量变化决定了生态系统碳储量的质量和空间分布格局。（4）随着海拔抬升,碳储量呈现出“先增后减”的趋势;随着坡度升高,碳储量呈现出“W”型变化趋势。（5）热点分析结果显示,2000—2020年间,碳储量热点区和冷点区零散分布在研究区内;2040年自然增长情景下,碳储量冷热点分布范围有逐渐变大的趋势;2040年生态保护情景较2020年,秦巴山地生态系统碳储量的冷热点分布范围整体变化不大。

Spatio-temporal variation and dynamic simulation of ecosystem carbon storage in the north-south transitional zone of China

Mountains are sensitive areas to global change and they play an important role in the ecological security and development of human society. The changes of mountain ecosystem services and the carrying capacity of the ecological environment have always been focusing on hotspots in geography and ecology. In this paper, the Qinling-Daba Mountains, the main body of the north-south transitional zone of China, is taken as the research object. The CA-Markov model and InVEST model are used to simulate and predict (2000-2040) the ecosystem carbon storage changes of the Qinling-Daba Mountains under different land-use scenarios. The spatial distribution difference of ecosystem carbon storage of the study area is discussed by using the hot spot analysis (Getis-Ord G_i^*). The results show that: (1) From 2000 to 2040, the main types of land use/land cover changes are farmland, forestland, grassland, and construction land. (2) From 2000 to 2020, the ecosystem carbon storage increased by 1.12×10⁷ t; under the natural growth scenario from 2020 to 2040, the carbon storage loss is severe, down by 50.24×10⁷ t; under the ecological protection scenario, there is less carbon loss, with a decrease of 29.52×10⁷ t, indicating that the adoption of ecological environment protection policies can effectively control the reduction of ecosystem carbon storage. (3) The changes in land use/land cover and ecosystem carbon storage show significant consistency. The change of land use quantity determined the quality and spatial distribution pattern of ecosystem carbon storage. (4) With the rise of the altitude, carbon stocks show a trend of "increasing first and then decreasing"; with the increase of the slope, carbon stocks show a "W"-shaped change trend. (5) The hot spot analysis results show that from 2000 to 2020, carbon storage hot spots and cold spots were scattered in the study area; under the natural growth scenario in 2040, the distribution range of carbon storage cold and hot spots will tend to increase gradually; compared with 2020, the ecological protection scenario in 2040 shows little change in the distribution range of the cold and hot spots of ecosystem carbon storage in the Qinling-Daba Mountains.