Xi Haojun, Li Tianhong
College of Environmental Science and Engineering, Peking University, Beijing 100871, China; State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems, Beijing 100871, China.
College of Environmental Science and Engineering, Peking University, Beijing 100871, China; State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems, Beijing 100871, China.
Sci Total Environ. 2024 Dec 1;954:176261. doi: 10.1016/j.scitotenv.2024.176261. Epub 2024 Sep 12.
Terrestrial ecosystems are critical to the global carbon cycle and climate change mitigation. Over the past two decades, the Yangtze River Basin (YRB) has implemented various ecological restoration projects and active management measures, significantly impacting carbon stock patterns. This study employed random forest models to analyze the spatial and temporal patterns of carbon stocks in the YRB from 2001 to 2021. In 2021, carbon density in the YRB ranged from 8.5 to 177.4 MgC/ha, with a total carbon stock of 18.05 PgC. Over 20 years, the YRB sequestered 1.26 billion tons of carbon, accounting for 11.28 % of the region's fossil fuel carbon emissions. Notably, forests exhibited the highest carbon density, averaging 98.01 ± 25.01 MgC/ha (2021) with a carbon stock growth rate of 51.6 TgC/yr. Piecewise structural equation model was used to assess the effects of climate and human activities on carbon density, revealing regional variability, with unique patterns observed in the source region. Human activities primarily influence carbon density indirectly through vegetation alterations., while climate change directly impacts ecosystem biophysical processes. These findings offer critical insights for climate mitigation and adaptation strategies, enhancing the understanding of carbon dynamics for sustainable development and global carbon management.
陆地生态系统对全球碳循环和缓解气候变化至关重要。在过去二十年中，长江流域实施了各种生态恢复项目和积极的管理措施，对碳储量格局产生了重大影响。本研究采用随机森林模型分析了2001年至2021年长江流域碳储量的时空格局。2021年，长江流域的碳密度在8.5至177.4 MgC/公顷之间，总碳储量为18.05 PgC。二十多年来，长江流域封存了12.6亿吨碳，占该地区化石燃料碳排放量的11.28%。值得注意的是，森林的碳密度最高，2021年平均为98.01±25.01 MgC/公顷，碳储量增长率为51.6 TgC/年。采用分段结构方程模型评估气候和人类活动对碳密度的影响，揭示了区域变异性，在源区观察到独特的模式。人类活动主要通过植被变化间接影响碳密度，而气候变化直接影响生态系统的生物物理过程。这些发现为气候缓解和适应策略提供了关键见解，增强了对碳动态的理解，以促进可持续发展和全球碳管理。
