Department of Geosciences and Geography, University of Helsinki, FI-00014 Helsinki, Finland;
Department of Geosciences and Geography, University of Helsinki, FI-00014 Helsinki, Finland.
Proc Natl Acad Sci U S A. 2021 Feb 16;118(7). doi: 10.1073/pnas.2023787118.
In the Amazon rainforest, land use following deforestation is diverse and dynamic. Mounting evidence indicates that the climatic impacts of forest loss can also vary considerably, depending on specific features of the affected areas. The size of the deforested patches, for instance, was shown to modulate the characteristics of local climatic impacts. Nonetheless, the influence of different types of land use and management strategies on the magnitude of local climatic changes remains uncertain. Here, we evaluated the impacts of large-scale commodity farming and rural settlements on surface temperature, rainfall patterns, and energy fluxes. Our results reveal that changes in land-atmosphere coupling are induced not only by deforestation size but also, by land use type and management patterns inside the deforested areas. We provide evidence that, in comparison with rural settlements, deforestation caused by large-scale commodity agriculture is more likely to reduce convective rainfall and increase land surface temperature. We demonstrate that these differences are mainly caused by a more intensive management of the land, resulting in significantly lower vegetation cover throughout the year, which reduces latent heat flux. Our findings indicate an urgent need for alternative agricultural practices, as well as forest restoration, for maintaining ecosystem processes and mitigating change in the local climates across the Amazon basin.
在亚马逊雨林,森林砍伐后的土地利用是多样化且动态的。越来越多的证据表明,森林丧失的气候影响也因受影响地区的具体特征而有很大差异。例如,森林砍伐斑块的大小会调节当地气候影响的特征。尽管如此,不同类型的土地利用和管理策略对当地气候变化幅度的影响仍不确定。在这里,我们评估了大规模商品农业和农村定居点对地表温度、降雨模式和能量通量的影响。我们的结果表明,土地-大气耦合的变化不仅是由森林砍伐的大小引起的,还与森林砍伐区域内的土地利用类型和管理模式有关。我们有证据表明,与农村定居点相比,大规模商品农业造成的森林砍伐更有可能减少对流降雨并增加地表温度。我们证明,这些差异主要是由于土地的更密集管理造成的,导致全年植被覆盖显著降低,从而减少了潜热通量。我们的研究结果表明,迫切需要采用替代农业实践以及森林恢复措施,以维持亚马逊盆地整个地区的生态系统过程并减缓当地气候的变化。