Bowring Simon P K, Li Wei, Mouillot Florent, Rosan Thais M, Ciais Philippe
Laboratoire des Sciences du Climat et de l'Environnement (LSCE), IPSL-CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France.
Laboratoire de Géologie, Département de Géosciences, Ecole Normale Supérieure (ENS), 24 rue Lhomond, 75231, Paris Cedex 05, France.
Nat Commun. 2024 Oct 24;15(1):9176. doi: 10.1038/s41467-024-53460-6.
Landscape fragmentation is statistically correlated with both increases and decreases in wildfire burned area (BA). These different directions-of-impact are not mechanistically understood. Here, road density, a land fragmentation proxy, is implemented in a CMIP6 coupled land-fire model, to represent fragmentation edge effects on fire-relevant environmental variables. Fragmentation caused modelled BA changes of over ±10% in 16% of [0.5°] grid-cells. On average, more fragmentation decreased net BA globally (-1.5%), as estimated empirically. However, in recently-deforested tropical areas, fragmentation drove observationally-consistent BA increases of over 20%. Globally, fragmentation-driven fire BA decreased with increasing population density, but was a hump-shaped function of it in forests. In some areas, fragmentation-driven decreases in BA occurred alongside higher-intensity fires, suggesting the decoupling of fire severity traits. This mechanistic model provides a starting point for quantifying policy-relevant fragmentation-fire impacts, whose results suggest future forest degradation may shift fragmentation from net global fire inhibitor to net fire driver.
景观破碎化在统计上与野火燃烧面积（BA）的增加和减少均相关。这些不同的影响方向尚未从机制上得到理解。在此，道路密度作为土地破碎化的一个代理变量，被应用于一个CMIP6陆-火耦合模型中，以体现破碎化边缘对与火灾相关的环境变量的影响。在16%的[0.5°]网格单元中，破碎化导致模拟的BA变化超过±10%。从经验估计来看，平均而言，更多的破碎化使全球净BA减少（-1.5%）。然而，在近期森林砍伐的热带地区，破碎化导致观测到的BA增加超过20%，与实际情况相符。在全球范围内，破碎化驱动的火灾BA随着人口密度的增加而减少，但在森林中它是人口密度的一个驼峰形函数。在一些地区，破碎化驱动的BA减少伴随着更高强度的火灾，这表明火灾严重程度特征出现了解耦。这个机制模型为量化与政策相关的破碎化-火灾影响提供了一个起点，其结果表明未来森林退化可能会使破碎化从全球火灾的净抑制因素转变为净驱动因素。
