How climate change and fire exclusion drive wildfire regimes at actionable scales
How climate change and fire exclusion drive wildfire regimes at actionable scales
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DOI：
10.1088/1748-9326/abd78e
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发表时间：
2021-02-01
影响因子：
6.7
通讯作者：
Adam, Jennifer C.
中科院分区：
文献类型：
--
作者：
Hanan, Erin J.;Ren, Jianning;Adam, Jennifer C.
在全球范围内，极端野火的频率正在增加，促使人们采取新的措施来减轻风险。然而，风险缓解战略的生态适宜性取决于驱动这些增加的因素。虽然区域综合将火灾活动的增加归因于气候变化和通过火灾排除而积累的燃料，但它们并没有在实施土地管理的尺度上分解因果驱动因素。火灾状态模型的最新进展可以帮助我们了解哪些驱动因素在管理相关尺度上占主导地位。我们利用历史气候和火灾排除情景在美国西北部内陆的两个流域进行了火灾状态模拟，这两个流域发生在干旱连续体的不同位置。在一个流域，气候变化是增加燃烧概率和大火频率的关键驱动因素；另一方面，火灾排除在一些地方占主导地位。我们还证明，由于气候变化导致火灾季节干旱增加，一些地区的燃料变得更加有限。因此，即使在流域内，燃料管理也必须在空间和时间上明确，以优化效率。为了指导管理，我们表明，土壤干旱（或暂时平均土壤湿度）的空间估计可以提供一个相对简单的一阶指标，表明流域中哪些地方的火灾是气候与燃料限制的，哪些地方的火灾最容易发生变化。
Extreme wildfires are increasing in frequency globally, prompting new efforts to mitigate risk. The ecological appropriateness of risk mitigation strategies, however, depends on what factors are driving these increases. While regional syntheses attribute increases in fire activity to both climate change and fuel accumulation through fire exclusion, they have not disaggregated causal drivers at scales where land management is implemented. Recent advances in fire regime modeling can help us understand which drivers dominate at management-relevant scales. We conducted fire regime simulations using historical climate and fire exclusion scenarios across two watersheds in the Inland Northwestern U.S., which occur at different positions along an aridity continuum. In one watershed, climate change was the key driver increasing burn probability and the frequency of large fires; in the other, fire exclusion dominated in some locations. We also demonstrate that some areas become more fuel-limited as fire-season aridity increases due to climate change. Thus, even within watersheds, fuel management must be spatially and temporally explicit to optimize effectiveness. To guide management, we show that spatial estimates of soil aridity (or temporally averaged soil moisture) can provide a relatively simple, first-order indicator of where in a watershed fire regime is climate vs. fuel-limited and where fire regimes are most vulnerable to change.