Bark Beetle Effects on Fire Regimes Depend on Underlying Fuel Modifications in Semiarid Systems
Bark Beetle Effects on Fire Regimes Depend on Underlying Fuel Modifications in Semiarid Systems
复制标题
DOI：
10.1029/2022ms003073
复制
发表时间：
2023-01
影响因子：
6.8
通讯作者：
Jianning Ren;E. Hanan;J. Hicke;C. Kolden;J. Abatzoglou;C. Tague;R. Bart;M. Kennedy;Mingliang Liu;J. Adam
中科院分区：
文献类型：
--
作者：
Jianning Ren;E. Hanan;J. Hicke;C. Kolden;J. Abatzoglou;C. Tague;R. Bart;M. Kennedy;Mingliang Liu;J. Adam
虽然野火、极端天气事件和昆虫暴发等自然干扰在全世界生态系统和流域的结构中发挥了关键作用，但气候变化加剧了许多干扰机制，这可能对生态系统过程和服务产生复杂的负面影响。最近的研究强调了了解大规模甲虫爆发后野火是增加还是减少的必要性。然而，观察性研究产生了好坏参半的结果。为了解决这一问题，我们在美国西部的一个半干旱流域应用了一个耦合的生态水文-火情-甲虫效应模型(RHESSys-WMFire-Beetle)。我们发现，在红色阶段(暴发后0-5年)，地面火灾范围、烧伤概率以及地面和树冠火灾严重程度都有所下降。在灰色阶段(暴发后6-15年)，地面火灾范围和地面和树冠火灾严重程度都随着死亡率的增加而增加。然而，火灾的可能性在高死亡率时达到了平台期(从碳去除的角度来看，火灾的概率为50%)。在旧阶段(暴发后一至几十年)，所有死亡率的火灾范围和严重程度仍在增加。然而，火灾概率在低至中等死亡率(≤50%)时增加，但在高死亡率(>；50%)时降低。野火的反应也取决于火势。在燃料有限的地方，火灾的可能性随着燃料负荷的增加而增加，而在燃料充足(可燃性有限)系统中，火灾的可能性降低是因为植物用水需求的减少导致燃料干燥度的降低。这个建模框架可以提高我们对驱动野火反应的机制的理解，并帮助管理人员预测火灾危险将在何时何地增加。
Although natural disturbances such as wildfire, extreme weather events, and insect outbreaks play a key role in structuring ecosystems and watersheds worldwide, climate change has intensified many disturbance regimes, which can have compounding negative effects on ecosystem processes and services. Recent studies have highlighted the need to understand whether wildfire increases or decreases after large‐scale beetle outbreaks. However, observational studies have produced mixed results. To address this, we applied a coupled ecohydrologic‐fire regime‐beetle effects model (RHESSys‐WMFire‐Beetle) in a semiarid watershed in the western US. We found that in the red phase (0–5 years post‐outbreak), surface fire extent, burn probability, and surface and crown fire severity all decreased. In the gray phase (6–15 years post‐outbreak), both surface fire extent and surface and crown fire severity increased with increasing mortality. However, fire probability reached a plateau during high mortality levels (>50% in terms of carbon removed). In the old phase (one to several decades post‐outbreak), fire extent and severity still increased in all mortality levels. However, fire probability increased during low to medium mortality (≤50%) but decreased during high mortality levels (>50%). Wildfire responses also depended on the fire regime. In fuel‐limited locations, fire probability increased with increasing fuel loads, whereas in fuel‐abundant (flammability‐limited) systems, fire probability decreased due to decreases in fuel aridity from reduced plant water demand. This modeling framework can improve our understanding of the mechanisms driving wildfire responses and aid managers in predicting when and where fire hazards will increase.