Have Altered Fire Regimes Reduced Forest Resilience to Climate Change?

火灾制度的改变是否降低了森林对气候变化的适应能力？

• 批准号: RGPIN-2014-06387
• 负责人: Daniels, Lori
• 金额: $ 2.48万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=588975
• 关键词: Altered; Fire; Regimes; Reduced; Forest

Wildfire is a key driver of forest dynamics. Changes to fire regimes triggered by subtle changes in climate and land use have potential major impacts on forests. The current rate and magnitude of climate change have the potential to exceed historical and evolutionary limits, jeopardizing ecological resilience so that ecosystems are unable to recover from disturbance. Thus, understanding fire regimes drivers is essential to anticipate potential consequences of climate change and develop effective adaptation and mitigation strategies to enhance forest resilience. My research has shown that mixed-severity fire regimes historically dominated in many montane cordilleran forests in British Columbia (BC) and the foothills of Alberta. In these forests, regional climate interacts with local controls by topography and human land use, resulting in complex fire regimes that can be difficult to quantify. These ecosystems appear particularly susceptible to rapid change due to the combined effects of climate change and fire exclusion. Improved understanding of the dynamics and drivers of mixed-severity fire regimes is urgently needed to assure the resilience of these forests. My long-term research program addresses this knowledge gap. Over the next 5 years my graduate students and I will complete a series of inter-related research projects designed to meet 3 short-term objectives: 1. To compare fire histories among regions in the montane cordilleran ecozone and determine if changes to fire regimes in the 20th century are pervasive 2. To quantify the relative importance of the mechanisms driving fire-regimes and their interactions 3. To initiate new research on the consequences of altered fire regimes on fuel hazards and forest resistance to crown fire – two indicators of resilience in mixed-severity fire regimes. The first phase of this research is a comparative analysis of fire histories in four distinct climatic regions in the montane cordilleran forests of western Canada: Rocky Mountains, Kootenays, Okanagan and Cariboo. We will use multiple lines of evidence to compare fire history among these study areas. This approach will enable us to determine if changes to historic fire regimes are pervasive among climatic regions and along elevation gradients. The second research phase investigates climate as a driver of fire regimes. We will compile modern fire and weather records for 1991-2010 to interpret the range of fire weather conditions associated with lightning-caused ignitions in the dry montane forests in BC. For a longer-term perspective, we will use our multi-century fire-scar records to test for widespread fire years within and among regions. We will compare our fire records with proxy-climate data to test for the influence of climatic variation and historic fire occurrence. Finally, we will quantify the consequences of 20th century fire exclusion on dry montane forests in BC. Fieldwork will quantify the degree to which forest composition, structure and fuels have changed in absence of surface fires. Fire behavior models will be used to simulate changes to fuel loads, climate and their interaction, ultimately testing their effects on forest resistance to crown fires. Four PhD, 3 MSc and at least 10 undergraduate students will be integrally involved with this research. Our research on fire regime drivers will help to (1) anticipate future fire regimes under the influence of climate change, (2) identify segments of the landscape where resilience has been reduced by fire exclusion, and (3) establish priorities and targets to guide ecological restoration and fuels mitigation implemented by the BC Ecological Restoration Program, Parks Canada and the Canadian Wildlife Service.

野火是森林动态的关键驱动因素。气候和土地利用的微妙变化引发的火灾制度的变化对森林有潜在的重大影响。目前气候变化的速度和幅度有可能超过历史和进化极限，危及生态复原力，使生态系统无法从干扰中恢复。因此，了解火灾制度的驱动因素对于预测气候变化的潜在后果和制定有效的适应和缓解战略以增强森林复原力至关重要。 我的研究表明，历史上在不列颠哥伦比亚省(BC)和艾伯塔省山脚下的许多山地科迪勒森林中，混合严重的火灾制度占据主导地位。在这些森林中，区域气候通过地形和人类土地利用与当地控制相互作用，导致复杂的火灾状况，可能很难量化。由于气候变化和防火的综合影响，这些生态系统似乎特别容易受到快速变化的影响。迫切需要更好地了解混合严重火灾制度的动态和驱动因素，以确保这些森林的复原力。我的长期研究计划解决了这一知识鸿沟。 在接下来的5年里，我和我的研究生们将完成一系列相互关联的研究项目，旨在实现3个短期目标： 1.比较科迪勒山生态带不同地区的火灾历史，并确定20世纪火灾制度的变化是否普遍 2.量化推动火区的机制及其相互作用的相对重要性 3.启动新的研究，研究改变的火灾制度对燃料危险和森林抵抗树冠火灾的影响--这是衡量混合严重火灾制度复原力的两个指标。 这项研究的第一阶段是对加拿大西部山地科迪勒兰森林四个不同气候区域的火灾历史进行比较分析：落基山脉、库特奈斯、奥卡纳根和卡里布。我们将使用多种证据来比较这些研究地区的火灾历史。这种方法将使我们能够确定历史火灾制度的变化是否在气候区域和海拔梯度上普遍存在。 第二个研究阶段调查气候作为火灾制度的驱动因素。我们将汇编1991-2010年的现代火灾和天气记录，以解释与公元前山区干燥森林中闪电引发的点火有关的一系列火灾天气条件。从更长远的角度来看，我们将使用我们几个世纪以来的火灾伤疤记录来测试地区内和地区之间大范围的火灾年份。我们将把我们的火灾记录与替代气候数据进行比较，以检验气候变化和历史火灾发生的影响。 最后，我们将量化20世纪火灾对公元前山地干燥森林的影响。实地调查将量化森林组成、结构和燃料在没有地面火灾的情况下发生变化的程度。火灾行为模型将用于模拟燃料负荷、气候及其相互作用的变化，最终测试它们对森林抵抗树冠火灾的影响。 4名博士、3名硕士和至少10名本科生将完整地参与这项研究。我们对火灾制度驱动因素的研究将有助于(1)预测气候变化影响下的未来火灾制度，(2)确定因排除火灾而降低弹性的景观部分，以及(3)建立优先事项和目标，以指导BC生态恢复计划、加拿大公园和加拿大野生动物服务实施的生态恢复和燃料缓解。