Understanding the coupled response of vegetation and fire to climatic variation since the Last Glacial Maximum

詹妮弗·马龙博士被授予美国国家科学基金会地球科学博士后奖学金，在威斯康星大学麦迪逊分校开展研究和教育计划。马龙博士将使用古环境数据和一个动态的全球植被-火模型来研究过去气候变化对火-植被相互作用的影响。她将首先对湖泊沉积物中的木炭和花粉数据进行荟萃分析，以重建区域到大陆尺度上百年至千年尺度的火灾和植被变化模式。然后，将使用一个尖端的、具有火功能的动态全球植被模型来模拟与今天(即6000年和21000年前)非常不同的气候条件下的古火活动。木炭和花粉分析的结果将通过数据模型比较来评估模型性能。最后，综合和数据模型比较的结果将被用来设计和实施植被-火灾耦合模型的敏感性实验。这些实验的目的将是促进我们对气候和植被如何控制火情，以及植被和火对未来潜在气候变化的反应范围的理解。全球变暖对植被和野火的可能影响在很大程度上是未知的。然而，我们知道，预计的气候变化将对生态系统动力学产生重大后果，包括干扰制度，特别是火灾制度变化的反馈将影响全球生物地球化学循环以及大气化学和物理。这种后果反过来威胁到生态系统服务，例如提供清洁的空气和水，从而威胁到人类的健康和生计。古火记录表明，火制度对气候变化高度敏感，特别是当变化突然时，无论变化的方向如何。这项研究将提高我们对火灾过程中自然变化的理解，从而提高我们模拟未来火灾变化的能力。研究结果还将为生态学家和自然资源管理者提供北美当前火灾制度变化的关键背景。与这项研究相关的外联和教育活动包括开发标准化和综合的过去火灾和植被变化数据集，将在公共网站上向更广泛的社区提供。马龙博士还将为主办机构的本科生和毕业生开发有关火灾、古生态学和古气候学的课程材料。

Dr. Jennifer Marlon is awarded an NSF Earth Sciences Postdoctoral Fellowship to carry out a research and education plan at the University of Wisconsin - Madison. Dr. Marlon will use paleoenvironmental data and a dynamic global vegetation-fire model to study past climate change impacts on fire-vegetation interactions. She will first conduct meta-analyses of charcoal and pollen data from lake sediments to reconstruct centennial- to millennial-scale patterns of fire and vegetation change at regional to continental scales. A cutting-edge, fire-enabled dynamic global vegetation model will then be used to simulate paleofire activity under climate conditions very different from today (i.e., 6000 and 21,000 years ago). Results from the charcoal and pollen analyses will be used to assess model performance through data-model comparisons. Finally, results from the synthesis and data-model comparison will be used to design and implement sensitivity experiments with the coupled vegetation-fire model. The aim of the experiments will be to advance our understanding of how climate and vegetation control fire regimes, and of the range of responses in vegetation and fire to potential future climate changes.The likely impacts of global warming on vegetation and wildfires at broad spatial scales are largely unknown. Yet, we know that projected climate changes will have major consequences for ecosystem dynamics, including disturbance regimes, and that feedbacks from changing fire regimes in particular will affect global biogeochemical cycles, as well as atmospheric chemistry and physics. Such consequences, in turn, threaten ecosystem services, such as the provisioning of clean air and water, and thus human health and livelihoods. Paleofire records indicate that fire regimes are highly sensitive to climate changes, particularly when the changes are abrupt, and regardless of the direction of change. This research will improve our understanding of natural variability in fire regimes and thus improve our ability to model future changes in fire. Results will also provide ecologists and natural resource managers with critical context for current fire-regime changes in North America. Outreach and education activities associated with this research include the development of standardized and integrated datasets of past fire and vegetation changes that will be made available to the broader community on a public website. Dr. Marlon will also develop course material on fire, paleoecology and paleoclimatology for undergraduates and graduates at the host institution.