Forests in flux: reconstructing ecotone shifts to improve understanding of climate--vegetation feedbacks

不断变化的森林：重建生态交错带变化以提高对气候-植被反馈的理解

• 批准号: RGPIN-2019-06221
• 负责人: Dawson, Andria
• 金额: $ 1.82万
• 依托单位: Mount Royal University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=738780
• 关键词: Forests; flux; reconstructing; ecotone; shifts

Climate change is predicted to impact all sectors of the Canadian economy. The ability of society to mitigate and adapt in response to these impacts relies in part on understanding how how climate-vegetation feedbacks (CVFs) amplify or mediate climatic changes; this is a central question in global change ecology. CVFs operate at multiple timescales. Fast processes (e.g., leaf-scale carbon fluxes) operate at sub-annual timescales, while slow processes (e.g., driven by changes in forest composition and structure) occur over decadal and longer timescales. Slow processes are rarely directly observed from instrumental data. However, predictions of the future terrestrial biosphere, CVFs, and the carbon cycle depend on current understanding of these slow processes. Networks of paleoecological data, particularly sediment pollen and dendroecological data, offer the strongest observational constraints on long-term vegetation dynamics; they allow for inference about ecological processes and feedbacks. Improved understanding of slow processes that influence CVFs requires the development of new approaches that leverage paleoecological data and understanding of biosphere-atmosphere interactions. The long-term objective of this research program is to improve understanding of feedbacks between the terrestrial biosphere and the atmosphere. This proposal describes a path towards this objective via a series of scaffolded projects that increase in complexity. More specifically, my intermediary objectives in order of increasing complexity are to: (1) develop new methods to reconstruct biophysical land cover attributes from paleoecological proxy data, (2) leverage and integrate information from these biophysical reconstructions and existing methods to test hypotheses about the impacts of vegetation on climate and vice versa, (3) develop new methods to formally assimilate biophysical reconstructions into Earth System Models, and (4) develop and implement data optimization strategies to fill in paleoecological data gaps. Canada is predicted to experience some of the largest climate changes this century; Boreal forests are thought to be highly sensitive to climate disruptions. These predicted changes are forcing land managers to develop new management strategies. However, understanding of CVFs remains a critical area of uncertainty. This research program addresses the lack of understanding of the fundamental processes that govern CVFs using a modern approach to data-model integration by combining advanced quantitative methods with existing evidence and understanding. These advances will inform climate adaptation planning by providing both managers and policymakers with transformative knowledge about slow processes and their impacts on CVFs.

预计气候变化将影响加拿大经济的所有部门。社会减缓和适应这些影响的能力部分依赖于对气候-植被反馈（CVFs）如何放大或调节气候变化的理解；这是全球变化生态学的一个核心问题。cvf在多个时间尺度上运行。快速过程（如叶片尺度的碳通量）在次年时间尺度上起作用，而缓慢过程（如由森林组成和结构变化驱动的过程）在十年和更长的时间尺度上发生。从仪器数据中很少直接观察到缓慢的过程。然而，对未来陆地生物圈、CVFs和碳循环的预测取决于目前对这些缓慢过程的理解。古生态数据网络，特别是沉积物花粉和树木生态数据，为长期植被动态提供了最强的观测约束；它们允许对生态过程和反馈进行推断。要更好地了解影响CVFs的缓慢过程，就需要开发利用古生态数据和了解生物圈-大气相互作用的新方法。这项研究计划的长期目标是提高对陆地生物圈和大气之间反馈的认识。该提案描述了通过一系列增加复杂性的脚手架项目实现这一目标的路径。更具体地说，我的中介目标按照复杂性的增加顺序是：(1)开发从古生态代理数据中重建土地覆盖生物物理属性的新方法；(2)利用和整合这些生物物理重建信息和现有方法来检验植被对气候影响的假设；(3)开发将生物物理重建信息正式同化到地球系统模型中的新方法；(4)开发和实施数据优化策略以填补古生态数据空白。据预测，加拿大将在本世纪经历一些最大的气候变化；北方森林被认为对气候破坏非常敏感。这些预测的变化正迫使土地管理者制定新的管理策略。然而，对CVFs的理解仍然是一个不确定的关键领域。本研究计划通过将先进的定量方法与现有证据和理解相结合，解决了对使用现代数据模型集成方法来管理CVFs的基本过程缺乏理解的问题。这些进展将为管理者和政策制定者提供有关缓慢过程及其对CVFs影响的变革性知识，从而为气候适应规划提供信息。