Impacts of Paleoclimatic Change and Disturbance on Past Ecosystem Dynamics and Peatland Carbon Accumulation

古气候变化和干扰对过去生态系统动态和泥炭地碳积累的影响

• 批准号: RGPIN-2020-03913
• 负责人: Lacourse, Terri
• 金额: $ 2.62万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=716565
• 关键词: Impacts; Paleoclimatic; Change; Disturbance; Past

Effective management of Canada's forest, lake and wetland resources requires long-term environmental monitoring. However, the impacts of climate change and disturbance extend over longer timescales than can be detected using real-time, direct observations. In addition, limited temporal perspectives can lead to ineffective management approaches with unanticipated consequences as new climate and disturbance regimes arise. Sedimentary archives from lakes and wetlands extend the temporal record by providing information on the effects of environmental change over decades, centuries and millennia. Understanding longer-term impacts is essential for setting realistic resource management goals that incorporate knowledge of natural ranges of variability, how ecosystems function under changing environmental conditions, and potential responses to ongoing and future change. The main objective of this research program is to determine the roles that climate and disturbance play in the long-term development and dynamics of ecosystems, with emphasis on forests, lakes and wetlands in Pacific Canada. Our approach relies on analyses of lake sediments and wetland deposits, which provide a long-term perspective that is not possible through direct observation of the modern environment. We use the sedimentological, chemical and biological composition of these sedimentary archives to track past ecosystem changes, identify past disturbance events such as forest fires, and determine ecosystem responses to changes in climate and disturbance regimes. Over the next five years, our research will concentrate on two focal points. We will determine the role of past changes in climate and fire regimes on forest composition, structure and function through analysis of fossil pollen and charcoal preserved in lake sediments. This will allow us to quantify natural changes in fire frequency and severity, to clarify the consequences of climate change for forests, and to identify potential analogues for predicting future responses as forests and fire regimes re-organize as climate changes. We will also investigate the impacts of past changes in climate on wetlands and their thick deposits of peat, which are important sinks and sources of carbon dioxide and methane. Peatlands play an important role in the global carbon cycle and have the potential to both mitigate and enhance global climate change through greenhouse gas storage and release. Our research will focus on improving our understanding of how peatlands form and the influence of past climate change on their long-term carbon accumulation. This will help strengthen predictions of peatland carbon storage and release under different climate change scenarios. Determining how forests and peatlands responded to past changes in climate and disturbance is vital for understanding the consequences of environmental change for Canada's natural resources and for guiding national forest and wetland management policies.

加拿大森林、湖泊和湿地资源的有效管理需要长期的环境监测。然而，气候变化和干扰的影响持续的时间比使用实时、直接观测所能检测到的时间尺度更长。此外，有限的时间视角可能导致无效的管理方法，随着新的气候和干扰制度的出现，可能会产生意想不到的后果。来自湖泊和湿地的沉积档案通过提供有关数十年、数百年和数千年环境变化影响的信息，扩展了时间记录。了解长期影响对于制定现实的资源管理目标至关重要，这些目标包括自然变化范围的知识、生态系统在不断变化的环境条件下如何运作以及对正在进行的和未来的变化的潜在反应。 这项研究计划的主要目标是确定气候和干扰在生态系统的长期发展和动态中所起的作用，重点是加拿大太平洋地区的森林、湖泊和湿地。我们的方法依赖于对湖泊沉积物和湿地沉积物的分析，这些分析提供了一个长期的视角，而通过直接观察现代环境是不可能的。我们使用这些沉积档案的沉积学、化学和生物成分来追踪过去的生态系统变化，识别过去的干扰事件，如森林火灾，并确定生态系统对气候和干扰制度变化的反应。 未来五年，我们的研究将集中在两个重点上。我们将通过分析保存在湖泊沉积物中的化石花粉和木炭来确定过去气候和火灾制度的变化对森林组成、结构和功能的影响。这将使我们能够量化火灾频率和严重程度的自然变化，澄清气候变化对森林的后果，并确定潜在的类似物，用于预测未来随着气候变化而重新组织的森林和火灾制度的反应。我们还将调查过去气候变化对湿地及其厚厚的泥炭沉积的影响，这些泥炭是二氧化碳和甲烷的重要汇和来源。泥炭地在全球碳循环中发挥着重要作用，并具有通过储存和释放温室气体来缓解和加强全球气候变化的潜力。我们的研究将集中于提高我们对泥炭地如何形成以及过去气候变化对其长期碳积累的影响的理解。这将有助于加强对不同气候变化情景下泥炭地碳储存和释放的预测。 确定森林和泥炭地如何应对过去的气候变化和干扰，对于了解环境变化对加拿大自然资源的影响以及指导国家森林和湿地管理政策至关重要。