Assisted migration of trees between populations as a climate change mitigation strategy for Canada's boreal forest

协助树木在种群之间迁移，作为加拿大北方森林的气候变化缓解策略

• 批准号: RGPIN-2019-06672
• 负责人: Girardin, Martin
• 金额: $ 2.7万
• 依托单位: Université du Québec à Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=746628
• 关键词: Assisted; migration; trees; between; populations

Countries have agreed that deep global net greenhouse gas (GHG) emission reductions are required to hold the increase in global average temperature to less than 2°C above pre-industrial levels. Forest-related mitigation activities have a significant role in such efforts. Notably, human-assisted movements of tree individuals between populations within species ranges (i.e. assisted gene flow) have the potential to increase atmospheric carbon removal by accelerating the rate of tree growth and increasing tree resistance and resilience to environmental and climatic stresses. In recent years, emphasis has strengthened around the utility of such activity as an adaptive measure so to maintain the health of forests in areas negatively impacted by climate change. While assisted gene flow could help to stabilize the health of these forests, it might also contribute to mitigation depending on the implications for forest carbon. Yet, there is uncertainty in this forest-related mitigation potential because a changing climate can pose negative feedback, i.e. assisted gene flow carries the risk if moved provenances remain exposed to climatic stresses to which they were not adapted.     The objectives for this research are to assess the implication of assisted gene flow on the long-term aboveground net primary productivity (NPP) of widespread conifer species in boreal Canada. This will be done by innovative use of dendroecological sampling of a network of common gardens with a process-based modeling framework in which the effects of assisted gene flow on long-term future NPP are tested. Specifically, the work will (1) Develop a retrospective analysis of the evolving NPP and its response to past climate conditions across species, populations, tree lifespan, and common gardens, (2) Find signs of local adaptation present in tree populations and (3) Assess the mitigation potential of assisted gene flow under future exposure to climate change. The hypothesis to be tested is that annual NPP, and its response to climate, exhibits a high degree of variation among populations, suggesting local adaptation and potential for mitigation. We consider forest mitigation potential as an enhancement of NPP that would result from introduction of non-local provenances, relative to a baseline where forests are managed for local provenances.     Canada will need to establish deep targets in keeping with the 2015 Paris Agreement that commits all countries to an aim of achieving a balance between global anthropogenic GHG emissions and removals in the second half of this century. Canada's large forest and its position as a major producer of harvested wood products mean that it is important to explore the potential of forest-related mitigation activities including assisted gene flow. This research will provide science based information that Canadian jurisdictions (e.g. provinces, territories) will be able to use for making informed decisions and policies concerning mitigation.

各国一致认为，需要大幅度减少全球温室气体净排放量，以将全球平均气温上升幅度控制在比工业化前水平高出2°C以下。与森林有关的减缓活动在这些努力中发挥重要作用。值得注意的是，在物种范围内的种群之间的树木个体的人类辅助移动（即辅助基因流动）有可能通过加速树木生长速度和提高树木对环境和气候压力的抵抗力和恢复力来增加大气中的碳去除。近年来，人们更加重视利用这种活动作为适应措施，以维持受气候变化不利影响地区的森林健康。虽然协助基因流动有助于稳定这些森林的健康，但也可能有助于减缓，这取决于对森林碳的影响。然而，这种与森林有关的减缓潜力存在不确定性，因为气候变化可能造成负反馈，即如果移动的种源仍然暴露在它们不适应的气候压力下，辅助基因流动就有风险。 本研究的目的是评估的影响，协助基因流的长期地上净初级生产力（NPP）的广泛分布在加拿大北部针叶树种。这将是通过创新使用的树木生态学采样网络的共同花园与一个基于过程的建模框架，在该框架中，辅助基因流的影响，对长期的未来净初级生产力进行测试。具体而言，这项工作将（1）对不断变化的NPP及其对物种，种群，树木寿命和普通花园过去气候条件的反应进行回顾性分析，（2）发现树木种群中存在的当地适应迹象，（3）评估未来暴露于气候变化下的辅助基因流的缓解潜力。有待检验的假设是，年度净初级生产力及其对气候的反应在种群之间表现出高度的差异，表明当地的适应和减缓潜力。我们认为，森林减缓潜力作为一个增强的NPP，这将导致引进非本地种源，相对于一个基线，森林管理的本地种源。 加拿大需要根据2015年《巴黎协定》制定深入的目标，该协定要求所有国家在本世纪后半叶实现全球人为温室气体排放和清除之间的平衡。加拿大森林面积大，是伐木制品的主要生产国，这意味着必须探索与森林有关的缓解活动的潜力，包括协助基因流动。这项研究将提供基于科学的信息，加拿大各管辖区（如省、地区）将能够利用这些信息做出有关缓解的知情决策和政策。