The role of mycorrhizae and mycorrhizal networks in tree species range shifts with climate change nad disturbance

菌根和菌根网络在树种范围随着气候变化和干扰而变化的作用

• 批准号: 298271-2009
• 负责人: Simard, Suzanne
• 金额: $ 3.64万
• 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=571463
• 关键词: role; mycorrhizae; mycorrhizal; networks; tree

Tree species ranges are predicted to shift dramatically in Canada with climate change, typically with northward migration at the leading edges and extensive mortality at the trailing edges. The ability of trees to migrate will depend not only on their genetic suitability, but also the hospitability of the new environment, including the presence of compatible ectomycorrhizal fungi (EMF) in soil, the severity of site disturbance, and the intensity of plant competition. Whereas previous research predicting tree species range shifts has focused on climatic and genetic factors, my program makes the novel contribution of examining the contributing biotic effects of EMF and mycorrhizal networks (MNs) in real species migration experiments using cutting edge techniques in isotope tracers, molecular biology (metagenomics, microsatellites, and DNA sequencing) and network analysis. Across a regional drought-stress gradient serving as a spatial proxy for climate change, I will study the roles of: (1) local EMF in facilitating migration of tree genotypes to new environments; (2) MNs formed by mature trees in facilitating natural regeneration, particularly of closely related (kin) genotypes; (3) disturbance severity in reorganizing the MN and affecting natural regeneration patterns; and (4) shifting interplant carbon source-sink gradients in transfer of carbon from dying to establishing trees. For (1), I will examine the role of EMF in establishment of non-local tree genotypes within assisted migration field and growth chamber experiments. For (2) and (3), I will plant kin and non-kin seed in mesh bag treatments (controlling for the formation and complexity ot MNs) either in natural gaps or within harvesting treatments that remove different levels of hub (highly connected) trees. For (4), I will manipulate seedling carbon source-sink gradients using defoliation treatments emulating natural tree senescence. The contributions of my program on the roles and mechanisms by which EMF and MNs facilitate tree range shifts, and how these affect plant community and soil carbon dynamics, will help scientists to predict forest ecosystem responses to climate change and managers to design practices for maintaining the resilience, carbon storage, and adaptive capacity of Canada's forests.

据预测，随着气候变化，加拿大的树种范围将发生巨大变化，典型的情况是向北迁移，边缘向北迁移，而后缘则会出现广泛的死亡。树木的迁徙能力不仅取决于它们的遗传适宜性，还取决于新环境的适应性，包括土壤中是否存在相容的外生菌根真菌(EMF)、立地干扰的严重程度以及植物竞争的强度。尽管以前预测树种范围转移的研究主要集中在气候和遗传因素上，但我的项目做出了新的贡献，利用同位素示踪、分子生物学(超基因组学、微卫星和DNA测序)和网络分析方面的尖端技术，在真实物种迁移实验中检验了电动势和菌根网络(MNS)的贡献生物效应。跨越作为气候变化空间替代指标的区域干旱胁迫梯度，我将研究以下方面的作用：(1)当地动势在促进树木基因型向新环境迁移方面的作用；(2)成熟树木形成的微生物网络在促进自然再生方面的作用，尤其是与之密切相关的(KIN)基因；(3)干扰严重程度对重组微生物网络并影响自然再生模式的影响；以及(4)植物间碳源-汇梯度的变化在碳从死亡转移到成树过程中的作用。对于(1)，我将在辅助迁移场和生长室实验中检验电动势在建立非本地树木基因型别中的作用。对于(2)和(3)，我将在网袋处理中种植亲缘和非亲缘种子(控制MN的形成和复杂性)，要么是在自然林隙中，要么是在移除不同水平的中枢(高度连接)树的收获处理中。对于(4)，我将使用模拟自然树木衰老的落叶处理来操纵苗木的碳源-碳汇梯度。我的项目关于EMF和MN促进树木范围转移的作用和机制，以及这些因素如何影响植物群落和土壤碳动态，将有助于科学家预测森林生态系统对气候变化的反应，并帮助管理者设计实践，以保持加拿大森林的弹性、碳储存和适应能力。