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: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=525950
• 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.

随着气候变化，预计加拿大的树种范围将发生巨大变化，通常是在前缘向北迁移，在后缘大量死亡。树木迁移的能力不仅取决于它们的遗传适宜性，还取决于新环境的适宜性，包括土壤中相容的外生菌根真菌（EMF）的存在、立地干扰的严重程度和植物竞争的强度。而以前的研究预测树种范围的变化主要集中在气候和遗传因素，我的计划作出了新颖的贡献，检查贡献生物效应的EMF和菌根网络（MN）在真实的物种迁移实验中使用尖端技术同位素示踪剂，分子生物学（宏基因组学，微卫星和DNA测序）和网络分析。通过一个区域干旱胁迫梯度作为气候变化的空间代理，我将研究：（1）当地电动势在促进树木基因型迁移到新环境中的作用;（2）由成熟树木形成的MN促进天然更新，特别是密切相关的（亲）基因型;（3）干扰强度在重组MN和影响天然更新模式中的作用;（4）从枯死到成树的碳转移过程中，改变了株间碳源-汇梯度。 对于（1），我将检查的作用，电磁场在建立非本地树木基因型内辅助迁移场和生长室实验。对于（2）和（3），我将在网袋处理（控制MN的形成和复杂性）中种植亲属和非亲属种子，无论是在自然林隙中还是在去除不同层次的枢纽（高度连接）树木的收获处理中。对于（4），我将使用模拟自然树木衰老的落叶处理来操纵幼苗碳源-汇梯度。我的程序的作用和机制的EMF和MNs促进树木范围的变化，以及这些如何影响植物群落和土壤碳动态的贡献，将有助于科学家预测森林生态系统对气候变化的反应和管理人员设计实践，以保持加拿大森林的恢复力，碳储存和适应能力。