Ice Storm Mycorrhizal Fungi data for Yancey et al. in press

Extreme weather events, such as ice storms, are increasing and have potentially large impacts on forests, including belowground structures such as fine roots and mycorrhizal fungi. Many forest trees rely on the mutualistic relationship between mycorrhizal fungi and plants; a relationship that when disrupted can negatively impact tree net primary productivity. We took advantage of a large-scale ice storm manipulation in the northeastern United States (US) to test the hypothesis that increasing ice storm intensity and frequency would reduce ectomycorrhizal fungal root tips per unit root length and arbuscular mycorrhizal fungal structures per unit root length, hereafter colonization. We found that ice storm intensity reduced spring ectomycorrhizal fungal and arbuscular mycorrhizal fungal colonization. However, these patterns changed in the fall where ice storm intensity still reduced ectomycorrhizal fungal root tips, but arbuscular mycorrhizal fungal colonization was higher in ice storm treatments than controls. The amount of ectomycorrhizal fungal root tips and arbuscular mycorrhizal fungal colonization differed seasonally: ectomycorrhizal fungal root tips were 1.7× higher in the spring than in the fall, while arbuscular mycorrhizal fungal colonization was 3× higher in the fall than in the spring. Our results indicate that mycorrhizal fungal colonization responses to ice storm severity vary temporally and by mycorrhizal fungal type. Further, arbuscular mycorrhizal fungi may recover from ice storms relatively quickly, potentially aiding forests in their recovery, whereas ice storms may have a longer lasting impact on ectomycorrhizal fungi.

极端天气事件（如冰风暴）的发生频率正逐年上升，且会对森林生态系统造成潜在的显著影响，其中包括地下结构，如细根与菌根真菌（mycorrhizal fungi）。多数林木依赖菌根真菌与植物之间的互利共生关系；一旦该关系遭到破坏，林木的净初级生产力便会受到负面影响。本研究依托美国东北部开展的大规模冰风暴操控实验，检验了如下假说：冰风暴强度与频率的提升，会降低单位根长的外生菌根真菌（ectomycorrhizal fungal）根尖数量与丛枝菌根真菌（arbuscular mycorrhizal fungal）结构丰度，下文统称为菌根定殖率。研究结果显示，冰风暴强度的提升会降低春季的外生菌根真菌与丛枝菌根真菌定殖率。但秋季的变化模式存在差异：冰风暴强度仍会降低外生菌根真菌根尖数量，而冰风暴处理组的丛枝菌根真菌定殖率却显著高于对照组。外生菌根真菌根尖数量与丛枝菌根真菌定殖率均存在显著的季节差异：春季的外生菌根真菌根尖数量较秋季高出1.7倍，而秋季的丛枝菌根真菌定殖率较春季高出3倍。本研究结果表明，菌根真菌定殖率对冰风暴强度的响应存在时间动态差异，且因菌根真菌类群的不同而有所区别。此外，丛枝菌根真菌可相对快速地从冰风暴扰动中恢复，或可助力森林生态系统的灾后修复；而冰风暴对外生菌根真菌的影响则可能更为持久。