Distinct fungal and bacterial responses to fire severity and soil depth across a ten-year wildfire chronosequence in beetle-killed lodgepole pine forests
Distinct fungal and bacterial responses to fire severity and soil depth across a ten-year wildfire chronosequence in beetle-killed lodgepole pine forests
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在被甲虫杀死的黑松林中，十年野火时间序列中真菌和细菌对火灾严重程度和土壤深度的独特反应
DOI：
10.1016/j.foreco.2023.121160
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发表时间：
2023
影响因子：
3.7
通讯作者：
Glassman, Sydney I.
中科院分区：
文献类型：
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作者：
Caiafa, Marcos V.;Nelson, Amelia R.;Borch, Thomas;Roth, Holly K.;Fegel, Timothy S.;Rhoades, Charles C.;Wilkins, Michael J.;Glassman, Sydney I.
由于野火的严重性和频率越来越高，加上昆虫爆发造成的树木死亡，小杆松林受到威胁。土壤微生物群落驱动着土壤地球化学循环，并与黑松菌根共生，在这些森林面对同时发生的全球变化威胁的生存和再生能力中发挥着关键作用。土壤微生物群落如何受到火灾严重程度和土壤深度的影响，以及它们如何随着时间的推移在现有的昆虫驱动的死亡率的黑松森林中恢复仍然是一个悬而未决的问题。在这里，我们采样了两个土壤深度（0-5和5-15厘米）和各种烧伤的严重程度在南落基山脉的十年野火时序。我们使用18 S和16 S rRNA基因的qPCR来评估真菌和细菌丰度的变化，并使用ITS 2和16 S扩增子测序来评估真菌和细菌的丰度和组成。我们的研究结果表明：1）更严重的火灾导致真菌和细菌的丰度和丰富度的较大减少，2）火灾对真菌和细菌群落的影响受土壤深度的调节，在较浅的土壤中影响更严重3）真菌和细菌群落在较老的火灾中表现出丰度和物种丰富度的部分恢复，4）火灾严重性是真菌和细菌群落结构的主要驱动力，但其影响随时间而变化，5）嗜火“喜火”真菌和细菌在燃烧地块中表现出增加的丰度，特别是在最近的火灾中，和6）共生外生菌根真菌特别受到甲虫导致的树木死亡和野火的复合效应的严重打击。他们表现出一贯的低丰度和丰富度的高严重性地块，并没有随着时间的推移而恢复，和未燃烧的地块有一个depaerated外生菌根社区。
Lodgepole pine forests are under threat due to wildfires of increasing severity and frequency coupled with tree mortality from insect outbreaks. Soil microbial communities, which drive biogeochemical cycles and partner in mycorrhizal symbiosis with lodgepole pines, play critical roles in the ability of these forests to survive and regenerate in the face of simultaneous global change threats. How soil microbial communities are influenced by fire severity and soil depth and how they recover over time in lodgepole pine forests with existing insect-driven mortality remains an open question. Here, we sampled two soil depths (0–5 and 5–15 cm) and various burn severities across a ten-year wildfire chronosequence in the Southern Rocky Mountains. We used qPCR of 18S and 16S rRNA genes to assess changes in fungal and bacterial abundance and ITS2 and 16S amplicon sequencing to assess fungal and bacterial richness and composition. Our results show that: 1) higher severity fires led to larger reductions of both fungal and bacterial abundance and richness, 2) the impact of fire on fungal and bacterial communities was modulated by soil depth, with more severe impacts in shallower soils 3) both fungal and bacterial communities exhibit a partial recovery of abundance and species richness in older fires, 4) fire severity is the main driver of fungal and bacterial community structure but its effect varied across time, 5) pyrophilous “fire-loving” fungi and bacteria exhibit an increased abundance in burned plots, particularly in recent fires, and 6) symbiotic ectomycorrhizal fungi are particularly hard hit by the compound effect of the beetle-driven tree mortality and wildfires. They exhibit a consistently low abundance and richness in the high severity plots which did not recover over time, and unburned plots have a depauperated ectomycorrhizal community.