College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou 310058, China.
Department of Animal, Plant and Soil Sciences, La Trobe University, Melbourne Campus, Bundoora, VIC 3086, Australia.
Sci Total Environ. 2022 Jan 20;805:150372. doi: 10.1016/j.scitotenv.2021.150372. Epub 2021 Sep 16.
Wildfire has profound and pervasive consequences for forest ecosystems via directly altering soil physicochemical properties and modulating microbial community. In this study, we examined the changes in soil properties and microbial community composition and structure at different periods after highly severe wildfire events (44 plots, 113 samples) in the Chinese Great Khingan Mountains. We also separated charcoal from burnt soils to establish the relationship between microbial community structures in soils and charcoal. We found that wildfire only significantly altered bacterial and fungal β-diversity, but had no effect on microbial α-diversity across a 29-year chronosequence. The network analysis revealed that the complexity and connectivity of bacterial and fungal communities were significantly increased from 17 years after fire, compared with either unburnt soils or soils with recent fires (0-4 years after fire). Differential abundance analysis suggested that bacterial and fungal OTUs were enriched or depleted only during 0-4 years after fire compared with the unburnt soils. In addition, soil pH, dissolved organic C and dissolved organic N were key determinants of soil bacterial and fungal communities during 17-29 years after fire. The fire-derived charcoal provided a new niche for microbial colonization, and microbes colonized in the charcoal had a significantly different community structure from those of burnt soils. Our data suggest that soil bacterial and fungal communities changed significantly during the recovery from fire events in terms of the abundance and co-occurrence networks in the boreal forest ecosystems.
野火通过直接改变土壤理化性质和调节微生物群落，对森林生态系统产生深远而普遍的影响。本研究通过对中国大兴安岭高强度野火事件后不同时期（44 个样地，113 个样本）土壤性质和微生物群落组成与结构的变化进行了研究。我们还从燃烧土壤中分离出木炭，以建立土壤和木炭中微生物群落结构之间的关系。结果表明，野火仅显著改变了细菌和真菌的β多样性，但在 29 年的时间序列内对微生物的α多样性没有影响。网络分析表明，与未燃烧土壤或近期火灾土壤（火灾后 0-4 年）相比，火灾后 17 年，细菌和真菌群落的复杂性和连通性显著增加。差异丰度分析表明，与未燃烧土壤相比，细菌和真菌 OTUs 仅在火灾后 0-4 年期间被富集或耗尽。此外，土壤 pH 值、溶解性有机碳和溶解性有机氮是火灾后 17-29 年土壤细菌和真菌群落的关键决定因素。火衍生的木炭为微生物定殖提供了一个新的小生境，而在木炭中定殖的微生物与燃烧土壤中的微生物群落结构有显著差异。我们的数据表明，在北方森林生态系统中，土壤细菌和真菌群落从火灾事件的恢复过程中，在丰度和共生网络方面发生了显著变化。
