Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou, China.
ISME J. 2021 Jul;15(7):1943-1955. doi: 10.1038/s41396-021-00896-z. Epub 2021 Jan 29.
Although pyrogenic organic matter (PyOM) generated during wildfires plays a critical role in post-fire ecosystem recovery, the specific mechanisms by which PyOM controls soil microbial community assembly after wildfire perturbation remain largely uncharacterized. Herein we characterized the effect of PyOM on soil bacterial communities at two independent wildfire-perturbed forest sites. We observed that α-diversity of bacterial communities was the highest in wildfire-perturbed soils and that bacterial communities gradually changed along a sequence of unburnt soil → burnt soil → PyOM. The microbial communities reconstructed from unburnt soil and PyOM resembled the real bacterial communities in wildfire-perturbed soils in their α-diversity and community structure. Bacterial specialists in PyOM and soils clustered in phylogenetic coherent lineages with intra-lineage pH-niche conservatism and inter-lineage pH-niche divergence. Our results suggest that PyOM mediates bacterial community assembly in wildfire-perturbed soils by a combination of environmental selection and dispersal of phylogenetic coherent specialists with habitat preference in the heterogeneous microhabitats of burnt soils with distinct PyOM patches.
尽管野火产生的热解有机物质（PyOM）在火灾后生态系统恢复中起着关键作用，但 PyOM 控制野火干扰后土壤微生物群落组装的具体机制在很大程度上仍未得到阐明。本文我们在两个独立的受野火干扰的森林地点表征了 PyOM 对土壤细菌群落的影响。我们观察到，细菌群落的α多样性在受野火干扰的土壤中最高，并且细菌群落沿着未燃烧土壤→燃烧土壤→PyOM 的顺序逐渐变化。从未燃烧土壤和 PyOM 重建的微生物群落与受野火干扰土壤中的实际细菌群落在α多样性和群落结构上相似。PyOM 和土壤中的细菌专性生物在系统发育上一致的谱系中聚类，具有谱系内 pH 生态位保守性和谱系间 pH 生态位分化。我们的结果表明，PyOM 通过环境选择和具有栖息地偏好的系统发育一致的专性生物的扩散来介导受野火干扰土壤中的细菌群落组装，这些专性生物在具有明显 PyOM 斑块的燃烧土壤的异质小生境中具有栖息地偏好。
