Fenner School of Environment and Society, The Australian National University, Canberra, ACT, Australia.
College of Engineering, IT and the Environment, Research Institute for Environment and Livelihoods, Charles Darwin University, Darwin, NT, Australia.
Mol Ecol. 2022 Jan;31(2):419-447. doi: 10.1111/mec.16242. Epub 2021 Nov 7.
Billions of microorganisms perform critical below-ground functions in all terrestrial ecosystems. While largely invisible to the naked eye, they support all higher lifeforms, form symbiotic relationships with ~90% of terrestrial plant species, stabilize soils, and facilitate biogeochemical cycles. Global increases in the frequency of disturbances are driving major changes in the structure and function of forests. However, despite their functional significance, the disturbance responses of forest microbial communities are poorly understood. Here, we explore the influence of disturbance on the soil microbiome (archaea, fungi and bacteria) of some of the world's tallest and most carbon-dense forests, the Mountain Ash forests of south-eastern Australia. From 80 sites, we identified 23,277 and 19,056 microbial operational taxonomic units from the 0-10 cm and 20-30 cm depths of soil respectively. From this extensive data set, we found the diversity and composition of these often cryptic communities has been altered by human and natural disturbance events. For instance, the diversity of ectomycorrhizal fungi declined with clearcut logging, the diversity of archaea declined with salvage logging, and bacterial diversity and overall microbial diversity declined with the number of fires. Moreover, we identified key associations between edaphic (soil properties), environmental (slope, elevation) and spatial variables and the composition of all microbial communities. Specifically, we found that soil pH, manganese, magnesium, phosphorus, iron and nitrate were associated with the composition of all microbial communities. In a period of widespread degradation of global forest ecosystems, our findings provide an important and timely insight into the disturbance responses of soil microbial communities, which may influence key ecological functions.
数十亿的微生物在所有陆地生态系统中发挥着至关重要的地下功能。尽管它们肉眼不可见，但它们为所有高等生物提供支持，与约 90%的陆地植物物种形成共生关系，稳定土壤并促进生物地球化学循环。全球干扰频率的增加正在驱动森林结构和功能发生重大变化。然而，尽管它们具有重要的功能意义，但森林微生物群落对干扰的响应仍知之甚少。在这里，我们探索了干扰对世界上一些最高和最密集碳储量的森林——澳大利亚东南部的山灰林土壤微生物组（古菌、真菌和细菌）的影响。从 80 个地点，我们分别从土壤的 0-10cm 和 20-30cm 深度鉴定出了 23277 个和 19056 个微生物操作分类单元。从这个广泛的数据集中，我们发现这些通常隐匿的群落的多样性和组成已经被人类和自然干扰事件改变了。例如，外生菌根真菌的多样性随着皆伐而减少，古菌的多样性随着择伐而减少，细菌多样性和整体微生物多样性随着火灾次数的增加而减少。此外，我们还确定了土壤性质（土壤特性）、环境（坡度、海拔）和空间变量与所有微生物群落组成之间的关键关联。具体而言，我们发现土壤 pH 值、锰、镁、磷、铁和硝酸盐与所有微生物群落的组成有关。在全球森林生态系统广泛退化的时期，我们的研究结果为土壤微生物群落对干扰的响应提供了重要而及时的见解，这可能会影响关键的生态功能。
