Abstract：
Soil microbial diversity mediates a wide range of key processes and ecosystem services influencing planetary health. Our knowledge of microbial biogeography patterns, spatial drivers and human impacts at the continental scale remains limited. Here, we reveal the drivers of bacterial and fungal community distribution in Australian topsoils using 1384 soil samples from diverse bioregions. Our findings highlight that climate factors, particularly precipitation and temperature, along with soil properties, are the primary drivers of topsoil microbial biogeography. Using random forest machine-learning models, we generated high-resolution maps of soil bacteria and fungi across continental Australia. The maps revealed microbial hotspots, for example, the eastern coast, southeastern coast, and west coast were dominated by Proteobacteria and Acidobacteria. Fungal distribution is strongly influenced by precipitation, with Ascomycota dominating the central region. This study also demonstrated the impact of human modification on the underground microbial community at the continental scale, which significantly increased the relative abundance of Proteobacteria and Ascomycota, but decreased Chloroflexi and Basidiomycota. The variations in microbial phyla could be attributed to distinct responses to altered environmental factors after human modifications. This study provides insights into the biogeography of soil microbiota, valuable for regional soil biodiversity assessments and monitoring microbial responses to global changes.
摘要：
土壤微生物多样性介导了影响行星健康的各种关键过程和生态系统服务。我们对微生物生物地理模式的了解，大陆尺度的空间驱动因素和人类影响仍然有限。这里,我们使用来自不同生物区域的1384个土壤样品揭示了澳大利亚表层土壤中细菌和真菌群落分布的驱动因素。我们的发现强调了气候因素，特别是降水和温度，连同土壤性质，是表土微生物生物地理学的主要驱动因素。使用随机森林机器学习模型，我们生成了澳大利亚大陆土壤细菌和真菌的高分辨率地图。地图揭示了微生物热点，例如,东海岸,东南沿海,西海岸以变形杆菌和酸性杆菌为主。真菌的分布受到降水的强烈影响，Ascomycota在中部地区占主导地位。这项研究还证明了人类修饰对大陆尺度的地下微生物群落的影响，显著增加了变形杆菌和子囊菌的相对丰度，但减少了绿氟菌和担子菌。微生物门的变化可归因于人类修饰后对改变的环境因素的不同反应。这项研究为土壤微生物群的生物地理学提供了见解，对于区域土壤生物多样性评估和监测微生物对全球变化的反应很有价值。
