Rare biosphere represents the majority of Earth's biodiversity and performs vital ecological functions, yet little is known about its biogeographical patterns and community assembly processes in terrestrial ecosystems. Herein, we investigated the community composition and phylogeny of rare (relative abundance <0.1%) and abundant (>1%) bacteria in dryland grassland soils on the Tibetan Plateau. Results revealed similar biogeographical patterns of rare and abundant bacteria at both compositional and phylogenetic levels, but rare subcommunity was more heavily influenced by stochasticity (72%) than the abundant (57%). The compositional variation of rare bacteria was less explained by environmental factors (41%) than that of the abundant (80%), while the phylogeny of rare bacteria (36%) was more explained than that of the abundant (29%). The phylogeny of rare bacteria was equally explained by local factors (soil and vegetation) and geospatial distance (11.5% and 11.9% respectively), while that of the abundant was more explained by geospatial distance (22.1%) than local factors (11.3%). Furthermore, a substantially tighter connection between the community phylogeny and composition was observed in rare (R ² = 0.65) than in abundant bacteria (R ² = 0.08). Our study provides novel insights into the assembly processes and biographical patterns of rare and abundant bacteria in dryland soils.

中文翻译：

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不同的组装机制是青藏高原草原土壤中稀有细菌和丰富细菌的相似生物地理模式的基础。

稀有的生物圈代表了地球生物多样性的绝大部分，并发挥着至关重要的生态功能，但对其地球地理生态系统中的生物地理模式和社区聚集过程知之甚少。在这里，我们调查了青藏高原旱地草地土壤中稀有细菌（相对丰度<0.1％）和丰富细菌（> 1％）的群落组成和系统发育。结果显示，在组成和系统发育水平上，稀有细菌和丰富细菌的生物地理模式相似，但是稀有亚社区受随机性的影响较大（72％），而不是丰富性（57％）。稀有细菌的组成变异较少受环境因素（41％）的解释，而不是富裕物种（80％）的解释，而稀有细菌的系统发育（36％）比富裕细菌（29％）的系统发生原因更多。稀有细菌的系统发生由局部因素（土壤和植被）和地理空间距离（分别为11.5％和11.9％）解释相同，而丰富细菌的系统发生由地理空间距离（22.1％）比局部因素（11.3％）解释得更多。 。此外，在稀有物种中，观察到群落系统发育与组成之间的紧密联系R ² = 0.65），而不是丰富的细菌（R ² = 0.08）。我们的研究为干旱地区土壤中稀有细菌和丰富细菌的组装过程和传记模式提供了新颖的见解。