Jia Xiu, Dini-Andreote Francisco, Salles Joana Falcão
Microbial Ecology Cluster, Genomics Research in Ecology and Evolution in Nature (GREEN), Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, 9747AG, The Netherlands.
Department of Plant Science, The Pennsylvania State University, Pennsylvania, University Park, PA, 16801, USA.
ISME Commun. 2022 Oct 3;2(1):96. doi: 10.1038/s43705-022-00177-6.
Most ecological communities harbor many rare species (i.e., the rare biosphere), however, relatively little is known about how distinct ecological processes structure their existence. Here, we used spatiotemporal data on soil bacterial communities along a natural ecosystem gradient to model the relative influences of assembly processes structuring the rare and common biospheres. We found a greater influence of homogeneous selection (i.e., imposed by spatiotemporally constant variables) mediating the assembly of the rare biosphere, whereas the common biosphere was mostly governed by variable selection (i.e., imposed by spatial and/or temporal fluctuating variables). By partitioning the different types of rarity, we found homogeneous selection to explain the prevalence of permanently rare taxa, thus suggesting their persistence at low abundances to be restrained by physiological traits. Conversely, the dynamics of conditionally rare taxa were mostly structured by variable selection, which aligns with the ability of these taxa to switch between rarity and commonness as responses to environmental spatiotemporal variations. Taken together, our study contributes to the establishment of a link between conceptual and empirical developments in the ecology of the soil microbial rare biosphere. Besides, this study provides a framework to better understand, model, and predict the existence and dynamics of microbial rare biospheres across divergent systems and scales.
大多数生态群落都包含许多稀有物种（即稀有生物圈），然而，对于不同的生态过程如何构建它们的存在，我们了解得相对较少。在这里，我们利用沿自然生态系统梯度的土壤细菌群落的时空数据，来模拟构建稀有和常见生物圈的组装过程的相对影响。我们发现，均匀选择（即由时空恒定变量施加）对稀有生物圈的组装有更大影响，而常见生物圈主要受可变选择（即由空间和/或时间波动变量施加）的支配。通过划分不同类型的稀有性，我们发现均匀选择可以解释永久稀有分类群的普遍存在，这表明它们在低丰度下的持续存在受到生理特征的限制。相反，条件性稀有分类群的动态主要由可变选择构建，这与这些分类群作为对环境时空变化的响应在稀有性和常见性之间切换的能力相一致。总之，我们的研究有助于在土壤微生物稀有生物圈生态学的概念发展和实证发展之间建立联系。此外，本研究提供了一个框架，以更好地理解、建模和预测不同系统和尺度上微生物稀有生物圈的存在和动态。
