Stochastic dispersal rather than deterministic selection explains the spatio-temporal distribution of soil bacteria in a temperate grassland

  • Spatial and temporal processes shaping microbial communities are inseparably linked but rarely studied together. By Illumina 16S rRNA sequencing, we monitored soil bacteria in 360 stations on a 100 square meter plot distributed across six intra-annual samplings in a rarely managed, temperate grassland. Using a multi-tiered approach, we tested the extent to which stochastic or deterministic processes influenced the composition of local communities. A combination of phylogenetic turnover analysis and null modeling demonstrated that either homogenization by unlimited stochastic dispersal or scenarios, in which neither stochastic processes nor deterministic forces dominated, explained local assembly processes. Thus, the majority of all sampled communities (82%) was rather homogeneous with no significant changes in abundance-weighted composition. However, we detected strong and uniform taxonomic shifts within just nine samples in early summer. Thus, community snapshots sampled from single points in time or space do not necessarily reflect a representative community state. The potential for change despite the overall homogeneity was further demonstrated when the focus shifted to the rare biosphere. Rare OTU turnover, rather than nestedness, characterized abundance-independent β-diversity. Accordingly, boosted generalized additive models encompassing spatial, temporal and environmental variables revealed strong and highly diverse effects of space on OTU abundance, even within the same genus. This pure spatial effect increased with decreasing OTU abundance and frequency, whereas soil moisture – the most important environmental variable – had an opposite effect by impacting abundant OTUs more than the rare ones. These results indicate that – despite considerable oscillation in space and time – the abundant and resident OTUs provide a community backbone that supports much higher β-diversity of a dynamic rare biosphere. Our findings reveal complex interactions among space, time, and environmental filters within bacterial communities in a long-established temperate grassland.

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Metadaten
Author:Tim Richter-Heitmann, Benjamin Hofner, Franz-Sebastian KrahORCiD, Johannes Sikorski, Pia K. Wüst, Boyke Bunk, Sixing Huang, Kathleen M. Regan, Doreen Berner, Runa S. Boeddinghaus, Sven Marhan, Daniel Prati, Ellen Kandeler, Jörg Overmann, Michael W. Friedrich
URN:urn:nbn:de:hebis:30:3-550394
DOI:https://doi.org/10.3389/fmicb.2020.01391
ISSN:1664-302X
Parent Title (German):Frontiers in microbiology
Publisher:Frontiers Media
Place of publication:Lausanne
Document Type:Article
Language:English
Date of Publication (online):2020/06/30
Date of first Publication:2020/06/30
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2020/07/02
Tag:community assembly; generalized additive model; soil bacteria communities; spatio-temporal analysis; variable selection
Volume:11
Issue:1391
Page Number:19
HeBIS-PPN:467140766
Institutes:Biowissenschaften / Institut für Ökologie, Evolution und Diversität
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - Namensnennung 4.0