Contrasting Diversity Patterns of Crenarchaeal, Bacterial and Fungal Soil Communities in an Alpine Landscape

Lucie Zinger,Serge Aubert,Philippe Choler,Florence Baptist,Abderrahim Bouasria,Roberto A Geremia,David P H Lejon,Jack Anthony Gilbert

doi:10.1371/journal.pone.0019950

Abstract

BackgroundThe advent of molecular techniques in microbial ecology has aroused interest in gaining an understanding about the spatial distribution of regional pools of soil microbes and the main drivers responsible of these spatial patterns. Here, we assessed the distribution of crenarcheal, bacterial and fungal communities in an alpine landscape displaying high turnover in plant species over short distances. Our aim is to determine the relative contribution of plant species composition, environmental conditions, and geographic isolation on microbial community distribution.Methodology/Principal FindingsEleven types of habitats that best represent the landscape heterogeneity were investigated. Crenarchaeal, bacterial and fungal communities were described by means of Single Strand Conformation Polymorphism. Relationships between microbial beta diversity patterns were examined by using Bray-Curtis dissimilarities and Principal Coordinate Analyses. Distance-based redundancy analyses and variation partitioning were used to estimate the relative contributions of different drivers on microbial beta diversity. Microbial communities tended to be habitat-specific and did not display significant spatial autocorrelation. Microbial beta diversity correlated with soil pH. Fungal beta-diversity was mainly related to soil organic matter. Though the effect of plant species composition was significant for all microbial groups, it was much stronger for Fungi. In contrast, geographic distances did not have any effect on microbial beta diversity.Conclusions/SignificanceMicrobial communities exhibit non-random spatial patterns of diversity in alpine landscapes. Crenarcheal, bacterial and fungal community turnover is high and associated with plant species composition through different set of soil variables, but is not caused by geographical isolation.

Highlights

Microorganisms play a key role in biogeochemical cycling and ecosystem functioning [1,2]
Microbial communities were characterized by means of Capillary Electrophoresis Single Strand Conformation Polymorphism (CE-SSCP) based on rRNA genes. Based on this data set, we addressed the following questions: (i) How do archaeal, bacterial and fungal soil communities change across this alpine landscape? (ii) What are the relative contribution of plant community composition, environmental conditions, and geographic isolation on microbial beta diversity patterns? (iii) Do the three microbial domains respond to these environmental drivers?
Annual radiations (Arad), live phytomass covaried with plant community composition

Summary

Introduction

Microorganisms play a key role in biogeochemical cycling and ecosystem functioning [1,2]. Understanding and predicting the spatial distribution patterns of microbial communities is crucial to anticipate ecosystem responses to global changes [2] These questions are extensively addressed for macro-organisms [3], microbial biogeography gained renewed interest only recently with the advent of molecular tools. Based on these molecular techniques, some studies provided evidence for habitat determinism (e.g. salinity, pH) on microbial community distribution regardless of geographic location [4,5] This support the BaasBecking hypothesis ‘‘everything is everywhere, but, the environment selects’’ [6], which assumes large dispersal potential and low extinction rate for microbes. Our aim is to determine the relative contribution of plant species composition, environmental conditions, and geographic isolation on microbial community distribution

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Conclusion