title: Similar processes but different environmental filters for soil bacterial and fungal community composition turnover on a broad spatial scale.
abstract: Spatial scaling of microorganisms has been demonstrated over the last decade. However, the processes and environmental filters shaping soil microbial community structure on a broad spatial scale still need to be refined and ranked. Here, we compared bacterial and fungal community composition turnovers through a biogeographical approach on the same soil sampling design at a broad spatial scale (area range: 13300 to 31000 km2): i) to examine their spatial structuring; ii) to investigate the relative importance of environmental selection and spatial autocorrelation in determining their community composition turnover; and iii) to identify and rank the relevant environmental filters and scales involved in their spatial variations. Molecular fingerprinting of soil bacterial and fungal communities was performed on 413 soils from four French regions of contrasting environmental heterogeneity (Landes<Burgundy≤Brittany<<South-East) using the systematic grid of French Soil Quality Monitoring Network to evaluate the communities' composition turnovers. The relative importance of processes and filters was assessed by distance-based redundancy analysis. This study demonstrates significant community composition turnover rates for soil bacteria and fungi, which were dependent on the region. Bacterial and fungal community composition turnovers were mainly driven by environmental selection explaining from 10% to 20% of community composition variations, but spatial variables also explained 3% to 9% of total variance. These variables highlighted significant spatial autocorrelation of both communities unexplained by the environmental variables measured and could partly be explained by dispersal limitations. Although the identified filters and their hierarchy were dependent on the region and organism, selection was systematically based on a common group of environmental variables: pH, trophic resources, texture and land use. Spatial autocorrelation was also important at coarse (80 to 120 km radius) and/or medium (40 to 65 km radius) spatial scales, suggesting dispersal limitations at these scales.
authors.affiliation: Unité Mixte de Recherche 1347 Agroécologie, Institut National de la Recherche Agronomique-AgroSup Dijon-Université de Bourgogne, Dijon, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Chemidlin Prévost-Bouré
authors.affiliation: Unité Mixte de Recherche 1347 Agroécologie-Plateforme GenoSol, Institut National de la Recherche Agronomique-AgroSup Dijon-Université de Bourgogne, Dijon, France.
authors.forename: Samuel
authors.initials: S
authors.lastname: Dequiedt
authors.affiliation: Unité Mixte de Recherche 555 Laboratoire de Biométrie et Biologie Evolutive, Université Lyon 1-Centre National de la Recherche Scientifique, Villeurbanne, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Thioulouse
authors.affiliation: Unité Mixte de Recherche 1347 Agroécologie-Plateforme GenoSol, Institut National de la Recherche Agronomique-AgroSup Dijon-Université de Bourgogne, Dijon, France.
authors.forename: Mélanie
authors.initials: M
authors.lastname: Lelièvre
authors.affiliation: Unité de Services 1106 InfoSol, Institut National de la Recherche Agronomique, Orléans, France.
authors.forename: Nicolas P A
authors.initials: NP
authors.lastname: Saby
authors.affiliation: Unité de Services 1106 InfoSol, Institut National de la Recherche Agronomique, Orléans, France.
authors.forename: Claudy
authors.initials: C
authors.lastname: Jolivet
authors.affiliation: Unité de Services 1106 InfoSol, Institut National de la Recherche Agronomique, Orléans, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Arrouays
authors.affiliation: Unité Mixte de Recherche 1347 Agroécologie-Plateforme GenoSol, Institut National de la Recherche Agronomique-AgroSup Dijon-Université de Bourgogne, Dijon, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Plassart
authors.affiliation: Unité Mixte de Recherche 1347 Agroécologie, Institut National de la Recherche Agronomique-AgroSup Dijon-Université de Bourgogne, Dijon, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Lemanceau
authors.affiliation: Unité Mixte de Recherche 1347 Agroécologie, Institut National de la Recherche Agronomique-AgroSup Dijon-Université de Bourgogne, Dijon, France; Unité Mixte de Recherche 1347 Agroécologie-Plateforme GenoSol, Institut National de la Recherche Agronomique-AgroSup Dijon-Université de Bourgogne, Dijon, France.
authors.forename: Lionel
authors.initials: L
authors.lastname: Ranjard
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics; D044822:Biodiversity; D017753:Ecosystem; D004777:Environment; D005602:France; D005658:Fungi / Q000145:classification* / Q000235:genetics; D005843:Geography; D012988:Soil Microbiology