title: Habitat generalists and specialists in microbial communities across a terrestrial-freshwater gradient.
abstract: Observations of distributions of microorganisms and their differences in community composition across habitats provide evidence of biogeographical patterns. However, little is known about the processes controlling transfers across habitat gradients. By analysing the overall microbial community composition (bacteria, fungi, archaea) across a terrestrial-freshwater gradient, the aim of this study was to understand the spatial distribution patterns of populations and identify taxa capable of crossing biome borders. Barcoded 454 pyrosequencing of taxonomic gene markers was used to describe the microbial communities in adjacent soil, freshwater and sediment samples and study the role of biotic and spatial factors in shaping their composition. Few habitat generalists but a high number of specialists were detected indicating that microbial community composition was mainly regulated by species sorting and niche partitioning. Biotic interactions within microbial groups based on an association network underlined the importance of Actinobacteria, Sordariomycetes, Agaricomycetes and Nitrososphaerales in connecting among biomes. Even if dispersion seemed limited, the shore of the lake represented a transition area, allowing populations to cross the biome boundaries. In finding few broadly distributed populations, our study points to biome specialization within microbial communities with limited potential for dispersal and colonization of new habitats along the terrestrial-freshwater continuum.
authors.affiliation: Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-75007 Uppsala, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Monard
authors.affiliation: Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-75007 Uppsala, Sweden.|Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, Norbyvägen 18D, SE-75236 Uppsala, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Gantner
authors.affiliation: Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, Norbyvägen 18D, SE-75236 Uppsala, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Bertilsson
authors.affiliation: Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-75007 Uppsala, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Hallin
authors.affiliation: Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-75007 Uppsala, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Stenlid
mesh_terms: D001105:Archaea / Q000235:genetics / Q000302:isolation & purification; D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification; D017753:Ecosystem; D005618:Fresh Water / Q000382:microbiology*; D005658:Fungi / Q000235:genetics / Q000302:isolation & purification; D012988:Soil Microbiology; D014871:Water Microbiology