title: Changes in fungal communities along a boreal forest soil fertility gradient.
abstract: Boreal forests harbour diverse fungal communities with decisive roles in decomposition and plant nutrition. Although changes in boreal plant communities along gradients in soil acidity and nitrogen (N) availability are well described, less is known about how fungal taxonomic and functional groups respond to soil fertility factors. We analysed fungal communities in humus and litter from 25 Swedish old-growth forests, ranging from N-rich Picea abies stands to acidic and N-poor Pinus sylvestris stands. 454-pyrosequencing of ITS2 amplicons was used to analyse community composition, and biomass was estimated by ergosterol analysis. Fungal community composition was significantly related to soil fertility at the levels of species, genera/orders and functional groups. Ascomycetes dominated in less fertile forests, whereas basidiomycetes increased in abundance in more fertile forests, both in litter and humus. The relative abundance of mycorrhizal fungi in the humus layer remained high even in the most fertile soils. Tolerance to acidity and nitrogen deficiency seems to be of greater importance than plant carbon (C) allocation patterns in determining responses of fungal communities to soil fertility, in old-growth boreal forests.
authors.affiliation: Uppsala BioCenter, Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Box 7026, Uppsala, SE-750 07, Sweden.
authors.forename: Erica
authors.initials: E
authors.lastname: Sterkenburg
authors.affiliation: Microbial Ecology, Department of Biology, Lund University, Lund, SE-223 62, Sweden.
authors.forename: Adam
authors.initials: A
authors.lastname: Bahr
authors.affiliation: Uppsala BioCenter, Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Box 7026, Uppsala, SE-750 07, Sweden.
authors.forename: Mikael
authors.initials: M
authors.lastname: Brandström Durling
authors.affiliation: Uppsala BioCenter, Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Box 7026, Uppsala, SE-750 07, Sweden.
authors.forename: Karina E
authors.initials: KE
authors.lastname: Clemmensen
authors.affiliation: Department of Soil and Environment, Swedish University of Agricultural Sciences, Box 7014, Uppsala, SE-750 07, Sweden.
authors.forename: Björn D
authors.initials: BD
authors.lastname: Lindahl
mesh_terms: D002244:Carbon / Q000032:analysis; D004875:Ergosterol / Q000378:metabolism; D005298:Fertility; D005658:Fungi / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D016014:Linear Models; D009584:Nitrogen / Q000032:analysis; D018515:Plant Leaves / Q000382:microbiology; D017422:Sequence Analysis, DNA; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D013045:Species Specificity; D066188:Taiga; D014197:Trees / Q000382:microbiology
chemical_list: D012987:Soil; D002244:Carbon; D009584:Nitrogen; D004875:Ergosterol
keywords: ecosystem fertility; ergosterol; fungal biomass; fungal communities; high-throughput sequencing; mycorrhiza