title: Carbon sequestration is related to mycorrhizal fungal community shifts during long-term succession in boreal forests.
abstract: Boreal forest soils store a major proportion of the global terrestrial carbon (C) and below-ground inputs contribute as much as above-ground plant litter to the total C stored in the soil. A better understanding of the dynamics and drivers of root-associated fungal communities is essential to predict long-term soil C storage and climate feedbacks in northern ecosystems. We used 454-pyrosequencing to identify fungal communities across fine-scaled soil profiles in a 5000 yr fire-driven boreal forest chronosequence, with the aim of pinpointing shifts in fungal community composition that may underlie variation in below-ground C sequestration. In early successional-stage forests, higher abundance of cord-forming ectomycorrhizal fungi (such as Cortinarius and Suillus species) was linked to rapid turnover of mycelial biomass and necromass, efficient nitrogen (N) mobilization and low C sequestration. In late successional-stage forests, cord formers declined, while ericoid mycorrhizal ascomycetes continued to dominate, potentially facilitating long-term humus build-up through production of melanized hyphae that resist decomposition. Our results suggest that cord-forming ectomycorrhizal fungi and ericoid mycorrhizal fungi play opposing roles in below-ground C storage. We postulate that, by affecting turnover and decomposition of fungal tissues, mycorrhizal fungal identity and growth form are critical determinants of C and N sequestration in boreal forests.
authors.affiliation: Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Box 7026, SE-75007, Uppsala, Sweden.
authors.forename: Karina E
authors.initials: KE
authors.lastname: Clemmensen
authors.affiliation: Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Box 7026, SE-75007, Uppsala, Sweden.
authors.forename: Roger D
authors.initials: RD
authors.lastname: Finlay
authors.affiliation: Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Box 7026, SE-75007, Uppsala, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Dahlberg
authors.affiliation: Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Box 7026, SE-75007, Uppsala, Sweden.
authors.forename: Jan
authors.initials: J
authors.lastname: Stenlid
authors.affiliation: Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden.
authors.forename: David A
authors.initials: DA
authors.lastname: Wardle
authors.affiliation: Department of Soil and Environment, Swedish University of Agricultural Sciences, Box 7014, SE-75007, Uppsala, Sweden.
authors.forename: Björn D
authors.initials: BD
authors.lastname: Lindahl
mesh_terms: D044822:Biodiversity; D057965:Carbon Sequestration; D017753:Ecosystem; D062312:Islands; D008954:Models, Biological; D038821:Mycorrhizae / Q000502:physiology*; D010802:Phylogeny; D013045:Species Specificity; D013548:Sweden; D066188:Taiga; D013997:Time Factors
keywords: 454-sequencing; Betula pubescens; Picea abies; Pinus sylvestris; boreal forest; carbon (C) sequestration; ectomycorrhizal exploration types; mycorrhizal symbiosis