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Research article - Peer-reviewed, 2015

Carbon sequestration is related to mycorrhizal fungal community shifts during long-term succession in boreal forests

Clemmensen, Karina Engelbrecht; Finlay, Roger; Dahlberg, Anders; Stenlid, Jan; Wardle, David; Lindahl, Björn

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 5000yr 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.See also the Commentary by Christopher W. Fernandez and Peter G. Kennedy

Keywords

454-sequencing; Betula pubescens; boreal forest; carbon (C) sequestration; ectomycorrhizal exploration types; mycorrhizal symbiosis; Picea abies; Pinus sylvestris

Published in

New Phytologist
2015, Volume: 205, number: 4, pages: 1525-1536
Publisher: WILEY-BLACKWELL