A group of ectomycorrhizal fungi restricts organic matter accumulation in boreal forest

Abstract

Boreal forest soils are important global carbon sinks, with significant storage in the organic topsoil. Decomposition of these stocks requires oxidative enzymes, uniquely produced by fungi. Across Swedish boreal forests, we found that local carbon storage in the organic topsoil was 33% lower in the presence of a group of closely related species of ectomycorrhizal fungi - Cortinarius acutus s.l.. This observation challenges the prevailing view that ectomycorrhizal fungi generally act to increase carbon storage in soils but supports the idea that certain ectomycorrhizal fungi can complement free-living decomposers, maintaining organic matter turnover, nutrient cycling and tree productivity under nutrient-poor conditions. The indication that a narrow group of fungi may exert a major influence on carbon cycling questions the prevailing dogma of functional redundancy among microbial decomposers. Cortinarius acutus s.l. responds negatively to stand-replacing disturbance, and associated population declines are likely to increase soil carbon sequestration while impeding long-term nutrient cycling.

Keywords

carbon sequestration; decomposition; functional guilds; functional redundancy; fungal communities; metabarcoding; mor layer; nitrogen; soil; statistical modelling

Published in

Ecology Letters
2021, volume: 24, number: 7, pages: 1341-1351
Publisher: WILEY

SLU Authors

• Lindahl, Björn

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

• Kyaschenko, Julia

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

• Varenius, Kerstin

  • Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
    

• Clemmensen, Karina

  • Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
    

• Dahlberg, Anders

  • Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
    

• Karltun, Erik

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

• Stendahl, Johan

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Ecology

Publication identifier

• DOI: https://doi.org/10.1111/ele.13746

Permanent link to this page (URI)

https://res.slu.se/id/publ/111880