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Research article2020Peer reviewedOpen access

Rhizosphere allocation by canopy-forming species dominates soil CO2 efflux in a subarctic landscape

Parker, Thomas C.; Clemmensen, Karina E.; Friggens, Nina L.; Hartley, Iain P.; Johnson, David; Lindahl, Bjorn D.; Olofsson, Johan; Siewert, Matthias B.; Street, Lorna E.; Subke, Jens-Arne; Wookey, Philip A.

Abstract

In arctic ecosystems, climate change has increased plant productivity. As arctic carbon (C) stocks predominantly are located belowground, the effects of greater plant productivity on soil C storage will significantly determine the net sink/source potential of these ecosystems, but vegetation controls on soil CO2 efflux remain poorly resolved.In order to identify the role of canopy-forming species in belowground C dynamics, we conducted a girdling experiment with plots distributed across 1 km(2) of treeline birch (Betula pubescens) forest and willow (Salix lapponum) patches in northern Sweden and quantified the contribution of canopy vegetation to soil CO2 fluxes and belowground productivity.Girdling birches reduced total soil CO2 efflux in the peak growing season by 53%, which is double the expected amount, given that trees contribute only half of the total leaf area in the forest. Root and mycorrhizal mycelial production also decreased substantially. At peak season, willow shrubs contributed 38% to soil CO2 efflux in their patches.Our findings indicate that C, recently fixed by trees and tall shrubs, makes a substantial contribution to soil respiration. It is critically important that these processes are taken into consideration in the context of a greening arctic because productivity and ecosystem C sequestration are not synonymous.

Keywords

Arctic; ectomycorrhizal fungi; girdling; rhizosphere; shrub expansion; soil CO2 efflux; treeline

Published in

New Phytologist
2020, Volume: 227, number: 6, pages: 1818-1830
Publisher: WILEY

      SLU Authors

      • Sustainable Development Goals

      Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss

      UKÄ Subject classification

      Ecology

      Publication identifier

      DOI: https://doi.org/10.1111/nph.16573

      Permanent link to this page (URI)

      https://res.slu.se/id/publ/105693