Vascular plant-mediated controls on atmospheric carbon assimilation and peat carbon decomposition under climate change

TY - JOUR

T1 - Vascular plant-mediated controls on atmospheric carbon assimilation and peat carbon decomposition under climate change

AU - Gavazov, Konstantin

AU - Albrecht, Remy

AU - Buttler, Alexandre

AU - Dorrepaal, Ellen

AU - Garnett, Mark H.

AU - Gogo, Sebastien

AU - Hagedorn, Frank

AU - Mills, Robert T.E.

AU - Robroek, Bjorn J.M.

AU - Bragazza, Luca

PY - 2018/9/1

Y1 - 2018/9/1

N2 - Climate change can alter peatland plant community composition by promoting the growth of vascular plants. How such vegetation change affects peatland carbon dynamics remains, however, unclear. In order to assess the effect of vegetation change on carbon uptake and release, we performed a vascular plant-removal experiment in two Sphagnum-dominated peatlands that represent contrasting stages of natural vegetation succession along a climatic gradient. Periodic measurements of net ecosystem CO2 exchange revealed that vascular plants play a crucial role in assuring the potential for net carbon uptake, particularly with a warmer climate. The presence of vascular plants, however, also increased ecosystem respiration, and by using the seasonal variation of respired CO2 radiocarbon (bomb-14C) signature we demonstrate an enhanced heterotrophic decomposition of peat carbon due to rhizosphere priming. The observed rhizosphere priming of peat carbon decomposition was matched by more advanced humification of dissolved organic matter, which remained apparent beyond the plant growing season. Our results underline the relevance of rhizosphere priming in peatlands, especially when assessing the future carbon sink function of peatlands undergoing a shift in vegetation community composition in association with climate change.

AB - Climate change can alter peatland plant community composition by promoting the growth of vascular plants. How such vegetation change affects peatland carbon dynamics remains, however, unclear. In order to assess the effect of vegetation change on carbon uptake and release, we performed a vascular plant-removal experiment in two Sphagnum-dominated peatlands that represent contrasting stages of natural vegetation succession along a climatic gradient. Periodic measurements of net ecosystem CO2 exchange revealed that vascular plants play a crucial role in assuring the potential for net carbon uptake, particularly with a warmer climate. The presence of vascular plants, however, also increased ecosystem respiration, and by using the seasonal variation of respired CO2 radiocarbon (bomb-14C) signature we demonstrate an enhanced heterotrophic decomposition of peat carbon due to rhizosphere priming. The observed rhizosphere priming of peat carbon decomposition was matched by more advanced humification of dissolved organic matter, which remained apparent beyond the plant growing season. Our results underline the relevance of rhizosphere priming in peatlands, especially when assessing the future carbon sink function of peatlands undergoing a shift in vegetation community composition in association with climate change.

KW - climate warming

KW - decomposition

KW - ecosystem respiration

KW - elevation gradient

KW - net ecosystem CO exchange

KW - peatlands

KW - rhizosphere priming

KW - vascular plant biomass

UR - http://www.scopus.com/inward/record.url?scp=85045388497&partnerID=8YFLogxK

U2 - 10.1111/gcb.14140

DO - 10.1111/gcb.14140

M3 - Article

C2 - 29569798

AN - SCOPUS:85045388497

SN - 1354-1013

VL - 24

SP - 3911

EP - 3921

JO - Global Change Biology

JF - Global Change Biology

IS - 9

ER -