Drought alters carbon fluxes in alpine snowbed ecosystems through contrasting impacts on graminoids and forbs

David Johnson, Jeremie Vachon, Andrea J. Britton, Rachel C. Helliwell

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Climate change is predicted to increase the frequency of drought events in alpine ecosystems with the potential to affect carbon turnover.

We removed intact turfs from a Nardus stricta alpine snowbed community and subjected half of them to two drought events of 8 d duration under controlled conditions. Leachate dissolved organic carbon (DOC) was measured throughout the 6 wk study period, and a 13CO2 pulse enabled quantification of fluxes of recent assimilate into shoots, roots and leachate and ecosystem CO2 exchange.

The amount of DOC in leachate from droughted cores was 62% less than in controls. Drought reduced graminoid biomass, increased forb biomass, had no effect on bryophytes, and led to an overall decrease in total above-ground biomass compared with controls. Net CO2 exchange, gross photosynthesis and the amount of 13CO2 fixed were all significantly less in droughted turfs. These turfs also retained proportionally more 13C in shoots, allocated less 13C to roots, and the amount of dissolved organic 13C recovered in leachate was 57% less than in controls.

Our data show that drought events can have significant impacts on ecosystem carbon fluxes, and that the principal mechanism behind this is probably changes in the relative abundance of forbs and grasses.

Original languageEnglish
Pages (from-to)740-749
Number of pages10
JournalNew Phytologist
Volume190
Issue number3
Early online date19 Jan 2011
DOIs
Publication statusPublished - 2011

Keywords

  • 13CO(2)
  • climate change
  • dissolved organic carbon
  • leachate
  • Nardus stricta
  • net CO2 exchange
  • plant diversity
  • upland grassland
  • phenol oxidase
  • soil
  • vegetation
  • decomposition
  • mycorrhiza
  • litter
  • plant
  • peatlands

Cite this

Drought alters carbon fluxes in alpine snowbed ecosystems through contrasting impacts on graminoids and forbs. / Johnson, David; Vachon, Jeremie; Britton, Andrea J.; Helliwell, Rachel C.

In: New Phytologist, Vol. 190, No. 3, 2011, p. 740-749.

Research output: Contribution to journalArticle

Johnson, David ; Vachon, Jeremie ; Britton, Andrea J. ; Helliwell, Rachel C. / Drought alters carbon fluxes in alpine snowbed ecosystems through contrasting impacts on graminoids and forbs. In: New Phytologist. 2011 ; Vol. 190, No. 3. pp. 740-749.
@article{5ab5123a26a3461c87d9dc9d3309eb9d,
title = "Drought alters carbon fluxes in alpine snowbed ecosystems through contrasting impacts on graminoids and forbs",
abstract = "Climate change is predicted to increase the frequency of drought events in alpine ecosystems with the potential to affect carbon turnover. We removed intact turfs from a Nardus stricta alpine snowbed community and subjected half of them to two drought events of 8 d duration under controlled conditions. Leachate dissolved organic carbon (DOC) was measured throughout the 6 wk study period, and a 13CO2 pulse enabled quantification of fluxes of recent assimilate into shoots, roots and leachate and ecosystem CO2 exchange. The amount of DOC in leachate from droughted cores was 62{\%} less than in controls. Drought reduced graminoid biomass, increased forb biomass, had no effect on bryophytes, and led to an overall decrease in total above-ground biomass compared with controls. Net CO2 exchange, gross photosynthesis and the amount of 13CO2 fixed were all significantly less in droughted turfs. These turfs also retained proportionally more 13C in shoots, allocated less 13C to roots, and the amount of dissolved organic 13C recovered in leachate was 57{\%} less than in controls. Our data show that drought events can have significant impacts on ecosystem carbon fluxes, and that the principal mechanism behind this is probably changes in the relative abundance of forbs and grasses.",
keywords = "13CO(2), climate change, dissolved organic carbon, leachate, Nardus stricta, net CO2 exchange, plant diversity, upland grassland, phenol oxidase, soil, vegetation, decomposition, mycorrhiza, litter, plant, peatlands",
author = "David Johnson and Jeremie Vachon and Britton, {Andrea J.} and Helliwell, {Rachel C.}",
year = "2011",
doi = "10.1111/j.1469-8137.2010.03613.x",
language = "English",
volume = "190",
pages = "740--749",
journal = "New Phytologist",
issn = "0028-646X",
publisher = "Wiley/Blackwell (10.1111)",
number = "3",

}

TY - JOUR

T1 - Drought alters carbon fluxes in alpine snowbed ecosystems through contrasting impacts on graminoids and forbs

AU - Johnson, David

AU - Vachon, Jeremie

AU - Britton, Andrea J.

AU - Helliwell, Rachel C.

PY - 2011

Y1 - 2011

N2 - Climate change is predicted to increase the frequency of drought events in alpine ecosystems with the potential to affect carbon turnover. We removed intact turfs from a Nardus stricta alpine snowbed community and subjected half of them to two drought events of 8 d duration under controlled conditions. Leachate dissolved organic carbon (DOC) was measured throughout the 6 wk study period, and a 13CO2 pulse enabled quantification of fluxes of recent assimilate into shoots, roots and leachate and ecosystem CO2 exchange. The amount of DOC in leachate from droughted cores was 62% less than in controls. Drought reduced graminoid biomass, increased forb biomass, had no effect on bryophytes, and led to an overall decrease in total above-ground biomass compared with controls. Net CO2 exchange, gross photosynthesis and the amount of 13CO2 fixed were all significantly less in droughted turfs. These turfs also retained proportionally more 13C in shoots, allocated less 13C to roots, and the amount of dissolved organic 13C recovered in leachate was 57% less than in controls. Our data show that drought events can have significant impacts on ecosystem carbon fluxes, and that the principal mechanism behind this is probably changes in the relative abundance of forbs and grasses.

AB - Climate change is predicted to increase the frequency of drought events in alpine ecosystems with the potential to affect carbon turnover. We removed intact turfs from a Nardus stricta alpine snowbed community and subjected half of them to two drought events of 8 d duration under controlled conditions. Leachate dissolved organic carbon (DOC) was measured throughout the 6 wk study period, and a 13CO2 pulse enabled quantification of fluxes of recent assimilate into shoots, roots and leachate and ecosystem CO2 exchange. The amount of DOC in leachate from droughted cores was 62% less than in controls. Drought reduced graminoid biomass, increased forb biomass, had no effect on bryophytes, and led to an overall decrease in total above-ground biomass compared with controls. Net CO2 exchange, gross photosynthesis and the amount of 13CO2 fixed were all significantly less in droughted turfs. These turfs also retained proportionally more 13C in shoots, allocated less 13C to roots, and the amount of dissolved organic 13C recovered in leachate was 57% less than in controls. Our data show that drought events can have significant impacts on ecosystem carbon fluxes, and that the principal mechanism behind this is probably changes in the relative abundance of forbs and grasses.

KW - 13CO(2)

KW - climate change

KW - dissolved organic carbon

KW - leachate

KW - Nardus stricta

KW - net CO2 exchange

KW - plant diversity

KW - upland grassland

KW - phenol oxidase

KW - soil

KW - vegetation

KW - decomposition

KW - mycorrhiza

KW - litter

KW - plant

KW - peatlands

U2 - 10.1111/j.1469-8137.2010.03613.x

DO - 10.1111/j.1469-8137.2010.03613.x

M3 - Article

VL - 190

SP - 740

EP - 749

JO - New Phytologist

JF - New Phytologist

SN - 0028-646X

IS - 3

ER -