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Biogeosciences An interactive open-access journal of the European Geosciences Union
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Volume 13, issue 9
Biogeosciences, 13, 2637–2651, 2016
https://doi.org/10.5194/bg-13-2637-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Biogeosciences, 13, 2637–2651, 2016
https://doi.org/10.5194/bg-13-2637-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 04 May 2016

Research article | 04 May 2016

Impact of water table level on annual carbon and greenhouse gas balances of a restored peat extraction area

Järvi Järveoja1, Matthias Peichl2, Martin Maddison1, Kaido Soosaar1, Kai Vellak3, Edgar Karofeld3, Alar Teemusk1, and Ülo Mander1,4 Järvi Järveoja et al.
  • 1Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia
  • 2Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
  • 3Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia
  • 4Hydrosystems and Bioprocesses Research Unit, National Research Institute of Science and Technology for Environment and Agriculture (IRSTEA), Antony, France

Abstract. Peatland restoration may provide a potential after-use option to mitigate the negative climate impact of abandoned peat extraction areas; currently, however, knowledge about restoration effects on the annual balances of carbon (C) and greenhouse gas (GHG) exchanges is still limited. The aim of this study was to investigate the impact of contrasting mean water table levels (WTLs) on the annual C and GHG balances of restoration treatments with high (ResH) and low (ResL) WTL relative to an unrestored bare peat (BP) site. Measurements of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes were conducted over a full year using the closed chamber method and complemented by measurements of abiotic controls and vegetation cover. Three years following restoration, the difference in the mean WTL resulted in higher bryophyte and lower vascular plant cover in ResH relative to ResL. Consequently, greater gross primary production and autotrophic respiration associated with greater vascular plant cover were observed in ResL compared to ResH. However, the means of the measured net ecosystem CO2 exchanges (NEE) were not significantly different between ResH and ResL. Similarly, no significant differences were observed in the respective means of CH4 and N2O exchanges. In comparison to the two restored sites, greater net CO2, similar CH4 and greater N2O emissions occurred in BP. On the annual scale, ResH, ResL and BP were C sources of 111, 103 and 268 g C m−2 yr−1 and had positive GHG balances of 4.1, 3.8 and 10.2 t CO2 eq ha−1 yr−1, respectively. Thus, the different WTLs had a limited impact on the C and GHG balances in the two restored treatments 3 years following restoration. However, the C and GHG balances in ResH and ResL were considerably lower than in BP due to the large reduction in CO2 emissions. This study therefore suggests that restoration may serve as an effective method to mitigate the negative climate impacts of abandoned peat extraction areas.

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Restoration is suggested as a strategy to reduce the large greenhouse gas (GHG) emissions from abandoned peat extraction areas. This study investigated GHG fluxes in restored sites with high and low water table level in comparison to a bare peat area. The results show that on the annual scale, both restored sites acted as similar GHG sources 3 years after restoration. However, their net GHG emissions were only half of those from the bare peat area, indicating considerable mitigation potential.
Restoration is suggested as a strategy to reduce the large greenhouse gas (GHG) emissions from...
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