Volume 21 (2018) Article 24
Greenhouse gas emissions from two rewetted peatlands previously managed for forestry
by C. Rigney, D. Wilson, F. Renou-Wilson, C. Müller, G. Moser and K.A. Byrne
Published online: 16.12.2018
The aim of this study was to investigate the controls on carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) dynamics on a blanket bog (at Pollagoona) and a raised bog (at Scohaboy) in Ireland after felling of plantation forestry and rewetting, and to produce annual balances for each gas at both sites. Gas fluxes were measured during a twelve-month period using the chamber method. Microsite types reflecting the dominant plant species at the chamber plots were identified and classified as Eriophorum-Sphagnum, Cladonia-Calluna and Molinia at Pollagoona and Eriophorum-Sphagnum, Cladonia-mosses, Eriophorum and brash (logging residues) at Scohaboy. The relationships between gas fluxes and environmental variables were assessed, and regression models were used to estimate annual CO2 and CH4 gas balances for each microsite type. Annual estimates of N2O exchange were calculated using seasonal means. Over the course of the study both sites acted as CO2 and CH4 sources. Although Pollagoona was an overall net source of CO2-C (131.6 ± 298.3 g m-2 yr-1), one microsite type (Cladonia-Calluna) acted as a strong sink for CO2-C (-142.8 g m-2 yr-1). Molinia microsites exhibited the highest CH4-C emissions (2.53 ± 1.01 g m-2 yr-1). Nitrous oxide emissions at Pollagoona were calculated as 12 ?g m-2 yr-1. Scohaboy acted as a large CO2-C source (585.3 ± 241.5 g m-2 yr-1) (all microsite types) despite re-vegetation of non-brash plots, due to the availability of fresh organic matter across the site. Scohaboy was also a CH4-C source, emitting 3.25 ± 0.58 g m-2 yr-1. Emissions of both CO2-C (819.31 ± 57.7 g m-2 yr-1) and CH4-C (4.76 ± 0.98 g m-2 yr-1) were highest from the brash plots. Annual N2O-N emissions were small over the study period (72 µg m-2 yr-1). Our results indicate that, despite remedial work being conducted on both peatlands to raise the water table, the C sink function has not yet been restored at either site.
Citation
Rigney, C., Wilson, D., Renou-Wilson, F., Müller, C., Moser, G. & & Byrne, K.A. (2018): Greenhouse gas emissions from two rewetted peatlands previously managed for forestry. Mires and Peat, 21(24), 1-21. (Online: http://www.mires-and-peat.net/pages/volumes/map21/map2124.php);
10.19189/MaP.2017.OMB.314
Reviewers
IMCG and IPS
acknowledge
the work of the reviewers.
|
