Annual gaseous carbon budgets of forest-to-bog restoration sites are strongly determined by vegetation composition

Angela L Creevy; Richard J Payne; Roxane Andersen; James G Rowson

doi:10.1016/j.scitotenv.2019.135863

Annual gaseous carbon budgets of forest-to-bog restoration sites are strongly determined by vegetation composition

Sci Total Environ. 2020 Feb 25:705:135863. doi: 10.1016/j.scitotenv.2019.135863. Epub 2019 Dec 2.

Authors

Angela L Creevy¹, Richard J Payne², Roxane Andersen³, James G Rowson⁴

Affiliations

¹ Edge Hill University, Geography Department, St Helens Road, Ormskirk, Lancashire L39 4QP, UK. Electronic address: angela.creevy@go.edgehill.ac.uk.
² University of York, Environment Department, Heslington, York YO10 5DD, UK.
³ Environmental Research Institute, University of the Highlands and Islands, Castle Street, Thurso KW14 7JD, UK.
⁴ Edge Hill University, Geography Department, St Helens Road, Ormskirk, Lancashire L39 4QP, UK.

PMID: 31972925
DOI: 10.1016/j.scitotenv.2019.135863

Abstract

Large areas of naturally open peatland in western Europe were drained and planted with non-native conifers in the twentieth century. Efforts are currently underway to restore many of these sites. Ultimately, forest-to-bog restoration aims to bring back functional peatlands that can sequester carbon but there is a lack of empirical evidence for whether current approaches are effective. Using a chronosequence design, we compared the annual gaseous carbon balance of two forest-to-bog restoration areas with an open area not subject to afforestation. A closed chamber method was used to determine gas fluxes (Net Ecosystem Respiration, Gross Primary Productivity, Net Ecosystem Exchange (NEE) and methane (CH₄)) over a twelve-month period for locations spanning the range of peatland microtopography and vegetation communities. Relationships between gas fluxes, vegetation/cover and environmental factors were analysed and regression models used to estimate annual CO₂ and CH₄ budgets. During the study period, NEE estimates (total gaseous C expressed as CO₂-eq) showed a net sink for the unafforested (-102 g C m^-² yr^-¹) and oldest (-131 g C m^-² yr^-¹) restoration area (17 years post-restoration 'RES 17 YRS'), whilst the youngest restoration area (6 years post-restoration 'RES 6YRS'), was a net source (35 g C m^-² yr^-¹). We observed significantly higher CH₄ emissions from restoration areas dominated by Eriophorum angustifolium compared with other peatland vegetation types. Sampling points with higher cover of Sphagnum were found to be most effective for C sequestration. Overall, vegetation composition/cover was observed to be an important factor determining C emissions from forest-to-bog restoration areas. These results suggest that restoration is effective in returning the carbon sink function of peatlands damaged by commercial forestry and - depending on restoration techniques - timescales of >10 years may be required.

Keywords: Carbon dioxide; Forestry; Methane; Peatland; Raised bog; Restoration.

MeSH terms

Carbon
Carbon Dioxide
Europe
Forests*
Gases
Methane
Wetlands*

Substances

Gases
Carbon Dioxide
Carbon
Methane