Restoration of afforested peatland: Immediate effects on aquatic carbon loss

Paul P J Gaffney; Mark H Hancock; Mark A Taggart; Roxane Andersen

doi:10.1016/j.scitotenv.2020.140594

Restoration of afforested peatland: Immediate effects on aquatic carbon loss

Sci Total Environ. 2020 Nov 10:742:140594. doi: 10.1016/j.scitotenv.2020.140594. Epub 2020 Jun 30.

Authors

Paul P J Gaffney¹, Mark H Hancock², Mark A Taggart³, Roxane Andersen⁴

Affiliations

¹ Environmental Research Institute, North Highland College, University of the Highlands and Islands, Castle Street, Thurso KW14 7JD, UK. Electronic address: Paul.Gaffney@uhi.ac.uk.
² RSPB Centre for Conservation Science, Etive House, Beechwood Park, Inverness IV2 3BW, UK.. Electronic address: mark.hancock@rspb.org.uk.
³ Environmental Research Institute, North Highland College, University of the Highlands and Islands, Castle Street, Thurso KW14 7JD, UK. Electronic address: Mark.Taggart@uhi.ac.uk.
⁴ Environmental Research Institute, North Highland College, University of the Highlands and Islands, Castle Street, Thurso KW14 7JD, UK. Electronic address: Roxane.Andersen@uhi.ac.uk.

PMID: 32640388
DOI: 10.1016/j.scitotenv.2020.140594

Abstract

Peatland restoration is undertaken to bring back key peatland ecosystem services, including carbon storage. In the case of drained, afforested blanket peatlands, restoration through drain blocking and tree removal may impact upon aquatic carbon concentrations and export, which needs to be accounted for when considering the carbon benefits of restoration. This study investigated concentrations and export of aquatic carbon from a drained, afforested blanket bog catchment, where 12% of the catchment underwent drain blocking and conifer removal (termed 'forest-to-bog' restoration), and from two control catchments: one in open bog and one that remained afforested. Using a before-after-control-impact (BACI) design, we found no significant increases in concentrations or export of aquatic carbon (DOC, POC or DIC) in the first year following forest-to-bog restoration (i.e. across the whole post-restoration period). However, increased DOC concentrations were observed in the first summer (2015) post-restoration, and seasonally increased DOC export was noted during storm events in the autumn of the same year. The lack of significant effects of forest-to-bog restoration on aquatic carbon export may be a consequence of the small proportion of the catchment (12%) undergoing management. In terms of management, the removal of more of the forestry residues (i.e., brash) may help to mitigate effects on aquatic carbon, by removing a potential DOC and POC source. Restoring small areas at a time (≤12%) should result in minimal aquatic carbon export issues, in contexts similar to the current study.

Keywords: Blanket bog; Conifer harvesting; Dissolved organic carbon (DOC); Drain blocking; Flow country; Water quality.