The Effects of Upland Peatland Vegetation Management on Carbon Exports and Water Quality

Abstract

Peatlands are important carbon reservoirs both nationally and globally, because they have the potential to be both sources and sinks of carbon. Dissolved organic carbon (DOC) is carbon lost from peatlands via the fluvial pathway. UK upland peatlands have a history of atmospheric deposition, degradation, and erosion as well as being extensively managed. Management of the upland peatlands presents an opportunity to maximise carbon storage and water quality benefits.
The research aim was to contribute toward the understanding of vegetation management effects upon peatland carbon exports and water quality. In the context of two studies: 1) bare peat ecological restoration (Bleaklow); 2) heather management through cutting and burning (Goyt Valley). Multi factorial designed in-field experiments were set up. Between 2007 and 2013, sites were monitored monthly for CO2 fluxes, water table (WT) depth and water samples were collected and analysed for DOC concentrations. The results were statistically analysed using general linear models and were critically discussed.
In both studies, water sample DOC was better explained through inter-annual monthly variation than variation between sites. Bleaklow bare peat restoration and Goyt Valley management did not significantly influence soil pore water DOC concentrations. However findings supported the use of gully blocking and stabilisation techniques to revegetate bare peat, raised WT, promoted CO2 influx through gross photosynthesis and reduced site acidification. Goyt Valley heather management through cutting was a good alternative to burning in dry localities (to raise WT). Runoff water and peat through-flow (at 10 cm depth) DOC was influenced by managed cutting and burning. Water sample DOC significantly varied along a peat profile (horizontally) and catchment. Through-flow DOC concentrations were greater than soil pore water at the wet locality and lower at the dry locality. The findings emphasised the importance of temporal and spatial scale when considering vegetation management effects on peatland carbon exports.