The response of CO2 fluxes from a peat soil to variation in simulated sheep trampling

The peat soils that underlie much of the UK uplands contain a significant store of carbon and although carbon cycling in UK peat has received a great deal of research attention there are relatively little data available on the physical impact of grazing on carbon dynamics in peat soils. Therefore, this study asked whether trampling of peat soils had a significant effect on a major carbon flux pathway of peat ecosystems i.e. surface exchange of CO2 with the atmosphere. This study simulated regular trampling by sheep on peat cores for a period of 6 months and monitored the CO2 exchange with the atmosphere. Additionally, it also investigated the impact of the cessation of trampling.Results show that photosynthesis and net ecosystem exchange of CO2 were significantly decreased following trampling by up to 75% relative to control cores. Cessation of trampling led to a significant increase in ecosystem respiration after just 3 months but photosynthesis and net ecosystem exchange were not significantly different to the pre-cessation period.

► UK peatlands are extensively managed for the grazing of livestock. ► CO2 from peat soils was monitored for 6 months following simulated trampling. ► Trampling of peat soils reduces CO2 fluxes by up to 75% relative to controls. ► Cessation of trampling led to varied responses for the different CO2 pathways.