A mesocosm study of the effect of restoration on methane (CH₄) emissions from blanket peat

In a mesocosm study, we investigated the effect of different restoration methods on methane (CH₄) emissions from, and the global warming potential (GWP) of, blanket peat. The controlled laboratory study involved two distinct components: Experiment 1 focused on greenhouse gas exchanges from blocked drains (grips) and evaluated the effects of restoration method, water-level dynamics and climate on CH₄ emissions and GWP. Experiment 2 assessed the role of plant functional type (PFT) on CH₄ emissions from restored peat outside of the grip. A nine month meteorological simulation (April- December) was completed, testing five hypotheses across the two experiments. We found that the method of grip blocking/damming does make a difference with respect to CH₄ emissions and GWP. Of the methods considered, damming with no infill between the dams is preferred to either of the methods involving infilling (heather bale and re-profiling). GWP of all within-grip restoration outcomes was positive (i.e., indicating a net warming effect), and was not influenced by climate or water-level regime. PFT influences CH₄ emissions but not GWP in restored blanket bog. When considering radiative forcing, this finding suggests that it does not matter which PFT dominates a restored area. It is noted that the laboratory findings are, in some senses, preliminary because the experiments consider only a relatively short period immediately after restoration.