Susan E. Ward

Abstract: Using a 50-year-old field experiment, we investigated the effects of the long-term land management practices of repeated burning and grazing on peatland vegetation and carbon dynamics (C). Plant community composition, C stocks in soils and vegetation, and C fluxes of CO2, CH4 and DOC, were measured over an 18-month period. We found that both burning and grazing reduced aboveground C stocks, and that burning reduced C stocks in the surface peat. Both burning and grazing strongly affected vegetation community composition, causing an increase in graminoids and a decrease in ericoid subshrubs and bryophytes relative to unburned and ungrazed controls; this effect was especially pronounced in burned treatments. Soil microbial properties were unaffected by grazing and showed minor responses to burning, in that the C:N ratio of the microbial biomass increased in burned relative to unburned treatments. Increases in the gross ecosystem CO2 fluxes of respiration and photosynthesis were observed in burned and grazed treatments relative to controls. Here, the greatest effects were seen in the burning treatment, where the mean increase in gross fluxes over the experimental period was greater than 40%. Increases in gross CO2 fluxes were greatest during the summer months, suggesting an interactive effect of land use and climate on ecosystem C cycling. Collectively, our results indicate that long-term management of peatland has marked effects on ecosystem C dynamics and CO2 flux, which are primarily related to changes in vegetation community structure.

TL;DR: It is found that although warming consistently increased respiration, the effect on net ecosystem CO2 exchange depended on vegetation composition, and it is suggested that vegetation change could alter peatland carbon sink strength under future climate change.

TL;DR: It is concluded that plant functional groups differentially influence the uptake and short-term flux of carbon in peatlands, suggesting that changes in the functional composition of vegetation resulting from global change have the potential to alter short- term patterns of carbon exchange in peats.

TL;DR: In this paper, nearly 5000 chamber measurements of CH4 flux were collated from 21 sites across the United Kingdom, covering a range of soil and vegetation types, to derive a parsimonious model that explains as much of the variability as possible, with the least input requirements.

TL;DR: It is demonstrated that methane-derived carbon is an important, but often neglected, contribution to the flux of carbon through the food webs of many productive or dystrophic lakes.