Peat accumulation and peat decomposition after human disturbance in French and Finnish mires

摘要

The primary production of two pristine Sphagnum-Carex peatlands in France and Finland were 274 and 629 g C (carbon) m-2 yr-1, respectively and accumulation/productivity ratios were 0,10 and 0,03 yr1 which represent 28 and 20 g C m-2 yr-1. The natural processes of peat accumulation were altered by human activities, i.e. forestry in Finland and agricultural use in France. At the French site, the main changes processes in the managed site were Sphagnum reduction and an increase in grasses. These changes diminished the C-flux to the litter while a part of the stock in the peat was released with the increase of decomposition of accumulated peat. At the Finnish site, the main changes in the managed site were the development of tree layer after drainage and an increase in peat respiration. Although litter production was increased, the increased decomposition also resulted i n the cessation of peat accumulation and decomposition of earlier accumulated peat.