Introduction
Since the last ice age, peatlands in Ireland have accumulated considerable stores of atmospheric carbon as a result of hydrological conditions within the peat profile that ensure that C input into the system is generally less than carbon losses.
Peatlands capture carbon dioxide and release methane.
The accumulation of carbon in stable peatlands can be regarded as sequestration to a store, while emission of carbon due to decomposition of long-term carbon stores would be regarded as a source.
Earlier estimates according to Hammond (1979) state that peatlands comprise 17% of the national land area of Ireland while the General soil Map’s (Gardiner and Radford, 1980) estimate is 16.7%. The estimate of the peat resource in the Republic of Ireland, derived from PEATGIS, a rule-based GIS methodology to quantify the national peat resource based on existing data sets, developed by Ward et al., 2007, suggests that peatlands cover ca. 0.95 MHa or ca. 14% of the total land area, and around 74% of the peatlands are disturbed in some way. These are similar to those estimated by the CORINE system, while the disturbance data are somewhat lower than the Irish Peatlands Conservation Council (IPCC) estimates of 82% for blanket bog and 92% for raised bog.
A raised peatland in a natural state has the greatest predicted C accumulation rate (+ 60 g C/m2/year) and when the peatland is disturbed there is a considerable reduction in the accumulation capacity (-17 g C/m2/year), consequently changing the peatland from a net sink to a net source (Ward et al., 2007).
Disturbance of Peatlands