Application of a global bioclimatic envelope model to assess the impact of climate change on the distribution of blanket peatlands in Great Britain

Blanket bogs are rain-fed mires that cover the landscape almost regardless of topography. The geographical extent of this type of peatland is highly sensitive to climate. We applied a global process-based bioclimatic envelope model, PeatStash, to predict the distribution of British blanket bogs. The model captures the present areal extent (Kappa=0.77) and is highly sensitive to both temperature and precipitation changes. When the model is run using the UKCIP02 climate projections for the time periods 2011-2040, 2041-2070 and 2071-2100, the geographical distribution of blanket bogs gradually retreats towards the north and the west. In the UKCIP02 high emissions scenario for 2071-2100 the blanket peat bioclimatic space is ~84% smaller than contemporary conditions (1961-90); only parts of the west of Scotland remain inside this space. Increasing summer temperature is the main driver of the projected changes in areal extent. Simulations using seven climate model outputs resulted in generally similar patterns of declining aereal extent of the bioclimatic space, although differing in degree. The results presented in this study should be viewed as a first step towards understanding the trends likely to affect the blanket bog distribution in Great Britain. The eventual fate of blanket bogs left outside their bioclimatic space remains uncertain.