Modelling long-term blanket peatland development in eastern Scotland

Abstract. Blanket peatlands constitute a rare ecosystem on a global scale but is the most important peatland type on the British Isles. Most long-term peatland development models have focussed on peat bogs and high-latitude regions. Here, we present a spatially-explicit hillslope model to simulate long-term blanket peatland development along complex hillslope topographies. To calibrate the model, the peatland architecture was reconstructed along 56 hillslope transects in the headwaters of the river Dee (633 km2) in eastern Scotland, resulting in a dataset of 866 soil profile descriptions. The application of the calibrated model using local pollen-based land cover and regional climate reconstructions over the last 12,000 years shows that the early-Holocene peatland development is largely driven by a temperature increase. An increase in woodland cover only has a slight positive effect on the peat growth potential contradicting the hypothesis that blanket peatland developed as a response to deforestation. Both the hillslope measurements and the model simulations demonstrate that the blanket peatland cover in the study area is highly variable both in extent and peat thickness stressing the need for spatially distributed peatland modelling. At the landscape scale, blanket peatlands were an important atmospheric carbon sink during the period 9.5 ka–6 ka BP. However, during the last six thousand years, the blanket peatlands are in a state of dynamic equilibrium with minor changes in the carbon balance.