Abstract
Abstract. Blanket peatlands constitute a rare ecosystem on a global scale, but blanket peatland 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 process-based 2-D hillslope model to simulate long-term blanket peatland development along complex hillslope topographies. To calibrate the model, the peatland architecture was assessed 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 (mean annual temperature and mean monthly precipitation) over the last 12 000 years shows that the Early Holocene peatland development was 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 9.5–6 kyr BP. However, during the last 6000 years, the blanket peatlands were in a state of dynamic equilibrium with minor changes in the carbon balance.
Highlights
Peatlands occur across the globe and contain up to one third of the global soil carbon stock, despite covering approximately less than 3 % of the Earth’s surface (Gorham, 1991; Xu et al, 2018)
The high calibrated decomposition rates can be attributed to the fact that these rates within the model do encompass peat decomposition within the soil profile, but they include other processes which lead to a decrease in peat thickness in the field such as particulate organic-carbon export through gully development and shallow mass movements
Pointby-point comparison still shows poor results, which can be attributed to the use of a single set of calibrated parameters and the idealized representation of the model domain. Both the field data and model simulations indicate that the blanket peatlands in the Upper Dee area developed mostly during the Atlantic period, with a peak in peat growth initiation dates around 9 kyr BP
Summary
Peatlands occur across the globe and contain up to one third of the global soil carbon stock, despite covering approximately less than 3 % of the Earth’s surface (Gorham, 1991; Xu et al, 2018). Blanket peatlands are spreads of peat of varying thickness, covering the underlying topography, “blanketing” the landscape (Lindsay, 1995). This peatland type occurs in hyperoceanic climates with cool and moist conditions throughout the year, and it is mostly confined to the maritime edges of the continents (Gallego-Sala and Prentice, 2013). Rare on a global scale, up to 6 % of the area of the United Kingdom is covered by blanket peatland (Jones et al, 2003). The large area of the Scottish blanket peatlands, covering 23 % of the country, compared to the international rarity of these environments, makes the Scottish peatlands a high-value target for conservation efforts (Fyfe et al, 2013; Tipping, 2008)
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call