Investigating Peatland Margins and Determining the Role of Peatland Margin Characteristics in the Resilience of Blanket Peatland
The Flow Country has recently been designated a UNESCO World Heritage Site, representing a globally rare peatland type called blanket bog. Despite this, many challenges face the future of this type of peatland, including the increased demand for renewable energy infrastructure, as well as decisions regarding current forestry on blanket bog. Understanding the resilience of blanket bog is imperative to inform decisions related to these challenges, particularly in the face of a rapidly changing climate which subjects blanket bog to droughts, wildfires and floods. This thesis addresses a key knowledge gap regarding peatland margins, which are often inconsistently defined in literature and face a sampling bias, resulting in limited understanding of these transitions. However, the potential role of peatland margins in maintaining a high water table at the peatland centre, along with their vulnerability to wildfires and human impacts means they could be key to understanding the mechanisms behind peatland resilience. An extensive field campaign across the Flow Country, employing transects across margin-to-centre gradients, demonstrated the variability in properties across the margin-to-centre transition. Notably, the riparian zone could be clearly defined using organic matter content. Stream order was found to be a key predictor in the area of influence of the boundary, and is recommended as a classification tool in future research. Using historic aerial photographs, the lateral movement of a river in the Flow Country was determined over a 76-year period. The river did not show consistent movement in a particular direction, however, key changes such as the dissolution of anabranched sections of the river had impacts of up to 10 m of change. Surprisingly, change in the peatland centre, was 5 times greater than the change measured in the river, in the form of pool expansion, suggesting that peatland centres may be more dynamic than their margins. A field campaign determined that areas under forestry and undergoing forestto- bog restoration contained a modified vegetational community. Interferometric Synthetic Aperture Radar (InSAR) derived condition classes indicated that peatland centres adjacent to forestry and forest-to-bog areas were stiffer than near-natural centres. This suggests that land use change within the margin-to-centre transition can affect the mechanical and hydrological properties of the entire peatland unit. This thesis has demonstrated the complexity in defining and characterising peatland margins in the Flow Country, nevertheless, it has advanced our understanding of peatland margins and proposed a valuable classification tool for future studies. Moving forward, the margin-to-centre transition should be better understood and classified when assessing peatland resilience, to better inform the protection of blanket bogs in future challenges.
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