Spatial variability of fluvial blanket peat erosion rates for the 21st Century modelled using PESERA-PEAT

Abstract

Many peatlands across the world suffer from degradation. Blanket peatlands are found mainly in high latitude oceanic areas and subpolar islands. Exacerbated erosion of blanket peatlands is common particularly where they have been disturbed by human influence or where climate has become more marginal for their functioning. A recently developed fluvial blanket peat erosion model, PESERA-PEAT was applied across 845km2 of blanket peatlands in the North Pennines of northern England. The aim was to evaluate the spatial and temporal variability of erosion rates under climate change and land management scenarios. Climate change data to the end of the 21st Century, derived from UKCP09 median emission projections aligned to the UK Met Office's historical meteorological dataset, were downscaled to 100m cells. Land management scenarios were developed which included intensified and extensified grazing, artificial drainage and prescribed burning. The modelling results showed that under current management, 21st Century climate change would slightly increase the overall fluvial erosion rates for the study region from the climatic baseline (2.2tha−1yr−1) to the 2080s (2.3tha−1yr−1). However, the predicted response to climate change was spatially very variable. Predicted erosion rates decreased at locations that are currently wet and cold while they increased in some warmer and drier locations by >50%. Summer desiccation was found to become more important for the study region under climate change. Thus, predicted autumn sediment yields became the biggest component of the annual budget by the 2080s. Less intensive management was shown to reduce blanket peat erosion but potentially enhance wildfire severity. The results demonstrated that land management change will be useful in mitigating the impact of 21st Century climate change on the amount and spatial pattern of blanket peat erosion. The results of our study can be used within blanket peatland regions to inform spatially-targeted management strategies.