Blanket bog vegetation response to wildfire and drainage suggests resilience to low severity, infrequent burning

Abstract

In 2019, a wildfire impacted an area of blanket bog and wet heath > 60 km2 in the Flow Country peatlands of northern Scotland, a site of global significance. Unusually the footprint of the wildfire included discrete areas of degraded, restored, and near-natural blanket bogs. Following the wildfire, we surveyed vegetation in 387 quadrats in burnt and unburnt areas. The study aimed to determine whether and how proximity to human-made drains and microtopography affected fire-vegetation interactions and included older wildfire sites and unburnt control sites for context. Overall, our study suggests that the 2019 Flow Country wildfire caused mostly superficial burning; except in the most degraded area, which burned more severely and where we recorded more profound impacts on the vegetation. We found higher cover of litter, which in turn led to increased localized fire damage in quadrats close to drains compared with quadrats away from the influence of drains. We also found greater fire impacts (e.g., proportions of moss burnt and Sphagnum discoloration) on hummocks, particularly where they were higher relative to the hollows. Overall, vegetation both near and away from drains largely resembled nearby unburnt sites within 20 years. Overall, our study suggests that the 2019 Flow Country wildfire caused mostly superficial burning, except in the most degraded areas. Vegetation communities of blanket bogs associated with conservation and restoration areas in the region appear to be largely resilient to occasional, low severity wildfires. This implies that management interventions that maintain wet conditions in peatlands have the potential to help reduce the risks of severe wildfires.