Restoration of a Degraded Raised Bog: Implications for Carbon Flux and Hydrological Recovery

Peatlands are globally important carbon stores that provide a range of ecological, climatic, and socio-economic benefits. However, large-scale peat extraction, drainage for agriculture, and conversion to forestry have changed many peatlands from long-term carbon sinks into carbon sources. While some of the best remaining examples of intact raised bogs in Western Europe occur on the island of Ireland, a large majority are degraded. In recent years, Ireland has undertaken an extensive programme of peatland restoration, with works carried out across approximately 30,000 ha of drained raised bog to enhance biodiversity and contribute towards international greenhouse gas reduction commitments. Understanding the impacts of such restoration efforts on peatland hydrology, carbon dynamics, and biodiversity is essential to ensure that measures are effective and achieving the outcomes required. This study presents data from the restoration of a drained area of All Saints Bog, a Natura 2000 raised bog site. Restoration measures included ditch blocking, re-profiling degraded areas, and contour bund construction with adjustable drains to regulate the hydrology. The effects of restoration are evaluated using a combination of eddy covariance, chamber measurements, water level monitoring, and remote sensing over a four-year period from 2021 to 2024. This period incorporated one year of pre-restoration, two years of active restoration, and one year of post-restoration. Hydrologically, restoration efforts appear to have been successful, with widespread rewetting across much of the site, recreating the conditions for active peat formation and the slow recovery of Sphagnum moss locally present. However, we found an approximate two-fold increase in net carbon fluxes between pre- and post-restoration, rising from 1.14 t CO₂-C ha⁻¹ y⁻¹ in 2021 to 2.37 t CO₂-C ha⁻¹ y⁻¹ in 2024. Furthermore, chamber-based spatial measurements showed a higher emission contribution from contour bunds compared to bare peat. Consequently, a programme of Sphagnum translocation and inoculation is planned for 2025 to hasten vegetation recovery. This long-term investigation will deepen our understanding of effective restoration efforts, which will provide insights to guide the development of future restoration strategies.