Restoring metal contaminated peatlands in Sudbury, Ontario

Industrial contamination has profoundly impacted peatland ecosystems, degrading their biodiversity and essential functions such as carbon sequestration. The Sudbury region in Ontario, Canada is one of the world's largest metal mining centres and historically the largest global point source of sulfur and metal pollution and serves as a critical case study for understanding and addressing these impacts. Peatlands closest to pollution sources have suffered extensive degradation, with keystone vegetation, including Sphagnum mosses, locally extinct and peat layers showing significant carbon losses. Developing innovative restoration techniques is crucial before undertaking regional-scale restoration of metal-impacted peatlands, ensuring chemical stressors are overcome effectively while minimizing sequestered metal release. In collaboration with regional stakeholders and academic institutions, our interdisciplinary team is pioneering innovative restoration techniques to reinstate peatland functionality in this toxic metal and metalloid-polluted landscape. Building on established practices, such as the moss-layer transfer technique, our modified approaches incorporate surface tilling, mulching, fertilization, and the reintroduction of donor peatland material. These interventions aim to overcome chemical stressors like persistent high concentrations of water-extractable metals (e.g., copper and nickel), which inhibit Sphagnum recovery. A restoration field trial began in fall 2023 with surface mulching, and in spring 2024 we applied restoration treatments of mulch, fertilizer, and planting. Here, we present results from the first growing season for peat chemistry, hydrology, greenhouse gas fluxes, and vegetation.