From Bare Peat to <i>Sphagnum</i> Cover: The Success of <i>Sphagnum</i> -fragment and Straw-Mulch Application for Initiating Peatland Restoration

Restoring degraded peatlands begins with hydrological restoration, but this alone may not fully re-establish key plant species such as Sphagnum mosses. To address the need for improving restoration outcomes, this study investigates the short-term effects of active revegetation on bare peat using a modified Moss Layer Transfer Technique (MLTT). Two treatment types were tested: Sphagnum fragments with mulch, mulch-only, and untreated bare peat as a control. Experiments were conducted across three locations in Norway to assess the recovery of Sphagnum cover and the establishment of other plant functional types over three years. Results showed a significant increase in Sphagnum cover in the Sphagnum treatment plots, reaching 65.6 % (± 3.5 SE) on average compared to 4.6 % (± 1.4 %) in mulch-only plots and 2.0 % (± 0.6 %) in controls, demonstrating the efficacy of active revegetation. The straw mulch treatment alone did not significantly enhance Sphagnum re-establishment, though some plant functional types, particularly mosses other than Sphagnum and Racomitrium as well as evergreen Ericaceae , benefited slightly. Sphagnum re-establishment success varied among the four species used, with S. angustifolium showing the highest establishment rates. Overall, our findings emphasise that active revegetation accelerates Sphagnum recovery, which is crucial for reducing greenhouse gas emissions and stabilising peatland hydrology. The use of straw mulch alone is of limited benefit for rapid Sphagnum recovery but may provide a stabilising microclimate. These results underline the need for integrating active revegetation with hydrological restoration for effective peatland restoration.