From Bare Peat to _Sphagnum_ Cover: The Success of _Sphagnum_-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.