Arctic ecosystem restoration with native tundra bryophytes

Bryophytes are ecologically essential to northern ecosystem restoration after disturbance. In this study, native bryophytes were used to revegetate two Arctic restoration sites. Different propagation types (small, medium, large fragments) and substrates (crushed rock, lake sediment, processed kimberlite in Canada; volcanic silt loam and crushed lava rock in Iceland) with two erosion control treatments (with and without cheesecloth) were evaluated. After two growing seasons, large bryophyte fragments resulted in the greatest density and total and live cover with erosion control and medium fragments resulted in the highest density and species occurrence without erosion control. Erosion control significantly increased live cover, total cover, species occurrence, and density, including a tempering effect on soil volumetric water content and temperature. Substrates with more heterogeneous surfaces (crushed rock, volcanic silt loam, crushed lava rock) yielded higher live cover, density, and spontaneous colonization than more homogeneous substrates (processed kimberlite, lake sediment) and can be more suitable for use in arctic ecosystems revegetation. The positive outcomes in both Canada and Iceland led to the conclusion that bryophyte propagation with large to medium fragments, erosion control with cheesecloth, and substrates with heterogeneous surfaces would be effective restoration approaches where bryophyte revegetation is a focus.