Peatland Ecology Research Group (PERG)
Université Laval
 
Scope
 
Restoration of fen plant communities after peat mining 2001 - 2008


Leader
Team
Description

This study, which started in 2001 with the master's project of Danielle Cobbaert and which was followed with the PhD project of Martha Graf, was concerned with the restoration of fen plant communities, dominated by Carices, on sedge peat surfaces after peat mining. We hypothesized that the restoration of fen plant communities was possible by applying techniques developed in North America for the restoration of bogs.

 


Objectives: The aim of these projects was to explore techniques for the restoration of fen plant communities on vacuum-extracted peatlands in North America. Descriptive and experimental research approaches were used to determine environmental and biological factors favouring fen restoration.


 


Locations: Rivière-du-Loup peatland, southern Québec, for Danielle Cobbaert's project (2001-2003). Martha Graf has visited 28 abandoned harvested fens across Canada and in Minnesota, USA, for her PhD project (2004-2008).

Danielle Cobbaert's project



Methods: The effectiveness of introducing fen plants with the application of donor seed bank was tested. The donor seed bank, containing seeds, rhizomes, moss fragments, and other plant diaspores, was collected from two different types of natural fens. A straw mulch treatment was applied to test its effects on fen plant establishment and richness. Terrace levels of different peat depths (15 cm, 40 cm, and 56 cm) were created to test the effects of different environmental site conditions on the success of revegetation.

Results: Applying donor seed bank from natural fens was found to increase significantly the fen plant cover and richness after two growing seasons. Straw mulch proved to significantly increase fen plant richness. The intermediate terrace level (40 cm) had the highest fen plant establishment. The low terrace level (15 cm) was richer in base cations compared to the reference sites, while the high terrace level (56 cm) was too dry and nitrate rich, perhaps explaining the lower success of plant establishment.

Conclusions: The application of donor diaspore material was demonstrated as an effective technique for establishing vascular fen plants. Further rewetting measures are considered necessary at the restoration site to create a fen ecosystem rather than simply restoring some fen species.


Martha Graf's project


 


The plant succession on abandoned, harvested peatlands where peat has been extracted to the minerotrophic layers was examined by Martha Graf to determine which plants frequently colonize these abandoned sites. After surveying 28 abandoned harvested fens across Canada and in Minnesota, USA. The spontaneous vegetation was not similar to the vegetation found on undisturbed fens from the same areas. Specifîcally, Sphagnum and Carex species, abundant on undisturbed fens were not found on abandoned vacuum-harvested fens. However, harvested fens were quickly recolonized by marsh species if they were not actively drained.


Plant survey of a fen (Photo: Martha Graf).



A field experiment was carried out to test two reintroduction techniques for Sphagnum and Carex species as well as the use of phosphate fertilizer. The application of donor diaspores, commonly used for dry peatland restoration was effective for reintroducing both Carex and Sphagnum species. In the past, the focus of fen restoration has been vascular plants.


Fen restoration experiment (Photo: Martha Graf).



In order to find out more about the environmental conditions necessary for the vegetative regeneration of eight common fen mosses, field and greenhouse experiments were carried out. The presence of shade was shown to greatly improve the regeneration of the mosses. The optimal water level for most species was just under the surface and Sphagnum species were shown to be the most successful at regenerating.


Greenhouse experiment (Photo: Martha Graf).



The findings of this research will aid the development of strategies for the restoration of fens on harvested peatlands.

Project's publication(s) & communication(s)



Back

© 2009 PERG. | All rights reserved. | C2000