Peatland restoration in southern Québec (Canada): A paleoecological perspective>

We used macrofossil analyses to reconstruct the long-term development of plant assemblages and the history of fire events in a bog in southern Québec which was partly disturbed by peat mining activities and recently restored. Our main objectives were to (i) determine to what extent the present-day plant assemblage of an unmined sector of the bog resembles the plant assemblages that have been reconstructed for different periods of the ecosystem’s development, (ii) establish the frequency of fire events and their impacts on plant assemblages, and (iii) interpret the results from the restoration experiment by considering the natural development of the peatland over recent millennia. Throughout the ombrotrophic stage of the peatland’s development, plant assemblages have been stable and do not seem to differ strongly from those observed today in the unmined sector of the bog. Consequently, the present-day plant assemblage of the unmined sector could be considered a good reference to evaluate the restoration success of the mined area. The bog landscape was characterized by significant tree cover dominated by black spruce for almost its entire period of development. Consequently, a restoration experiment resulting in Sphagnum-dominated vegetation with a dense black spruce cover in the near future should not be considered a failure. Macrofossil analyses suggest that postfire vegetation succession occurring in the study site and elsewhere is similar to that resulting from restoration experiments conducted in eastern Canadian bogs. In both cases, the input of nutrients (biomass burning or artificial fertilization) strongly stimulates the growth of Polytrichum strictum colonies, which are rapidly overgrown by Sphagnum colonies in burned bogs. Therefore, it is possible that the restoration method used in eastern Canada will result in rapid vegetation succession culminating in a Sphagnum-dominated peatland. This case study shows that a detailed reconstruction of the history of a site is a valuable tool for clearly establishing the goals of a restoration program.