Canadian Forest Service Publications
Using functional diversity as an indicator of restoration success of a cut over bog. 2013. D'Astous, A.; Poulin, M.; Aubin, I.; Rochefort, L.Ecological Engineering 61:519-526.
Issued by: Great Lakes Forestry Centre
Catalog ID: 35149
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A trait-based approach was used to evaluate the restoration success of a moss layer transfer technique on the herbaceous community of a cut-over bog. In order to understand the herbaceous dynamics following restoration, the bog was monitored prior to restoration and biannually over ten subsequent years, in two initial drainage conditions (dry peat fields and wet ditches), and compared to seven undisturbed bogs. Herbaceous community found prior to and in the early stage after restoration were characterized by species associated to mesic soil conditions with a fen-like pH, ruderal or wetland species, species with mycorrhiza or exotic species. These species did not persist in the latter stage after restoration and were replaced by species that are carnivorous, are associated to variable water availability and show mostly sexual reproduction. The extent of changes in traits composition of the herbaceous community between the early and latter stages after restoration showed the importance of multiple-year monitoring to evaluate restoration projects. The trait composition found in the latter stage after restoration appeared to converge toward the reference ecosystem where the community was characterized by species with large seeds, associated to humid soil conditions and a forest or peatland habitat. Lower trait diversity was found in the latter stage after restoration than in the reference ecosystem, especially in peat fields. In addition, species and functional diversity pattern varied with the initial drainage conditions, decreasing in peat fields while remaining stable in ditches. This suggests that different initial topography for restoration might help increase species and functional diversity of a managed ecosystem. Finally, our results outline measures to improve the moss layer transfer technique: sowing herbaceous species with large seeds in the latter stage after restoration, applying the restoration technique as soon as exploitation has terminated or removing all vegetation (including seeds and rhizomes) from the site to be restored.
Plain Language Summary
We evaluated the success of an ecological restoration technique in a cut-over bog that had been mechanically exploited for peat in the 1970s. We compared plant characteristics in the bog to a reference area over a 10-year period. We selected eight plant traits (from the TOPIC database) associated with plant survival, reproductive success, or environmental adaptation. This technique is useful because it allows comparison between ecosystems that may not have the same plant species. We found changes in trait pattern over time, with a convergence toward the reference ecosystem after 10 years, which shows the importance of long term monitoring to evaluate success. The study was also useful to examine the effectiveness of the moss layer transfer technique commonly used in peatland restoration because it can help target specific traits or processes that are not self-restoring. For example, it may be necessary to sow species with large seeds during the latter stages of restoration.