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In a controlled field experiment, we tested the effect of plant biodiversity on carbon accumulation in a formerly-extracted peatland that was rewetted and re-vegetated. We monitored carbon fluxes in experimental units re-vegetated with different numbers and types of characteristic minerotrophic peatland species, planted in monoculture and mixed treatments. Using measured environmental variables, we modelled the different components of carbon flux (photosynthesis, respiration and methane flux) and simulated the Net Seasonal Carbon Flux for three standard wetness scenarios of each planting treatment. We tested the effect of species and functional group richness, species and functional group identity and species interactions on Net Seasonal Carbon Flux. Our findings did not indicate any significant effect of the richness of species or plant functional groups on carbon accumulation. However, the presence of key species was important; Carex aquatilis, particularly when planted alone, significantly increased carbon accumulation; other graminoid species were not associated with the same effect. Mixed-species treatments did not accumulate more carbon than was expected of the same species when planted in monoculture, providing no evidence for an overall species interaction effect. Our results suggest that in the context of restored minerotrophic peatlands, species identity is more important than species/functional group richness or species-interaction for driving carbon accumulation. [ABSTRACT FROM AUTHOR]

Following ecosystem-scale restoration of a post-harvested bog in Eastern Canada, a long term monitoring program was set up. Peat, water and plant chemistry data were collected during 7 years in a restored peatland, an adjoining post-harvested non-restored peatland, and in a neighboring natural peatland to determine the potential of chemistry data for evaluating of restoration success over time. We used a multivariate Principal Response Curves (PRC) approach to study the temporal evolution of peat, water, and plant tissue chemistry. Nitrogen, iron, and sodium were the most responsive elements to restoration in the peat. Water chemistry was still different between natural and restored sections 7 years after restoration, but the difference was not constant over the growing season. The analyses of plant tissue chemistry provided useful information related to fundamental processes (nutrient retention/leaching, plant nutrition). Among other, it highlighted P deficiencies in the non-restored section, and nutrient replenishment in the restored plant tissues. P levels appear to be a good indicator of restoration success and should be used routinely in monitoring studies. Since the three plants species tested in this study displayed different responses to restoration, we also recommend targeting key species or functional groups for monitoring. [ABSTRACT FROM AUTHOR]

Early attempts at peatland restoration have been aimed mostly at rewetting the peat, which alone has proven inadequate to ensure good regeneration of Sphagnum mosses. Sphagnum mosses can be actively reintroduced by scattering Sphagnum fragments (diaspores) on bare peat surfaces and by sheltering them against desiccation. The present study aims at refining the restoration techniques to reintroduce Sphagnum where the surface conditions of cutover peatlands are too harsh for natural Sphagnum establishment. The objective is to increase local moisture conditions of the peat by reprofiling the surface to invert the camber created during drainage operations. Sphagnum diaspores were spread in the concavity. Reprofiling fields increased Sphagnum establishment compared to control sites. The addition of two plastic sheets on the edge of the field reduced evaporation and directed precipitation towards the middle of the field. When they were combined with reprofiling, there was a further increase in the establishment success of Sphagnum. [ABSTRACT FROM AUTHOR]

Exploitation of peatlands results in the degradation of hydrophysical conditions suitable for the re-establishment of peat-forming vegetation, notably Sphagnum mosses. Regeneration of peat-forming mosses necessitates a high and stable water table. The objective of this studywas to evaluate the performance of open water reservoirs constructedto improve the hydrologic conditions required for growth of Sphagnum. A section of abandoned peatland, where former drainage ditches havebeen blocked, was treated by excavating reservoir ditches at 3-, 5-,and 8-m intervals to increase the local water storage. The colonization of Sphagnum fuscum and S. angustifolium diaspores scattered on the experimental baulks between the reservoir ditches was measured. Results indicate that water storage increased at the experimental site. The water table was higher and more stable, with an average maximum depth of 0.46 m at the rewetted site compared to 0.55 m at the controlsite. The volumetric moisture content of the surface peat was improved by rewetting, showing an average of 62% compared to 55% at the control site. Negative soil water tension at the -0.1 m depth was ameliorated at the experimental sites and nearly eliminated where 5-m experimental ditch-reservoir spacing was employed. Sphagnum establishment was successful on all experimental baulks, showing a higher percentage cover where soil moisture was more readily available. [ABSTRACT FROM AUTHOR]