Cutover Peatlands Research Articles

Net ecosystem CO2 exchange of a cutover peatland rehabilitated with a transplanted acrotelm

Natural peatlands are an important component of the global carbon cycle, representing a net long-term sink of atmospheric carbon dioxide (CO2). The natural carbon storage function of these ecosystems can be severely impacted due to peatland drainage and peat extraction, leading to large and persistent sources of atmospheric CO2 following peat extraction abandonment. Standard restoration techniques aim to restore the peatland to a carbon-accumulating system through various water management techniques to improve hydrological conditions and through reintroducing Sphagnum at the surface. However, restoring the hydrology of peatlands can be expensive due to the cost of implementing the various restoration techniques. This study examines the net ecosystem CO2 exchange of a new extraction—restoration technique where the acrotelm is preserved and replaced directly on the cutover surface. Peat respiration at the experimental restored acrotelm (110.5 g C·m−2over the study period: May 20–August 18) was significantly lower than at the natural peatland (144.8 and 203.7 g C·m−2, wet and dry plots respectively). However, gross ecosystem production (GEP) at the experimental site was significantly reduced (-54.0 and -34.4 g C·m−2) compared to the natural site (-179.2 and -162.0 g C·m−2). Consequently, this was a growing season net emitter of CO2 to the atmosphere over the season at the experimental site (78.5 and 56.5 g C·m−2 and a growing season sink of CO2 at the natural site (-17.6 and -22.8 g C·m−2). Light response curves indicated that maximum GEP was significantly lower at the experimental site; however, it is likely that the percentage of living and dead vegetation at the plots post restoration had a large control on this lower productivity as plots with more living vegetation had higher overall productivity (GEP). Nevertheless, the experimental site did maintain limited productivity post-extraction, indicating that the carbon dynamics of the system was maintained due to this acrotelm restoration process, thereby likely returning the ecosystem toward a natural sink of atmospheric CO2 faster than natural rehabilitation and current restoration techniques. As such, this approach to peat extraction may be an environmentally preferred approach to use.

Contribution of plant photosynthate to soil respiration and dissolved organic carbon in a naturally recolonising cutover peatland

The aim of this study was to investigate how three vascular plant species ( Calluna vulgaris, Eriophorum angustifolium and Eriophorum vaginatum) colonising an abandoned cutover peatland affect fluxes of recent photosynthate to dissolved organic carbon (DOC), soil and plant respiration and shoot biomass. We used in situ 13CO 2 pulse labelling to trace carbon (C) throughout a 65 day pulse chase period. Between 16 and 35% of the pulse of 13C remained in shoot biomass after 65 days with significant differences between C. vulgaris and E. angustifolium ( P = 0.009) and between C. vulgaris and E. vaginatum ( P = 0.04). A maximum of 29% was detected in DOC beneath labelled plants and losses of 13C from peat respiration never exceeded 0.16% of the original pulse, showing that little newly fixed C was allocated to this pool. There were no significant differences between the different plant species with respect to 13C recovered from DOC or via peat respiration. More C was lost via shoot respiration; although amounts varied between the three plant species, with 4.94–27.33% of the 13C pulse respired by the end of the experiment. Significant differences in 13C recovered from shoot respiration were found between C. vulgaris and E. angustifolium ( P = 0.001) and between E. angustifolium and E. vaginatum ( P = 0.032). Analysis of δ 13C of microbial biomass indicated that recently assimilated C was allocated to this pool within 1 day of pulse labelling but there were no significant differences in the 13C enrichment of the microbial biomass associated with the different plant species. The data suggest that peat respiration represents a small flux of recent assimilate compared to other fluxes and pools and that different vascular plant species show considerable variation in the quantities and dynamics of C allocated to DOC.

Interactions among fungal community structure, litter decomposition and depth of water table in a cutover peatland

Peatlands are important reservoirs of carbon (C) but our understanding of C cycling on cutover peatlands is limited. We investigated the decomposition over 18 months of five types of plant litter (Calluna vulgaris, Eriophorum angustifolium, Eriophorum vaginatum, Picea sitchensis and Sphagnum auriculatum) at a cutover peatland in Scotland, at three water tables. We measured changes in C, nitrogen (N) and phosphorus (P) in the litter and used denaturing gradient gel electrophoresis to investigate changes in fungal community composition. The C content of S. auriculatum litter did not change throughout the incubation period whereas vascular plant litters lost 30-40% of their initial C. There were no differences in C losses between low and medium water tables, but losses were always significantly less at the high water table. Most litters accumulated N and E. angustifolium accumulated significant quantities of P. C, N and P were significant explanatory variables in determining changes in fungal community composition but explained <25% of the variation. Litter type was always a stronger factor than water table in determining either fungal community composition or turnover of C, N and P in litter. The results have implications for the ways restoration programmes and global climate change may impact upon nutrient cycling in cutover peatlands.

Growing Black Chokeberry (Aronia melanocarpa) in Cut-over Peatlands

This project was established to evaluate the feasibility of black chokeberry [Aronia melanocarpa (Michx.) Ell.] culture on Canadian cut-over peatlands and to define its appropriate production practices. We tested the effects of different fertilizer rates, application methods, and mulches on the vegetative development and berry production of seedlings over a 6-year period (2000 to 2006). Fertilization was essential for survival of the plants. A low fertilizer rate (131 g/plant of 1.7N–4.1P–12K) ensured adequate vegetative development for good establishment. Applying such a rate for 2 consecutive years proved to be more beneficial than a single dose of fertilizer for increasing plant height, crown width, and height growth. However, fruit yield was best when fertilized with the highest dose tested (550 g/plant of 3.4N–8.3P–24.2K). Black plastic mulch had a positive effect on height, width, and growth of the plants. More weeds were observed when the fertilizer was applied to the surface as compared with soil incorporation. However, this study revealed that black chokeberry is tolerant of weeds. Based on these results, black chokeberry is a promising plant for the management of cut-over peatlands for both vegetative growth and fruit production.

Temporal patterns of litter production by vascular plants and its decomposition rate in cut-over peatlands

ABSTRACT Peatlands are an important carbon (C) store but many have been drained and damaged by mechanical harvesting. Little is known about ecological processes on abandoned peatlands that have recolonized naturally nor the impact of plants on C balance of these sites. Over the course of 13 months, we measured amounts of litter falling from three different species colonizing an abandoned peat bog in north-eastern Scotland to calculate potential inputs of C and nitrogen (N). In parallel, a litter bag experiment quantified C loss from the litter of these species over 18 months. Calluna vulgaris produced the greatest amounts of litter (276 ± 32.3 g dwt m−2 yr−1); Eriophorum angustifolium produced 10.9 ± 2.6 g dwt m−2 yr−1 and Eriophorum vaginatum produced 42.3 ± 3.5 g dwt m−2 yr−1. Carbon loss varied from 30% (E. vaginatum) to 40% (Calluna) over 18 months, but differences among the three species were not significant. Overall, these findings indicate that Calluna can make significant inputs of C and N into de...

FTIR spectroscopy can be used as a screening tool for organic matter quality in regenerating cutover peatlands

Vegetational changes during the restoration of cutover peatlands leave a legacy in terms of the organic matter quality of the newly formed peat. Current efforts to restore peatlands at a large scale therefore require low cost and high throughput techniques to monitor the evolution of organic matter. In this study, we assessed the merits of using Fourier transform infrared (FTIR) spectra to predict the organic matter composition in peat samples at various stages of peatland regeneration from five European countries. Using predictive partial least squares (PLS) analyses, we were able to reconstruct peat C:N ratio and carbohydrate signatures with reasonable accuracy, but not the micromorphological composition of vegetation remains. Despite utilising different size fractions, both carbohydrate (<200 μm fraction) and FTIR (bulk soil) analyses report on the composition of plant cell wall constituents in the peat and therefore essentially reveal the composition of the parent vegetational material. The accuracy of the FTIR-based PLS models for C:N ratios and carbohydrate signatures was adequate to allow for their use as initial screening tools in the evaluation of the present and future organic matter composition of peat during monitoring of restoration efforts.

Dissolved organic carbon export from a cutover and restored peatland

AbstractHigh demand for horticultural peat has increased peatland drainage and peat extraction in Canada. The hydrology and carbon cycling of these cutover peatlands is greatly altered, necessitating active restoration efforts to permit the regeneration of Sphagnum mosses and the re‐establishment of natural peatland function. The effect of peatland extraction and restoration on the export of dissolved organic carbon (DOC) was examined for three successive seasons (May to October, 1999 to 2001) at two different sites (cutover and restored) in eastern Québec. A shift towards higher DOC concentrations was observed following peatland extraction (maximum: 182·6 mg L−1) and concentrations remained high post‐restoration (maximum: 191·0 mg L−1). The cutover site exported more DOC than the restored site in all three study seasons. The highest exports occurred during the wettest year (1999), with cutover and restored site export of 10·3 and 4·8 g m−2, respectively. In 2000, 8·5 g C m−2 was released from the cutover site, while the restored site released less than half that amount (3·4 g C m−2). In 2001, the restored site released about the same amount of DOC as in the previous year (3·5 g C m−2), while the cutover site load dropped to 6·2 g C m−2. Both sites were net exporters of DOC in all years. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Species-specific effects of plants colonising cutover peatlands on patterns of carbon source utilisation by soil microorganisms

Root exudates and litter are the main sources of inputs of labile carbon into the microbial pool in successional ecosystems. Here we studied whether typical pioneer species ( Eriophorum vaginatum, Eriophorum angustifolium and Calluna vulgaris) alter the functional response of the microbial community of a previously cutover peatland. Peat was sampled at three depths (0–5, 20–25 and 40–45 cm) from beneath these species and from bare soil areas. MicroResp analysis using ecologically relevant, radiolabelled, carbon sources showed significant separation in community level physiological profiles (CLPP) of soil microorganisms according to peat depth. This effect was also reflected in microbial biomass carbon, which also decreased with increasing depth. Furthermore, distinct differences in CLPP were observed between the three plant species and the bare soil in the absence of an effect on microbial biomass carbon or total soil carbon. The plant species effects were driven by differential utilisation of xylose, glutamic acid, lysine and phenylethylamine. The data suggest that ‘new’ carbon inputs from plants colonising abandoned cutover peatland may support communities of microorganisms that have functionally distinct roles in carbon turnover.

Moisture dynamics and hydrophysical properties of a transplanted acrotelm on a cutover peatland

AbstractThe natural carbon storage function of peatland ecosystems can be severely affected by the abandonment of peat extraction, influencing peatland drainage, leading to large and persistent sources of atmospheric CO2. Moreover, these cutover peatlands have a low and variable water table position and high tension at the surface, creating harsh ecohydrological conditions for vegetation re‐establishment, particularly peat forming Sphagnum moss. Standard restoration techniques aim to restore the peatland to a carbon accumulating system through various water management techniques to improve hydrological conditions and by reintroducing Sphagnum at the surface. However, restoring the hydrology of peatlands can be expensive due to the cost of implementing the various restoration techniques. This study examines a peat extraction‐restoration technique where the acrotelm is preserved and replaced directly on the cutover peat surface. An experimental peatland adopting this acrotelm transplant technique had both a high water table and peat moisture conditions providing sufficient water at the surface for Sphagnum moss. Average water table conditions were higher at the experimental site (−8·4 ± 4·2 cm) compared to an adjacent natural site (−12·7 ± 6·0 cm) suggesting adequate moisture conditions at the restored surface. However, the experimental site experienced high variability in volumetric moisture content (VMC) in the capitula zone (upper 2 cm) where large diurnal changes in VMC (∼30%) were observed, suggesting possible disturbance to the peat matrix structure during the extraction‐restoration process. However, soil–water retention analysis and physical peat properties (porosity and bulk density) suggest that no significant differences existed between the natural and experimental sites. Any structural changes within the peat matrix were therefore minimal. Moreover, low soil‐water tensions were maintained well above the laboratory measured critical Sphagnum threshold of 33% (−100 mb) VMC, further indicating favourable conditions for Sphagnum moss survival and growth. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Changes in Fungal Community Composition in Response to Vegetational Succession During the Natural Regeneration of Cutover Peatlands

Despite the importance of peatlands as a major store of sequestered carbon and the role of fungi in releasing sequestered C, we know little about the community structure of fungi in peatlands. We investigated these across a gradient of naturally regenerating peatland vegetation using denaturing gradient gel electrophoresis (DGGE) and clone libraries of fragments of the fungal rRNA internal transcribed spacer (ITS) region. Significant changes in the fungal community structure of peat samples at different stages of regeneration were observed, which relate to the composition of the vegetation recolonizing these sites. Cloning and sequence analysis also demonstrated a potential shift in the relative abundance of the main fungal phyla. Some of the clones identified to genus level were highly related to fungi known to play a role in the degradation of plant litter or wood in similar ecosystems and/or form mycorrhizal associations. In addition, several fungal isolates highly related to peat clones were obtained, and their enzymic capacity to degrade structural plant tissues was assessed. Together, these results suggest that the fungal community composition of peat may be an important indicator of the status of regeneration and potential carbon sequestration of cutover peatlands.

Land-use scenarios for Finnish cut-over peatlands - based on the mineral subsoil characteristics

In Finland, peat harvesting sites are exploited down almost to the mineral soil and the properties of mineral subsoil have considerable influence on the suitability for the various afteruse forms. Chemical and physical features of the mineral subsoil must be studied when after-use is planned, to ensure no harmful effects follow. Research on mineral subsoils was carried out on Finnish peat production sites in 1997 – 1998 and 9800 hectares of peat production areas slowly getting exhausted were studied. The cutover area clearly suitable for forestation covered 57 % of the study area. The area well suitable for agriculture or energy crop growing covered 26 – 42 % of the study – depending if boulder-poor tills were included or excluded. Even larger areas might be possible for agriculture if for example remaining peat layer was used for compensating physical features of the mineral subsoil. Approximately 11 % was recommended for mire regeneration because of sensitive bottom soils, but much larger areas were possible for mire regeneration. In 9 % of all cases fine miner al subsoils were on pool-forming locations and would this way offer sites best suitable for mire regeneration or even bird sanctuaries. Both EC and pH of the mineral subsoils were related to the presence of sulphur. The concentrations of Ca, Mg and K followed the finematerial percentage. Based on this study minimum analysis recommended was for pH, sulphur content and fine material (< 0.06 mm) percentage. Other relevant elements were calcium, magnesium and potassium. Different land-use scenarios were created for areas in after-use, released from peat production and in peat production (2004). These scenarios were based on the mineral subsoil suitability for different after-use forms. In these scenarios the total area annual carbon fixation values varied between 0.096 and 0.152 million t C a -1 , when carbon emissions were not included.

Spontaneous revegetation of mined peatlands in eastern Canada

Many North American peatlands previously mined for horticultural peat have been abandoned recently, allowing natural recolonization to occur. The two dominant methods for peat extraction, hand block-cutting and vacuum-mining, have created distinctly different abandoned surfaces, leading to different recolonization patterns. Both types of exploitation can be found throughout eastern Canada where we conducted a vast survey of 26 abandoned mined peatlands in the provinces of Québec and New Brunswick. The aim of this study is to describe the revegetation patterns and to assess the impact of local and regional variables as well as the time since abandonment on Sphagnum re-colonization. We inventoried the vegetation structure in all trenches (2571) and baulks (2595) of abandoned block-cut areas as well as in all vacuum fields (395) of the mechanically mined areas. We also conducted detailed species relevés in 242 of these peat fields. In comparison to vacuum-mined peatlands, block-cut peatlands regenerated remarkably well. Approximately 80% of all baulks and trenches in block-cut peatlands had 50% or higher cover of ericaceous shrubs compared with only 16% found on vacuum fields. Herb cover in the three types of abandoned fields was similar to that in natural peatlands. However, Sphagnum percent cover was below 2% in baulks and vacuum fields and was 30% on average in the trenches, which is clearly below cover estimates in natural peatlands. Sphagnum cover and richness were both higher in trenches with thin residual peat deposit, and Sphagnum richness increased with latitude. Our surveys revealed that abandoned mined peatlands have a high diversity of peatland vascular plants species and a low diversity of non-peatland species.Key words: cutover peatlands, regeneration, milled peatlands, block-cut peatlands, vacuum-mined peatlands, colonization patterns.

Greenhouse Gas Emissions from Canadian Peat Extraction, 1990–2000: A Life-cycle Analysis

This study uses life-cycle analysis to examine the net greenhouse gas (GHG) emissions from the Canadian peat industry for the period 1990-2000. GHG exchange is estimated for land-use change, peat extraction and processing, transport to market, and the in situ decomposition of extracted peat. The estimates, based on an additive GHG accounting model, show that the peat extraction life cycle emitted 0.54 x 10(6) t of GHG in 1990, increasing to 0.89 x 10(6) t in 2000 (expressed as CO2 equivalents using a 100-y time horizon). Peat decomposition associated with end use was the largest source of GHGs, comprising 71% of total emissions during this 11-y period. Land use change resulted in a switch of the peatlands from a GHG sink to a source and contributed an additional 15%. Peat transportation was responsible for 10% of total GHG emissions, and extraction and processing contributed 4%. It would take approximately 2000 y to restore the carbon pool to its original size if peatland restoration is successful and the cutover peatland once again becomes a net carbon sink.

Simulating soil water dynamics in a cutover bog

A simulation model flow in cutover peat systems (FLOCOPS) was developed to improve the current understanding of the hydrology of cutover peatlands and the water management programs designed to restore them. FLOCOPS considers temporal variability in peat bulk density, shrinkage character and θ‐Ψ (soil moisture–pressure head) relationships, volume changes due to compression, and changes to saturated hydraulic conductivity (KS) and saturated volumetric soil moisture (θS). FLOCOPS was evaluated by comparing simulated and observed 1998–1999 trends in elevation change (thickness of peat deposit), water table, θ, and Ψ. FLOCOPS effectively represented observed trends in elevation change, θ, and Ψ. A sensitivity analysis indicated that FLOCOPS was most sensitive to the retention, storage, and consolidation characteristics of the peat. Volume changes reduced hydrological variability, whereas low water retentivity and high water storage helped maintain high and stable θ, Ψ, and water table position. The sensitivity of the peat system's hydrology to changes in pore structure suggests that minimizing changes to the peat's characteristic pore structure during extraction and subsequent abandonment of the peatland will result in significantly more favorable hydrological conditions for bog restoration.

On the Use of Shallow Basins to Restore Cutover Peatlands: Plant Establishment

Abstract Since the early 1990s, restoration techniques have been developed for milled and cutover peatlands in eastern Canada. These techniques are based on the active reintroduction of peatland plant diaspores, blocking drainage, and the use of straw mulch to improve surface conditions. This study examines the effectiveness of using shallow (20 cm deep) basins of various widths to improve the success of current peatland restoration techniques. It comprises three different experiments, each spanning three or four growing seasons and combining both small‐scale manual and large‐scale mechanized plant reintroductions. Cover data recorded in two of the experiments were regressed against a series of environmental factors to determine how Sphagnum establishment success was related to abiotic variables such as moisture, water ponding, surface roughness, and mulch cover. Results of these experiments demonstrate that shallow basins were generally effective at promoting Sphagnum establishment and that this effect extends beyond the positive impact that basins have on hydrological conditions. Basins of various widths were equally successful. Soil‐moisture content (linear positive effect) and duration and severity of flooding events (quadratic effect) were shown to be determinant of plant recovery. Other factors such as the density of straw cover (positive effect) and surface roughness (negative effect) were also instrumental in explaining local variation in Sphagnum cover. Plant cover after three and four growing seasons averaged 20–25% in mechanical reintroductions and 40–60% in manual reintroductions, demonstrating the overall effectiveness of the restoration techniques used.

Vertical micro-distribution and response to nitrogen deposition of testate amoebae in Sphagnum.

Previous studies have shown the existence of a vertical micro-distribution of testate amoebae in the first centimeters of Sphagnum and their response to nutrient enrichment. In order to test the response of testate amoebae to depth and N addition in dry moss carpets recolonizing cutover peatlands, we sampled Sphagnum that had received 0, 1, 3, or 10g N m(-2) yr(-1) for three years. The mosses were cut into three segments: 0-1cm, 1-3cm and 3-5cm and analyzed for testate amoebae. The overall diversity (22 taxa) was high considering the dryness of the site, but the species richness of individual samples was low (mean 6.6). The presence of several species characteristic of wetter conditions suggests that they have a broader tolerance than usually believed and/or have a high colonization potential. Species richness increased with depth. Assulina muscorum was most abundant in the top segment, while Phryganella acropodia, Heleopera rosea and Nebela militaris were most abundant in the deepest segment. Neither the metabolism type nor the shell characteristics significantly explained the vertical distribution of species. There was no overall response of testate amoebae to N, although one species, Bullinularia indica, was significantly more abundant in the fertilized than in the control plots.

Statistical characterization of the spatial variability of soil moisture in a cutover peatland

AbstractSoil moisture is a significant variable in its importance to the validation of hydrological models, but it is also the one defining variable that ties in all components of the surface energy balance and as such is of major importance to climate models and their surface schemes. Changing the scale of representation (e.g. from the observation to modelling scale) can further complicate the description of the spatial variability in any hydrological system. We examine this issue using soil moisture and vegetation cover data collected at two contrasting spatial scales and at three different times in the snow‐free season from a cutover peat bog in Cacouna, Québec. Soil moisture was measured using Time Domain Reflectometry (TDR) over 90 000 m2 and 1200 m2 grids, at intervals of 30 and 2 m respectively. Analyses of statistical structure, variance and spatial autocorrelation were conducted on the soil moisture data at different sampling resolutions and over different grid sizes to determine the optimal spatial scale and sampling density at which these data should be represented. Increasing the scale of interest without adequate resolution in the measurement can lead to significant inconsistency in the representation of these variables. Furthermore, a lack of understanding of the nature of the variability of soil moisture at different scales may produce spurious representation in a modelling context. The analysis suggests that in terms of the distribution of soil moisture, the extent of sampling within a grid is not as significant as the density, or spacing, of the measurements. Both the scale and resolution of the sampling scheme have an impact on the mean of the distribution. Only approximately 60% of the spatial pattern in soil moisture of both the large and small grid is persistent over time, suggesting that the pattern of moisture differs for wetting and drying cycles. Copyright © 2003 John Wiley &amp; Sons, Ltd.

Role and character of seasonal peat soil deformation on the hydrology of undisturbed and cutover peatlands

This paper describes the nature and magnitude of peat soil volume changes and its relation to seasonal changes in water table at an undisturbed bog peatland and on two cutover sections of the same peatland and its effect on hydraulic conductivity. In the latter two sites, operations had ceased 2 and 7 years prior to this study, respectively. The water table dropped to a maximum depth of 40, 50, and 68 cm, respectively, at the undisturbed, 2‐year, and 7‐year abandoned sites and a resulted in subsidence of 0.96, 3.84, and 2.65 cm m−1, respectively. At the undisturbed site, surface elevation changes did not always correspond to water table changes, but peat underwent a period of swelling even as the water table fell, probably due to the accumulation of methane in soil pores. At all sites most volume change occurred in the upper 50 cm layer, with maximum strain of 5, 15, and 5% at the undisturbed, 2‐year, and 7‐year abandoned sites, respectively, and was strongly related to water table decline. A model of peat deformation in the zone of saturation (100 cm depth), based on changes in saturated soil moisture (6%), grossly overestimated strain (1%) in the saturated zone, and again methane accumulation was the suspected cause of the soil moisture decrease. Peat compression (and perhaps methane accumulation) caused hydraulic conductivity to decrease over two orders of magnitude at 75, 125, and 170 cm depth. The decrease in hydraulic conductivity as a peatland dries may be an important self‐preservation mechanism (i.e., against further water loss).

Moisture controls on Sphagnum growth and CO2 exchange on a cutover bog

Summary 1. Abandoned cutover peatlands are persistent sources of atmospheric CO2. Net ecosystem CO2 exchange and Sphagnum net primary production of an abandoned block‐cut bog were measured in the field and in the laboratory using gas exchange techniques to determine the processes controlling CO2 exchange in these ecosystems. 2. Sphagnum net primary production was offset by peat respiration, resulting in the peatland becoming a net source of CO2 during the summer months. 3. Sphagnum photosynthesis was greatest at wet sites. In addition, sites with vascular plant cover photosynthesized at approximately twice the rate of sites where vascular plants were removed. 4. Laboratory results indicate that drying and wetting cycles negatively affect Sphagnum net primary production and net ecosystem CO2 exchange. Sphagnum and peat respiration increased 4–14‐fold upon rewetting, whereas Sphagnum photosynthesis did not recover until 20 days of saturation. 5. Synthesis and applications. This research emphasizes the importance of stable moisture availability for the growth of Sphagnum and the eventual development of a new acrotelm on the cutover bog surface. Restoration techniques must therefore include companion species and a constant moisture supply above the minimum threshold for Sphagnum mosses.

Sphagnum production and decomposition in a restored cutover peatland

Natural peatlands represent a long-termsink of atmospheric carbon dioxide(CO2), however, drained and extractedpeatlands can represent a source ofatmospheric CO2. The restoration ofSphagnum mosses on abandoned milledpeatlands has the potential to sequesteratmospheric CO2 thereby returning thepeatland to a peat accumulating system.Micrometeorological and chambermeasurements of net ecosystem CO2exchange are proven methods forinvestigating production and decompositionprocesses in both natural, extracted, andrestored peatlands. However, this approachis relatively expensive because ofinfrastructure and human resources that notonly limits potential use for ecologicalmanagers but it limits the number of sitesthat can be monitored due to high spatialvariability. Here we present crank wire anddestructive sampling productionmeasurements, litter bag decompositionmeasurements and measurements of netecosystem CO2 exchange made in arestored peatland and natural peatlandsites nearby. The objectives were to assessproduction and decomposition rates in thetwo systems as well as to compare thedifferent measurements techniques.Estimates of Sphagnum fuscumproduction at a restored peatland, usingthe different methods, followed the trend:crank wire S.capillifolium) according to their abilityto withstand harsh conditions on restoredpeat surfaces. Decomposition rate was alsosignificantly greater (p<0.05) for S. capillifolium than S. fuscum,resulting in an overall plant accumulationgreater for S. fuscum. Although therestored surfaces were fairly young,production rates estimated on cutoversurfaces that were fully covered with athin Sphagnum mat compared withproduction rates observed in natural sitesnearby.