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The provision of critical ecosystem services like carbon sequestration by peatlands has been degraded around the globe. Peatland restoration represents an opportunity to tackle the twin global emergencies of climate breakdown and biodiversity decline. Nonetheless, restoration success relies on a sound understanding of recovery trajectories associated with different restoration techniques. Focusing on temperate/boreal Sphagnum‐dominated peatlands, we used a quantitative meta‐analysis of 28 studies representing 275 sites in 11 countries to test for effects of peatland status (intact, restored, and degraded), varying restoration interventions and time since restoration on vegetation as a key indicator of peatland condition and functioning. Enhanced restoration (such as active revegetation) resulted in recovery to predisturbance levels within 30–35 years for Sphagnum mosses, and 20–25 years for many other peatland specialist species, and was the only restoration approach where positive outcomes were seen across all vegetation response variables. The use of standard restoration techniques, such as rewetting, was projected to result in cover of Sphagnum mosses and peatland specialist plants reaching that of intact sites within 45–55 years post‐restoration. Passive restoration (cessation of the degrading activity with no active restoration) generally elicited limited recovery of keystone peatland vegetation (Sphagnum spp.) even after multiple decades. A lack of standardization in monitoring severely constrains the analysis of peatland restoration outcomes. Increased funding for monitoring and reporting outcomes, and improved monitoring consistency, could greatly enhance our understanding of peatland restoration ecology and improve practice. [ABSTRACT FROM AUTHOR]

Bogs are known to be relatively resistant and resilient to fire, due to the dominance of wet Sphagnum mosses. Indeed, Sphagnum mosses by holding water, ensure bog resistance, and by regenerating from any fragments left post‐fire, ensure bog resilience. The return of several ecological attributes has been reported in the literature post‐restoration. However, the resistance and resilience have not yet been evaluated in restored peatlands. A fire affecting an extracted peatland restored 10 years ago provided the opportunity to (1) evaluate the losses post‐fire, in terms of phytobiomass and plant cover and (2) assess early vegetation recovery after one growing season post‐fire. The fire response of the restored peatland, in terms of resistance and short‐term resilience, differed between the main plant communities. Sphagnum Lawn communities (Sphagnum species from the Acutifolia subgenus and Eriophorum vaginatum) showed greater resistance to fire losing proportionally less phytobiomass (17%) than Wet Hollow communities (44%) (Sphagnum species from the Cuspidata subgenus and Scirpus cyperinus). Greater resistance of the Sphagnum Lawn likely comes from the Acutifolia Sphagnum species growing in dense carpets with good water retention, along with the E. vaginatum tussocks being able to retain humidity below the tussocks, whereas the looser growth habit of Cuspidata Sphagnum species do not have good capillary rise capacity and Scirpus produced litter that can produce a good fuel. This study reinforces the idea that a peatland restoration approach using reintroduction material dominated by Acutifolia Sphagnum species and tussock cottongrass provides a better resistance and short‐term resilience of restored peatlands. [ABSTRACT FROM AUTHOR]

Litter decomposition is a key process controlling carbon (C) sequestration in Sphagnum dominated peatlands. Peatland drainage lowers the water table, increases vascular plant richness, and alters species evenness. We hypothesized that abiotic and biotic changes following peatland drainage would greatly accelerate litter decomposition. This hypothesis was tested by a litter decomposition experiment in an undrained and a drained area of a peatland which was partially drained 30 years ago. Litter bags filled with shoots of the peat moss Sphagnum magellanicum and leaves of the dwarf shrub Potentilla fruticosa as single species and species mixtures with three evenness treatments were placed at the surface of the peatland. After 6 months (from August onwards) of decomposition, the single species litter of Potentilla fruticosa, with low initial C/N ratio, decomposed much faster than S. magellanicum litter, with high initial C/N ratio in both undrained and drained areas. Overall, mixed litter produced antagonistic effects (observed values less than expected) on decomposition and C/N ratio. Litter mixtures dominated by S. magellanicum showed lower mass loss than other mixtures. Contrary to our expectation, the undrained area showed higher decomposition than the drained area. Our study suggests that drainage-induced alteration in plant diversity slows down litter decomposition in a short term. However, in drained peatlands, lower C/N ratio of mixed litter may enhance decomposition and reduce C sequestration over time. [ABSTRACT FROM AUTHOR]

Restoration of degraded peatland ecosystems (by rewetting) is undertaken to bring back key ecosystem services. However, the restoration process can have a range of ecohydrological effects, due to the associated physical and biogeochemical disturbance. In the case of northern peatlands drained by large and deep ditches, the rewetting effects are relatively unknown. The raised bog Grande plée Bleue (1,500 ha) is one of the largest pristine bogs in the St‐Lawrence lowlands in North America; however, it contained an old (>60 years), 750 m long, 3.5 m deep, and 8 m wide ditch. Rewetting of the area affected by the ditch was carried out by the construction of six dams at 40 cm elevation intervals and felling of all trees (with diameter at breast height >10 cm) within 30 m. Water table was restored to levels similar to intact bog reference sites, only at elevation differences up to 17 cm from the nearest lower dam, while rewetting did not affect pore‐water chemistry. Five to 6 years post‐rewetting, the cover of both pioneer mosses, and late successional mosses (Sphagnum) had not changed significantly compared with pre‐rewetting. This may have been due to the presence of dense shrub cover. For more effective ecohydrological restoration, dams should be spaced at smaller elevation intervals (e.g., every 20 cm of elevation or less), to allow recovery of water table along the entire length of the ditch, and vegetation introduction using the moss layer transfer technique may accelerate Sphagnum recruitment, especially in the few first metres from the ditch. [ABSTRACT FROM AUTHOR]

The study central goal was to analyze secondary succession in a degraded peatland: (1) Sphagnum distribution trends and (2) successional patterns. Main study sites were adjacent abandoned pastures, where grazing was carried out in former peatland and where degradation had occurred, hereafter referred as degraded peatland. (1) Degraded peatland was mapped in 2006 (while it was still a pasture, grazed for over 30 years), and throughout the study period in 2013 (2 years post-abandonment) and 2015 (4 years post-abandonment). The baseline assessment of 2006 revealed that Sphagnum spp. were present in 7% of the area, which pointed at the resilience of the peat ecosystem. After the grazing ceased, Sphagnum cover increased to 17% and 39%, in the next 2 and 4 years respectively post animal removal. (2) To gain a general comprehension of flora and vegetation changes along the regenerative sucession, 48 permanent plots were established in the degraded peatland. In two other study sites, a further twenty plots were established, ten plots in a semi-natural peatland area where grazing ceased 30 years ago and ten others in a natural peatland. These were monitored between July 2012 and July 2015 (triannual). After 4 years, the formerly degraded peatland showed considerable recovery with a growth of Sphagnum spp. cover as well as other species like Calluna vulgaris, tending to become more similar to semi-natural and natural peatlands. Grazing cessation induced the regenerative succession that could lead to self-recovery, which, in optimal conditions, could be an alternative to active restoration in Azores. [ABSTRACT FROM AUTHOR]

Aims: Separating the effect of resource competition from allelopathy in plants is challenging and it has never been attempted in closely related co-occurring bryophytes. In peatlands, peat mosses (Sphagnum spp.) show niche differentiation along water table level (WTL) gradient. Our aim was to evaluate whether the hummock species, S. magellanicum would be a winner at low WTL due to its allelopathic advantage and the hollow species, S. angustifolium would win by virtue of its superior competitive ability but not of allelopathy at high WTL due to dilution of its allelochemicals. Methods: We used a nested, field experimental design, with two WTL treatments—low WTL (hummock habitat) and high WTL (hollow habitat)—and three different inter-specific interactions: 1) monoculture; 2) mixed culture without activated charcoal; and 3) mixed culture with activated charcoal added to the neighbor. We measured growth and biochemical traits of the two species and compared the index of relative neighbor effect on each other. Results: We discovered a trade-off between biomass production (competitive outcome) and phenolic content (allelopathy) in these species. At low WTL, allelopathy of the hummock species is the main mechanism to suppress the hollow species, whereas at high WTL, competition is the main driver to suppress the hummock species. Conclusions: Competitive advantage in Sphagnum is mediated by both resource competition and allelopathy of the co-occurring species through niche differentiation along a WTL gradient. Unlike vascular plants, Sphagnum mosses can serve as excellent model organisms in studying allelopathic interaction since they bypass the complexity of plant-soil interactions. [ABSTRACT FROM AUTHOR]

Ecosystem restoration frequently involves the reintroduction of plant material in the degraded ecosystem. When there are no plant nurseries or seeds available on the market, the plant material has to be harvested in the wild, in a "donor ecosystem." A comprehensive assessment of donor ecosystem recovery is lacking, especially for Sphagnum‐dominated donor peatlands, where all top vegetation is harvested mechanically with different practices. We aimed to evaluate (1) the regeneration of vegetation, especially of Sphagnum mosses, to determine which harvesting practices are best to enhance recovery and (2) the influence of the site hydrological conditions and meteorological variables of the first complete growing season postharvesting on peat moss regeneration. Twenty‐five donor sites covering a 17‐year chronosequence (harvested 1–17 years ago) were inventoried along with 15 associated natural reference sites located in Quebec, New Brunswick, and Alberta, Canada. All donor sites aged 10 years or more were dominated by Sphagnum mosses, though plant composition varied between donor and their associated reference sites because of the wetter conditions at harvested donor sites. Harvesting practices strongly influenced donor site recovery, showing that the skills of the practitioner are an essential ingredient. Harvesting practices minimizing donor site disturbances are recommended, such as the choice of the adequate donor site (localization, hydrologic conditions, vegetation), the use of less disruptive methods, and harvesting when the soil is deeply frozen. This study demonstrated that harvesting surface plant material for peatland restoration is not detrimental towards the recovery of near‐natural peatland ecosystems. [ABSTRACT FROM AUTHOR]

Peatland restoration in North America ( NA) was initiated approximately 25 years ago on peat-extracted bogs. Recent advances in peatland restoration in NA have expanded the original concepts and methodology. Restoration efforts in NA now include restoring peatlands from many diverse types of disturbances (e.g. roads, agriculture, grazing, erosion, forestry, and petrol industry infrastructure impacts) and occur in a greater array of peatland types (e.g. fens and swamps). Because fens are groundwater and surface flow driven, techniques to restore the hydrology of fens are generally more complicated than bogs. Restoring a greater variety of peatland types on a large-scale basis (>10 ha) commands new techniques for reestablishing a broader array of plants other than Sphagnum spp., including non- Sphagnum mosses, sedges, nonericaceous shrubs, and trees. The rationale for restoring peatlands has expanded to include legal requirements, wetland mitigation and banking, climate mitigation, water quality, and as part of responsible ecosystem management for industry or society. In the past 25 years, peatland restoration in NA has evolved from (1) trial and error to a more empirically based scientific approach, (2) small site-specific experiments to landscape-scale restoration (e.g. hydrological connectivity, ecological fragmentation), and (3) individual stakeholder (academic) to multiple stakeholders across jurisdictional boundaries (private, local, and regional governmental agencies, NGOs, and so on). However, many research gaps still exist that must be addressed to enhance our ability to restore peatlands successfully. [ABSTRACT FROM AUTHOR]

Peat mosses ( Sphagnum) are ecosystem engineers-species in boreal peatlands simultaneously create and inhabit narrow habitat preferences along two microhabitat gradients: an ionic gradient and a hydrological hummock-hollow gradient. In this article, we demonstrate the connections between microhabitat preference and phylogeny in Sphagnum. Using a dataset of 39 species of Sphagnum, with an 18-locus DNA alignment and an ecological dataset encompassing three large published studies, we tested for phylogenetic signal and within-genus changes in evolutionary rate of eight niche descriptors and two multivariate niche gradients. We find little to no evidence for phylogenetic signal in most component descriptors of the ionic gradient, but interspecific variation along the hummock-hollow gradient shows considerable phylogenetic signal. We find support for a change in the rate of niche evolution within the genus-the hummock-forming subgenus Acutifolia has evolved along the multivariate hummock-hollow gradient faster than the hollow-inhabiting subgenus Cuspidata. Because peat mosses themselves create some of the ecological gradients constituting their own habitats, the classic microtopography of Sphagnum-dominated peatlands is maintained by evolutionary constraints and the biological properties of related Sphagnum species. The patterns of phylogenetic signal observed here will instruct future study on the role of functional traits in peatland growth and reconstruction. [ABSTRACT FROM AUTHOR]

Highlights: [•] Innovative restoration approach specific to peatlands pools. [•] Ericaceous shrubs transplanted near pools reduce frost heave by 52%. [•] Ericaceae promote Sphagnum majus establishment at water edge of restored pools. [Copyright &y& Elsevier]

Abstract: Mosses are keystone species in peatlands and are an important part of the vegetation of the pre-mined peatlands. Therefore, mosses should be included in rehabilitation projects following oil sands exploitation in north-western Canada. However, mosses growing in post-mined landscapes must tolerate elevated salinity levels found in oil sands process water (OSPW). Knowledge of salinity tolerance and thresholds for fen mosses is needed to place these mosses in the newly created landscapes. We tested the effects of NaCl and Na2SO4 on four fen moss species growing in Petri dishes in growth chambers. We simulated two scenarios: (1) four immersion times (¼, 1, 3 and 7 days) in NaCl (0%, 20%, 60% or 100% of the concentration found in OSPW) mimicking periodic flooding and (2) a permanent saline influence (NaCl or Na2SO4 alone or in combination at 0%, 30%, 50% or 70% of the concentrations found in OSPW) mimicking situations of high water tables with different contamination levels. The effects on moss growth were estimated by counting new innovations of Bryum pseudotriquetrum, Campylium stellatum, Sphagnum warnstorfii and Tomenthypnum nitens. All tested mosses tolerated saline levels typically found in post-mined landscapes (up to 500mgL−1 of NaCl and 400mgL−1 of Na2SO4) for up to 100 days of exposure. Short periods of immersion (up to 7 days independently of salt concentrations) induced the production of innovation in non-Sphagnum species, but S. warnstorfii was more rapidly impacted at higher salt concentrations. Short pulses of salt (from 6h to 7 days) did not influence the formation of new innovations for C. stellatum and T. nitens. Salt type (NaCl and/or Na2SO4) had no effect on moss growth. However, a longer exposure (100 days) with saline water, even at low concentrations, diminished the formation of new innovations for B. pseudotriquetrum and T. nitens. C. stellatum was the least affected by salinity and thus we suggest it is the best species to reintroduce in constructed fens. [Copyright &y& Elsevier]

Our study found that a water level close to the surface and a seedbed composed of bare peat or a Sphagnum carpet favored the germination of vascular species associated with pools in peatlands. A greenhouse experiment was conducted to study the impact of seedbed and water level on the germination and growth of 7 plant species associated with pools: Carex limosa L, C magellanica Lam. ssp. irrigua (Wahlenb.) Hultén, C. oligosperma Michx., C pauciflora Lightf., and Rhynchospora alba (L.) Vahl from the Cyperaceae family as well as Drosera intermedia Hayne (Droseraceae) and Scheuchzeria palustris L. (Scheuchzeriaceae). The 3 seedbeds tested were 1) bare peat; 2) a carpet of Sphagnum cuspidatum Ehrh. ex Hoffm. and 5. faiiax (Klinggr.) Klinggr. (Sphagnaceae); and 3) a carpet of Cladopodieila fiuitans (Nees) H. Buch (Cephalaziaceae), common bryophytes along pool edges. Seedbeds were combined with 2 water levels (0 and 10 cm below the soil surface) in a complete factorial block design. Germination periods were generally longer when seeds were submitted to drier conditions and placed on C. fiuitans carpets. Conditions favoring biomass production were more variable among species. These results will facilitate the identification of the best ecological conditions for successful establishment of pool edge species in the context of restoration projects, thereby increasing biodiversity and ecological value of restored peatlands. [ABSTRACT FROM AUTHOR]

Abstract: Establishment of specific vascular plants and Sphagnum species, as well as asymmetrical competition and facilitation between the two types of plants are apparently important in the development of microtopography in peatlands. To determine whether peatland vascular plants can facilitate the initiation of Sphagnum hummocks, and consequently the differentiation of bog microtopography, we investigated the effects of vascular plant life form and structure on Sphagnum stem length and biomass. We showed that Sphagnum stem length and biomass were enhanced by low density of vascular plants and other introduced structures, which thus favoured hummock formation. Dense covers of vascular plants also promoted moss height growth, but the Sphagnum stems were etiolated and fluffy, their densities were too low and biomass was too small to initiate clear hummocks. We also showed that vascular plants contributed to microhabitats with stable temperatures and high relative humidity favourable to Sphagnum growth. Stress-gradient hypothesis, predicting that the relative frequencies of facilitation and competition events will vary inversely along abiotic stress gradients, could explain the nature of the interaction between mosses and vascular plants. At the onset of microstructures formation in peatlands, abiotic stress is probably more important and facilitation events could be frequent. Microclimatic effects of vascular plants may be essential for Sphagnum growth. Then, the presence of ericaceous shrubs or young trees enhances the microtopography by physically reinforcing the hummocks. During accentuation of microtopography, the positive interactions between Sphagnum mosses and vascular plants may be replaced by competition as abiotic stress declines. This study introduces new evidence for the role of vascular plants in the formation and maintenance of hummocks, especially under drier growing conditions. [Copyright &y& Elsevier]

Fen bryophytes are an important component of natural fens and should be included in fen restoration projects. The goal of this study was to examine the regeneration capabilities of nine bryophytes common to moderate-rich and poor fens in North America. A greenhouse experiment was carried out to examine the limitations and optima for the regeneration of fen bryophytes under different light and water regimes. A field experiment tested these same bryophytes in the presence of three potential nurse-plants. In the greenhouse experiment, the presence of shade increased regeneration success for eight out of nine species. A high water level was ideal for the regeneration of the majority of species tested. In the field experiment, Sphagnum species had the highest regeneration, and all species had higher regeneration under a dense canopy of herbaceous plants. Fen bryophytes show good potential for use in restoration projects because the tested bryophytes regenerated well from fragments. [ABSTRACT FROM AUTHOR]

Polytrichum strictum is a pioneer plant frequently found on bare peat substrate after perturbations (fire, peat extraction). Can this moss facilitate the return of Sphagnum species or other boreal plants after disturbances? Field surveys of abandoned peatlands after peat extraction revealed that Sphagnum was always found in association with P. strictum carpets. We conducted field experiments in abandoned peatlands and showed that P. strictum carpets were able to keep Sphagnum fragments more humid than bare peat but only when the P. strictum carpets were not totally bone dry. In general, daytime temperatures beneath P. strictum carpets and fragments were reduced during the day and increased during the night compared to bare peat. Polytrichum strictum carpets acted as a seed trap, retaining more artificial seeds than bare peat. Polytrichum strictum can be a nurse-plant: after 16 months, vascular plants transplanted in the P. strictum carpet were healthier than the ones planted on bare peat. The use of P. strictum as a nurse-plant in boreal forest or peatland restoration is recommended for sites prone to frost heaving and with harsh microclimatic conditions. [ABSTRACT FROM AUTHOR]

1. Peatlands have suffered great losses following drainage for agriculture, forestry, urbanisation, or peat mining, near inhabited areas. We evaluated the faunal and vegetation patterns after restoration of a peatland formerly mined for peat. We assessed whether bog pools created during restoration are similar to natural bog pools in terms of water chemistry, vegetation structure and composition, as well as amphibian and arthropod occurrence patterns. 2. Both avian species richness and peatland vegetation cover at the site increased following restoration. Within bog pools, however, the vegetation composition differed between natural and man-made pools. The cover of low shrubs, Sphagnum moss, submerged, emergent and floating vegetation in man-made pools was lower than in natural pools, whereas pH was higher than in typical bog pools. Dominant plant species also differed between man-made and natural pools. 3. Amphibian tadpoles, juveniles and adults occurred more often in man-made pools than natural bog pools. Although some arthropods, including Coleoptera bog specialists, readily colonised the pools, their abundance was two to 26 times lower than in natural bog pools. Plant introduction in bog pools, at the stocking densities we applied, had no effect on the occurrence of most groups. 4. We conclude that our restoration efforts were partially successful. Peatland-wide vegetation patterns following restoration mimicked those of natural peatlands, but 4 years were not sufficient for man-made pools to fully emulate the characteristics of natural bog pools. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 drain- age, 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. [ABSTRACT FROM AUTHOR]

Sphagnum dominated peatlands do not rehabilitate well after being cutover (mined) for peat and some action needs to be taken in order to restore these sites within a human generation. Peatland restoration is recent and has seen significant advances in the 1990s. A new approach addressing the North American context has been developed and is presented in this paper. The short-term goal of this approach is to establish a plant cover composed of peat bog species and to restore a water regime characteristic of peatland ecosystems. The long-term objective is to return the cutover areas to functional peat accumulating ecosystems. The approach developed for peatland restoration in North America involves the following steps: 1) field preparation, 2) diaspore collection, 3) diaspore introduction, 4) diaspore protection, and 5) fertilization. Field preparation aims at providing suitable hydrological conditions for diaspores through creation of microtopography and water retention basins, re-shaping cutover fields and blocking ditches. It is site specific because it depends largely on local conditions. The second step is the collection of the top 10 centimetres of the living vegetation in a natural bog as a source of diaspores. It is recommended to use a ratio of surface collected to surface restored between 1: 10 and 1: 15 in order to minimize the impact on natural bogs and to insure rapid plant establishment in less than four years. Diaspores are then spread as a thin layer on the bare peat surfaces to be restored. It has been demonstrated that too scant or too thick a layer decreases plant establishment success. Diaspores are then covered by a straw mulch applied at a rate of 3 000 kg ha-1 which provides improved water availability and temperature conditions. Finally, phosphorus fertilization favours more rapid substrate colonization by vascular plants, which have been shown to help stabilize the bare peat surface and act as nurse plants to the Sphagnum mosses. [ABSTRACT FROM AUTHOR]

Site preparation for restoration of peat-mined bogs in eastern Canada frequently involves the construction of bunds or shallow basins to enhance peat moisture content. As a consequence, Sphagnum reintroduced within restored areas may be subjected to extended periods of flooding, particularly following snow melt or heavy rainfall. This paper examines two aspects of the effect of flooding on growth and development of Sphagnum: (1) the production of innovations (growth buds and shoots) and capitula from plant fragments (six species) under continuous, intermittent or non-flooding conditions, and (2) the growth response of whole plants (10 species) under long-term continuous shallow flooding.The development response of Sphagnum fragments to short-term continuous (8–10 cm), intermittent (−1 to +1 cm) or non-flooding conditions (−3 to 0 cm), was investigated in growth chambers. Environmental parameters were selected to investigate the possible differential effects of early spring flooding (10:7 °C, day:night), or inundation following heavy rainfall events later in the season (20–25:20 °C, day:night). Both temperature regimes yielded similar results. After 1 month of flooding the number of innovations was generally similar to that for non-flooded controls. However, after a further 3 months, fragments that had been flooded for 1 month (either continuously or intermittently) produced more capitula than non-flooded fragments. Although S. fuscum, a hummock-forming species, showed delayed formation of innovations, flooding still increased final capitula production.The growth response of whole Sphagnum plants to long-term continuous flooding in the field (+1 cm), revealed that most species grew well, but that several becoming etiolated. These modifications may result in plants more prone to desiccation during drier events than individual with a regular growth form.It is concluded that limited periods of shallow flooding could enhance Sphagnum development in restored areas. Care must be exercised though, as deep or extensive inundation may result in excessive plant etiolation or cause severe physical disturbances to the restorated areas. [Copyright &y& Elsevier]

Abstract Basins 20-, 10-, and 4-m wide were excavated 15 to 20 cm into cutover peat fields near Lac Saint Jean, Québec, Canada to facilitate the establishment of Sphagnum mosses. Sphagnum diaspores (fragments) and straw mulch were spread over the excavated surfaces, a control peat field, and a mulch-protected site without basins. Mean water tables in the 20-, 10-, and 4-m wide basins and the mulch-protected site were 27.2, 8.3, 11.4, and 9.7 cm higher, respectively, than in the control peat field in May to August 1996. Similar improvements were observed in 1997 (a drier summer). The higher water table was due to lowering of the peat surface with respect to the local water table, retention of meltwater and stormwater by the peripheral ridges formed during excavation, retention of water during drier periods by the groundwater mound beneath the ridges, and mulch. Soil moisture was always higher in the experimental basins than in the control peat field or in the mulch-protected site, demonstrating the superior soil wetness characteristic of sites with basins and straw mulch. Water tension data signaled the absence of the capillary fringe (i.e., capillary drainage) near the surface for some finite period, thus possibly limiting water for best Sphagnum growth. At the experimental basins and mulch-protected site, 100% of these periods lasted four or fewer days. In the control peat field, 20% of the periods when capillary drainage had occurred lasted more than four days, with one period of 17 days. The mulch protection alone provided considerable improvement in hydrological conditions compared with the control peat field, but the additional water retained in the experimental basins protected against Sphagnum desiccation and loss during more extreme dry periods. [ABSTRACT FROM AUTHOR]

. Bogs, economically valuable wetlands, are subjected to exploitation in southern Canada. We addressed plant conservation within bogs mined for peat, in which small undisturbed remnants are left, mostly at the margins of the mined areas. The main goal of the study was to test whether these remnants act as refuges for plants which could recolonize areas that are planned for restoration after mining is completed. Mosses, lichens and vascular plants were sampled in remnants of 24 mined bogs in southeastern Canada during the summer of 1997. The vegetation was also sampled at the margins and centres of 24 nearby natural bogs in plots similar in size to these remnants. Using similarity analysis and ordination techniques, we found that plant species assemblages in remnants of mined bogs differ from those near the margins of natural bogs, and that certain species are associated with the centre of natural bogs, due to the presence of pools. We also showed that water conditions of remnants are affected by drainage due to peat mining. Sphagnum moss showed itself to be a key indicator of mining effects on vegetation. Implications for peat resource management and bog conservation are discussed. [ABSTRACT FROM AUTHOR]

Annual linear growth, net primary production, and decomposition of Sphagnum fuscum, Sphagnum magellanicum, and Sphagnum angustifolium were measured under experimental acidification and natural conditions in a poor fen at the Experimental Lakes Area (ELA), Ontario, Canada. Acidification increased growth and production of most species (2 out of 3 in the oligotrophic zone, and 2 out of 3 in the minerotrophic zone) in the first 2 yr. After 2-3 yr of artificial acidification, growth and production were not stimulated to the same extent in experimental areas as in earlier years. After 4 yr, growth and production in the experimental area declined so that they were the same as controls for 4 of the 6 treatments. Therefore, the effect of the acid treatment changed over the years. With 4 yr of simulated 'acid rain,' decomposition was unaffected. Our results suggest that the fertilizing effect of SO42- and NO3- in North American acid precipitation as suggested previously in the literature is a very short-term one, at least for this type of peatland. Under natural conditions, in the oligotrophic central zone of mire 239, production for hollow species was somewhat greater than for hummock species for the 4 yr studied. Since the decomposition rate ratio between hummock-top, mid-hummock, and hollow species is roughly in the ratio 7:9:13, the rate of peat accumulation should be higher in hummocks. Hence hummocks appear to be maintained in this poor fen due to low decomposition rates rather than relatively high production. For 3 of the 4 yr studied (1985-1987) in the minerotrophic edge zone, hummock production (303, 175, and 156 g°m-2°yr-1, respectively) was greater than hollow (198, 100, and 97 g°M-2°yr-1) and mid-hummock production (103, 59, and 52 g°m-2°yr-1). The relative decomposition rates of the species had the same ratio as in the oligotrophic zone. Thus hummocks appear to be expanding in this minerotrophic edge zone at a faster rate than in the oligotrophic zone. [ABSTRACT FROM AUTHOR]

The re-establishment of Sphagnum mosses on bare peat surfaces is one of the main challenges faced in the restoration of post-harvested peatlands. One suggested approach to ensure moss recolonization is to use fragments of Sphagnum plants collected from a natural area as diaspores. The regeneration and recolonization potential of fragments of different species of Sphagnum were tested on bare peat, both in the field and in a greenhouse. We examined how diaspore size, density and depth of origin influence recolonization and re-establishment success. The greenhouse experiment also tested the impact of water level on Sphagnum regeneration and recolonization. Field and laboratory experiments showed that only the surface layer (0—19 cm) of a peat profile contained enough viable material to be of practical use as a source of diaspores. Small (0.5-cm), medium (1-cm) or large (2-cm) diaspores had similar recolonization success. Obtaining a precise and even size of fragments will not, therefore, he an important aspect to consider when scaling up to the quantities needed for restoring large surfaces. Greenhouse experiments showed that water level in the peat column greatly influences the recolonization success of Sphagnum diaspores. Most species reacted positively to wetter conditions, with the notable exception of S. fuscum. A density of 450 Sphagnum plants per m² resulted in some Sphagnum species covering up to 50% of the peat surface in 3 months and 100% in 6 months, when the water table was close to the peat surface in the greenhouse experiment. Sphagnum cover reached 5–10% after 3 months in the drier treatments of the greenhouse experiment and was generally comparable to the results obtained in the field after one season of growth under shade cloth. Improving the humidity conditions offered to diaspores is by far the most promising approach to reduce the quantity of diaspores needed to re-establish a significant moss cover rapidly on a post­harvested surface. The selection of appropriate species and densities according to the dryness of the surface to be restored are two other elements to consider in minimizing the amount of source material needed for restoration. [ABSTRACT FROM AUTHOR]

In the original publication, the Table 1 was published incorrectly. The correct version of Table 1 is given in this correction. The original article has been corrected. [ABSTRACT FROM AUTHOR]

The article cites a research study on the restoration of sphagnum dominated peatlands. This study has emerged as a new scientific field in the last fifteen years. The need to restore peatlands was partly induced by the wider recognition of wetland values in the landscape and the recent extensive commercial uses of peatlands for horticultural products, cranberry production, energy fuels, etc. In the last few years, several studies focused on identifying the barriers to rapid primary/secondary succession of sphagnum species and trying to restore or measure the return of different ecosystem functions of a peatland.

Phosphate rock fertilization is commonly used in peatland restoration to promote the growth of Polytrichum strictum , a nurse plant which aids the establishment of Sphagnum mosses. The present study tested whether 1) phosphorus fertilization facilitates the germination of P. strictum spores and 2) biochar derived from local pig manure can replace imported phosphate rock currently used in peatland restoration. Various doses of biochar were compared to phosphate rock to test its effect directly on P. strictum stem regeneration (in Petri dishes in a growth chamber) and in a simulation of peatland restoration with the moss layer transfer technique (in mesocoms in a greenhouse). Phosphorus fertilization promoted the germination of P. strictum spores as well as vegetative stem development. Biochar can effectively replace phosphate rock in peatland restoration giving a new waste management option for rural regions with phosphorus surpluses. As more available phosphorus was present in biochar, an addition of only 3–9 g m −2 of pig manure biochar is recommended during the peatland restoration process, which is less than the standard dose of phosphate rock (15 g m −2 ). [ABSTRACT FROM AUTHOR]

Sphagnum farming refers to the cultivation of Sphagnum mosses to produce Sphagnum biomass sustainably. Some possible uses of these fibers are as ingredients in growing substrates, as floral moss, as plant packaging during transport, or as moss reintroduction material for peatland restoration projects. Because this biomass production is sustainable, Sphagnum farming should reduce human impacts on natural peatlands. Despite its various benefits, research on Sphagnum farming is limited. To determine if Sphagnum farming is feasible on a large-scale basis (on the order of 900–1500 m 2 size basin), 6 yearly production cycles were implemented in trenches of former block-cut peatland in eastern Canada. These sites were monitored over seven growing seasons. Sphagnum cover (67%) and accumulated biomass (787 g m −2 ) from the culture basins were similar or superior to surveys from restored peatlands. However, cover and biomass values differed greatly among production cycles when comparing the time elapsed since the creation of the basins. Differences in productivity during different cycles were largely coupled with variations of water table levels compared to intrinsic properties of plant interactions. We believe that the optimization of water access (for example through automated of irrigation systems) for Sphagnum mosses would greatly improve the productivity of Sphagnum farming. [ABSTRACT FROM AUTHOR]

Abstract: The Bois-des-Bel Sphagnum peatland (Rivière du Loup, QC) was restored in 1999 after 20 years of abandonment. Restoration work included not only the blockage of drainage ditches, but also the reintroduction of plant material including Sphagnum remains. Following restoration, the physicochemical and microbial characteristics (biomass, activity and composition) of the peat were analysed. The goal was to investigate the functional status of the restored ecosystem. The high N:P (>20) and N:K (>15) ratios indicated possible K and P deficiencies in the restored and the cutover sites, which is mainly associated with the intense leaching and the high degree of decomposition of the peat in these sites. The concentrations of , P and K in the top layer of the restored site were closer to those of the natural site, which indicated a possible effect of restoration on the physicochemistry of the restored site. Microbial biomass values derived from the FE technique followed a gradient natural>restored>cutover through the profile, which was not the case with the SIR technique. Values from SIR varied overall between 0.19 and 4.88mg C g−1 and were significantly higher in the natural site. The natural peatland site had significantly (P<0.05) greater cumulative C–CO2 production (surface aerobic: 4.5–8.7μg C–CO2 g−1 h−1). The poor organic matter quality was the main explanation for the low respiration rates of the surface layer in the restored and the cutover site. All CO2 respiration data were plotted against time and the resulting curves were successfully fitted to a global kinetic model. Methane production was detected at low but measurable rates in the natural and the restored samples, but not in the cutover peat. Overall, the results confirmed the existence of a lag between the positive response of vegetation to restoration and that of the microbial compartment. This study also pointed out that some physicochemical dysfunctions remained even after three growing seasons following restoration in the subsurface horizons studied. [Copyright &y& Elsevier]

Abstract: This study examines the recovery of the microbial compartment following active restoration of a North American ombrotrophic peatland extracted for horticultural peat-based substrates and restored by the Sphagnum moss transfer method. We used phospholipid fatty acids (PLFAs) to portrait the microbial community structure and Community Level Physiological Profiles (CLPP) to describe the functional diversity of the microbial communities. Our results indicate that the PLFA profiles were different between the beginning and the end of the growing season, but that it was impossible to distinguish five different vegetation classes found along the disturbance-recovery gradient on the basis of the microbial community structure. The pH, the cover of mosses, Ledum groenlandicum and Eriophorum vaginatum var. spissum were the best environmental predictors for the PLFA composition. The newly formed peat found in aerobic conditions beneath restored Sphagnum carpets had the highest decomposition capacity, whereas the lowest rates were found in the surface samples of non-restored conditions or in the deepest horizons of the natural samples. A large proportion of the variation in the physiological profiles was explained with variables related to the vegetation cover, the physicochemical environment and the microbial structure of the community, which is very promising for future monitoring studies. Overall, this study demonstrates that the recovery of particular plant groups, namely mosses and shrubs in restored peatlands might be the driver of changes occurring in the structure of the microbial communities in restored peatlands. [Copyright &y& Elsevier]