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Arctic ecosystems are undergoing rapid changes, including increasing disturbance by herbivore populations, which can affect plant species coexistence and community assemblages. Although the significance of mosses in Arctic wetlands is well recognized, the long‐term influence of medium‐sized herbivores on the composition of moss communities has received limited attention. We used data from a long‐term (25 years) Greater Snow Goose (Anser caerulescens atlanticus) exclusion experiment in Arctic tundra wetlands to assess changes in the composition of moss communities at multiple spatial scales (cell, 4 cm2; quadrat, 100 cm2; exclosure, 16 m2). We investigated how snow goose grazing and grubbing can alter the composition of the moss community by measuring changes in alpha and beta diversity, as well as in the strength of plant interspecific interactions between moss species. Our results indicate that goose foraging significantly increased species diversity (richness, evenness, and inverse Simpson index) of moss communities at the cell and quadrat scales but not the exclosure scale. Goose foraging reduced the dissimilarity (beta diversity) of moss communities at all three scales, mainly due to decreased species turnover. Furthermore, goose foraging increased positive interaction between moss species pairs. These findings emphasize the critical role of geese in promoting moss species coexistence and increasing homogeneity in Arctic wetlands. This study illustrates how top‐down regulation by herbivores can alter plant communities in Arctic wetlands and highlights the importance of considering herbivores when examining the response of Arctic plant biodiversity to future climate change. [ABSTRACT FROM AUTHOR]

Arctic ecosystems are undergoing rapid changes, including increasing disturbance by herbivore populations, which can affect plant species coexistence and community assemblages. Although the significance of mosses in Arctic wetlands is well recognized, the long‐term influence of medium‐sized herbivores on the composition of moss communities has received limited attention. We used data from a long‐term (25 years) Greater Snow Goose (Anser caerulescens atlanticus) exclusion experiment in Arctic tundra wetlands to assess changes in the composition of moss communities at multiple spatial scales (cell, 4 cm2; quadrat, 100 cm2; exclosure, 16 m2). We investigated how snow goose grazing and grubbing can alter the composition of the moss community by measuring changes in alpha and beta diversity, as well as in the strength of plant interspecific interactions between moss species. Our results indicate that goose foraging significantly increased species diversity (richness, evenness, and inverse Simpson index) of moss communities at the cell and quadrat scales but not the exclosure scale. Goose foraging reduced the dissimilarity (beta diversity) of moss communities at all three scales, mainly due to decreased species turnover. Furthermore, goose foraging increased positive interaction between moss species pairs. These findings emphasize the critical role of geese in promoting moss species coexistence and increasing homogeneity in Arctic wetlands. This study illustrates how top‐down regulation by herbivores can alter plant communities in Arctic wetlands and highlights the importance of considering herbivores when examining the response of Arctic plant biodiversity to future climate change. [ABSTRACT FROM AUTHOR]

Copyright of Naturaliste Canadien is the property of La Societe Provancher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

Despite bryophytes being well adapted to various ecological settings, they are rarely considered in reclamation projects. In this study, propagation regenerative capabilities of bryophytes on different substrates (sand, amphibolite, and pegmatite) and conditions (with or without peat amendment, shade and shredding) were tested in greenhouse and field experiments. In the greenhouse trial, after 6 months of reintroduction, Racomitrium species (Racomitrium canescens (Hedw.) Brid. and Racomitrium elongatum Frisvoll.) had higher regeneration compared to Polytrichum species (Polytrichum juniperinum Hedw. mixed with Polytrichum piliferum Hedw.; a combination of shade (65% shading) and peat amendment (0.5 cm depth) was found to be particularly effective, resulting in up to 100% of Racomitrium species regeneration; shredding the stems of Polytrichum species into small pieces of 0.5–1.0 cm inhibited its regeneration. In the field trial, peat amendment had no effect on moss regeneration. The addition of fluvioglacial sand or till on waste rocks promoted bryophytes regeneration in both the greenhouse and field. These results provide science-based practical knowledge to support the inclusion of native bryophytes in waste rock restoration plans for mines located in northern boreal forests. [ABSTRACT FROM AUTHOR]

The moss layer transfer technique has been developed to restore the carbon sequestration function and typical vegetation of Sphagnum-dominated peatlands after peat extraction in North America. However, the technique does not lead to successful bryophyte establishment when applied to peatlands with a richer residual fen peat. Therefore, we evaluated an alternative method of active rewetting and passive vegetation establishment using vegetation surveys and carbon dioxide and methane (CH4) flux measurements at a post-extracted fen in southern Manitoba, Canada. After one growing season post-rewetting, wetland vegetation established and the site was a net carbon sink over the growing season. However, high abundance of Carex lasiocarpa 10 years post-treatment led to higher CH4 emissions than the reference ecosystem. Successful establishment of wetland vegetation is attributed to the area being surrounded by undisturbed fens that can provide a local source of plant propagules. Bryophyte expansion was less successful than vascular plants, likely due to episodic flooding and shading from the sedge communities. Therefore, careful management of water levels to just below the peat surface is needed if reference vegetation community recovery is the goal of restoration. Water level management will also play a key role in controlling CH4 emissions to maximize carbon sequestration potential. [ABSTRACT FROM AUTHOR]

Monthly variation in accumulation and release of phenolics in bryophytes, and their allelopathic effects are little known despite their ecological significance. We conducted a field transplant experiment to investigate Sphagnum growth and extracellular enzymes that modulate phenolic contents and release along water table level (WTL) gradient. Specifically, we assessed monthly changes in height increment, phenolic release, and allelopathic effect during the growing season, as well as extracellular enzymes at the end of the experiment, for the two Sphagnum species: Sphagnumangustifolium C.E.O. Jensen, 1896, a hollow dwelling species, and Sphagnum magellanicum Bridel, 1798, a hummock species. Both Sphagnum species showed season- and WTL-dependent height increment and released phenolics. Sphagnum angustifolium exhibited negative allelopathy regardless of WTL, while S. magellanicum demonstrated mainly positive allelopathy at high WTL and negative allelopathy at low WTL. The degree of allelopathy was not contingent on phenolic release, but phenolic production was negatively correlated with height growth of the two species at their atypical habitats. Moreover, phenoloxidase or peroxidase did not show high activity at low WTL compared to high WTL. Our findings demonstrate for the first time that the strength and direction of allelopathy in Sphagnum may vary depending on the growing precipitation and temperature, WTL, and inter- and intraspecific trait variability. Longer term experiments may further elucidate the seasonal dynamics and mechanism of Sphagnum allelopathy. [ABSTRACT FROM AUTHOR]

During more than five centuries of human colonization, 50% of original peatlands in Azores have been destroyed or degraded, mainly due to pasture use, resulting in landscape changes and a loss of ecosystem biodiversity and services. This study aims to identify the most effective measures in the recovery and to detect initial responses (2 years). These are the first restoration experiments, carried out in a background of complete absence of strategies adapted for Azores pastured peatlands. In a post‐pastured peatland, 24 experiments were implemented, repeated in more degraded (northern) and more natural (southern) areas. The experiments were combinations of restoration measures, with the introduction of Juniperus brevifolia, Calluna vulgaris, and Sphagnum palustre and the use of management techniques to control herbaceous cover (alien‐rich herbaceous cover competing with Sphagnum or peatland natural shrubs): intensive and extensive grazing and grass cutting. Principal response curves and redundancy analyses were used to assess changes in the flora and the physicochemical parameters. Globally there was an increase in Sphagnum cover and a decrease in herbaceous species. This was accompanied by an increase in organic matter and a decrease in nitrogen. In more natural parcels (large artificially divided areas where different experiments were implemented), the most positive tendencies were associated with the combination of J. brevifolia planting and grass cutting. In more degraded areas, treatments had a lower impact, as the results tended to be similar to the control, pointing to an important natural regenerative succession dynamic that overlapped the response to the implemented treatments. [ABSTRACT FROM AUTHOR]

Peatland ecosystem restoration following oil mining activities in Alberta, Canada, aims at reestablishing crucial peatland functions, such as wildlife habitat, water storage and filtration, peat accumulation, and carbon sequestration. To reinstate peatland functions, characteristic hydrological conditions are necessary to support the establishment and growth of characteristic wetland vegetation. Following in situ oil sands well pad disturbances in the Peace River and Cold Lake Oil Sands regions in Alberta, we evaluated the efficiency of peatland restoration approaches including different groundwork and revegetation techniques. Groundwork techniques included the complete removal (CR) or partial removal (PR) of the former in situ well pads' mineral fill and revegetation included the spontaneous revegetation via natural ingress of diaspores from nearby peatlands, or managed revegetation via planting of Carex aquatilis, Larix laricina, and Salix lutea. We assessed the plant species composition, biochemical and hydrological properties of all study areas, including restored peatland areas, an unrestored area, and reference areas (REF) for comparison. Ten years post‐restoration, in the restored areas the mean total plant cover was 57% with an average of 35 vascular plant and bryophyte species, while in REF 68% mean total plant cover and an average of 64 plant species were recorded. Respectively, characteristic peatland species contributed to 61 and 100% of the species composition. PR and hydrological connection to the adjacent peatland resulted in near surface water table and the highest peatland plant species diversity, while CR promoted the formation of a shallow open water area. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Society for Ecological Restoration (SER) published the second edition of its International Principles and Standards for the Practice of Ecological Restoration in 2019. We conducted a pan‐Canadian study using semi‐structured interviews with restoration professionals to explore the extent to which restoration practitioners are aware of the document and use it. Overall, we found that direct uptake of the document by practitioners was lower than expected, with approximately 37.7% of all participants that were both aware of and consulting the publication for guidance in their practice of ecological restoration. This is due in part to low awareness of the document itself, with only a small majority (56.5%) of interviewees being aware of it. Other reasons listed by practitioners such as the structure of the publication, its added value, and its suitability for on‐the‐ground work revealed why some individuals aware of the existence of the document still failed to consult it. Here, we present a more nuanced assessment of these observations and share our findings with the ecological restoration community to address this disconnection. With intensifying pressures to achieve restoration success internationally, SER's guidance is critical. We analyze why it seems guidance from SER is not being taken up as fully as it might, and ways in which future versions may be improved. [ABSTRACT FROM AUTHOR]

Nutrient availability for tundra vegetation could change drastically due to increasing temperatures and frequency of nitrogen deposition in the Arctic. Few studies have simultaneously examined the response of plant communities to these two pressures over a long period. This study aims to assess which driver between increasing nitrogen (N) and phosphorus (P) availability through global warming and increasing N availability alone via N deposition is more likely to transform arctic wetland vegetation and whether there is a time lag in this response. An annual fertilization experiment simulating these nutrient inputs was conducted for 17 years in the Canadian High-Arctic to assess the impact on aboveground net primary productivity, floristic composition, and plant nutrient concentration. While the primary productivity of mosses remains unchanged by fertilization after 17 years, productivity of graminoids was increased slightly by N addition (36% increase at the highest dose). In contrast, the primary productivity of graminoids increased strongly with N/P addition (over 227% increase). We noted no difference in graminoid productivity between the 2nd and 5th year of the experiment, but we observed a 203% increase between the 5th and 17th year in the N/P addition treatments. We also noted a 49% decrease in the total moss cover and an 155% increase in the total graminoid cover between the 2nd and 17th year of N/P addition. These results indicate that the impact of warming through increased N/P availability was greater than those of N deposition alone (N addition) and promoted the transition from a moss-dominated tundra to a graminoid-dominated tundra. However, this transition was subject to a time lag of up to 17 years, suggesting that increased productivity of graminoids resulted from a release of nutrients via the decomposition of lower parts of the moss mat. [ABSTRACT FROM AUTHOR]

Copyright of Botany is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

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]

A low rate of establishment in brown mosses is generally observed following large-scale restoration of fens. As brown mosses are important components in peat accumulation in fens, their low recovery rate has been a concern in the past decade. It was suggested that the restoration method used for bogs, the Moss Layer Transfer Technique (MLTT) should be adapted for fen restoration by identifying factors limiting the establishment and recovery of brown mosses. In this study, we evaluated the regeneration potential of four common brown mosses, Aulacomnium palustre, Campylium stellatum, Scorpidium cossonii and Tomentypnum nitens, according to three factors that can have an impact during restoration: 1) distance of the fragment below the moss apex, 2) mechanical fragmentation of mosses, and 3) enhanced nutrient availability, and this, in growth chambers (within Petri dishes) and field experiments. Under controlled conditions, similar results were obtained for all four brown mosses studied: the severe fragmentation of mosses most drastically improved their regeneration potential. Phosphate fertilization, even at the lowest dose, increased moss regeneration, and brown mosses showed higher recovery in the first 3 cm below the apex. Liming only improved the regeneration of C. stellatum. However, unclear, and even contradicting results were obtained when treatments were applied in the field, where an overall very low establishment of brown mosses was observed in response to the rather prevailing adverse environmental conditions (e.g., erosion, frost heaving, low water table level). The direct application of some of our results into an adapted version of MLTT might be challenging, as it may require a certain level of meticulosity that large-scale mechanical fen restoration cannot provide. [ABSTRACT FROM AUTHOR]

In this study, our goal was to adapt the moss layer transfer technique (MLTT), first developed to restore degraded Sphagnum‐dominated peatland explicitly with a bryophyte layer, to a former in‐situ oil sands well‐pad constructed with nearby mineral fill in northwestern Alberta, Canada. Mineral fill was either completely removed or partially removed with residual fill buried under excavated and decompacted peat, followed by the transfer of donor moss collected from nearby linear features with different plant communities in peatlands. Three years after MLTT, peatland vegetation covers 63% of the site. Carex spp. dominate with 36% coverage, followed by mosses at 12%, including 3% Sphagnum spp. and 8% fen mosses, and shrubs at 8%. Different substrate adjustment treatments and types of donor moss had negligible impact on vegetation development although areas without MLTT remained devoid of mosses and had the lowest peatland species cover. Instead, surface elevation, moisture conditions, and substrate chemistry played important roles in shaping the vegetation communities. The prompt introduction and establishment of peatland donor species through MLTT was crucial to the overall re‐establishment of peatland vegetation. This is the first full pad scale study to prove that a flat, moist peat surface created by the removal and/or burial of mineral fill can support peatland vegetation development, particularly ground layer bryophytes. Overall, the reclaimed well‐pad appears to be on trajectory toward becoming a functional peatland and our approaches should be considered and tested in future well‐pad reclamation trials. [ABSTRACT FROM AUTHOR]

Across Canada's boreal forest, disturbances from in situ oil sands mining, including well‐pads, significantly impact vast areas of the landscape. The creation of well‐pads requires removal of vegetation and placement of mineral fill, which essentially stops any carbon (C) sequestration on the once peatland ecosystem. It is important that, once no longer in use, these well‐pads are restored as long‐term C (peat) accumulation is what defines peatland ecosystem. However, little is known about the recovery of greenhouse gas exchange post‐restoration of these features. We studied a decommissioned well‐pad located in a treed poor fen that was restored using three soil adjustment treatments (SATs): (1) complete mineral fill removal (Peat‐Dec); (2) partial pad removal and burial under peat layer (BUPL); and (3) mixing mineral and peat by inversion (Mixed‐P‐M). The recreated peat surface was revegetated with donor peatland species using the moss layer transfer technique (MLTT). The objectives of this paper were to (1) quantify plot‐scale seasonal carbon dioxide (CO2) and methane (CH4) exchange of the SATs, 2–4 years post‐restoration compared to reference sites and (2) determine the influence of several environmental variables on CO2 and CH4 exchange. All SATs proved effective in recreating a soil surface needed to support peatland vegetation as shown by similar rates of net ecosystem exchange (NEE). Equally, both types of vegetation reintroduced led this site on a trajectory toward functioning as a net C sink. [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]

Peatland pools present unique fauna and flora and contribute significantly to peatland biodiversity. The ecological functionality of artificial pools in restored peatlands is poorly documented. In this study, we investigated arthropod assemblages of 21 artificial pools in a restored fen in southeastern Canada and 16 pools from four pristine fens as reference ecosystems. Three years following restoration, predacious diving beetles (Coleoptera: Dytiscidae) and spiders (Araneae) were sampled within and around pools using minnow traps and pitfall traps, respectively. We used Bayesian community occupancy models to document arthropod recolonization. Twenty‐one dytiscid species were captured in pools. Dytiscid species richness was higher in artificial pools than in reference pools. Three dytiscid species were more likely to occur in deeper pools. Dytiscid species composition in artificial pools differed from reference pools. Seventy‐seven spider species were captured around pools. Spider species richness was higher around artificial pools than around reference pools. Seventeen spider species responded to vegetation cover, either positively or negatively. In contrast, spider species composition was similar between artificial and reference pools. We conclude that artificial pools should be along a gradient of pool depth, but also that fast‐growing vegetation should be introduced on pool margins to foster a quicker return of arthropod assemblages similar to reference ecosystems. [ABSTRACT FROM AUTHOR]

Copyright of Botany is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

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]

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]

The moss layer transfer technique is effective at restoring extracted peatland surfaces. However, remnant peatlands persist on the periphery of extracted surfaces. These remnant peatlands drop steeply to extracted surfaces, producing artificial ecotones that are more challenging to restore. We asked to what degree natural ecotones at undisturbed reference fens can act as models for the restoration of artificial ecotones around an extracted peatland, and whether management actions can ameliorate conditions in artificial ecotones. We compared changes in elevation, water table, peat, and multiple vegetation characteristics between natural ecotones and unmanaged artificial ecotones. We then clear‐cut peripheral strips, completely filled perimeter canals, and smoothed peripheral slopes around sections of the extracted surfaces to assess whether hydrological conditions improved. Without management, artificial ecotones are not good models of natural ecotones. The elevation gradient is steep, and water tables drop steeply within 8 m of blocked perimeter canals, with possible effects at 25 m. The consequent vegetation had denser tree saplings, faster tree growth, almost no moss cover, and low moss species richness. After these management actions, water tables increased to within approximately 5 cm of those along natural ecotones. Future study is required to assess the extent of vegetation recovery, but these results hold promise for a more holistic rehabilitation of ecotones on the periphery of extracted peatland surfaces. We present recommendations to optimize the management actions on the periphery of extracted peatlands. [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]

Peatlands after drainage and extraction are large sources of carbon (C) to the atmosphere. Restoration, through re‐wetting and revegetation, aims to return the C sink function by re‐establishing conditions similar to that of an undrained peatland. However, the time needed to re‐establish C sequestration is not well constrained due to the lack of multi‐year measurements. We measured over 3 years the net ecosystem exchange of CO2 (NEE), methane (FCH4), and dissolved organic carbon (DOC) at a restored post‐extraction peatland (RES) in southeast Canada (restored 14 years prior to the start of the study) and compared our observations to the C balance of an intact reference peatland (REF) that has a long‐term continuous flux record and is in the same climate zone. Small but significant differences in winter respiration driven by temperature were mainly responsible for differences in cumulative NEE between years. Low growing season inter‐annual variability was linked to constancy of the initial spring water table position, controlled by the blocked drainage ditches and the presence of water storage structures (bunds and pools). Half‐hour FCH4 at RES was small except when Typha latifolia‐invaded drainage ditches were in the tower footprint; this effect at the ecosystem level was small as ditches represent a minor fraction of RES. The restored peatland was an annual sink for CO2 (−90 ± 18 g C m−2 year−1), a source of CH4 (4.4 ± 0.2 g C m−2 year−1), and a source of DOC (6.9 ± 2.2 g C m−2 year−1), resulting in mean net ecosystem uptake of 78 ± 17 g C m−2 year−1. Annual NEE at RES was most similar to wetter, more productive years at REF. Integrating structures to increase water retention, alongside re‐establishing key species, have been effective at re‐establishing the net C sink rate to that of an intact peatland. We measured over 3 years the net ecosystem exchange of CO2, methane, and dissolved organic carbon (DOC) at a restored post‐extraction peatland and compared our observations to the C balance of an intact reference peatland that has a long‐term continuous flux record. The restored peatland was an annual sink for CO2, and a source of methane and DOC, resulting in a mean annual net ecosystem uptake of C. Integrating structures to increase water retention, alongside re‐establishing key species, have been effective at re‐establishing the net C sink rate to that of an intact peatland. [ABSTRACT FROM AUTHOR]

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Peatlands are abundant in the boreal region of Canada but little is known about their restoration on oil sands well pads. The goal of this study is to compare the reintroduction of different peatland plant communities and substrate amendments/decompaction in order to rehabilitate peatland vegetation on former in situ well pads constructed in wetlands. One field experiment tested which peatland plant communities (Shrubby Rich Fen, Treed Rich Fen) would best colonize different substrates (sawdust, clay loam, mix sawdust-clay, peat, surface roughness). We found that the moss layer transfer technique (MLTT) facilitated the establishment of peatland communities on residual mineral soil used to construct the pad, when shaved back to an average water level of the surrounding wetland. The choice of peatland plant community is key to the introduction of bryophytes. Peat amendment facilitated the establishment of plants, whereas soil decompaction had no effect. The MLTT is a promising approach to restore fen plants on well pads. We recommend a scale-up experiment for a whole well site to test the validity of MLTT along different pad removal techniques. [ABSTRACT FROM AUTHOR]

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Copyright of Botany is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Several studies contributed to the development of restoration techniques for open Sphagnum-dominated habitats on peat-extracted bogs. Yet, in exception to some afforestation efforts, connectivity between restored sites and surrounding landscapes has received little attention. The general goal of this study is to ameliorate management of very shallow peat fields (<30 cm) located within the margins of peat-extracted bogs. Firstly, to assist decision making in peatland management, baseline ecological conditions, peat physicochemistry and spontaneous vegetation recolonization were assessed for 18 of these fields. This first study revealed that (1) concentrations of several macro-nutrients are almost one order of magnitude lower for unrestored fields than previously characterized natural lagg habitats of the same region, and (2) there is little spontaneous colonization. In a second study, peat chemistry and soil/air microclimate were evaluated in plantations established on shallow residual peat (a 21-year-old Larix laricina plantation and an 18-year-old Picea mariana plantation) and compared to adjacent unrestored shallow bare-peat fields. This second study showed that afforested peat fields are characterized by (1) a soil enriched in nutrients, notably in N, P, and K, and (2) a more humid and cooler microclimate at the soil/air interface, with less daily humidity and temperature fluctuations. These results indicate that afforestation is an appropriate approach to start an ecological recovery. Yet, the absence of natural recolonization by herbs and mosses in the understory of afforested peat fields suggests that reintroduction of appropriate understory species should also be considered if the goal is to restore a fully functional ecosystem. [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]

Background and Aims: Peatland methane (CH) fluxes may vary between plant types; however, in mixed communities, the specific role of each species is difficult to distinguish. The goal of this study was to determine the individual and interacting effect of moss, graminoid and shrub plant functional types on CH dynamics of experimentally planted plots in a rewetted minerotrophic peatland. Methods: We measured CH flux, pore water CH concentration and CH production and oxidation potential in pure stands of reintroduced Tomenthypnum nitens (Hedw.) Loeske, Carex aquatilis Wahlenb, or Myrica gale L., as well as mixtures of T. nitens + C. aquatilis and T. nitens + M. gale. Methane flux was also measured on bare peat plots. Results: The presence of both the graminoid C. aquatilis and the shrub M. gale resulted in the highest CH production potential in near surface peat (10 cm). The presence of moss ( T. nitens) and C. aquatilis significantly increased CH oxidation potential. Water table position was a significant control on CH flux, but the presence of C. aquatilis maintained higher flux even at dry plots. Plots including C. aquatilis had significantly lower pore water CH concentration at 30 cm depth, likely reflecting CH oxidation and transport. Conclusions: Management of restored sites aiming to reduce CH flux should focus on hydrology, i.e. water table position. The presence of graminoids enhances CH flux, while moss presence may result in lower CH emission. [ABSTRACT FROM AUTHOR]

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Vascular plants associated to natural peatland pools do not spontaneously colonize edges of man-made pools in restored peatlands and have proven to be recalcitrant to the usual restoration techniques. The goal of this study was to evaluate the effect of the species used as a seedbed ( Cladopodiella fluitans, Sphagnum cuspidatum, or Sphagnum magellanicum) and its developmental stage (established carpet or newly reintroduced fragments) on establishment success in the field of the seeds of four vascular species: Carex limosa, Carex magellanica, Carex oligosperma, and Scheuchzeria palustris. The germination rate was measured after one season and growth after two seasons. Seedbed composition and developmental stage had no effect on Carex, whereas the germination of S. palustris was higher on S. cuspidatum. Growth of vascular plants was slightly improved on S. magellanicum carpets and was lower on seedbeds of C. fluitans. Our results lead us to recommend seeding at the same time as bryophyte fragments are spread and fostering introduction of Sphagnum mosses, preferably to C. fluitans, around artificial pool edges. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Ecological gradients have always been a central theme of plant ecology. Yet, very little is known on the bog-lagg-mineral land gradient. Improved knowledge of this gradient is important to the understanding of wetland plant ecology and wetland delineation alike. In this study, the relation between vegetation composition and peat thickness is analysed in 20 raised bogs of eastern Canada using split moving window dissimilarity analysis. Four different transition types are identified: (1) an abrupt transition without an ecotonal community; (2) a narrow transition with a lagg-swamp ecotonal community (most common transition type); (3) a narrow transition with two ecotonal communities (a lagg-fen and a lagg-swamp); and (4) a broad transition with a large wetland adjacent to the bog. Laggs that could be defined as separate habitat (type 1) occured, on average, on peat soil over 30 cm thick (defined as > 30 % dry mass of organic matter), making the lagg an integral part of the peatland complex. Other unique features of the lagg are: (1) a very densely structured habitat where trees, shrubs, herbs and Sphagnum mosses are abundant; (2) soils characterised by relatively high contents of total nitrogen and total phosphorus, but a particularly low N:P ratio (8.7 ± 2.5); and (3) a relatively high water table, which fluctuates substantially (from −33 to +10 cm in site A; from −12 to +10 in site B). [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ABSTRACT Fens represent a large array of ecosystem services, including the highest biodiversity found among wetlands, hydrological services, water purification and carbon sequestration. Land-use change and drainage has severely damaged or annihilated these services in many parts of North America and Europe; restoration plans are urgently needed at the landscape level. We review the major constraints on the restoration of rich fens and fen water bodies in agricultural areas in Europe and disturbed landscapes in North America: ( i) habitat quality problems: drought, eutrophication, acidification, and toxicity, and ( ii) recolonization problems: species pools, ecosystem fragmentation and connectivity, genetic variability, and invasive species; and here provide possible solutions. We discuss both positive and negative consequences of restoration measures, and their causes. The restoration of wetland ecosystem functioning and services has, for a long time, been based on a trial-and-error approach. By presenting research and practice on the restoration of rich fen ecosystems within agricultural areas, we demonstrate the importance of biogeochemical and ecological knowledge at different spatial scales for the management and restoration of biodiversity, water quality, carbon sequestration and other ecosystem services, especially in a changing climate. We define target processes that enable scientists, nature managers, water managers and policy makers to choose between different measures and to predict restoration prospects for different types of deteriorated fens and their starting conditions. [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]

The organic matter accumulation potential of a restored bog was estimated over 2 years as a balance between losses to decomposition and inputs through above-ground net primary productivity (AGNPP) in five micro-habitats of increasing complexity (relating to the moss carpet thickness and the number of vegetation functional groups). Decomposition and accumulation rates variations were hypothesized to lead to higher organic matter accumulation potential in the more complex micro-habitats. In general, for a given litter type, the mass losses and decomposition rates were rather homogeneous between micro-habitats, but, they were correlated to the cover of particular species: Eriophorum vaginatum with slower decomposition rates, and Ledum groendlandicum or Kalmia angustifolia with higher rates. Therefore, the abundance of some peatland species, rather than the habitat complexity itself, was a driver of decomposition rates. While the Sphagnum AGNPP did not compensate for decomposition losses, the organic matter accumulation potential was tipped towards a sink (positive) by the contribution of vascular species to the AGNPP. The organic matter accumulation potentials are much improved by the presence of Sphagnum, but from a restoration perspective, promoting the growth of vascular peatland species might also be a key to achieving a positive balance of organic matter accumulation. [ABSTRACT FROM AUTHOR]

Developing objective tools for tracking progress of restored sites is of general concern. Here, we present an innovative approach based on principal response curves (PRC) and species classification according to their preferential habitats to monitor changes in community composition. Following large-scale restoration of a cut-over peatland, vegetation was surveyed biannually over 8 years. We evaluated whether the establishing plant communities fell within the range of natural variation. We used both general diversity curves and PRC applied on plant species grouped by preferred habitat to compare restored sites and unrestored sites to a reference ecosystem. After 8 years, diversity and richness differed between the sites, with Forest and Ruderal species more prominent in unrestored sites, and Peatland, Forest, and Wetland species dominant in restored sites. The PRC revealed that the restored site became rapidly dominated by typical peatland plants, the main drivers of temporal changes being Sphagnum rubellum, Pohlia nutans, and Mylia anomala. Some differences remained between the restored and the undisturbed species pools: the former had more herbaceous species associated with wetlands such as Calamagrostis canadensis and Typha latifolia and the latter had more forested species like Kalmia angustifolia throughout the study. PRC revealed to be an efficient tool identifying species driving changes at the community level after restoration. In our case study, examining PRC scores after classifying species according to their preferred habitat allowed to illustrate objectively how restoration promotes target species (associated to peatlands) and how lack of intervention benefits ruderal species. [ABSTRACT FROM AUTHOR]

Monitoring is an essential step to assess vegetation trajectories post-restoration and ultimately evaluate success. In this paper, we compare two monitoring methods, the line-point intercept (LPI) and the permanent plot (PP) methods, for evaluating plant recovery of a restored cut-over peatland (8.5 ha), following a 'moss layer transfer technique'. We used the LPI method to estimate covers (from frequency measures) for each plant species using a systematic grid of approximately 5,700 points (every 3 m × 5 m). In parallel, 43 PP (3 m × 8 m) were established and used to evaluate plant covers. The post-restoration recovery of vegetation was assessed against a reference ecosystem encompassing the variation in species cover from natural undisturbed peatlands in the same region. For all plant groups considered, the LPI consistently showed higher cover estimates than the PP method. Discrepancy between the two methods was particularly evident for the Ericaceae group. A complementary sampling method, the line-intercept (LI), showed strong correlations with the visual estimations of Ericaceae covers (akin to PP), suggesting an overestimation from the LPI method. Most life form groups of the restored peatlands are developing a structure similar to the regional reference ecosystem 8 years post-restoration with the herb group being still most dissimilar. Indeed, when analyzing the temporal evolution of the different key peatland plant components, several are within the range of regional abundance values or moving positively towards range of cover abundance of the reference system such as Sphagnum cover, a key peat-accumulating plant group. [ABSTRACT FROM AUTHOR]

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]

Questions How has plant species composition changed following initiation of microstructures in re-vegetated cutover peatlands? How many years are required for plant species composition of re-vegetated cutover peatlands to resemble natural boreal bogs? Location Newly formed S phagnum carpets on restored, cutover peatlands (in Canada) or re-vegetated spontaneously after site abandonment (in Estonia) and on undisturbed natural bogs nearby. Methods Plant frequencies (point intercept method) and abundances (vegetation quadrats) were assessed along linear transects. At each assessment point, moss surface height was measured relative to a local reference point (lowest point on a given transect) to associate frequencies or abundances to a position in the gradient of microtopography. PCAs (separately for Canada and Estonia) were conducted to follow evolution of plant species frequency in the gradient of microtopography in re-vegetated sites and similarity with those of natural peatlands. In Canada, regressions were also performed to estimate relationships between moss surface height and vascular plant cover (ericaceous shrubs and Cyperaceae) as well as time required for vascular plant cover to become similar to that of natural bogs. Results Species composition was still dissimilar to microstructures of natural bogs 10 yr post-restoration and 70 yr post-abandonment; however, some trends were observed in re-vegetated peatlands. The greatest differences were for ericaceous species (two- to three-fold less abundant in re-vegetated peatlands), dominant Cyperaceae, and relative proportions of S phagnum. In addition, hummock formation was closely related to dense (>50%) ericaceous cover. Conclusions All species tolerant to abiotic conditions prevailing in re-vegetated sites contributed to initiation of microtopography, although some species were found in atypical positions within the gradient of microtopography. Random events and establishment priority seemed initially to be more important in temporal evolution of microstructures than plant interactions. However, ecological restoration could effectively reduced time needed for species occurrences to approach those in natural peatlands, relative to time required for recovery of spontaneously re-vegetated peat extraction sites. [ABSTRACT FROM AUTHOR]

Copyright of Botany is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Question: How many years are required for a gradient of microtopography to be initiated in revegetated cutover peatlands and become similar to natural bogs? Location: Newly formed Sphagnum carpets on cutover peatlands that revegetated spontaneously after site abandonment (in Estonia), or following active restoration (in Canada) and on undisturbed natural bogs nearby. Methods: Moss surface height was measured along linear transects above a local reference level (the lowest point for a given transect). Heights of at least 20 cm were associated with hummocks. Frequency distributions of surface height and principal component analyses (separately for Canada and Estonia) were conducted to follow the evolution of microtopography in revegetated sites and their similarity with those of natural peatlands. In Canada, regressions were also performed to estimate the time required for the microtopography in revegetated cutover peatlands to become similar to that found in natural bogs. Results: Only 10-30 yr were needed for microstructures comparable to those in natural bogs to develop on restored peatlands where Sphagnum diaspores have been reintroduced. However, this process may take more than a century in cutover peatlands left to revegetate spontaneously. Conclusions: In cutover peatlands with spontaneous revegetation, hummock-hollow formation starts on bare peat which lacks both plant propagules and viable seed banks, and the initiation of microstructures is probably more akin to the process that occurs naturally. Nonetheless, hummock-hollow microtopography resembling that found in natural bogs without pools appeared, in all of the examined cutover peatlands, over periods that are short in terms of peatland development time-scales. Active peatland restoration could effectively reduce the time required for initiation of microtopography by about 70 yr. [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]