Development of floating rafts after the rewetting of cut-over bogs: the importance of peat quality

The usual method of restoring cut-over bogs is to rewet the peat surface, but this often leads to the remaining peat layers being deeply inundated. For Sphagnum-dominated vegetation to develop at deeply inundated locations, it is important for floating rafts of buoyant residual peat to develop. In this study, the chemical and physical characteristics of buoyant and inundated peat collected from rewetted cut-over bog were compared. In general, buoyant peat was poorly humified; high methane (CH₄) production rates (≥2?µmol?g^?1?DW?day^?1) were important to ensure buoyancy. Although the peat water CH₄ concentrations increased with depth, the CH₄ production rates were higher in the uppermost peat layers. High CH₄ production rates were related positively with P concentrations and negatively with lignin concentrations. The pH to bulk density ratio (≥0.05) also appeared to be a good indicator of CH₄ production rates, providing an easy and cheap way to measure the variable for restoration practitioners. Our results indicated that analysing certain simple characteristics of the residual peat can greatly improve the success of the rewetting measures taken in cut-over bogs. If the analysis reveals that the residual peat is unsuitable for floating raft formation, deep inundation is inappropriate unless suitable peat from other locations can be introduced.     

Development of floating rafts after the rewetting of cut-over bogs: the importance of peat quality

The usual method of restoring cut-over bogs is to rewet the peat surface, but this often leads to the remaining peat layers being deeply inundated. For Sphagnum-dominated vegetation to develop at deeply inundated locations, it is important for floating rafts of buoyant residual peat to develop. In this study, the chemical and physical characteristics of buoyant and inundated peat collected from rewetted cut-over bog were compared. In general, buoyant peat was poorly humified; high methane (CH₄) production rates (2 µmol g ^–1 DW day ^–1) were important to ensure buoyancy. Although the peat water CH₄ concentrations increased with depth, the CH₄ production rates were higher in the uppermost peat layers. High CH₄ production rates were related positively with P concentrations and negatively with lignin concentrations. The pH to bulk density ratio (0.05) also appeared to be a good indicator of CH₄ production rates, providing an easy and cheap way to measure the variable for restoration practitioners. Our results indicated that analysing certain simple characteristics of the residual peat can greatly improve the success of the rewetting measures taken in cut-over bogs. If the analysis reveals that the residual peat is unsuitable for floating raft formation, deep inundation is inappropriate unless suitable peat from other locations can be introduced.     

Effects of a hydrological protection zone on the restoration of a raised bog: a case study from Northeast-Germany 1997–2008

We investigated the changes of water level and vegetation in a restored cut-over raised bog in response to a hydrological protection zone established around the bog. The restoration began 1997 and techniques involved ditch blocking within and around the bog to stimulate a return to conditions of intact bog ecosystems. In order to monitor the rehabilitation of the raised bog, water levels and vegetation have been recorded since before restoration measures began. The monitoring is ongoing, but an assessment of 15 year’s data (1994–2008) is presented. A hydrological protection zone with continuous high water levels could be established around the raised bog which minimizes the runoff of precipitation. Shortly after the first measures, the water levels increased significantly at all dipwells. Parallel to the increasing water levels a vascular plant species assemblage and a diverse Sphagnum community developed. In particular Sphagnum fimbriatum, S. palustre, S. recurvum and S. squarrosum spread efficiently. The cover of trees decreased significantly because of high water levels and ongoing acidification by Sphagnum spp. The high water levels have stimulated the re-vegetation and the hydrology self-regulation of the acrotelm. The successful regeneration of the acrotelm particularly became apparent in years with below-average precipitations (e.g. 2008), when the water levels in the central parts of the raised bog did not fall back to the low level reached in previous years, which had also remarkably water deficits (e.g. 2003).     

Animal and vegetation patterns in natural and man-made bog pools: implications for restoration

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.     

Conservation of bog plant species assemblages: Assessing the role of natural remnants in mined sites

Abstract. 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.     

Assessing long‐term hydrological and ecological responses to drainage in a raised bog using paleoecology and a hydrosequence

Question: We studied vegetation succession after drainage in a bog, as an analogue for potential persistent water table drawdown due to climate change. We asked: (1) how does bog vegetation change following a long‐term water table lowering and (2) how are effects of drainage on hydrology and vegetation distributed temporally and spatially? Location: Mer Bleue peatland, Ontario, Canada (45.41°N, 75.48°W). Methods: Analyses of changes in vegetation and hydrology associated with drainage were examined spatially along a hydrosequence and temporally using paleoecological reconstructions from peat cores (testate amoebae, pollen) in a drained portion of a peatland untouched for 85 years following drainage. Relationships between modern vegetation and water table were assessed through clustering and ordination analyses of vegetation relevés. Results: Post‐drainage increases in tree cover, especially Betula and Larix, decreases in Sphagnum cover and shifts in species composition of dominant shrubs were observed. Present‐day vegetation patterns along the hydrosequence were primarily related to seasonal variability of water table depth. Paleoecological records reveal that where the present‐day vegetation has been impacted by drainage, persistent water table lowering occurred in response to drainage. However, in an area with relatively natural vegetation, a transient drop in water table depth occurred at the time of drainage. Conclusions: Temporal and spatial patterns revealed that the bog response to drainage was spatially and temporally heterogeneous, and probably mediated by feedbacks among vegetation, peat structure and hydrology. Spatial patterns along the hydrosequence were similar to those observed in paleoecological reconstructions, but the use of the two complementary techniques provides additional insights.     

Field Simulation of Global Change: Transplanting Northern Bog Mesocosms Southward

A large proportion of northern peatlands consists of Sphagnum-dominated ombrotrophic bogs. In these bogs, peat mosses (Sphagnum) and vascular plants occur in an apparent stable equilibrium, thereby sustaining the carbon sink function of the bog ecosystem. How global warming and increased nitrogen (N) deposition will affect the species composition in bog vegetation is still unclear. We performed a transplantation experiment in which mesocosms with intact vegetation were transplanted southward from north Sweden to north-east Germany along a transect of four bog sites, in which both temperature and N deposition increased. In addition, we monitored undisturbed vegetation in control plots at the four sites of the latitudinal gradient. Four growing seasons after transplantation, ericaceous dwarf shrubs had become much more abundant when transplanted to the warmest site which also had highest N deposition. As a result ericoid aboveground biomass in the transplanted mesocosms increased most at the southernmost site, this site also had highest ericoid biomass in the undisturbed vegetation. The two dominant Sphagnum species showed opposing responses when transplanted southward; Sphagnum balticum height increment decreased, whereas S. fuscum height increment increased when transplanted southward. Sphagnum production did not differ significantly among the transplanted mesocosms, but was lowest in the southernmost control plots. The dwarf shrub expansion and increased N concentrations in plant tissues we observed, point in the direction of a positive feedback toward vascular plant-dominance suppressing peat-forming Sphagnum in the long term. However, our data also indicate that precipitation and phosphorus availability influence the competitive balance between Sphagnum, dwarf shrubs and graminoids.     

Restoration of Sphagnum and restiad peatlands in Australia and New Zealand reveals similar approaches

Peatlands in Australia and New Zealand are composed mainly of Restionaceous and Cyperaceous peats, although Sphagnum peat is common in wetter climates (Mean Annual Precipitation > 1,000 mm) and at higher altitudes (>1,000 m). Experimental trials in two contrasting peatland types—fire‐damaged Sphagnum peatlands in the Australian Alps and cutover restiad bogs in lowland New Zealand—revealed similar approaches to peatland restoration. Hydrological restoration and rehydration of drying peats involved blocking drainage ditches to raise water tables or, additionally in burnt Sphagnum peatlands, peat‐trenching, and the use of sterilized straw bales to form semipermanent “dam walls” and barriers to spread and slow surface water movement. Recovery to the predisturbance vegetation community was most successful once protective microclimates had been established, either artificially or naturally. Specifically, horizontally laid shadecloth resulted in Sphagnum cristatum regeneration rates and biomass production 3–4 times that of unshaded vegetation (Australia), and early successional nurse shrubs facilitated establishment of Sporadanthus ferrugineus (New Zealand) within 2–3 years. On severely burnt or cutover sites, a patch dynamic approach using transplants of Sphagnum or creation of restiad peat “islands” markedly improved vegetation recovery. In New Zealand, this approach has been scaled up to whole mine‐site restoration, in which the newly vegetated islands provide habitat and seed sources for plants and invertebrates to spread onto surrounding areas. Although a vegetation cover can be established relatively rapidly in both peatland types, restoration of invertebrate communities, ecosystem processes, and peat hydrological function and accumulation may take many decades.     

Effects of elevated CO2 and vascular plants on evapotranspiration in bog vegetation

We determined evapotranspiration in three experiments designed to study the effects of elevated CO₂ and increased N deposition on ombrotrophic bog vegetation. Two experiments used peat monoliths with intact bog vegetation in containers, with one experiment outdoors and the other in a greenhouse. A third experiment involved monocultures and mixtures of Sphagnum magellanicum and Eriophorum angustifolium in containers in the same greenhouse. To determine water use of the bog vegetation in July–August for each experiment and each year we measured water inputs and outputs from the containers. We studied the effects of elevated CO₂ and N supply on evapotranspiration in relation to vascular plant biomass and exposure of the moss surface (measured as height of the moss surface relative to the container edge). Elevated CO₂ reduced water use of the bog vegetation in all three experiments, but the CO₂ effect on evapotranspiration interacted with vascular plant biomass and exposure of the moss surface. Evapotranspiration in the outdoor experiment was largely determined by evaporation from the Sphagnum moss surface (as affected by exposure to wind) and less so by vascular plant transpiration. Nevertheless, elevated CO₂ significantly reduced evapotranspiration by 9–10% in the outdoor experiment. Vascular plants reduced evapotranspiration in the outdoor experiment, but increased water use in the greenhouse experiments. The relation between vascular plant abundance and evapotranspiration appears to depend on wind conditions; suggesting that vascular plants reduce water losses mainly by reducing wind speed at the moss surface. Sphagnum growth is very sensitive to changes in water level; low water availability can have deleterious effects. As a consequence, reduced evapotranspiration in summer, whether caused by elevated CO₂ or by small increases in vascular plant cover, is expected to favour Sphagnum growth in ombrotrophic bog vegetation.     

Methane dynamics of recolonized cutover minerotrophic peatland: Implications for restoration

In North America, mulching of vacuum-harvested sites combined with blocking of the drainage system is widely used for peatland restoration to accelerate Sphagnum establishment. However, peat extraction in fen peatlands or exposure of deeper minerotrophic peat layers results in soil chemistry that is less suitable for re-establishment of Sphagnum moss. In this situation, restoration of plant species characteristic of minerotrophic peatlands is desirable to return the site to a carbon accumulating system. In these cases, it may be worthwhile to maintain spontaneously revegetating species as part of restoration if they provide desirable ecosystem functions. We studied the role of six spontaneously recolonizing vegetation communities for methane (CH₄) emissions and pore water CH₄ concentration for two growing seasons (2008 and 2009) at an abandoned minerotrophic peatland in southeastern Quebec. We then compared the results with bare peat and adjacent natural fen vegetation. Communities dominated by Eriophorum vaginatum, Carex aquatilis and Typha latifolia had CH₄ flux an order of magnitude greater than other cutover vegetation types and natural sites. In contrast, Scirpus atrocinctus and Equisetum arvense had CH₄ emission rates lower than natural hollow vegetation. We found seasonal average water table and vegetation volume had significant correlation with CH₄ flux. Water table and soil temperature were significantly correlated with CH₄ flux at plots where the water table was near or above the surface. Pore water CH₄ concentration suggests that CH₄ is being produced at the cutover peatland and that low measured fluxes likely result from substantial oxidation of CH₄ in the unsaturated zone. Understanding ecosystem functions of spontaneously recolonizing species on cutover fens can be used to help make decisions about the inclusion of these communities for future restoration measures.     

Interacting effects of elevated atmospheric CO<Subscript>2</Subscript> and hydrology on the growth and carbon sequestration of <Emphasis Type="Italic">Sphagnum</Emphasis> moss

Peatlands are a critical carbon store comprising 30% of the Earth’s terrestrial soil carbon. Sphagnum mosses comprise up to 90% of peat in the northern hemisphere but impacts of climate change on Sphagnum mosses are poorly understood, limiting development of sustainable peatland management and restoration. This study investigates the effects of elevated atmospheric CO₂ (eCO₂) (800 ppm) and hydrology on the growth of Sphagnum fallax, Sphagnum capillifolium and Sphagnum papillosum and greenhouse gas fluxes from moss–peat mesocosms. Elevated CO₂ levels increased Sphagnum height and dry weight but the magnitude of the response differed among species. The most responsive species, S. fallax, yielded the most biomass compared to S. papillosum and S. capillifolium. Water levels and the CO₂ treatment were found to interact, with the highest water level (1 cm below the surface) seeing the largest increase in dry weight under eCO₂ compared to ambient (400 ppm) concentrations. Initially, CO₂ flux rates were similar between CO₂ treatments. After week 9 there was a consistent three-fold increase of the CO₂ sink strength under eCO₂. At the end of the experiment, S. papillosum and S. fallax were greater sinks of CO₂ than S. capillifolium and the ? 7 cm water level treatment showed the strongest CO₂ sink strength. The mesocosms were net sources of CH₄ but the source strength varied with species, specifically S. fallax produced more CH₄ than S. papillosum and S. capillifolium. Our findings demonstrate the importance of species selection on the outcomes of peatland restoration with regards to Sphagnum’s growth and GHG exchange.     

Distribution and development of necroticSphagnum patches in two Estonian raised bogs

Sphagnum mosses dominate the plant cover of boreal bogs and accumulate carbon as peat. However, discoloured necroticSphagnum patches are also common in bogs. NecroticSphagnum inhibits peat accumulation, and consequently these areas may sink with respect to their surroundings with healthy mosses and continuing peat accumulation. Therefore, necrotic patches in the moss carpet could have an important role in triggering the succession ofSphagnum communities and the differentiation of bog microtopography. Our main aim was to find out how necroticSphagnum patches are distributed on a microtopographic gradient and amongSphagnum species. Based on these results we discuss the development and likely role of necrotic patches. It was found that necrotic patches occur on all types of bog microforms and contain the most of commonSphagnum species. Necrotic patches were more common and larger in wet hollows. The development of necrotic patches depends on their location on the microtopographic gradient. Necrotic patches on higher microforms usually re-vegetate, whereas those in hollows can result in mud-bottom hollows.     

Effects of Increased Nitrogen Deposition on the Distribution of 15N-labeled Nitrogen between Sphagnum and Vascular Plants

To elucidate the sensitivity of bog ecosystems to high levels of nitrogen (N) deposition, we investigated the fate of ¹⁵N-labeled N deposition in bog vegetation in the Netherlands, both at ambient and increased N deposition. We doubled N deposition by adding 5 g N m^?2 y^?1 as dissolved NH₄NO₃ during three growing seasons to large peat monoliths (1.1 m diameter) with intact bog vegetation kept in large outdoor containers. A small amount of ¹⁵N tracer was applied at the start of the second growing season, and its distribution among Sphagnum, vascular plant species, and peat was determined at the end of the third growing season. The ¹⁵N tracer was also applied to additional plots at the untreated field site to check for initial distribution. One week after addition, 79% of the total amount of ¹⁵N retrieved was found in the living Sphagnum layer and less than 10% had been captured by vascular plants. Fifteen months later, 63% of the total amount of ¹⁵N retrieved was still present in the living Sphagnum layer at ambient N deposition. Increased N deposition significantly reduced the proportion of ¹⁵N in Sphagnum and increased the amount of ¹⁵N in vascular plants. Deep-rooting vascular plant species were significantly more ¹⁵N enriched, suggesting that at higher atmospheric inputs N penetrates deeper into the peat. Our results provide the first direct experimental evidence for that which has often been suggested: Increased atmospheric N deposition will lead to increased N availability for vascular plants in ombrotrophic mires.     

Microclimatic buffering and resource‐based habitat in a glacial relict butterfly: significance for conservation under climate change

In contrast to several organisms that have already shown range shifts to the north as a response to climate change, southern populations of relict species are trapped in isolated altitudinal habitats. Therefore, there is a growing interest to better understand their habitat use, with particular attention to the thermal aspects and associated significance for their habitat management. We address this issue by a study of larval habitat use relative to vegetation structure and microclimate in a glacial relict butterfly of peat bog ecosystems, using a functional, resource‐based habitat approach. We analysed caterpillar presence and density relative to vegetation composition (reflecting gradients of humidity, temperature, and natural succession of the peat bog) and to the availability and quality of thermal refuges for caterpillars (i.e., structures provided by Sphagnum hummocks). We also tested caterpillar survival rates under different temperature and humidity treatments. We found that (1) Boloria aquilonaris was a specialist butterfly of early successional stages with very humid zones of peat bog, (2) the lack of Sphagnum hummocks reduced larval habitat suitability, and hence the population density, and (3) a reduction of the thermal buffering ability of Sphagnum hummocks was observed in less humid, degraded parts, or late‐successional stages of peat bog. A larval rearing experiment showed a significant impact of temperature on caterpillar survival; survival being higher at lower temperature. Our field and laboratory results support the idea that the thermal environment exploited by caterpillars should be considered as a functional resource and included in a population‐specific habitat definition. Appropriate management of the peat bog habitat of this glacial relict species should not exclusively focus on the larval and adult feeding resources, but also on the quality of thermal refuges provided by Sphagnum hummocks in humid zones of the peat bog, especially in the current critical context of climate warming.     

An evaluation of the use of translocated blanket bog vegetation for heathland restoration

Abstract. The decision was taken by an opencast coal mining company to translocate on-site blanket bog vegetation, on completion of mining, at a site in Co. Durham, UK, both to preserve it and to use it to enhance recolonization. The vegetation of the treatments was monitored for seven years after site completion and this paper reports on the progress of the translocated material and its effect on recolonization. Translocation of large turves of blanket bog into carefully prepared receptor cells preserved most of the vegetation intact, but resulted in severe decline in the frequency of Sphagnum, while the design of the receptor site as strips of translocated vegetation enclosing strips of spread, stored peat accelerated recolonization of the intervening bare peat by Calluna vulgaris, but not of other target species. This attempt to translocate blanket bog vegetation and at the same time use it to accelerate recolonization was only partly successful. It was concluded that the ecological requirements of species known to be significant for ecosystem function, such as Sphagnum, must be fulfilled if translocation of blanket bog is to be attempted in future.     

A palaeoecological study of holocene peat bog sections in Germany and The Netherlands,based on the analysis of pollen,spores and macro- and microscopic remains of fungi,algae, cormophytes and animals

A Holocene peat section of the Engbertsdijksveen (The Netherlands) was analysed at centrimetre intervals for all kinds of micro- and macrofossils in order to obtain maximum information regarding local vegetation and animal succession and regional changes in the prevailing vegetation types. The analysed micro- and macrofossils are illustrated, described and interpreted. Among them are about 70 fungal taxa, about 25 animal taxa, at least 4 algae, and about 15 fossils of unknown identity or origin.The taxonomic designation, matrix, host- or substrate specificity and indicator value of representatives of five different groups of fossils have been tabulated.The fruit-bodies of several taxa distinguished as spore types were found during the macrofossil analysis, e.g., ascospores, mycelium and fruit-bodies of the parasite Meliola cf. niessleana (Type 14) are present in the levels in which Calluna vulgaris played a role in the local vegetation.The ascomycete Geoglossum sphagnophilum was, according to its spore distribution, a common element in the bog vegetation during the Atlantic and Subboreal periods.Zygospores of Mougeotia cf. gracillima (Type 61) and other Zygnemataceae indicate the levels where these algae could grow during the local succession in the peat bog. The zygospores indicate phases of shallow, stagnant, mesotrophic open water during spring.Conventional analysis of pollen and macro-remains with a high resolution in time (centimetre diagrams), the above-mentioned new information, and the correlation of events inside and outside the site of the peat bog lead to the following main conclusions:The Atlantic-Subboreal transition, well known for its elm decline, could be correlated with a local change in bog vegetation. Following the alteration of wet Scheuchzeria palustris vegetation with hummock vegetation in the Atlantic period, the appearance of a Molinia coerulea peat coincides with the elm decline. According to the present ecology of M. coerulea, this change must have been caused by a seasonally recurring, considerable lowering of the groundwater level during summer. During winter the groundwater rose so far that in spring shallow open water prevailed and Mougeotia cf. gracillima could develop. This local vegetational succession indicates an unstable climatic period with pronounced dry seasons during the early Subboreal.During the climatic deterioration of the Subboreal-Subatlantic transition the incidence of Corylus avellana decreased. The Corylus pollen curve shows several cyclic fluctuations during this period (1400-600 B.C.). Depressions in the Corylus pollen curve correspond with particularly wet local vegetation (more oceanic, possibly cooler phases), Corylus pollen maxima correspond with relatively dry bog vegetation (less oceanic, possibly warmer phases). These cyclic fluctuations correspond to approximately 150–200 historical years each. The increasing oceanicity ultimately resulted in the formation of peat by Sphagnum species of the section Cymbifolia. In this Subatlantic Cymbifolia peat the fluctuations of the minor constituent Sphagnum cf. rubellum are clearly correlated with the fluctuations of the curve of the rhizopod Amphitrema flavum. This phenomenon is interpreted as a reflection of more and less oceanic phases during the Subatlantic period.All available data were expressed in curves, in order to indicate changes in local and perhaps regional moisture conditions.Ther percentages of plants indicating human influence are relatively low during the Neolithic and Bronze Age. During the Iron Age the influence of prehistoric man was relatively important. Secale cereale was already grown during the secondary century B.C. Population density decreased again during the second century A.D.The present study is intended as a first step towards a more detailed knowledge of the changing ecosystems of bogs and forests and in their response to changing environmental factors, such as minor and major climatic cycles.     

Effects of shallow flooding on vegetation and carbon pools in boreal peatlands

Question: What are the effects of shallow flooding on boreal peatlands on vegetation composition and size of carbon pools in the living and dead vegetation? Location: Lake 979, Experimental Lakes Area, northwestern Ontario, Canada. Methods: A boreal basin peatland complex with treed bog, open bog, and open water was experimentally flooded by raising water level ca. 1.3 m. Vegetation and above‐ground biomass were compared between pre‐flood conditions and those nine years after flooding. Peat accumulation since flooding was also quantified. Results: Flooding caused almost all trees to die, leading to a net loss of 86% of the above‐ground living plant biomass after nine years of the flooding. Floating up of peat was rapid in the central part of the basin, and the floating peat mats were characterized by newly established open bog community. Wetland types were diversified from bog into open bog, fen, and marsh, accompanied with great species turnover. Floating open bog community accumulated the greatest amount of peat since flooding. Conclusions: This study shows that shallow flooding of bog vegetation can lead to quick re‐establishment of open bog vegetation upon the floating up of peat mats as well as changes to more diverse vegetation over decadal time spans. We estimate that the carbon pools in 2002 in living and dead plant biomass since 1992 are comparable to what they were in the above‐ground biomass in 1992. Flooding caused an initial net decrease in carbon stores, but carbon in the pre‐flood living plant biomass was replaced by both carbon in dead biomass of the pre‐flood vegetation and newly sequestered carbon in new peat growth and post‐flood living plant biomass. Possible vegetation change toward bog‐dominated system could lead to increasing rate of new peat growth, which could affect future carbon sink/source strength of the system.     

Bacterial and Fungal Communities in a Degraded Ombrotrophic Peatland Undergoing Natural and Managed Re-Vegetation

The UK hosts 15–19% of global upland ombrotrophic (rain fed) peatlands that are estimated to store 3.2 billion tonnes of carbon and represent a critical upland habitat with regard to biodiversity and ecosystem services provision. Net production is dependent on an imbalance between growth of peat-forming Sphagnum mosses and microbial decomposition by microorganisms that are limited by cold, acidic, and anaerobic conditions. In the Southern Pennines, land-use change, drainage, and over 200 years of anthropogenic N and heavy metal deposition have contributed to severe peatland degradation manifested as a loss of vegetation leaving bare peat susceptible to erosion and deep gullying. A restoration programme designed to regain peat hydrology, stability and functionality has involved re-vegetation through nurse grass, dwarf shrub and Sphagnum re-introduction. Our aim was to characterise bacterial and fungal communities, via high-throughput rRNA gene sequencing, in the surface acrotelm/mesotelm of degraded bare peat, long-term stable vegetated peat, and natural and managed restorations. Compared to long-term vegetated areas the bare peat microbiome had significantly higher levels of oligotrophic marker phyla (Acidobacteria, Verrucomicrobia, TM6) and lower Bacteroidetes and Actinobacteria, together with much higher ligninolytic Basidiomycota. Fewer distinct microbial sequences and significantly fewer cultivable microbes were detected in bare peat compared to other areas. Microbial community structure was linked to restoration activity and correlated with soil edaphic variables (e.g. moisture and heavy metals). Although rapid community changes were evident following restoration activity, restored bare peat did not approach a similar microbial community structure to non-eroded areas even after 25 years, which may be related to the stabilisation of historic deposited heavy metals pollution in long-term stable areas. These primary findings are discussed in relation to bare peat oligotrophy, re-vegetation recalcitrance, rhizosphere-microbe-soil interactions, C, N and P cycling, trajectory of restoration, and ecosystem service implications for peatland restoration.     

Sphagnum re-introduction in degraded peatlands: The effects of aggregation,species identity and water table

In European peatlands which have been drained and cut-over in the past, re-vegetation often stagnates after the return of a species-poor Sphagnum community. Re-introduction of currently absent species may be a useful tool to restore a typical, and more diverse, Sphagnum vegetation and may ultimately improve the functioning of peatland ecosystems, regarding atmospheric carbon sequestration. Yet, the factors controlling the success of re-introduction are unclear. In Ireland and Estonia, we transplanted small and large aggregates of three Sphagnum species into existing vegetation. We recorded changes in cover over a 3-year period, at two water levels (?5 and ?20 cm).Performance of transplanted aggregates of Sphagnum was highly species specific. Hummock species profited at low water tables, whereas hollow species profited at high water tables. But our results indicate that performance and establishment of species was also promoted by increased aggregate size. This mechanism (positive self-association) has earlier been seen in other ecosystems, but our results are the first to show this mechanism in peatlands. Our results do not agree with present management, which is aimed at retaining water on the surface of peat remnants in order to restore a functional and diverse Sphagnum community. More than the water table, aggregate size of the reintroduced species is crucial for species performance, and ultimately for successful peatland restoration.     

Aquatic microinvertebrate abundance and species diversity in peat bogs of Tierra del Fuego (Argentina)

Peat bogs are regarded as extreme environments due to their low pH and low nutrient concentration, and thus hold a unique biota adapted to these particular conditions. The island of Tierra del Fuego encompasses the southernmost extensive peat bog area in the world, and is therefore particularly interesting from a biogeographical viewpoint. Within the same peat bog, different environment types can be identified: clear ponds, vegetated ponds and Sphagnum patches. In this study we compare the abundance, richness and species diversity of microinvertebrates (Copepoda, Cladocera and Rotifera) in these three types of environments from two peat bogs (Andorra and Rancho Hambre). Out of the 29 taxa recorded, 19 were common to both peat bogs, including four cladocerans endemic to Southern Patagonia and three rotifers endemic to Fuegian peat bogs. The rotifers were the dominant group in all environment types from Rancho Hambre, while in Andorra the Sphagnum moss was dominated by copepods, particularly harpacticoids. The results revealed that the environment type rather than peat bog was the key factor at explaining differences in species richness and diversity among microinvertebrate communities. This study highlights the importance of Sphagnum moss as a low diversity extreme environment which supports highly endemic species.