Techniques for restoring fen vegetation on cut‐away peatlands in North America

Question: Which restoration measures (reintroduction techniques, reintroduction timing and fertilization) best enable the establishment of fen species on North American cut‐away peatlands? Location: Rivière‐du‐Loup peatland, southern Québec, Canada. Methods: In total, eight treatments which tested a combination of two reintroduction techniques, two reintroduction timings and the use of phosphorus fertilization were tested in a field experiment within a completely randomized block design. Results: Sphagnum transfer, a reintroduction technique commonly used for bog restoration in North America, was effective for establishing Sphagnum and Carex species. The hay transfer method, commonly used for fen restoration in Europe, was much less successful, probably due to questionable viability of reintroduced seeds. The treatments which included light phosphorus fertilization, had a higher Carex cover after three growing seasons. The timing of the reintroductions had no impact on the success of vegetation establishment. However, vegetation reintroduction should be carried out in the spring while the ground is still frozen to minimize other ecological impacts. Conclusions: The success of the diaspore reintroduction technique on small‐scale units indicates that a large‐scale restoration of fens using this technique is feasible.     

Use of Shallow Basins to Restore Cutover Peatlands: Hydrology

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

Experimental restoration of a fen plant community after peat mining

Question: Which restoration measures (introduction of donor diaspore material, application of straw mulch, alteration of residual peat depths) contribute to the establishment of a fen plant community on minerotrophic surfaces after peat mining? Location: Rivière‐du‐Loup peatland, southern Québec, Canada at 100 m a.s.1. Methods: The effectiveness of introducing fen plants with the application of donor diaspore material was tested. The donor diaspore material, containing seeds, rhizomes, moss fragments, and other plant propagules, was collected from two different types of natural fens. We tested whether the application of straw mulch would increase fen species cover and biodiversity compared to control plots without straw mulch. Terrace levels of different peat depths (15 cm, 40 cm, and 56 cm) were created to test the effects of different environmental site conditions on the success of re‐vegetation. Results: Applying donor seed bank from natural fens was found to significantly increase fen plant cover and richness after the two growing seasons. Straw mulch proved to significantly increase fen plant richness. The intermediate terrace level (40 cm) had the highest fen plant establishment. Compared to reference sites, the low terrace level (15 cm) was richer in base cations, whereas the high terrace level (56 cm) was much drier. Conclusions: The application of donor diaspore material was demonstrated as an effective technique for establishing vascular fen plants. Further re wetting measures are considered necessary at the restoration site to create a fen ecosystem rather than simply restoring some fen species.     

North American approach to the restoration of Sphagnum dominated peatlands

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

Energy and moisture considerations on cutover peatlands: surface microtopography, mulch cover and Sphagnum regeneration

This study examined (i) the effect of artificially created microtopography and straw mulch on the soil moisture and (ii) energy balance and the establishment of a Sphagnum cover on a cutover peatland. Straw mulch caused rainfall interception approaching 2 mm per event. Although interception represented 44% of the total rainfall over the measurement period, water that evaporated from the mulch used energy that would otherwise have been used to evaporate soil water. Thus, the net effect of interception by mulch was negligible. The soil heat flux below the mulch was only 13% of the bare soil value and was decoupled from the daily net radiation. Net radiation over the bare soil was 15% greater than over the mulch. However, because of the greater heat flux into the bare peat, the energy available for sensible and latent heat fluxes was similar between the mulch covered and bare peat. Average evaporation from mulch and bare soil was estimated to be 2.6 and 3.1 mm d⁻¹, respectively. Soil water tension 1 cm below the surface remained above −100 cm (mb) all season (100% of the time) when a mulch was used, compared to only 30% of the time in the bare soil. Correspondingly, the water table was sustained above the 40 cm depth, 60% of time in the mulch covered site, compared to only 40% of the time in the bare peat site. Negative relief elements of the microtopography were wetter and cooler than positive relief elements. However, when under a mulch, the negative relief elements provided no additional benefit, in terms of temperature or soil moisture amelioration. The control site with a mulch cover was equivalent or better than negative relief elements with a mulch cover. Taking into account the poorer performance of positive relief elements, even when mulch covered, the creation of surface microtopography reduced the overall moisture content of the site. Sphagnum established and spread only when the diaspores were protected with a straw mulch. All microtopography types tested had no effect on the establishment of Sphagnum mosses when the microtopography treatments, including positive and negative relief elements, were treated as a whole, although being in a depression helped Sphagnum establishment.     

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.     

Restoration of pool margin communities in cutover peatlands

Two experiments were conducted for developing restoration techniques for pool margin communities in cutover peatlands. We first aimed to measure the regeneration potential of a typical edge pool liverwort, Cladopodiella fluitans (Nees) H. Buch. We introduced C. fluitans in floating baskets in a restored peatland. We tested three fragment sizes (patches of 2 cm², stretched patches and shredded fine fragments of 0.1-1 mm), two introduction densities (ratio between surface of collected areas and surface of restored areas of 1:5 and 1:10) as well as the effect of a straw mulch. After two years, the percentage covers of C. fluitans were five times larger in experimental units protected with straw than in those without protection. Yet, the fragment sizes and the densities tested had no effect on the regeneration of the liverwort. The second experiment aimed to test a moss layer transfer approach to restore plant diversity around pool margins. We tested four communities, dominated by (1) Sphagnum cuspidatum Hoffman, (2) Sphagnum fallax (H. Klinggraff) H. Klinggraff, (3) Sphagnum papillosum Linberg as well as (4) a mixed community composed of equal quantities of C. fluitans, S. cuspidatum and S. papillosum. We introduced plant material in two density ratios (1:5 and 1:10). Sphagnum mosses did colonize pool margins, and showed even more than 60% cover for some treatments after three growing seasons, but the recovery of the introduced vascular plants remained below 5% for most species. The establishment of pool vascular species thus seems to be more intricate than for bryophytes and specific introduction techniques might be needed.     

An overview of peatland restoration in North America: where are we after 25 years?

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.     

Simulated Small Scale Disturbances Increase Decomposition Rates and Facilitates Invasive Species Encroachment in a High Elevation Tropical Andean Peatland

Tropical alpine peatlands are important carbon reservoirs and are a critical component of local hydrological cycles. In high elevation peatlands slow decomposition rates result from a nutrient‐poor substrate resistant to decay. The responses of páramo peatland ecosystems to increased nutrient additions and physical disturbance due to agricultural activities are unknown. Here, we conducted a two‐year fertilization and physical disturbance experiment in a Sphagnum—dominated peatland in the Central Andes of Colombia. We hypothesized that fertilization and physical disturbance will diminish the ability of the peat to store organic matter by increasing decomposition and that vascular plants will displace Sphagnum as the dominant plant group. We simulated cattle activity by adding manure as a fertilizer and physical disturbance as a proxy for cattle trampling. Species composition varied in proportion to the intensity of disturbance. Sphagnum cover was reduced under any disturbance treatment. Non‐native grasses usually found in cattle pastures invaded treatments with fertilizer additions or physical disturbance. Overall aboveground plant biomass doubled in fertilized treatments, suggesting that plant biomass production was nutrient limited. Decomposition rates tripled in disturbed treatments as compared to controls. This reduces the ability of the peatland to store organic matter. Andean peatlands are prized ecological assets; however, our results show that the El Morro páramo peatland experienced increased decomposition rates over short time periods after small‐scale disturbances. This created profound consequences for the ecological services offered by these peatlands.     

Harvesting surface vegetation does not impede self‐recovery of Sphagnum peatlands

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.     

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.     

Using palaeoecology to support blanket peatland management

Many peatlands have a recent history of being degraded by extraction, drainage, burning, overgrazing and atmospheric pollution often leading to erosion and loss of peat mass. Restoration schemes have been implemented aimed at rewetting peatlands, encouraging revegetation of bare peat or shifting the present vegetation assemblage to an alternative. Here we demonstrate the use of palaeoecological techniques that allow reconstruction of the historical development of a blanket peatland and provide a historical context from which legitimate restoration targets can be determined and supported. We demonstrate the applicability of simple stratigraphic techniques to provide a catchment-wide peatland development history and reinforce this with a detailed macrofossil reconstruction from a central core. Analysis at Keighley Moor Reservoir Catchment in northern England showed that the present vegetation state was ‘atypical’ and has been characteristic for only the last c. 100 years. Sphagnum moss was an important historic contributor to the vegetation cover between 1500 years ago and the early 1900s. Until the early 1900s Sphagnum occurrence fluctuated with evidence of fire, routinely returning after fire demonstrating good resilience of the ecosystem. However, from the turn of the 20th century, Sphagnum levels declined severely, coincident initially with a wildfire event but remaining extremely diminished as the site regularly underwent managed burning to support grouse moor gun sports where practitioners prefer a dominant cover of heather. It is suggested that any intention to alter land management at the site to raise water tables and encourage greater Sphagnum abundance is in line with peatland development at the site over the past 1500 years. Similar palaeoecological studies providing historical context could provide support for restoration targets and changes to peatland management practice for sites globally.     

Reduction of solar UV-B mediates changes in the Sphagnum capitulum microenvironment and the peatland microfungal community

The influence of near-ambient and reduced solar UV-B radiation on a peatland microfungal community was assessed by exposing experimental plots to UV-selective filtration. Replicate plots were covered with special plastic films to effect treatments of near-ambient and attenuated solar UV-B. The microfungal community from the top 1 cm of Sphagnum capitulum in a Tierra del Fuego peatland was censused throughout three growing seasons, between 1999 and 2002. Sphagnum capitula under near-ambient UV-B were more compressed and held more water than capitula under reduced UV-B. This water had a greater conductivity and was more acidic under near-ambient UV-B, as would be expected with increased leaching from the Sphagnum leaves. Nine regularly occurring hyphal fungi from the peatland were identified, at least to genus. Over three field seasons, no treatment effect on total fungal colony abundance was recorded, but individual species abundance was increased (Mortierella alpina), decreased (Penicillium frequentans), or was unaffected (P. thomii, Aureobasidium) by near-ambient UV-B. Species richness was also slightly lower under near-ambient UV-B. These treatment differences were smaller than seasonal or inter-annual fluctuations in abundance and species richness. In a growth chamber experiment, lamp UV-B treatments indicated that realistic fluxes of UV-B can inhibit fungal growth in some species. In addition to this direct UV-B effect, we suggest that changes in the peatland fungal community under near-ambient solar UV-B may also result from increased nutrient and moisture availability in the Sphagnum capitulum. The subtle nature of the responses of peatland fungi to solar UV-B suggests that most fungal species we encountered are well adapted to current solar UV-B fluxes in Tierra del Fuego.     

Plant species composition and vegetation structure of Sphagnum cultivation sites

Aims

The cultivation of Sphagnum mosses in paludiculture has high potential for the use of formerly drained peatlands under wet conditions. The aim of this study was to evaluate the plant species composition and vegetation structure of Sphagnum cultivation sites in comparison with near-natural donor sites and rewetted sites without Sphagnum introduction.

Location

Central Europe, northwest Germany close to the Dutch–German border.

Methods

The treatments (rewetting with and without Sphagnum introduction) and a near-natural donor as a reference were each studied at three different sites. At each site, bryophyte and vascular plant species composition as well as parameters of vegetation structure were sampled in 40 randomly positioned plots of 25 cm × 25 cm.

Results

In addition to the highly frequent Sphagnum, several further plant species typical of bogs were introduced. At two cultivation sites, the species composition showed a high degree of similarity to the near-natural donor sites, whereas the third site was more similar to the rewetted sites without the introduction of Sphagnum biomass. Rewetted sites were species-poor in comparison with all other sites. Apart from a high cover of Sphagnum, the vegetation structure at the cultivation sites differed significantly from the near-natural donor sites.

Conclusions

Sphagnum cultivation sites can be used to grow donor material for peatland restoration and contribute to species conservation by providing substitute habitat for bog-typical and threatened plant species.     

Rapid loss of an ecosystem engineer: Sphagnum decline in an experimentally warmed bog

Sphagnum mosses are keystone components of peatland ecosystems. They facilitate the accumulation of carbon in peat deposits, but climate change is predicted to expose peatland ecosystem to sustained and unprecedented warming leading to a significant release of carbon to the atmosphere. Sphagnum responses to climate change, and their interaction with other components of the ecosystem, will determine the future trajectory of carbon fluxes in peatlands. We measured the growth and productivity of Sphagnum in an ombrotrophic bog in northern Minnesota, where ten 12.8‐m‐diameter plots were exposed to a range of whole‐ecosystem (air and soil) warming treatments (+0 to +9°C) in ambient or elevated (+500 ppm) CO₂. The experiment is unique in its spatial and temporal scale, a focus on response surface analysis encompassing the range of elevated temperature predicted to occur this century, and consideration of an effect of co‐occurring CO₂ altering the temperature response surface. In the second year of warming, dry matter increment of Sphagnum increased with modest warming to a maximum at 5°C above ambient and decreased with additional warming. Sphagnum cover declined from close to 100% of the ground area to <50% in the warmest enclosures. After three years of warming, annual Sphagnum productivity declined linearly with increasing temperature (13–29 g C/m² per °C warming) due to widespread desiccation and loss of Sphagnum. Productivity was less in elevated CO₂ enclosures, which we attribute to increased shading by shrubs. Sphagnum desiccation and growth responses were associated with the effects of warming on hydrology. The rapid decline of the Sphagnum community with sustained warming, which appears to be irreversible, can be expected to have many follow‐on consequences to the structure and function of this and similar ecosystems, with significant feedbacks to the global carbon cycle and climate change.     

Climate change drives a shift in peatland ecosystem plant community: Implications for ecosystem function and stability

The composition of a peatland plant community has considerable effect on a range of ecosystem functions. Peatland plant community structure is predicted to change under future climate change, making the quantification of the direction and magnitude of this change a research priority. We subjected intact, replicated vegetated poor fen peat monoliths to elevated temperatures, increased atmospheric carbon dioxide (CO₂), and two water table levels in a factorial design to determine the individual and synergistic effects of climate change factors on the poor fen plant community composition. We identify three indicators of a regime shift occurring in our experimental poor fen system under climate change: nonlinear decline of Sphagnum at temperatures 8 °C above ambient conditions, concomitant increases in Carex spp. at temperatures 4 °C above ambient conditions suggesting a weakening of Sphagnum feedbacks on peat accumulation, and increased variance of the plant community composition and pore water pH through time. A temperature increase of +4 °C appeared to be a threshold for increased vascular plant abundance; however the magnitude of change was species dependent. Elevated temperature combined with elevated CO₂ had a synergistic effect on large graminoid species abundance, with a 15 times increase as compared to control conditions. Community analyses suggested that the balance between dominant plant species was tipped from Sphagnum to a graminoid‐dominated system by the combination of climate change factors. Our findings indicate that changes in peatland plant community composition are likely under future climate change conditions, with a demonstrated shift toward a dominance of graminoid species in poor fens.     

Restoration of managed pine fens: effect on hydrology and vegetation

Question: How does restoration affect the hydrology and the understorey vegetation of managed pine fens? Location: Oligotrophic pine fens in Natura 2000 areas in Kainuu, eastern Finland. Methods: Eleven managed pine fens and eight pristine reference pine fens were chosen for the study in 2005. The managed fens, which had been drained for forestry during the 1970s and 1980s, were restored in 2007. The water table was monitored in all fens over four growing seasons during 2006 to 2009, and vegetation was surveyed from permanent sample plots in 2006 and 2009. Results: Before restoration in 2006, the water table was at a significantly lower level in the managed fens compared with the pristine fens. Immediately after restoration, the water table rose to the same level as in the pristine fens, and this change was permanent. Forest drainage had had little impact on the understorey vegetation of the managed fens in the three decades before restoration, with species typical of pristine fens still dominating the sites. Forest dwarf shrubs and feather mosses had started to increase in cover, but mire dwarf shrubs and Sphagnum mosses still dominated the managed fens. Only the typical hollow species Sphagnum majus, Sphagnum balticum and Scheuzeria palustris were missing from the managed fens. Two years after restoration, the changes in species composition were also marginal, with increased cover of mire dwarf shrubs and sedges being the only significant change. Conclusions: The success of restoration of oligotrophic pine fens seems likely, given that changes in hydrological functioning occurred rapidly, and since little change has occurred in the vegetation composition after draining. Speeding up the regeneration process in these peatland types by restoration may, therefore, be recommended, especially if the drainage effect extends to nearby pristine mires and influences their biodiversity.     

Animal Colonization of Restored Peatlands: Inoculation of Plant Material as a Source of Insects

Ecological restoration of mined peatlands in North America involves active reintroduction of bog plant species. Animals are not actively reintroduced, thus the re‐establishment of peatland fauna must occur either by inoculation along with introduced plant material or by dispersal. We examined the extent to which insects are reintroduced to restored sites with plant material by rearing insects from shredded vegetation collected in three donor sites. We assessed differences in abundance, diversity, and composition of taxonomic and trophic groups among seasons and sites. Abundance and species richness did not differ by season, but species assemblages did. The three sites were significantly different in abundance, but not in species richness and assemblages. Few insects emerged from the vegetation, suggesting that shredded plant material may not be the primary source of insect colonists. Insects likely recolonize by active or passive dispersal from the surrounding area. The species pool was similar among donor sites; consequently a mined site could be inoculated with vegetation from another peatland in the same region and this would not affect the insect assemblages at the initial stage of establishment. Diapause may be a major factor for emergence success among seasons of collection. Knowledge of how restoration techniques influence establishment of insect communities will help predict longer‐term outcomes of restoration on biotic communities in peatlands.     

Composition and structure of macroinvertebrate communities in contrasting open-water habitats in Irish peatlands: implications for biodiversity conservation

The purpose of this study was to consider the relative importance of several habitat variables in explaining the patterns in the structure of macroinvertebrate assemblages in open-water habitats, in relatively intact bogs and fens, which should inform conservation strategies. It was hypothesised that variables relating to the size of the water body would differentiate the communities and that some species would be unique to certain conditions. The macroinvertebrate communities from pools >100 m², 10.1–100 m² and Sphagnum hollows were characterised using sweep sampling for eight intact peatland sites across four bog types, and related to habitat variables including pool size, Sphagnum cover and hydrochemistry. Results showed community composition and structure differed significantly between deep, permanent pools and shallow, drought-sensitive Sphagnum hollows, with larger invertebrates, such as Odonates and Dytiscinae, rarely found in the hollows. Sphagnum cover accounted for a substantial amount of the variation in community composition. An examination of life-history strategies found species dependent on predictable conditions for juvenile development to be more abundant in pools. In contrast, taxa that could delay juvenile development until conditions were favourable were more abundant in Sphagnum hollows. These results highlight the importance of habitat heterogeneity in maintaining macroinvertebrate diversity in peatlands.     

Polytrichum Strictum as a Solution to Frost Heaving in Disturbed Ecosystems: A Case Study with Milled Peatlands

Substrate instability is a common problem in many disturbed ecosystems. In the case of milled harvested peatlands, the pioneer moss Polytrichum strictum is commonly found; it is well adapted to tolerate the harsh microclimatic conditions and peat instability of these sites. A field experiment was used to determine the effectiveness of P. strictum against frost heaving, a major type of disturbance on bare peat. Wooden dowels and fir trees (Abies balsamea) placed in a P. strictum carpet experienced almost no frost heaving, whereas heaving was severe on bare peat. Reintroduced P. strictum fragments thinly spread on bare peat reduced but did not eliminate frost heaving. Straw mulch (a protective cover often required in peatland restoration) effectively reduced heaving in the fall, but was less effective in the spring because it had partially decomposed. The P. strictum carpet, P. strictum fragments, and straw mulch reduced frost heaving by reducing the number of freeze–thaw cycles, by slowing the rate of ground thaw in the spring, and by reducing the unfrozen water content of the peat during the spring thaw. Different species of Polytrichum mosses should be considered for the restoration or regeneration of disturbed ecosystems where soil stability is problematic.