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Schematic presentation of a Eriophorum vaginatum tussock and the location of vegetation sample plot transects. (Drawing by M. Koistinen).
Source publication
We studied the vegetation patterns around cottongrass tussocks with varying characteristics in a cut-away peatland 20 years after abandonment. When the effect of water table level variation was eliminated, the remaining variation in vegetation was related to (i) tussock characteristics and (ii) distance and orientation from a particular tussock. Lo...
Contexts in source publication
Context 1
... bay were analyzed. At each tussock, four 30-cm-long transects, one in each cardinal direction, were established in order to detect changes in vegetation as a function of distance from the base of the tussock. Each transect consisted of six adjoining 5 × 5 cm (0.0025 m 2 ) sam- ple plots, with the first one next to the tussock's leaf sheath bundle (Fig. 1). If there was a neighbouring tussock closer than 30 cm, a shorter transect was laid out. However, these cases were omitted from the statistical analyses, and the total number of sample plots used was ...
Context 2
... diameter and height of each cottongrass tussock (DIAM, HEIGHT) and the diameter and height of tussock's leaf sheath bundle (DLSB, HLSB) were measured (Fig. 1). The variable shade index (SI) was calculated by multiplying the diameter of the tus- sock by the height of the tussock's leaf sheath bundle (Fig. 1). The proportion of the tussock's living leaves (LIVING) was estimated as a percentage projection cover of all leaves. The distance from the tussock's base (DIST) in the four cardinal ...
Context 3
... diameter and height of each cottongrass tussock (DIAM, HEIGHT) and the diameter and height of tussock's leaf sheath bundle (DLSB, HLSB) were measured (Fig. 1). The variable shade index (SI) was calculated by multiplying the diameter of the tus- sock by the height of the tussock's leaf sheath bundle (Fig. 1). The proportion of the tussock's living leaves (LIVING) was estimated as a percentage projection cover of all leaves. The distance from the tussock's base (DIST) in the four cardinal directions (N, E, S, W) were used to describe the degree of ...
Context 4
... positive interaction between DIST and SI (sheltering cavity around the tussock, Fig. 1) found for all the studied species indicates that the smaller the tussock, the nearer the plants have to occur to find a microsite similar to that further away from the base of a larger tussock (Tables 3 and 4, Figs. 5 and 6). This is in accordance with the increasing gra- dient in exposure from near the base of tussock to further away, ...
Citations
... These are the most frequent sites of peat fires [6,36], although post-fire vegetation changes specifically in the burnt areas of abandoned peat mining fields are not frequent research subjects. The main studies of vegetation dynamics in abandoned peat extraction fields are related to their rewetting [37][38][39][40][41][42]. The pathways and dynamics of vegetation formation after peat extraction may vary considerably, but in any case, they require long-term observation [43,44]. ...
... The method involves draining a peatland by creating deep hillside channels along its contour, and progressively deepening the field channels as the peat is drained, which are naturally drained to the degree technologically required in the peat extraction fields. Deeply drained milled peat extraction fields are problematic environments for successful plant spontaneous revegetation because of dryness, destroyed propagule banks, temperature fluctuations on bare peat surfaces, and other negative factors [34,[37][38][39][40][41]. Therefore, such sites require reclamation after the cessation of milling. ...
... After 30-50 years, areas with sphagnum mosses may appear [60]. Separately, the role of cotton-grass in the pioneering development of cutover peat extraction fields has been noted [37]. ...
On examples of n × 100 m2 permanent plots laid in 2005 on peatlands disturbed by quarrying and milling peat extraction in Meshchera National Park (central European Russia), changes in vegetation cover and environmental factors during self-revegetation, the impact of wildfire, and rewetting are considered. Peat extraction pits are overgrown with floating mats, on which mire, predominantly mesotrophic, vegetation is formed. Cofferdams with retained original mire vegetation contribute to the formation of a spatially diverse mire landscape, but they can also be prone to natural fires. The environmental conditions at the abandoned milled peat extraction sites do not favour natural overgrowth. The driest areas can remain with bare peat perennially. Such peatlands are the most frequent targets of wildfires, which have a severely negative impact and interrupt revegetation processes. Alien plant species emerge and disappear over time. To prevent wildfires and create conditions favourable for the restoration of mire vegetation, rewetting is required. With an average ground water level (GWL) during the growing season of −5 to +15 cm, mire vegetation can actively re-establish. Communities with near-aquatic and aquatic plants can form on flooded areas with GWL of +30. This generally contributes to both fire prevention and wetland diversity.
... Moreover, E. vaginatum acts as a companion species to facilitate the growth and establishment of other peat-forming species, especially Sphagnum mosses, during early stages of restoration and peatland succession (Marinier et al., 2004;Tuittila et al., 2000). ...
One metric of peatland restoration success is the re‐establishment of a carbon sink, yet considerable uncertainty remains around the time‐scale of carbon sink trajectories. Conditions post‐restoration may promote the establishment of vascular plants such as graminoids, often at greater density than would be found in undisturbed peatlands, with consequences for carbon storage. Although graminoid species are often considered as a single plant functional type (PFT) in land‐atmosphere models, our understanding of functional variation among graminoid species is limited, particularly in a restoration context.
We used a traits‐based approach to evaluate graminoid functional variation and to assess whether different graminoid species should be considered a single PFT or multiple types. We tested hypotheses that greenhouse gas fluxes (CO2, CH4) would vary due to differences in plant traits among five graminoid species in a restored peatland in central Alberta, Canada. We further hypothesized that species would form two functionally distinct groupings based on taxonomy (grass, sedge).
Differences in gas fluxes among species primarily reflected variation in leaf physiology related to photosynthetic efficiency and resource‐use, and secondarily by plant size. Multivariate analyses did not reveal distinct functional groupings based on taxonomy or environmental preferences. Rather, we identified functional groups defined by plant traits and carbon fluxes that are consistent with ecological strategies related to differences in growth rate, resource‐acquisition and leaf economics, representing plants with either a strategy to grow quickly and invest in resource capture or to prioritize structural investment and resource conservation. These functional groups displayed larger average carbon fluxes compared to graminoid PFTs currently used in modelling.
Synthesis. Existing PFT designations in peatland models may be more appropriate for pristine or high‐latitude systems than those under restoration. Although replacing PFTs with plant traits remains a challenge in peatlands, traits related to leaf physiology and growth rate strategies offer a promising avenue for future applications.
... One of these, Polytrichastrum longisetum, was not observed in the study plots in the field but has been observed in the surroundings of the study site. This moss is known to colonize disturbed organic soils (Tuittila et al. 2000). Our results show that many perennial mosses such as Dicranum, Hylocomium and Kiaeria also emerge from diaspore bank. ...
Purpose
Soil diaspore banks of bryophytes are poorly known in tundra grasslands, yet can be important for the maintenance of local bryophyte assemblages. We examined the effects of fertilization and grazing exclusion on above-ground bryophyte assemblages and soil diaspore banks in a tundra grassland.
Methods
We collected soil diaspore samples and recorded the cover of above-ground bryophytes from a full-factorial experiment with NPK fertilization and grazing exclusion treatments (a Nutrient Network site in NW Finland). Soil diaspore samples were germinated on trays in a greenhouse. We analyzed the compositions of diaspore bank assemblages and of above-ground assemblages and assessed their responses to the experimental treatments.
Results
The diaspore bank contained c. 50% of taxa found in above-ground assemblages; 26 bryophyte taxa germinated from the diaspore bank, while 40 taxa were found in the above-ground assemblages. These communities had distinct species compositions: the diaspore bank was dominated by Pohlia nutans, while above-ground assemblages were dominated by several species. NPK fertilization and grazing exclusion had negative effects on bryophyte richness and cover in above-ground assemblages, and weaker effects on these responses in the diaspore bank.
Conclusion
Soil diaspore banks comprise about half of the bryophyte taxa encountered in above-ground assemblages. Bryophyte diaspore banks are more buffered against nutrient enrichment and grazing exclusion than above-ground assemblages, suggesting that diaspore banks may enhance persistence and recovery of local bryophyte assemblages from environmental changes.
... Vascular plants improve the microclimate by increasing relative humidity and balancing surface temperatures. Furthermore, they also access deeper soil water with their roots and could, once established, improve the survival and growth of Sphagnum, especially in drier climates or when abiotic conditions are sub-optimal (Tuittila et al. 2000, Pouliot et al. 2011, Guêné-Nanchen et al. 2017. However, at the same time, vascular plants might increase evapotranspiration due to their higher leaf area index and deeper roots and could thus contribute to the lower water table at Provinzialmoor. ...
Sphagnum farming aims to produce peat moss fibres for horticultural growing media or founder material for bog restoration. The objective of this study was to examine the establishment of Sphagnum on cut-over bog with shallow layers (average 78 cm) of highly decomposed "black peat" under different hydrological starting conditions. One of the two study sites in northwestern Germany was established directly after peat extraction, while the other one has been rewetted 7 years prior to its installation. Irrigation ditches were installed on these sites for water management. Sphagnum fragments were introduced and covered with straw mulch or geotextile for protection. The establishment of Sphagnum and the site conditions, including vascular plant growth, were evaluated to determine the supporting and limiting factors for Sphagnum farming under the difficult hydrological conditions of shallow highly decomposed peat (low porosity, low hydraulic conductivity). The cultivation of Sphagnum mosses is possible on shallow layers of highly decomposed peat. Sphagnum growth in cover and carpet thickness was significantly higher at the site that had previously been rewetted and had a thicker layer of residual peat. The areas covered with a geotextile showed significantly lower percentages of Sphagnum cover compared to those covered with straw mulch. While sufficient water quantity and quality are known to be prerequisites for Sphagnum farming, a sufficient peat layer thickness seems to be an additional factor for successful Sphagnum establishment and growth. Maintaining an optimal water table proved to be a challenge for these shallow layers of highly decomposed peat, as the low hydraulic conductivity of the peat has impeded a complete irrigation of the sites. Furthermore, the irrigation effort might need to be increased to compensate for additional water loss into the subsoil. On such sites with difficult hydrological and soil conditions, a favourable microclimate provided by vascular plants and a rewetted surrounding area can promote successful establishment of Sphagnum and can even partially counterbalance effects of a low water table.
... June 2021 | Volume 9 | Article 658470 6 Vegetation Three years post-restoration, the bryophyte cover was low onto the restored strip (CI 95% 2-17%) in comparison to the reference ecosystem (CI 95% 94-100%). Nevertheless, the bryophyte cover in the restored strip was dominated by Sphagnum (S. rubellum, S. medium, S. angustifolium) species with the presence of three pioneer mosses often found in degraded peatland (Polytrichum strictum, Dicranella cerviculata and Pohlia nutans; Poulin et al., 1999;Poulin et al., 2005;Tuittila et al., 2000). Vegetation cover of the main plant strata found in the peatland differed between the restored strip and the reference ecosystem, except for trees and shrubs other than ericaceous species ( Figure 5). ...
Mineral roads in peatlands change the nature of the substrate, influence the water table level of the peatland on either side of the road and the physicochemical characteristics of the water and peat. These changes can in turn affect plant community composition. The efficiency of an innovative and affordable method for the restoration of peatlands impacted by roads was evaluated: the Burial Under Peat Technique. To be considered effective from an ecological point of view, the technique should meet restoration goals by 1) confining the chemical elements and compounds potentially leaching from the mineral material; 2) creating and maintaining a restored surface elevation similar to the adjacent peatland for optimal rewetting; and 3) re-establishing typical peatland vegetation communities. Three years post-restoration, water sampled at various depths and distances to the buried road presented chemical elements and compounds concentrations similar to the means measured in the pristine surrounding peatland for most of the ions analyzed. The different steps of the technique ensured the reestablishment of an elevation similar to the surrounding peatland. The return of peatland plant communities was slow, mainly due to local factors (e.g., presence of drainage ditches). Furthermore, the Burial Under Peat Technique fulfilled the restoration objectives in re-establishing an acid organic soil. Finally, it is a cost-effective method in comparison to completely removing the mineral material and transporting new material to fill the depression left by the excavation of the road.
... Mean peat moisture at the surface (∼20 cm depth) was 67% for Eriophorum tussocks at the drained bog (compared to 92% at the pristine bog), slightly drier than the range (>70%) noted for increased E. vaginatum growth at an extracted peatland in Quebec (Lavoie et al 2005). Although frequently observed for disturbed bogs and fens (Tuittila et al 2000, Lavoie et al 2005, deeper water tables and reduced peat moisture content at the drained site may prevent the expansion of E. vaginatum or other sedge species within the bare peat pools. ...
Drier conditions caused by drainage for infrastructure development, or associated with global climate warming, may test the resilience of carbon-rich northern peatlands. Feedbacks among biological and
hydrological processes maintain the long-term stability of peatlands, but if hydrological thresholds are passed, these feedbacks may be weakened, causing a shift in ecosystem state and potentially large losses of carbon (C). To determine peatland response to hydrological change, we examined the structure (vegetation composition and hydrology) and biogeochemical function (carbon dioxide exchange) of a pristine bog and a bog subject to ∼7 years localised drainage (caused by regional groundwater drawdown due to mine dewatering) in the Hudson Bay Lowland, Canada. Water tables at the drained
bog were ∼1m below the hummock surface at the time of study compared to ∼0.3m at the pristine bog. For hummocks and intermediate microforms at the drained bog, plant production was
significantly less than at the pristine bog, most likely due to small changes in vegetation structure (reduced Sphagnum cover and smaller shrub leaf:stem ratios) caused by deeper water tables and
significantly reduced moisture content of surface peat. Despite these changes in vegetation and hydrology, net ecosystem production (NEP) remained positive (C sink) for these microforms at the drained bog. Dry pools with mostly bare peat at the drained bog had negative NEP (C source to atmosphere), in stark contrast to Sphagnum- and sedge-dominated pools at the pristine bog with small but positive NEP. Our study shows that dry pools now occupy an unstable state, but the hydrological thresholds for a shift in ecosystem state have not yet been reached for hummocks and intermediate microforms at the drained bog. However, weak or no relationships between water table depth, peat surface moisture content, and plant production for these microforms at the drained bog, suggest that drainage has weakened the hydrological feedbacks regulating peat production, causing peat
accumulation to slow. If drier conditions prevail, this reduced resilience increases the potential for a shift in ecosystem state and raises the risk of large C loss due to continued decomposition of deeper peat in oxic conditions, and wildfire.
... Woody species with slow growth rates such as Chamaedaphne calyculata and Rhododendron groenlandicum, and hummock species that usually expand more slowly such as Sphagnum fuscum (Pouliot et al. 2011, were most positively correlated to time since restoration. The 'bare peat and litter' component and Eriophorum vaginatum, one of the few species that can spontaneously colonise peatlands after peat extraction activities (Tuittila et al. 2000, Campbell et al. 2003, occupied more surface area at the more recently restored sites. ...
Managers of restoration projects need readily applicable tools that give them an unequivocal declaration of success or failure based on primary goals that may vary according to different jurisdictions. We used restored extracted Sphagnum peatlands in Canada to illustrate how different types of plant communities assigned to different restoration outcomes can be identified from readily measurable descriptors. Vegetation was surveyed from 5-10 years after restoration at 2-3 year intervals in a total of 274 permanent plots in 66 restored peatlands located across 4500 km, from Alberta in the drier continental interior to the wetter maritime coastal province of New Brunswick. Plant community data were subjected to a k-means clustering that resulted in three restoration outcome categories. A linear discriminant analysis (LDA) model (the "declaration tool") correctly classified 91 % of the plots in a calibration database that included 75 % of the peatlands, and 93 % of the validation database (25 % of the peatlands), into the restoration outcome categories, using plant strata and number of years since restoration (only) as descriptors. The model includes classification functions that can be used to assign a new plot (not used to construct the model) to its restoration outcome category. We found that ~70 % of the severely degraded peatland is successfully regenerating towards the target plant community.
... Woody species with slow growth rates such as Chamaedaphne calyculata and Rhododendron groenlandicum, and hummock species that usually expand more slowly such as Sphagnum fuscum (Pouliot et al. 2011, were most positively correlated to time since restoration. The 'bare peat and litter' component and Eriophorum vaginatum, one of the few species that can spontaneously colonise peatlands after peat extraction activities (Tuittila et al. 2000, Campbell et al. 2003, occupied more surface area at the more recently restored sites. ...
Managers of restoration projects need readily applicable tools that give them an unequivocal declaration of success or failure based on primary goals that may vary according to different jurisdictions. We used restored extracted Sphagnum peatlands in Canada to illustrate how different types of plant communities assigned to different restoration outcomes can be identified from readily measurable descriptors. Vegetation was surveyed from 5-10 years after restoration at 2-3 year intervals in a total of 274 permanent plots in 66 restored peatlands located across 4500 km, from Alberta in the drier continental interior to the wetter maritime coastal province of New Brunswick. Plant community data were subjected to a k-means clustering that resulted in three restoration outcome categories. A linear discriminant analysis (LDA) model (the "declaration tool") correctly classified 91 % of the plots in a calibration database that included 75 % of the peatlands, and 93 % of the validation database (25 % of the peatlands), into the restoration outcome categories, using plant strata and number of years since restoration (only) as descriptors. The model includes classification functions that can be used to assign a new plot (not used to construct the model) to its restoration outcome category. We found that ~70 % of the severely degraded peatland is successfully regenerating towards the target plant community.
... In addition, intermittent dry conditions (Fig. 3) may have made re-colonisation impossible for Sphagnum species (Price and Whitehead 2001). Eriophorum vaginatum has been shown to recolonise gullies starting from zones of redeposited peat (Crowe et al. 2008) and facilitate recolonization by other species (Tuittila et al. 2000). On Dartmoor, in nearby areas where lower connectivity has limited erosion Fig. 7 Temporal relationship between soil temperature (°C) at a depth of 5 cm (a-c) or water table depth (cm below ground surface) (d-f) and total (a and d), heterotrophic (b and e) and autotrophic (c and f) below-ground respiration from the vegetated haggs (n= 6). ...
... This would be expected to halt the expansion of the peat pans and encourage peat deposition behind dams which should provide zones for colonisation by pioneering species such as Eriophorum spp. (Crowe et al. 2008) which may facilitate recolonization by other species (Tuittila et al. 2000). In rewet cut-away peatlands high and stable water tables have been found to rapidly increase Eriophorum spp. ...
Peatlands are recognised as an important but vulnerable ecological resource. Understanding the effects of existing damage, in this case erosion, enables more informed land management decisions to be made. Over the growing seasons of 2013 and 2014 photosynthesis and ecosystem respiration were measured using closed chamber techniques within vegetated haggs and erosional peat pans in Dartmoor National Park, southwest England. Below-ground total and heterotrophic respiration were measured and autotrophic respiration estimated from the vegetated haggs. The mean water table was significantly higher in the peat pans than in the vegetated haggs; because of this, and the switching from submerged to dry peat, there were differences in vegetation composition, photosynthesis and ecosystem respiration. In the peat pans photosynthetic CO2 uptake and ecosystem respiration were greater than in the vegetated haggs and strongly dependent on the depth to water table (r² > 0.78, p < 0.001). Whilst in the vegetated haggs, photosynthesis and ecosystem respiration had the strongest relationships with normalised difference vegetation index (NDVI) (r² = 0.82, p < 0.001) and soil temperature at 15 cm depth (r² = 0.77, p = 0.001). Autotrophic and total below-ground respiration in the vegetated haggs varied with soil temperature; heterotrophic respiration increased as water tables fell. An empirically derived net ecosystem model estimated that over the two growing seasons both the vegetated haggs (29 and 20 gC m⁻²; 95% confidence intervals of − 570 to 762 and − 873 to 1105 gC m⁻²) and the peat pans (7 and 8 gC m⁻²; 95% confidence intervals of − 147 to 465 and − 136 to 436 gC m⁻²) were most likely net CO2 sources. This study suggests that not only the visibly degraded bare peat pans but also the surrounding vegetated haggs are losing carbon to the atmosphere, particularly during warmer and drier conditions, highlighting a need for ecohydrological restoration.
... The strong overlap between the autecology of individual species and synecology of respective functional groups may seem to be evident, but this assumption has rarely been evaluated. The ecology of mires (sensu lato) has largely been described via requirements of individual species, but sometimes species have been clustered taxonomically, functionally or by ecological response (Van der Valk 1981, Tuittila et al. 2000, Groeneveld & Rochefort 2002, González et al. 2013. Therefore, we propose that the assembly of vegetation in abandoned peatextraction areas is a suitable system to test the similarity of ecological filters between core species and their respective functional groups. ...
... At the core species level, successional accumulation over time was confirmed for some well-known early arrival species, such as bog species E. vaginatum and bilocal P. sylvestris (Tuittila et al. 2000, Campbell et al. 2003. However, we detected even more evident time-dependence for some other species, such as bog species T. alpinum and Aulacomnium palustre, and bilocals E. nigrum and P. schreberi. ...
The combined autecology of individual species is expected to reflect the synecology of their respective functional groups and vice versa, but this assumption has been rarely assessed. We estimated this similarity in limiting ecological filters using vegetation survey data from 64 abandoned extracted peatlands in Estonia, which form a 50-year chronosequence of secondary succession. Partial overlap was found between filters predicting the occurrence of individual core species and richness in their respective functional groups. These overlapping filters were microtopographical form (flats, margins, ditches), time since abandonment, and various properties of peat. At the functional group level, time since abandonment and habitat properties showed clear interactions with microform type. Bog species and acidophilous bilocals successfully established on flats and ditch margins when residual peat was acidic and poorly decayed, while species of fens and mineral soils preferentially established in ditches of large extraction fields, where residual peat had higher pH and higher mineral content. We also detected some effects of landscape-level (patch area and forest neighbourhood) and regional filters (continentality); however, their limiting role was inconsistent. Many ecological filters also were shared between functional groups at the species level, but the optimal levels of these filters differed between groups. We conclude that even in species-poor habitats, both the autecology of individual species and the synecology of functional groups should be considered during habitat restoration. In peatland restoration, the following management strategies are advised to direct a faster and more successful trajectory: controlling the depth of peat extraction, partial filling of ditches, introducing plant propagules and managing mineral dust pollution.
