Search

Land-use changes and anthropogenic disturbances are major threats to biodiversity, affecting ecosystem function and recovery. In boreal Alberta, Canada, petroleum development has led to extensive landscape fragmentation, notably through linear clearings created for seismic exploration that remove surface vegetation and microtopography. Despite partial recovery on forested seismic lines, peatland recovery is often arrested, impacting wildlife and carbon dynamics. Restoration efforts employ silviculture techniques to create microtopography and foster tree growth, but the efficacy of restoration treatments in restoring peatland plant diversity remains uncertain. We compared taxonomic, phylogenetic, and functional diversity of understory plant communities across treated and untreated seismic lines, alongside reference sites in treed bogs and fens. Treated lines generally had a twofold increase in plant height, leaf dry matter content, and foliar nitrogen and phosphorus contents compared to reference sites. In bogs, treated lines differed from reference conditions driven by increases in herbaceous taxa, while fens displayed disparities mainly in taxonomic and phylogenetic diversity. Differential responses of bogs and fens underline the necessity for tailored management strategies. Changes in plant diversity away from restoration targets have implications for ecosystem recovery, emphasizing the importance of long-term monitoring to evaluate the effectiveness of silviculture techniques in restoring boreal peatland plant communities. [ABSTRACT FROM AUTHOR]

An environmental proxy routinely used in paleoecological studies of peatlands is testate amoebae, which are used to infer successional and hydrological shifts through time. However, since many species of protists globally remain undescribed, important ecological information about community assemblages and their interaction with environmental conditions in both the past and present has potential gaps. During the analysis of testate amoeba assemblages from peat cores across the Hudson and James Bay region of Canada, a testate amoeba that has not been formally described was discovered with high abundance in subfossil assemblages (up to 50%). We describe this new species, Pyxidicula muskegii sp. nov., using morphometric measurements of tests from these peat core records and demonstrate its environmental preferences using modern samples collected from the same region. The hemispheric shape and irregular areolar surface pattern on the test, along with its preference for lawns in both fens and bogs, support that P. muskegii is a new species. This species is also found in much lower relative abundance in modern samples (<3%) than in paleo-peat core records. This difference in modern and paleo-assemblage suggests that there is a taphonomic bias in their relative abundance with depth, which we attribute to their organic test that is less prone to decomposition. Therefore, it is critical to include rare taxa within future transfer function models to incorporate their environmental tolerances and improve model predictions. [ABSTRACT FROM AUTHOR]

Fire plays a major role in the structuring and functioning of boreal ecosystems. As peatlands are important components of boreal forests, the impact of fire upon these wetter ecosystems is increasingly studied, but with the focus on treed peatlands and Sphagnum-dominated bogs so far. Important fires occurring more frequently in the past decade in southern Northwest Territories (Canada) provide the opportunity to assess early post-fire vegetation regeneration in open rich fens (one, two, and five years post-fire) and to better understand early recovery succession. We aimed to (i) evaluate whether and how open rich fens are affected by fire, and (ii) describe short-term vegetation regeneration for both bryophytes and vascular species. A shift was observed between pioneer bryophytes and brown mosses between the second and fifth year post-fire. Vascular plants, especially slow-growing species and the ones reproducing mainly by seeds, recovered partially. The first bryophyte species recovering were pioneer species adapted to colonize burned environments such as Marchantia polymorpha L. or Ceratodon purpureus (Hedw.) Brid. For vascular plant species, the ones previously present and able to regrow rapidly from unburned plant structures (base of tussocks, rhizomes, roots) were represented by species like Betula glandulosa Michx. or Carex aquatilis Wahlenb. The wetter conditions and lower fuel availability of fen depressional biotopes were important factors controlling the resistance and regeneration of species associated with them. [ABSTRACT FROM AUTHOR]

The ability to distinguish peatland types at the landscape scale has implications for inventory, conservation, estimation of carbon storage, fuel loading, and postfire carbon emissions, among others. This paper presents a multisensor, multiseason remote sensing approach to delineate boreal peatland types (wooded bog, open fen, shrubby fen, treed fen) using a combination of multiple dates of L-band (24 cm) synthetic aperture radar (SAR) from ALOS PALSAR, C-band (∼5.6 cm) from ERS-1 or ERS-2, and Landsat 5 TM optical remote sensing data. Imagery was first evaluated over a small test area of boreal Alberta, Canada, to determine the feasibility of using multisensor SAR and optical data to discriminate peatland types. Then object-based and (or) machine-learning classification algorithms were applied to 3.4 million ha of peatland-rich subregions of Alberta, Canada, and the 4.24 million ha region of Michigan's Upper Peninsula where peatlands are less dominant. Accuracy assessments based on field-sampled sites show high overall map accuracies (93%-94% for Alberta and Michigan), which exceed those of previous mapping efforts. [ABSTRACT FROM AUTHOR]

The Sandhill Fen reclamation watershed, commissioned by Syncrude Canada Ltd., is the first attempt to reclaim a self-sustaining peat-forming wetland on a previously mined area. Here, we quantified net nitrogen mineralization rates at Sandhill Fen in the first and second years since initiation (2013-2014). Our main objective was to determine whether nitrogen production potentials at Sandhill Fen were similar to six regional fens sampled across an ombrotrophic-minerotrophic peatland gradient. In the second year, net nitrogen mineralization rates across Sandhill Fen (2014 mean = 20.2 mg N·m−2·day−1; 0.9 mg N·kg−1·day−1) were quite comparable with the benchmark fen sites (2013-2014 pooled means = 20.6 mg N·m−2·day−1; 5.9 mg N·kg−1·day−1). However, in areas exhibiting low gravimetric soil moisture content at Sandhill Fen, net nitrification contributed more than 50% to the net N mineralization total, an uncommon observation in natural fen type wetlands. These findings highlight the importance of managing soil moisture levels during the early stages of reclamation to (1) maintain relatively anaerobic soil conditions, and (2) facilitate microbial-mediated processes to fall within an acceptable range of variation comparable to undisturbed Albertan fens. [ABSTRACT FROM AUTHOR]

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

Several boreal fens belong to the patterned fen category, which is composed of two compartments, the pool (or hollow), and the string (or hummock) compartments. Both compartments are distributed perpendicular to the mire slope and drainage flow. The surface of patterned fens is repeatedly invaded by water, which is known to affect the original pool-string pattern through the creation and enlargement of pools, a process caused by the action of aqualysis. Aqualysis refers to the destruction of the vegetation cover by flooding of low-elevated strings or lawns causing the formation and enlargement of pools. It is argued here that the nature and composition of the pool structure (number and size) reveal the state of development of patterned fens of the boreal environment. Quantitative and spatial data for pool size structure in 24 fens of northern Quebec, including 4881 pools, were used for the assessment of patterned fen development. Among the main factors influencing patterned fen development, area and slope contribute to the construction of the peatland surface. Also, watershed area, alternating strings and hollows, and peat thickness all facilitate pool creation and expansion. The construction of the pool structure of most fens has been a long process of ecosystem building. This probably explains why most sloping fens, i.e, moderate- and steep-sloping fens, are today at an equilibrium stage characterized by the coexistence of pools of all sizes with the smallest pools being the most numerous. In contrast, most low-sloping fens have developed toward a lacustrine stage with a bimodal distribution of small and very large pools. Boreal patterned fens of all developmental stages will be subject to increased pool size and number in the near future if more humid climatic conditions prevail. [ABSTRACT FROM AUTHOR]

Northern peatlands represent a long-term net sink for atmospheric CO2, but these ecosystems can shift from net carbon (C) sinks to sources based on changing climate and environmental conditions. In particular, changes in water availability associated with climate control peatland vegetation and carbon uptake processes. We examined the influence of changing hydrology on plant species abundance and ecosystem primary production in an Alaskan fen by manipulating the water table in field treatments to mimic either sustained flooding (raised water table) or drought (lowered water table) conditions for 6 years. We found that water table treatments altered plant species abundance by increasing sedge and grass cover in the raised water table treatment and reducing moss cover while increasing vascular green area in the lowered water table treatment. Gross primary productivity was lower in the lowered treatment than in the other plots, although there were no differences in total biomass or vascular net primary productivity among the treatments. Overall, our results indicate that vegetation abundance was more sensitive to variation in water table than total biomass and vascular biomass accrual. Finally, in our experimental peatland, drought had stronger consequences for change in vegetation abundance and ecosystem function than sustained flooding. [ABSTRACT FROM AUTHOR]

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

Groundwater chemistry is a major determinant of assemblages of various taxonomic groups in spring fens, but its effect on insect assemblages has not been proved yet. We investigated dipteran assemblages at 17 isolated spring fens, which encompass the whole mineral richness gradient from rich (calcareous) to poor (highly acidic) sites, and analyzed faunal patterns at two contrasting mesohabitats: flowing water and standing water. The effect of water chemistry, substratum features, discharge, and temperature on the dipteran assemblages were assessed using PERMANOVA and GAM. Highly diverse dipteran assemblages (156 taxa) were closely related to the mineral richness gradient at both mesohabitats, showing a continual and nearly complete species exchange along the gradient, while their total abundance and taxa density did not change significantly. The assemblages included both habitat generalists and taxa specifically associated with acidic, moderate, or calcareous conditions. The mineral richness gradient was also reflected by changes in substratum properties, thus creating a complex environmental gradient that we suggest is the main environmental gradient structuring aquatic assemblages in spring fens. [ABSTRACT FROM AUTHOR]

Linear infrastructures are known to facilitate the spread of undesirable species in ecosystems. Compared with other types of infrastructure, the role of power line rights-of-way (ROWs) as dispersal vectors remains poorly understood, especially with regard to peatlands. The aim of our study was to evaluate their impacts on the vegetation of ombrotrophic (bog) and minerotrophic (fen) peatlands. The vegetation communities within and adjacent to power line ROWs were sampled in 23 bogs and 11 fens in southern Québec. In fens, invasive species were found in abundance along the first 250 m within ROWs, while native non-peatland species were able to spread into entire ROWs. Invasive species were also able to colonize the adjacent fen habitats but were mostly concentrated in the first 4 m from ROW edges. Some species were, however, able to establish at more than 43 m from ROWs. Invasive and native non-peatland species were mostly restricted to the first 31 m within ROWs intersecting a bog and almost none dispersed in the adjacent bog habitats. Overall, the average cover of native non-peatland and invasive species in ROWs was mostly related to intrinsic abiotic conditions such as water pH, water conductivity, and water table level, while landscape surrounding the peatland and historical variables (e.g., time elapse since the construction of the ROW) had few impacts in both bogs and fens. Les infrastructures linéaires peuvent faciliter la dispersion des espèces indésirables. Comparativement aux autres types d'infrastructures, le rôle des emprises de lignes électriques comme vecteurs de dispersion demeure peu connu, surtout dans les tourbières. L'objectif de notre étude était d'évaluer les impacts de ces emprises sur la végétation des tourbières ombrotrophes «bogs» et minérotrophes «fens». Nous avons échantillonné la végétation de 23 emprises de lignes électriques traversant des bogs et de 11 autres traversant des fens, dans le sud du Québec. Nous avons également échantillonné la flore des habitats tourbeux adjacents à ces emprises. Dans les emprises traversant les fens, les espèces envahissantes étaient présentes en abondance dans les 250 premiers mètres, alors que les espèces indigènes non-tourbières pouvaient se propager dans l'ensemble des emprises. Les espèces envahissantes étaient également présentes dans les habitats adjacents aux fens, mais surtout dans les quatre premiers mètres en bordure des emprises. Certaines de ces espèces étaient toutefois encore présentes à plus de 43 mètres des emprises. À l'inverse, les espèces envahissantes et non-tourbières étaient surtout confinées le long des 31 premiers mètres dans les emprises traversant les bogs et pratiquement aucune n'était présente dans les habitats adjacents aux bogs. Dans l'ensemble, la susceptibilité des tourbières à l'envahissement dans les emprises est surtout liée aux conditions abiotiques des sites comme le pH et la conductivité de l'eau, et le niveau de la nappe phréatique, tandis que le paysage qui entoure les tourbières et les variables historiques (p. ex., le temps écoulé depuis la construction de l'emprise) ont peu d'effets sur les bogs et les fens. [ABSTRACT FROM AUTHOR]

In 1958, 85% of the peat-bog complex Kyselovský les, in the Czech Republic, was flooded with water from the Lipno reservoir. A new vegetation pattern has spontaneously developed in the newly established shoreline and replaced the original peat-bog vegetation dominated by bog pine (Pinus rotundata Link) forest. This vegetation pattern consists of zonal strips with relatively sharp borders. This zonation is a mosaic of sedge fens, reed canary grass (Phalaris arundinacea L.) beds, tussock cottongrass (Eriophorum vaginatum L.) stands, and a community dominated by ericaceous shrubs. The study focused on the vegetation development of this zonal vegetation. Measurements of the water table level, groundwater pH, and conductivity, together with terrain microtopography, were done to estimate the ways in which the water reservoir influences the mire vegetation. The most important factor is lake water fluctuation, which explained most of the vegetation gradient variability. Lake water fluctuations were represented by lake water levels, which directly flooded a certain part of the gradient from 1990 to 2006 for a known number of days. [ABSTRACT FROM AUTHOR]

Plant diversity and rarity have been relatively well studied for bryophytes in Canadian western boreal peatlands, but little information exists for vascular plants. Diversity, community composition, and rarity of bryophytes and vascular plants were determined and relationships examined among these and environmental variables in five peatland types at Duck Mountain, Manitoba: wooded bogs, black spruce swamps, wooded moderate-rich fens, open moderate-rich fens, and open extreme-rich fens. Total diversity was 298 species comprising 86 bryophytes and 212 vascular plants. Mean diversity followed a unimodal distribution over a bog – rich fen gradient. Wooded moderate-rich fens (59.0) and black spruce swamps (53.4) had the highest mean diversity, whereas wooded bogs (32.3) and open extreme-rich fens (34.7) had the lowest mean diversity. Occurrences of locally rare species followed the same general pattern, and provincially rare vascular plants were found primarily in wooded moderate-rich fens and black spruce swamps and were mostly orchids. Reasons for these patterns are complex, but high diversity appears to be related to high habitat heterogeneity and moderate environmental variables, e.g., pH and alkalinity, and low diversity appears to be related to environmental extremes, e.g., pH and alkalinity. Boreal wooded moderate-rich fens and black spruce swamps have comparatively high plant diversity and rarity and require consideration if the focus is biodiversity conservation. This will become increasingly important in landscapes where development pressures are high. [ABSTRACT FROM AUTHOR]

Net ecosystem productivity (NEP) during August 2003 was measured by using eddy covariance above 17 forest and 3 peatland sites along an east–west continental-scale transect in Canada. Measured sites included recently disturbed stands, young forest stands, intermediate-aged conifer stands, mature deciduous stands, mature conifer stands, fens, and an open shrub bog. Diurnal courses of NEP showed strong coherence within the different ecosystem categories. Recently disturbed sites showed the weakest diurnal cycle; and intermediate-aged conifers, the strongest. The western treed fen had a more pronounced diurnal pattern than the eastern shrub bog or the Saskatchewan patterned fen. All but three sites were clearly afternoon C sinks. Ecosystem respiration was highest for the young fire sites. The intermediate-aged conifer sites had the highest maximum NEP (NEPmax) and gross ecosystem productivity (GEPmax), attaining rates that would be consistent with the presence of a strong terrestrial C sink in regions where these types of forest are common. These results support the idea that large-scale C cycle modeling activities would benefit from information on the age-class distribution and disturbance types within larger grid cells. Light use efficiency followed a pattern similar to that of NEPmax and GEPmax. Four of the five recently disturbed sites and all three of the peatland sites had low water use efficiencies. [ABSTRACT FROM AUTHOR]

Presents a study that analyzed the hydrologic regime, plant production and carbon dioxide and carbon-hydrogen[sub4] emissions for three pristine fens and two fens that are potentially affected by the Grand Ditch water project diversion in the Colorado Rocky Mountain. Description of the study areas; Hydrologic and ecologic effects of water diversions and dams on low-elevation riparian ecosystems; Carbon cycling in the pristine fens.

Presents high-resolution Holocene peat accumulation and macrofossil data from the Upper Finto Fen (UPF) in west-central Alberta. Sediment lithology; Zonation of macrofossil diagram; Rates and pattern of carbon accumulation; Possible cause of the convex age-depth shape of peat accumulation curves at UPF.

Investigates the vegetation, environment and ecological gradients present on three calcareous mires in the South Park Valley, Park County, Colorado. Geologic and hydrogeomorphic setting; Fen habitats and species associations; Ecological processes influencing South Park mire vegetation.