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Copyright of Ecoscience (Ecoscience) is the property of Taylor & Francis Ltd 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.)

This study investigated how hydrogeological setting influences aquifer–peatland connections in slope and basin peatlands. Steady-state groundwater flow was simulated using Modflow on 2D transects for an esker slope peatland and for a basin peatland in southern Quebec (Canada). Simulations investigated how hydraulic heads and groundwater flow exported toward runoff from the peatland can be influenced by recharge, hydraulic properties, and heterogeneity. The slope peatland model was strongly dominated by horizontal flow from the esker. This suggests that slope peatlands are dependent on the hydrogeological conditions of the adjacent aquifer reservoir, but are resilient to hydrological changes. The basin peatland produced groundwater outflow to the surface aquifer. Lateral and vertical peat heterogeneity due to peat decomposition or compaction were identified as having a significant influence on fluxes. These results suggest that basin peatlands are more dependent on recharge conditions, and could be more susceptible to land use and climate changes. [ABSTRACT FROM AUTHOR]

With the densification of cities, it is imperative to identify urban ecosystems that should be protected or restored. We aimed to determine the conservation and restoration needs in a large urban park (1,35 km2) in Quebec City (Canada), based on site history, current species richness, floristic uniqueness, and floristic quality assessment of its diverse ecosystems: forest, swamp, wooded peatland, open peatland, and marsh. We evaluated the cover of all vascular species in 70 plots (400 m2) and assessed 18 environmental variables. We found that forest and swamp plots were the richest while peatland plots were the poorest, with marsh plots showing intermediate values. Ecological uniqueness (LCBD) was not correlated with richness (ρ = 0.17; p > 0.05), with marsh and peatland plots showing the highest and lowest uniqueness, respectively. With a regression tree, we identified canopy openness as the most influential variable explaining plot uniqueness across all ecosystems, especially in the peatland, indicating that future recreational development should be avoided in open ecosystems. By plotting ecological uniqueness (LCBD) with tolerance to disturbance (Mean C) values, we identified areas that could benefit from conservation or restoration, and areas that could sustain future development for recreational use. For each area, floristic composition, site characteristics, and past land-use history were investigated further to identify appropriate actions. The open peatland was identified as the main conservation priority, but actions will be needed to limit rapid tree encroachment. Three marshes were identified as areas that would floristically benefit from restoration actions. Still, since they also act as natural retention basins hosting species adapted to the soil conditions, we suggested monitoring the expansion of exotic and invasive species. Approaches developed and lessons learned from this project will serve as guidelines for municipalities aiming to implement a restoration and management plan in urban parks. • Ecological uniqueness and tolerance to disturbance helps management of urban parks. • Ecological uniqueness is not correlated to plant richness in forest and wetlands. • Restoration actions are needed to protect the open peatland from tree encroachment. • Canopy openness is associated to high ecological uniqueness. • Forested peatlands are sites compatible with development of public activities. [ABSTRACT FROM AUTHOR]

Aims Habitat connectivity is important in conservation since isolation can diminish the potential of a population for adaptation and increase its risk of extinction. However, conservation of naturally patchy ecosystems such as peatlands has mainly focused on preserving specific sites with exceptional characteristics, neglecting the potential interconnectivity between patches. In order to better understand plant dynamics within a peatland network, we assessed the effect of population isolation on genetic distinctiveness, phenotypic variations and germination rates using the peatland-obligate white-fringed orchid (Platanthera blephariglottis). Methods Fifteen phenotypic traits were measured for 24 individuals per population (20 distinct populations, Quebec, Canada) and germination rates of nearly 20 000 seeds were assessed. Genetic distinctiveness was quantified for 26 populations using single nucleotide polymorphism markers obtained via a pooled genotyping-by-sequencing approach. Geographic isolation was measured as the distance to the nearest population and as the number of populations occurring in concentric buffer zones (within a radius of 2, 5 and 10 km) around the studied populations. Important Findings All phenotypic traits showed significant differences among populations. Genetic results also indicated a pattern of isolation-by-distance, which suggests that seed and/or pollen exchange is restricted geographically. Finally, all phenotypic traits, as well as a reduced germination rate, were correlated with either geographic isolation or genetic distance. We conclude that geographic isolation likely restricts gene flow, which in turn may affect germination. Consequently, it is imperative that conservation programs take into account the patchy nature of such ecosystems, rather than targeting a few specific sites with exceptional character for preservation. [ABSTRACT FROM AUTHOR]

Gray birch ( Betula populifolia Marshall) is a pioneer tree species that generally colonizes both poor, dry soils and disturbed sites. Its current range appears to be expanding, and it has been observed to establish gradually and often massively in ombrotrophic peatlands. We examined data from sites within and beyond its continuous range that have been subjected to macrofossil analyses to determine whether this species was more abundant during certain periods since deglaciation. The most abundant macroremains were found in the eastern United States and date from the early Holocene (11 700 - 7000 cal. BP). Gray birch was present in mixed forests in which fires were probably more frequent than today. Only a few sites, located in pine barrens that experienced recurrent fires, show a continuous presence of the species during the middle and late Holocene. Palaeoecological data suggest that the colonization of peatlands by gray birch is a recent phenomenon (20th century), and one unique in peatland history. Anthropic disturbances seem to create conditions that foster this species, which could consequently increase its range in the coming decades. [ABSTRACT FROM AUTHOR]

In areas where peatlands are abundant, they are likely to play a significant role in the hydrological and hydrogeological dynamics of a watershed. Although individual case studies are reported in the literature, there is a large range of aquifer-peatland interactions and there is a need to understand the controls of these interactions. The objectives of this study were (1) to better understand aquifer-peatland connections and how these may be predicted by geology and geomorphic location and (2) to provide a variety of reference sites for glacial geological settings. Slope and depression peatlands were studied in the Abitibi-Témiscamingue region and in the St. Lawrence Lowlands, two contrasting regions of southern Quebec. A total of 12 transects that span a shallow aquifer-peatland interface were instrumented with piezometers. Field investigations included peatland characterization, monthly water level monitoring, and continuous hydraulic head measurements with pressure transducers. The results indicate that 7 of the 12 transects receive groundwater from the surrounding shallow aquifer. At the peatland margin, four lateral flow patterns were identified and associated with slope peatlands (parallel inflow and divergent flow) and with depression peatlands (convergent flow and parallel outflow). Vertical hydraulic gradients suggest that water flows mainly downwards, i.e. from the peatland to the underlying mineral deposits. Vertical connectivity appears to decrease as the distance from the peatland margin increases. All of these exchanges are important components in the sustainability of peatland hydrogeological functions. The regional comparison of aquifer-peatland flow dynamics performed in this study provides a new set of referenced data for the assessment of aquifer-peatland connectivity. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Questions What vegetation changes occurred over three decades on two large temperate peatlands (1115 ha) isolated in an agricultural landscape and affected by a human-ignited fire? Location Southwest Québec, Canada. Methods In 2012, we revisited 103 plots first sampled in 1984-85. Changes in species composition were evaluated using the Sørensen dissimilarity index, in species frequency with Chi-square goodness-of-fit tests, and in species cover using one-sample t-tests. Tree encroachment was evaluated using aerial photographs and satellite imagery. We used linear discriminant analyses ( LDA) and ANOVA to evaluate the impact of tree encroachment on species composition. Results We found a floristic dissimilarity of 35% between 1984 and 1985 and 2012. Most species whose frequency and mean cover increased were peatland species, while most species with lower frequency and mean cover in 2012 were non-peatland species. The total area occupied by forest increased from 26% to 51%, an overall gain of 280 ha of forest. The species composition of old and new forests as well as of open sectors was highly distinct, as shown by the LDA that correctly assigned 97% of the sampling plots to these groups. Non-peatland species were 15 and five times more abundant than peatland species in old and new forests than open habitats, respectively. Conclusions Gradual drying of the peatland margins due to drainage of the surrounding catchment, as well as post-fire succession are likely the main drivers of the changes observed. Overall, our study showed that peatlands isolated in an anthropogenic landscape are dynamic ecosystems where vegetation communities can experience substantial changes in a short time frame. The broader implication is that peatland conservation in highly modified landscapes must be linked to restoration. [ABSTRACT FROM AUTHOR]

Abstract: Plant macrofossil and testate amoebae analyses were conducted on a sedimentary core taken from a headwater peatland located near the summit of a hill at the northern extension of the Adirondack Mountains (Québec, Canada). The aims were to reconstruct the developmental stages of the peatland and to examine the allogenous and autogenous factors associated with its long-term dynamics. Results were compared with a quantitative paleoclimatic reconstruction based on the modern analog technique using pollen data from the same core. The long-term development of the peatland (pond—rich fen—intermediate fen—poor fen—bog) mainly reflects an autogenous hydroseral succession. Active peat accumulation under the relatively dry climate of the Early Holocene suggests that summer temperature was a critical factor in peat accumulation through enhanced biomass production. A major long-term decrease in net peat accumulation rates and a progressive decline of mean water-table depth occurred during the Mid- to Late-Holocene (7900–500calyr BP), even though annual precipitation was abundant at the time. The high summer temperature associated to the highest evapotranspiration rates maintained a low water table which in turn led to strong humification of the peat. A similar, synchronous pattern in vertical peat accumulation dynamics characterized another nearby peatland. Based on these results, we suggest that small peatlands situated atop a watershed and/or within a small watershed are ecosystems sensitive to changes in precipitation and/or evapotranspiration, due to their limited water supply. [Copyright &y& Elsevier]

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

Abstract: Ecosystem integrity often needs to be evaluated rapidly; indicator species may be used to do so. In this study we aim to evaluate whether White Fringed Orchid is an indicator of ombrotrophic peatland (Sphagnum bog) integrity in northeastern North America. The study was carried out in 113 sampling plots located in 60 bogs of southern Quebec, Canada. Vegetation (species cover and strata) and abiotic variables were collected within the plots and disturbance variables were determined using aerial photographs and satellite imagery. The level of integrity on each plot was assessed by calculating a Floristic Quality Assessment Index (FQAI) and an Anthropogenic Activity Index (AAI). Data were analyzed with ANOVAs, multivariate techniques and logistic multiple regression. Results indicated that the presence and abundance of White Fringed Orchid were positively linked to the FQAI and negatively to the perimeter/area ratio variable, suggesting that this species is most abundant and frequent at sites that are less disturbed and influenced by human activities. ANOVA showed that the AAI was lower in plots with high orchid abundance than in those without, suggesting that the orchid grows in more pristine sites. Our study showed that White Fringed Orchid abundance and presence may be used to rapidly and accurately evaluate Sphagnum bog integrity. [Copyright &y& Elsevier]