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Maria Greger - One of the best experts on this subject based on the ideXlab platform.

Tim R Moore - One of the best experts on this subject based on the ideXlab platform.

  • The role of cotton-grass (Eriophorum vaginatum) in the exchange of CO2 and CH4 at two restored peatlands, eastern Canada
    Ecoscience, 2020
    Co-Authors: Michele Marinier, Stephan Glatzel, Tim R Moore
    Abstract:

    Abstract:We measured methane (CH4) and carbon dioxide (CO2) exchanges from bare peat and Eriophorum vaginatum ssp. spissum tussocks at recently restored harvested peatlands near Shippagan, New Brunswick and Riviere-du-Loup, Quebec over three growing seasons (May to October). Average seasonal CH4 emission rates ranged from -1 to 65 mg·m-2·d-1, with a generally weak relationship with water table position. A stronger relationship was seen between CH4 emissions and above-ground plant biomass. CH4 fluxes from E. vaginatum tussocks were larger than those from bare peat surfaces and increased with increasing above-ground biomass and photosynthetic rate. Clipping fresh leaves from tussocks reduced the CH4 emission rates by 79%. Photosynthesis rates were large in tussocks, ranging from 0.9 to 3.4 g CO2-C·m-2·h-1 at high light levels, and respiration rates (autotrophic + heterotrophic) ranged from -0.1 to -1.3 g CO2-C·m-2·h-1. Some tussocks exhibited net CO2 loss to the atmosphere, even under high light levels. Alt...

  • videographic analysis of Eriophorum vaginatum spatial coverage in an ombotrophic bog
    Remote Sensing, 2013
    Co-Authors: Margaret Kalacska, Pablo J Arroyomora, Eva Snirer, Carrie Herzog, Tim R Moore
    Abstract:

    The use of Remotely Piloted Aircraft Systems (RPAS) as well as newer automated unmanned aerial vehicles is becoming a standard method in remote sensing studies requiring high spatial resolution (<1 m) and very precise temporal data to capture phenological events. In this study we use a low cost rotorcraft to map Eriophorum vaginatum at Mer Bleue, an ombrotrophic bog located east of Ottawa, ON, Canada. We focus on E. vaginatum because this sedge plays an important role in methane (CH4) gas exchange in peatlands. Using the remote controlled rotorcraft we were able to record, process, and mosaic 11.1 hectares of 4.5 cm spatial resolution imagery extracted from individual frames of video recordings (post georegistration RMSE 4.90 ± 4.95 cm). Our results, based on a supervised classification (96% accuracy) of the red, green, blue image planes, indicate a total tussock cover of 2,417 m2. Because the basal area of the plant is more relevant for calculating its contribution to the CH4 flux, the tussock area was related to the basal area from field data (R2 = 0.88, p < 0.0001). Our final results indicate a total basal area of 1,786 ± 62.8 m2. Based on temporal measurements of CH4 flux from the peatland as a whole that vary over the growing season, we estimate the E. vaginatum contribution to range from 3.0% to 17.3% of that total. Overall, our low cost approach was an effective non-destructive way to derive E. vaginatum coverage and estimate CH4 exchange over the growing season.

  • Videographic Analysis of Eriophorum Vaginatum Spatial Coverage in an Ombotrophic Bog
    Remote Sensing, 2013
    Co-Authors: Margaret Kalacska, Eva Snirer, Carrie Herzog, J. Pablo Arroyo-mora, Tim R Moore
    Abstract:

    The use of Remotely Piloted Aircraft Systems (RPAS) as well as newer automated unmanned aerial vehicles is becoming a standard method in remote sensing studies requiring high spatial resolution (

  • the role of cotton grass Eriophorum vaginatum in the exchange of co2 and ch4 at two restored peatlands eastern canada
    Ecoscience, 2004
    Co-Authors: Michele Marinier, Stephan Glatzel, Tim R Moore
    Abstract:

    We measured methane (CH4) and carbon dioxide (CO2) exchanges from bare peat and Eriophorum vaginatum ssp. spissum tussocks at recently restored harvested peatlands near Shippagan, New Brunswick and...

Eva Stoltz - One of the best experts on this subject based on the ideXlab platform.

Jukka Laine - One of the best experts on this subject based on the ideXlab platform.

  • nitrate uptake by Eriophorum vaginatum controls n2o production in a restored peatland
    Soil Biology & Biochemistry, 2005
    Co-Authors: Eevastiina Tuittila, Harri Vasander, Jukka Laine, Niko Silvan, Veikko Kitunen
    Abstract:

    Abstract The clear dependence of N 2 O production through denitrification on available nitrate ( NO 3 − ) in soil has been shown in many studies. Since N availability similarly limits the growth of plants, the resource competition with vegetation limits the activity of denitrifying microbes and may consequently moderate the N 2 O emissions from peatlands. We used NO 3 − uptake by Eriophorum vaginatum L. as a vegetation competition factor for microbes. The species was selected for the experiment because it has high nutrient use efficiency in low-nutrient conditions and high nutrient uptake efficiency in luxuriant nutrient conditions. We measured gaseous N flux as N 2 O (end product of denitrifier activity) in a restored peatland in central Finland with acetylene inhibition technique over a growing season from sample plots with varying NO 3 − addition levels and E. vaginatum cover. The resource competition effects were analysed with a model that used exponential decay dependence of N 2 O flux on the leaf area of E. vaginatum , and saturating response of N 2 O flux to NO 3 − addition level. The model explained the variation in N 2 O fluxes well ( R 2 =0.86). The model simulation showed that the increasing nutrient uptake of E. vaginatum decreased the N 2 O fluxes exponentially. Simultaneously, denitrification appeared to saturate even in conditions with high availability of NO 3 − and low level of competition by vegetation. Thus, E. vaginatum is an effective competitor for NO 3 − in sedge-dominated peatlands that controls the availability of NO 3 − for denitrification, and consequently moderates the N 2 O emissions from peatlands.

  • Eriophorum vaginatum plays a major role in nutrient immobilisation in boreal peatlands
    2004
    Co-Authors: Niko Silvan, Eevastiina Tuittila, Harri Vasander, Jukka Laine
    Abstract:

    The temporal growth pattern, above- and below-ground biomass allocation of Eriophorum vaginatum (cottongrass) and its nutrient immobilisation dynamics were studied in a greenhouse experiment. The temporal growth pattern was also studied in a field experiment with three N and P addition levels in a restored peatland buffer in central Finland. The greatest seasonal increase in accumulated N and P occurred in roots and stems and leaf sheaths concurrently with the highest leaf elongation and new daughter tiller production. The amounts of N and P immobilised in cottongrass tissues were 73 g N m –2 (91% of the added N) and 13 g P m –2 (77% of the added P). A remarkable liberation of P into outflow water was observed at the end of the growing period. The annually increasing mass of dead organs of cottongrass, typically highly resistant to decomposition, forms a potential long-term sink for nutrients.

  • vegetation patterns around Eriophorum vaginatum l tussocks in a cut away peatland in southern finland
    Botany, 2000
    Co-Authors: Eevastiina Tuittila, Hannu Rita, Harri Vasander, Jukka Laine
    Abstract:

    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. Logit regression showed a positive interaction between distance from the base of a tussock and a tussock's sheltering properties for all the studied plant species, indicating that the smaller the tussock the nearer plants have to be to find a favourable microsite. A southerly direction, which is the most exposed to solar irradiation, was the most inhospitable microsite. Our results indicated that cottongrass tussocks may offer a variety of microsites for colonizers with varying ecological requirements.Key words: cut-away peatland, colonization, Eriophorum vaginatum, facilitation, logit models, ordination.

James B Mcgraw - One of the best experts on this subject based on the ideXlab platform.

  • northward displacement of optimal climate conditions for ecotypes of Eriophorum vaginatum l across a latitudinal gradient in alaska
    Global Change Biology, 2015
    Co-Authors: James B Mcgraw, Gaius R Shaver, Cynthia C Bennington, Milan C Vavrek, Jessica B Turner, Sara Souther, Ned Fetcher
    Abstract:

    Plants are often genetically specialized as ecotypes attuned to local environmental conditions. When conditions change, the optimal environment may be physically displaced from the local population, unless dispersal or in situ evolution keep pace, resulting in a phenomenon called adaptational lag. Using a 30-year-old reciprocal transplant study across a 475 km latitudinal gradient, we tested the adaptational lag hypothesis by measuring both short-term (tiller population growth rates) and long-term (17-year survival) fitness components of Eriophorum vaginatum ecotypes in Alaska, where climate change may have already displaced the optimum. Analyzing the transplant study as a climate transfer experiment, we showed that the climate optimum for plant performance was displaced ca. 140 km north of home sites, although plants were not generally declining in size at home sites. Adaptational lag is expected to be widespread globally for long-lived, ecotypically specialized plants, with disruptive consequences for communities and ecosystems.

  • tiller population dynamics of reciprocally transplanted Eriophorum vaginatum l ecotypes in a changing climate
    Population Ecology, 2015
    Co-Authors: Jennifer L S Chandler, Gaius R Shaver, James B Mcgraw, Cynthia C Bennington, Milan C Vavrek, Ned Fetcher
    Abstract:

    Moist tussock tundra, dominated by the sedge Eriophorum vaginatum L., covers approximately 3.36 × 108 km2 of arctic surface area along with large amounts of subarctic land area. Eriophorum vaginatum exhibits ecotypic differentiation along latitudinal gradients in Alaska. While ecotypic differentiation may be beneficial during periods of climate stability, it may be detrimental as climate changes, causing adaptational lag. Following harvest of a 30-year reciprocal transplant experiment, age-specific demographic data on E. vaginatum tillers were collected to parameterize a Leslie matrix. Yellow Taxi analysis, based on Tukey’s Jackknife, was used to determine mean pseudovalues of tiller population growth rate (\(\overline{{\phi_{i} }}\)) for four source populations of E. vaginatum tussocks that were transplanted to each of three gardens along a latitudinal gradient. Source populations responded differentially along the latitudinal gradient. Survival and daughter tiller production influenced differences seen at the mid-latitude garden, and the overall tiller population performance was generally improved by northward transplanting relative to southward transplanting. A comparison of home-source \(\overline{{\phi_{i} }}\) and away-source \(\overline{{\phi_{i} }}\) within the same transplant garden indicates no home-site advantage. Although populations were still growing when transplanted to home-sites (\(\overline{{\phi_{i} }}\) = 1.056), tiller population growth rate increased as ΔGDD became more negative relative to the home site (i.e., as tussocks were transplanted north). These results imply that populations are affected by climate gradients in a manner consistent with adaptational lag. This study documenting the response of high-latitude ecotypes to climate gradients may be an indication of the possible future effects of climate shift in more southern latitudes.

  • clinal variation in stomatal characteristics of an arctic sedge Eriophorum vaginatum cyperaceae
    American Journal of Botany, 2012
    Co-Authors: Caitlin A Peterson, James B Mcgraw, Ned Fetcher, Cynthia C Bennington
    Abstract:

     Premise of the study: In a large reciprocal transplant experiment, Eriophorum vaginatum tussocks transplanted along a latitudinal gradient in Alaska’s interior exhibited genetic differentiation and phenotypic plasticity for vegetative traits. Using the same tussocks 30 yr later, we used estimates of growing season temperature at each site to ask whether there was a climatic cline for stomatal density, size, and conductance.  Methods: We created impressions of the abaxial leaf surfaces of the transplanted individuals for viewing under a microscope and measured stomatal density (SD) and length (SL) for 224 individuals. We used SD and SL to estimate stomatal conductance ( C ). Separate one-way analyses of variance were performed to quantify the effect of population genetic differences and latitudinal environmental variation on stomatal characteristics.  Key results: Our data suggest that stomatal size was infl uenced by both genetics and environment and that plasticity for stomatal density produced highest densities at the coolest sites. Stomatal conductance increased with decreasing temperature of site from which the populations originated.  Conclusions: Our results demonstrate a cline in stomatal conductance in E. vaginatum , with some ability of populations to plastically produce an appropriate phenotypic response in a new environment. Because the species is a dominant species in many arctic plant communities, its ability to produce an appropriate stomatal phenotype and to optimize water use effi ciency by decreasing stomatal conductance in warmer environments could affect both community composition and total primary productivity in future, warmer climates.

  • ecological genetic variation in seed banks iv differentiation of extant and seed bank derived populations of Eriophorum vaginatum
    Arctic and alpine research, 1993
    Co-Authors: James B Mcgraw
    Abstract:

    Ecological genetic comparisons were made between tussocks of Eriophorum vaginatum established from the seed bank in a bladed site and tussocks in undisturbed tundra at Eagle Creek, Alaska. In one experiment, tussocks were reciprocally transplanted between the bladed and undisturbed sites, and, in a second experiment, progeny from the seed rain and soil seed bank in undisturbed tundra were compared. Measurements made 3, 4, and 5 yr after transplanting showed that the two populations were genetically distinct in some morphological characters (leaf length and rate of flowering) and in ecological response to site variation (leaf length and relative growth rate). In the greenhouse experiment, plants from the seed bank differed from those in the seed rain immediately following germination, although these differences were not persistent. In combination with other studies ofcottongrass tundra at Eagle Creek, these results suggest that E. vaginatum seedlings emerging from the deeply buried seed bank may represent early-successional genotypes that numerically dominate this seed bank, but as adults are reduced in numbers as succession proceeds toward a closed vegetation.