Identification of two genera of N2-fixing cyanobacteria growing on three feather moss species in boreal forests of Quebec, Canada

2006 ◽  
Vol 84 (6) ◽  
pp. 1025-1029 ◽  
Author(s):  
Daniel Houle ◽  
Simon Bilodeau Gauthier ◽  
Serge Paquet ◽  
Dolors Planas ◽  
Annabelle Warren
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Pleurozium Schreberi ◽  
Large Area ◽  
Moss Species ◽  
Feather Moss ◽  
Canadian Boreal Forest ◽  
First Time

The recent discovery that N2 fixation rates by the feather moss carpet of boreal Scandinavian forests increases with stand maturity has put into question the paradigm that N2 fixation is negligible in mature boreal forest. The N2 fixation was attributed to a previously unknown association between Nostoc sp., a N2-fixing cyanobacteium and Pleurozium schreberi (Brid.) Mitt., a feather moss that is abundant worldwide in the boreal forest. Here we report for the first time that this association also exists in the Canadian boreal forest. We discovered, however, that Nostoc was found growing not only on Pleurozium but also on two other moss species ( Hylocomnium splendens (Hedw.) Br. Eur. and Ptillium crista-castrensis (Hedw.) De Not.). In addition, the N2-fixing cyanobacterium Stigonema sp. was observed on the three moss species mentioned above, indicating the existence of six different associations. At least one of the six associations was found at 9 of 13 sites that are representative of a large area of the Quebec boreal forest. These findings suggest possibilities for further research, aimed at measuring the unaccounted for N2-fixing potential of the feather moss carpet in Canadian boreal forests.

The response of the feather moss, Pleurozium schreberi, to 5 years of simulated acid precipitation in the Canadian boreal forest

1988 ◽  
Vol 66 (1) ◽  
pp. 82-88 ◽  
Author(s):  
Thomas C. Hutchinson ◽  
Martha G. Scott
Keyword(s):  
Boreal Forest ◽  
Dry Weight ◽  
Acid Precipitation ◽  
Permanent Plots ◽  
Pleurozium Schreberi ◽  
Forest Site ◽  
Percent Cover ◽  
Feather Moss ◽  
Lateral Branches ◽  
Canadian Boreal Forest

Permanent plots dominated by the feather moss, Pleurozium schreberi (Brid.) Mitt., were established at a Canadian boreal forest site to study the effects of simulated acid precipitation on percent cover, growth, and photosynthesis of vegetation. For a 5-year period, beginning in 1981, plots of P. schreberi received twice-monthly sprayings of simulated rain, adjusted to pH 5.6, 4.0, 3.5, 3.0, or 2.5 with a 2:1 molar mixture of sulfuric and nitric acids. Unsprayed plots were also monitored. Almost complete elimination of the moss had occurred in the plots sprayed with pH 2.5 by the end of the 2nd year of treatment, and substantial decreases in cover were also recorded at pH 3.0 and 3.5 over the 5 years. Significant reductions of up to 75% in total and living frond height and dry weight were recorded at pH 3.5 and lower. Lateral branches produced in acid-treated plots also were stunted and few in number. This decline in growth and percent cover of P. schreberi may have resulted from the decreased net photosynthetic rates measured in the field and would be accelerated by increased rates of evapotranspiration in the altered moss microhabitat.

scholarly journals Large-area mapping of Canadian boreal forest cover, height, biomass and other structural attributes using Landsat composites and lidar plots

2018 ◽  
Vol 209 ◽  
pp. 90-106 ◽  
Author(s):  
Giona Matasci ◽  
Txomin Hermosilla ◽  
Michael A. Wulder ◽  
Joanne C. White ◽  
Nicholas C. Coops ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Forest Cover ◽  
Large Area ◽  
Canadian Boreal Forest

Integrating accessibility and intactness into large-area conservation planning in the Canadian boreal forest

2013 ◽  
Vol 167 ◽  
pp. 371-379 ◽  
Author(s):  
Ryan P. Powers ◽  
Nicholas C. Coops ◽  
Trisalyn Nelson ◽  
Michael A. Wulder ◽  
C. Ronnie Drever
Keyword(s):  
Boreal Forest ◽  
Conservation Planning ◽  
Large Area ◽  
Canadian Boreal Forest

scholarly journals Abundance and Impacts of Competing Species on Conifer Regeneration Following Careful Logging in the Eastern Canadian Boreal Forest

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 177 ◽  
Author(s):  
Louis-Philippe Ménard ◽  
Jean-Claude Ruel ◽  
Nelson Thiffault
Keyword(s):  
Boreal Forest ◽  
Basal Area ◽  
Low Fertility ◽  
Percent Cover ◽  
Large Area ◽  
Competing Species ◽  
Competing Vegetation ◽  
Conifer Regeneration ◽  
Ericaceous Shrubs ◽  
Canadian Boreal Forest

Managing competing vegetation is crucial in stand establishment strategies; forecasting the abundance, composition, and impact of competing vegetation after harvesting is needed to optimize silviculture scenarios and maintain long-term site productivity. Our main objective was to identify factors influencing the short-term abundance and composition of competing vegetation over a large area of the Canadian boreal forest. Our second objective was to better understand the mid-term evolution of the regeneration/competing vegetation complex in cases of marginal regeneration conditions. We used operational regeneration surveys of 4471 transects sampled ≈5 years after harvesting that contained data on regeneration, competing vegetation, elevation, ecological classification, soil attributes, and pre-harvest forest stands. We performed a redundancy analysis to identify the relationships between competing vegetation, harvesting and biophysical variables. We then estimated the probability of observing a given competing species cover based on these variables. In 2015, we re-sampled a portion of the sites, where conifer regeneration was marginal early after harvesting, to assess the temporal impact of different competing levels and species groups on the free-to-grow stocking, vigour and basal area of softwood regeneration. Results from the first inventory showed that, after careful logging around advance growth, ericaceous shrubs and hardwoods were not associated with the same sets of site attributes. Ericaceous shrubs were mainly found on low fertility sites associated with black spruce (Picea mariana (Mill.) BSP) or jack pine (Pinus banksiana Lamb.). The distinction between suitable environments for commercial shade-intolerant hardwoods and non-commercial hardwoods was less clear, as they responded similarly to many variables. Analysis of data from the second inventory showed a significant improvement in conifer free-to-grow stocking when commercial shade-intolerant hardwood competing levels were low (stocking 0%–40%) and when ericaceous shrubs competing levels were moderate (percent cover 26%–75%). In these conditions of marginal regeneration, the different types and intensities of competition did not affect the vigour or basal area of softwood regeneration, 9–14 years after harvesting.

scholarly journals A Comparative Analysis of Burned Area Datasets in Canadian Boreal Forest in 2000

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Laia Núñez-Casillas ◽  
José Rafael García Lázaro ◽  
José Andrés Moreno-Ruiz ◽  
Manuel Arbelo
Keyword(s):  
Comparative Analysis ◽  
Boreal Forest ◽  
Boreal Forests ◽  
Burned Area ◽  
Diverse Group ◽  
Spatial Accuracy ◽  
Noaa Avhrr ◽  
Fire Activity ◽  
Canadian Boreal Forest ◽  
Area Data

The turn of the new millennium was accompanied by a particularly diverse group of burned area datasets from different sensors in the Canadian boreal forests, brought together in a year of low global fire activity. This paper provides an assessment of spatial and temporal accuracy, by means of a fire-by-fire comparison of the following: two burned area datasets obtained from SPOT-VEGETATION (VGT) imagery, a MODIS Collection 5 burned area dataset, and three different datasets obtained from NOAA-AVHRR. Results showed that burned area data from MODIS provided accurate dates of burn but great omission error, partially caused by calibration problems. One of the VGT-derived datasets (L3JRC) represented the largest number of fire sites in spite of its great overall underestimation, whereas the GBA2000 dataset achieved the best burned area quantification, both showing delayed and very variable fire timing. Spatial accuracy was comparable between the 5 km and the 1 km AVHRR-derived datasets but was remarkably lower in the 8 km dataset leading, us to conclude that at higher spatial resolutions, temporal accuracy was lower. The probable methodological and contextual causes of these differences were analyzed in detail.

Photosynthesis and respiration of feather mosses fumigated at different hydration levels with SO2

1983 ◽  
Vol 61 (5) ◽  
pp. 1456-1461 ◽  
Author(s):  
William E. Winner ◽  
J. Derek Bewley
Keyword(s):  
Recovery Period ◽  
Pleurozium Schreberi ◽  
Hylocomium Splendens ◽  
Moss Species ◽  
Feather Moss ◽  
Feather Mosses ◽  
Rate Of Photosynthesis ◽  
Free Environment ◽  
Photosynthesis And Respiration

Fumigation with SO2 of the three feather mosses Pleurozium schreberi, Hylocomium splendens, and Ptilium crista-castrensis results in an immediate decline in their rate of photosynthesis but has no effect upon respiration. Pleurozium schreberi is the most sensitive of the three species, even though they all take up the same amount of SO2. Thus, the feather moss species appear to have similar degrees of SO2 avoidance (uptake) but dissimilar degrees of SO2 tolerance. With increasing desiccation, respiration declines equally in all three species, but photosynthesis declines most rapidly for P. schreberi. The immediate effects of SO2 upon photosynthesis of water-limited and of fully hydrated feather mosses are similar, but after a 24-h recovery period in an SO2-free environment photosynthesis remains impaired only in those mosses fumigated in the fully hydrated state. This probably is related to the larger amounts of SO2 absorbed by hydrated mosses.

Dynamics of the boreal forests of the Laurentian Highlands, Canada

1985 ◽  
Vol 15 (1) ◽  
pp. 252-261 ◽  
Author(s):  
Charles V. Cogbill
Keyword(s):  
Boreal Forests ◽  
Fire Disturbance ◽  
Stand Dynamics ◽  
Time Interval ◽  
Large Area ◽  
Feather Moss ◽  
Natural Fires ◽  
Jack Pine Forests ◽  
Overstory Trees ◽  
Tree Increment

Analyses of species composition and tree increment cores from 145 stands in central Québec were used to determine the forest history and stand dynamics. Windspread fires, possibly synchronous, burned across central Québec in at least three periods of record (1661–1663, 1779–1791, 1869–1871). The average fire rotation (time interval between natural fires burning the equivalent of a large area) for spruce – feather moss forests was approximately 130 years, and 70 years in either deciduous or jack pine forests. The traditional succession concept of continual recruitment leading to an all-aged forest was not evident in these forests. About 70% of the overstory trees were established in the first 30 years after fire disturbance, with little recruitment after this time. These initial trees dominate the canopy for up to 250 years with mortality becoming prominent after 130 years. The short average time between disturbances precludes the probable degeneration into old shrub-filled stands typical of old age.

Identification of potential organisms of relevance to Canadian boreal forest and northern lands for testing of contaminated soils

2006 ◽  
Vol 14 (2) ◽  
pp. 137-167 ◽  
Author(s):  
J Römbke ◽  
S Jänsch ◽  
R Scroggins
Keyword(s):  
Boreal Forest ◽  
Contaminated Soils ◽  
Boreal Forests ◽  
Method Development ◽  
Species Selection ◽  
Carabid Beetles ◽  
Test Species ◽  
Research Activities ◽  
Collembolan Species ◽  
Canadian Boreal Forest

A literature review has been performed with the aim of identifying potential soil invertebrate species, culturing techniques, and testing methodologies of relevance to Canadian boreal forest, taiga, and tundra ecozones. This was achieved through a review of European and Canadian ecological and ecotoxicological literature. The criteria for candidate species selection included habitat, frequency and abundance, origin, taxonomy, practicability, and stress tolerance. Nineteen species or genera common to both Northern Europe and Canada were identified as proposed test organisms in ecotoxicological test methodologies. Some of these species are currently in culture at various European or Canadian laboratories. Three earthworm and one collembolan species were recommended for further method development, while two more collembolan species as well as a yet to be identified Canadian species of four genera of enchytraeids, nematods, predatory mites, and carabid beetles were recommended but need further research. A number of issues with the recommended species were identified that would need resolution through focused research. Also, additional potential test species were identified based on their frequency of occurrence in boreal forests and northern lands for possible further method development consideration. Available information and current research activities on Canadian soil invertebrates relevant to the boreal forest, taiga, and tundra ecozones should be compiled using a similar classification and short-list selection process as used for this contribution to help identify additional candidate test species. The recommended species could be used as part of a test battery covering litter layer and mineral soils of Canadian boreal forests and northern lands.Key words: Carabidae, Collembola, Enchytraeidae, Gamasida, Lumbricidae, Nematoda.

A review of exotic earthworm observations in the Canadian boreal forest and taiga zones

2022 ◽  
Author(s):  
Jean-David Moore ◽  
Rock Ouimet ◽  
John W. Reynolds
Keyword(s):  
Carbon Source ◽  
Boreal Forest ◽  
Boreal Forests ◽  
Carbon Sink ◽  
Acid Soils ◽  
Taiga Zone ◽  
Earthworm Species ◽  
Exotic Earthworms ◽  
Harsh Climate ◽  
Canadian Boreal Forest

In the last decades, concerns have emerged that boreal forests could convert from a carbon sink to a carbon source, thus accentuating climate change. Although forest fire is generally mentioned as the main factor that could cause the boreal forest to transition to a carbon source, other factors, such as exotic earthworm activity, could also play an important role. Invasive exotic earthworms can also affect nutrient cycling, biodiversity and forest dynamics. In this context, a better knowledge of the distribution of exotic earthworms can help understand the likely changes in the ecosystems that they have colonized. Here we report the results of an exhaustive literature review of the presence of exotic earthworms in the Canadian boreal forest and taiga zones. We identified 230 sectors containing 14 earthworm species (11 exotic, 2 native and 1 putative native) in 6 provinces and 3 territories across Canada’s boreal forest and taiga zone. We also report 23 as-yet unpublished observations from the province of Quebec. We note the presence of earthworms in environments (acid soils, harsh climate) that were historically considered inadequate for their survival. This suggests that the portion of Canada’s boreal forests suitable for their presence or colonization is larger than what was previously believed. This study represents the first compilation of exotic earthworm presence in this large northern area. Factors that could affect their distribution and potential effects on boreal ecosystems are also discussed. Globally, several earthworm species seem to be overcoming the previously assumed limitation by temperature and pH.

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