Vegetation and pollen relationships in eastern Canada

1993 ◽  
Vol 71 (2) ◽  
pp. 193-210 ◽  
Author(s):  
George A. King

The relationship between the vegetation and modern pollen assemblages in eastern Canada is summarized and analyzed using isopoll maps, ordination, and cluster analysis. The major vegetation zones are shrub tundra, forest tundra (divided into shrub and forest subzones), lichen woodland, closed black spruce forest, mixed boreal forest, and coastal barrens. The pollen assemblages of these zones are distinguished by differences in the relative abundance of a few important pollen types rather than by floristic differences. Northern zones have relatively high Cyperaceae and low Picea pollen percentages, and southern zones have high Picea and Abies pollen percentages. Surface samples from each vegetation zone generally form distinctive groups in the ordination analysis. However, samples from the shrub subzone of the forest tundra cluster with shrub tundra samples, and lichen woodland samples cluster with samples from the closed black spruce forest and the forest subzone of the forest tundra. Cluster analysis separates the samples into geographically distinct groups. However, these groups generally contain samples from several vegetation zones. The surface sample data set analyzed here will prove useful in reconstructing the vegetation history of the region. Key words: pollen surface samples, modern vegetation, eastern Canada.


1991 ◽  
Vol 28 (4) ◽  
pp. 643-648 ◽  
Author(s):  
K. Gajewski

Modern pollen spectra from a series of lakes in northwestern Quebec reflect the major vegetation zones of the forest–tundra transition from latitude 55°N to 59°N. Shrub tundra samples are dominated by Betula and herb pollen, whereas Picea percentages are between 10 and 20%. Lichen woodland samples can contain over 60% Picea, with Betula and Alnus crispa each less than 20%. Pollen assemblages from the shrub subzone of the forest–tundra resemble those of the shrub tundra, while those from the forest subzone resemble lichen woodland samples. Maximum percentages of Alnus crispa are found in the forest–tundra. Classification of the samples using cluster analysis and an ordination by principal coordinates analysis suggest that densely and sparsely forested regions can be discriminated.



1980 ◽  
Vol 10 (4) ◽  
pp. 491-497 ◽  
Author(s):  
Andrew N. Rencz ◽  
Allan N. Auclair

Parabolic and logarithmic regressions were used to relate tree diameter to the biomass of root, root crown, bole, branch, needle, cone, and epiphytic lichens for a sample of 15 Piceamariana (Mill) trees occupying lichen woodland in the subarctic of eastern Canada. In 22 of 27 regressions both models yielded r2 values >0.82. Biomass estimates of total tree and individual component dry weights resulted in estimates with less than 6.5% difference between biomass estimates by logarithmic versus parabolic equations. For this data set the logarithmic model appeared more appropriate than the parabolic form. Validity of the regressions was judged on r2, analysis of variance, and examination of residuals. Equations generated in this study were considered to be inapplicable to P. mariana growing in closed forest. Problems in extrapolation were discussed.



2005 ◽  
Vol 35 (3) ◽  
pp. 674-681 ◽  
Author(s):  
Mathieu Côté ◽  
Jean Ferron ◽  
Réjean Gagnon

We used an extensive vertebrate exclosure experiment to evaluate black spruce (Picea mariana (Mill.) B.S.P.) postdispersal seed and seedling predation by invertebrates in three boreal habitats of Eastern Canada: recent burn, spruce–moss, and lichen woodland. Between 9% and 19% of seeds were eaten by invertebrates. Seed predation was higher in recent burns than in spruce–moss and lichen woodlands. Abundance and diversity of potential invertebrate seed consumers sampled in pitfall traps also varied among habitat types. Among the invertebrate seed consumers sampled, Myrmica spp. (Hymenoptera: Formicidae) and Pterostichus adstrictus (Eschscholtz, 1823) (Coleoptera: Carabidae) were the most numerous; Formica spp. (Hymenoptera: Formicidae) and Pterostichus punctatissimus (Randall, 1838) (Coleoptera: Carabidae) were also present. Between 2% and 12% of juvenile black spruce seedlings were eaten by invertebrates. The most important seedling consumers were slugs (molluscs). Invertebrate predation of seeds and seedlings was highest (19% and 12%) in recent burns, indicating that invertebrate predation may significantly influence black spruce regeneration in these sites.



2015 ◽  
Vol 82 ◽  
pp. 1-11 ◽  
Author(s):  
Laure N. Soucémarianadin ◽  
Sylvie A. Quideau ◽  
M. Derek MacKenzie ◽  
Alison D. Munson ◽  
Juliette Boiffin ◽  
...  


2009 ◽  
Vol 6 (3) ◽  
pp. 5507-5548 ◽  
Author(s):  
O. Bergeron ◽  
H. A. Margolis ◽  
C. Coursolle

Abstract. This study reports continuous automated measurements of forest floor carbon (C) exchange over feathermoss, lichen, and sphagnum micro-sites in a black spruce forest in eastern North America during snow-free periods over three years. The response of soil respiration (Rs-auto) and forest floor photosynthesis (Pff) to environmental factors was determined. The seasonal contributions of scaled up Rs-auto adjusted for spatial representativeness (Rs-adj) and Pff (Pff-eco) relative to that of total ecosystem respiration (Re) and photosynthesis (Peco), respectively, were also quantified. Shallow soil temperature explained 67–86% of the variation in Rs-auto for all ground cover types, while deeper soil temperatures were related to Rs-auto only for the feathermoss micro-sites. Base respiration was consistently lower under feathermoss, intermediate under sphagnum, and higher under lichen during all three years. The Rs-adj/Re ratio increased from spring through autumn and ranged from 0.85 to 0.87 annually for the snow-free period. The Rs-adj/Re ratio was negatively correlated with the difference between air and shallow soil temperature and this correlation was more pronounced in autumn than summer and spring. Maximum photosynthetic capacity of the forest floor (Pffmax) saturated at low irradiance levels (~200 μmol m−2 s−1) and decreased with increasing air temperature and vapor pressure deficit for all three ground cover types, suggesting that Pff was more limited by desiccation than by light availability. Pffmax was lowest for sphagnum, intermediate for feathermoss, and highest for lichen for two of the three years. Pff normalized for light peaked at air temperatures of 5–8°C, suggesting that this is the optimal temperature range for Pff. The Pff-eco/Peco ratio varied seasonally from 13 to 24% and reached a minimum in mid-summer when both air temperature and Peco were at their maximum. On an annual basis, Pff-eco accounted for 17–18% of Peco depending on the year and the snow-free season totals of Pff-adj were 23–24% that of Rs-adj.







1963 ◽  
Vol 43 (1) ◽  
pp. 97-106 ◽  
Author(s):  
R. L. Halstead ◽  
J. M. Lapensee ◽  
K. C. Ivarson

In a laboratory experiment, liming resulted in an average decline of 3.6 per cent in the total organic phosphorus content of incubated surface samples of seven acid soils from eastern Canada. Increases of 2.6 and 5.1 per cent in 1N H2SO4- and 4N HCl-soluble inorganic phosphorus, respectively, and a decrease of 46.4 per cent in NaHCO3-soluble organic phosphorus (pH 8.5) provided further evidence of mineralization of organic phosphorus following liming. There was some evidence, however, that the differences in NaHCO3-soluble organic phosphorus following liming were due only in part to mineralization, since Ca(OH)2 added to a soil just prior to extraction with NaHCO3 had a repressive effect on the solubility of the organic phosphorus compounds.Some mineralization of organic phosphorus occurred when unlimed samples were incubated in the laboratory for 9 months.Marked increases in microbiological activity, as indicated by increased numbers of microorganisms, and increased CO2 and NO3-nitrogen production, were associated with lower values for extractable organic phosphorus following liming. Partial sterilization of samples with toluene lowered biological activity in the unlimed and limed samples. Toluene was found, however, to have a positive effect on release of phosphorus from organic form.



2007 ◽  
Vol 13 (3) ◽  
pp. 577-590 ◽  
Author(s):  
ALLISON L. DUNN ◽  
CAROL C. BARFORD ◽  
STEVEN C. WOFSY ◽  
MICHAEL L. GOULDEN ◽  
BRUCE C. DAUBE


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