Midwinter aggregation in the northern red-backed vole, Clethrionomys rutilus

1977 ◽  
Vol 55 (9) ◽  
pp. 1404-1409 ◽  
Author(s):  
Stephen D. West
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Early Spring ◽  
Dispersion Pattern ◽  
Short Supply ◽  
Advantages And Disadvantages ◽  
Composition And Structure ◽  
Moss Layer ◽  
Clethrionomys Rutilus ◽  
Trapping Grid

Livetrapping in black spruce (Picea mariana) taiga 60 km north of Fairbanks, Alaska, during 1972–1973 revealed that the dispersion pattern of the capture points for a population of northern red-backed voles varied greatly with season. The population was distributed without apparent aggregation from midsummer (July) until early winter (mid-November). During midwinter all animals were found in one section of the trapping grid. In early spring (April) the voles moved apart, and by May they appeared once more evenly distributed. The composition and structure of vegetation inside and outside of the area of aggregation was analyzed, and a significantly thicker moss layer was found within the area of aggregation. Possible advantages and disadvantages of the midwinter aggregation to individual voles are discussed. It is suggested that habitat limitation in terms of a short supply of suitable overwintering sites is a reasonable explanation for the observed aggregation.

Clonal and nonclonal genetic structure of subarctic black spruce (Picea mariana) populations in Yukon territory

Botany ◽  
2011 ◽  
Vol 89 (2) ◽  
pp. 133-140 ◽  
Author(s):  
Marios Viktora ◽  
Rodney A. Savidge ◽  
Om P. Rajora
Keyword(s):  
Genetic Structure ◽  
Picea Mariana ◽  
Black Spruce ◽  
A Priori ◽  
Nuclear Genome ◽  
Yukon Territory ◽  
Fire Disturbance ◽  
Clone Size ◽  
Flat Terrain ◽  
Individual Trees

Black spruce (Picea mariana) reproduces sexually from seeds and asexually by layering. There is a prevalent concept that clonal reproduction maintains populations of this species in the subarctic and arctic regions. We used microsatellite DNA markers of the nuclear genome to investigate the genetic structure of montane and subalpine black spruce populations from the Western Yukon Plateau in relation to this concept. Sixty individual trees at a minimum distance of 4 m from each other were sampled from each of four populations and individual trees were genotyped for eight microsatellite loci. Each of the 60 individuals from three montane pure black spruce populations growing on flat terrain at relatively low elevations had unique multilocus genotypes, indicating an absence of clonal structure in those populations. However, in an anthropologically undisturbed climax white spruce-dominated subalpine black spruce population on a northwest slope near Mount Nansen, the majority of the sampled individuals belonged to eight genetically distinct clones (genets). Clone size differed by altitude, the dominant genet being nearest the timberline–tundra ecotone. The results indicate that black spruce reproduction is variable and adaptive, being primarily sexual in flat-terrain montane populations previously subjected to fire disturbance, but mixed vegetative–sexual in the anthropogenically undisturbed subalpine population. This study is the first to employ molecular markers a priori to examine the mode of reproduction in natural black spruce populations.

scholarly journals Comparative Height Growth of Eastern Larch and Black Spruce in Northwestern Ontario

1978 ◽  
Vol 54 (6) ◽  
pp. 296-297 ◽  
Author(s):  
Douglas A. Mead
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Height Growth ◽  
Larix Laricina ◽  
Stem Analysis ◽  
Northwestern Ontario ◽  
Analysis Methods ◽  
Spruce Stands

Height growth of eastern larch (Larix laricina (Du Roi) K. Koch) and black spruce (Picea mariana (Mill.) B.S.P.) was determined using standard stem analysis methods on trees from two sites in northwestern Ontario. The data were obtained from mixed larch-spruce stands which were relatively undisturbed. The larch exhibited substantially better height growth than the spruce through age 65.

SEASONAL DAMAGE BY INSECTS AND SQUIRRELS TO FEMALE REPRODUCTIVE STRUCTURES OF BLACK SPRUCE, PICEA MARIANA (MILL.) B.S.P.

1988 ◽  
Vol 120 (12) ◽  
pp. 1113-1121 ◽  
Author(s):  
Y.H. Prévost ◽  
J.E. Laing ◽  
V.F. Haavisto
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Choristoneura Fumiferana ◽  
Tamiasciurus Hudsonicus ◽  
Red Squirrel ◽  
Red Squirrels ◽  
Reproductive Structures ◽  
Cone Axis ◽  
Viable Seeds ◽  
Cone Growth

AbstractThe seasonal damage to female reproductive structures (buds, flowers, and cones) of black spruce, Picea mariana (Mill.) B.S.P., was assessed during 1983 and 1984. Nineteen insects (five Orders) and the red squirrel, Tamiasciurus hudsonicus (Erxleben), were found feeding on these reproductive structures. Collectively, these organisms damaged 88.9 and 53.5% of the cones in 1983 and 1984, respectively. In the 2 years, Lepidoptera damaged 61.8% of the cones in 1983 and 44.4% of the cones in 1984. The spruce budworm, Choristoneura fumiferana (Clem.), and the spruce coneworm, Dioryctria reniculelloides Mut. and Mun., were the most important pests. Cones damaged by Lepidoptera could be classed into three categories: (a) severe, yielding no seeds; (b) moderate, yielding 22.3 seeds per cone; and (c) light, yielding 37.5 seeds per cone. Undamaged cones yielded on average 39.9 seeds per cone. Red squirrels removed 18.8% of the cones in 1983 and none in 1984. The spruce cone axis midge, Dasineura rachiphaga Tripp, and the spruce cone maggot, Lasiomma anthracinum (Czerny), caused minor damage in both years. Feeding by spruce cone axis midge did not reduce cone growth significantly or the number of viable seeds per cone, but feeding by the spruce cone maggot did. During both years new damage by insects to the female reproductive structures of the experimental trees was not observed after mid-July. In 1983 damage by red squirrels occurred from early to late September. In 1984 damage to cones on trees treated with dimethoate was 15.6% compared with 53.5% for untreated trees, without an increase in the number of aborted cones.

Prediction and evaluation of borate distribution in Eastern black spruce (Picea mariana var. mariana) wood products

2015 ◽  
Vol 49 (3) ◽  
pp. 457-473 ◽  
Author(s):  
Thierry Koumbi-Mounanga ◽  
Paul I. Morris ◽  
Myung J. Lee ◽  
Nasmus M. Saadat ◽  
Brigitte Leblon ◽  
...  
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Wood Products

scholarly journals On the choice of priority approaches towards taxation of the population

2021 ◽  
pp. 19-35
Author(s):  
Anna Vital'evna Tikhonova
Keyword(s):  
Socioeconomic Development ◽  
Integrated Approach ◽  
Income Taxes ◽  
Tax Rates ◽  
Scientific Discussion ◽  
Advantages And Disadvantages ◽  
Correlation And Regression Analysis ◽  
Composition And Structure ◽  
Taxation System

The object of this research is the system of taxation of the population, while the subject is the composition and structure of taxes paid by private entities. The author analyzes the two priority approaches towards building the optimal and utmost fair system of taxation of private entities – through the object of “income” or “consumption”. Detailed analysis is conducted on the advanced Russian and foreign research on the topic. The author outlines the advantages and disadvantages of each approach from the perspective of horizontal and vertical justice, individual utility and its discounting. The scientific discussion on the absolute viability of taxation of income and consumption of the population is allocated into a separate chapter of the research. Based on the qualitative theoretical analysis, the author concludes on the rationality of choosing integrated approach towards creation of taxation system of the population. The cornerstone in this regard is the determination of the optimal ratio of consumption and income taxes. For this purpose, the author develops the original methodology based on the scattering matrix of 87 countries of the world, correlation and regression analysis of the indicators of their economic development and tax rates. The scientific novelty of consists in substantiation of the existence of substantial connection between the ratio of taxes on consumption and income of the population and the level of socioeconomic development of the country.

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