scholarly journals Écologie de nidification du moucherolle à côtés olive dans un paysage sous aménagement forestier de la forêt boréale de l’Est

2017 ◽  
Vol 141 (2) ◽  
pp. 53-60
Author(s):  
Alexandre Anctil ◽  
Hilde Marie Johansen ◽  
Junior A. Tremblay
Keyword(s):  
Picea Mariana ◽  
Perisoreus Canadensis ◽  
Aire De Répartition ◽  
Aménagement Forestier

Le moucherolle à côtés olive (Contopus cooperi) a subi un important déclin depuis la fin des années 1960. La mise en place de mesures visant à favoriser son rétablissement est par contre limitée par notre manque de connaissances sur l’écologie de la nidification de l’espèce. L’objectif de cette étude était d’acquérir des connaissances sur le succès et l’habitat de nidification du moucherolle à côtés olive dans un paysage sous aménagement forestier de la forêt boréale de l’Est. Au cours des étés 2015 et 2016, 38 sites occupés par au moins 1 moucherolle à cotés olive ont été répertoriés et un total de 13 nids, tous dans des épinettes noires (Picea mariana) vivantes, ont été trouvés. Le succès de nidification a été évalué à 53,8 %, la prédation, potentiellement par le mésangeai du Canada (Perisoreus canadensis), et les conditions météorologiques adverses étant les 2 causes d’échec les plus probables. À l’échelle du paysage, les moucherolles à côtés olive ont sélectionné les peuplements mixtes, les bordures forestières et les coupes récentes. Notre étude aura permis d’obtenir d’importantes informations sur l’écologie de la nidification du moucherolle à côtés olive dans l’est de son aire de répartition.

Multistage Scatter-Hoarding Decisions in the Gray Jay (Perisoreus canadensis)

Bird Behavior ◽  
1997 ◽  
Vol 12 (1) ◽  
pp. 7-14 ◽  
Author(s):  
Thomas A. Waite ◽  
John D. Reevet
Keyword(s):  
Scatter Hoarding ◽  
Perisoreus Canadensis

Canada Jay (Perisoreus canadensis)

2020 ◽  
Author(s):  
Dan Strickland ◽  
Henri R. Ouellet
Keyword(s):  
Perisoreus Canadensis

The vegetation and chemical properties of patterned fens in the Swan Hills, north central Alberta

1975 ◽  
Vol 53 (23) ◽  
pp. 2776-2795 ◽  
Author(s):  
D. H. Vitt ◽  
P. Achuff ◽  
R. E. Andrus
Keyword(s):  
Picea Mariana ◽  
Vascular Plants ◽  
Chemical Properties ◽  
Vegetation Patterns ◽  
North Central ◽  
Water Flows ◽  
Sphagnum Magellanicum ◽  
Ledum Groenlandicum ◽  
Menyanthes Trifoliata ◽  
And Chemical Properties

Three patterned fens in north central Alberta were analyzed to elucidate vegetation patterns in vascular plants and bryophytes. Two flark associations dominated by Menyanthes trifoliata and Carex limosa, both of which had Sphagnum jensenii and Drepanocladus exannulatus phases, were recognized. The strings consist of two associations; one is dominated by Betula glandulosa, Tomenthypnum falcifolium, and Aulacomnium palustre; the second is dominated by Picea mariana, Sphagnum magellanicum, and Ledum groenlandicum. An intensive analysis of one fen reveals that these mires are ‘poor fens’ with a mean pH of 5.2 and Ca2+concentration of 2.3 ppm. The fens occur on low drainage divides and Ca2+ is depleted as water flows through the fens. An ecological series of bryophytes is described in the transitions between flarks and strings.

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.

A test of the predator avoidance hypothesis to explain delayed onset of communal breeding

2019 ◽  
Vol 97 (4) ◽  
pp. 332-339
Author(s):  
D. Strickland ◽  
E. Brouwer ◽  
T.M. Burg
Keyword(s):  
Predator Avoidance ◽  
Group Living ◽  
Breeding Cycle ◽  
Communal Breeding ◽  
The Family ◽  
Perisoreus Canadensis ◽  
Insufficient Time ◽  
Anticosti Island ◽  
Free Environment ◽  
Late Stages

A neglected question in the study of communal breeding concerns why alloparental behaviour begins at variously late stages in the breeding cycle. In group-living corvids, the delay tends to be longer in species that are small and (or) typically have only a small nonbreeder complement. This pattern has been attributed to the relatively poor defensive capabilities of such species and their consequently greater need to minimize predator-attracting traffic to the nest or fledglings. We tested this predator avoidance hypothesis with the Canada Jay (Perisoreus canadensis (Linnaeus, 1766)), a species in which the feeding of young by any nonbreeders in the family group is delayed until the fledgling period. We reasoned that, on Anticosti Island, Quebec (Canada), in the absence of squirrels and other nest predators, nonbreeders might be permitted to feed nestlings as well as fledglings, and that breeders might feed nestlings more frequently (with smaller food loads) than on the mainland. We found no evidence for either prediction and thus no support for the predator avoidance hypothesis but suggest that Anticosti Canada Jays may have had insufficient time to evolve behaviour more appropriate for their predator-free environment. Secondarily, we confirmed that in all observed instances, the nonbreeders were offspring of the breeding pair from previous years and that they therefore failed to provision nestlings in spite of an apparent genetic interest to do so.

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