scholarly journals Habitat Segregation Among Songbirds in Old-Growth Boreal Mixedwood Forest

2004 ◽  
Vol 118 (1) ◽  
pp. 45 ◽  
Author(s):  
Enid E. Cumming

The foraging behaviour of ten species of insectivorous songbirds — Boreal Chickadee (Poecille hudsonicus), Golden-crowned Kinglet (Regulus satrapa), Ruby-crowned Kinglet (R. calendula), Blue-headed Vireo (Vireo solitarius), Tennessee (Vermivora peregrina), Blackburnian (Dendroica fusca), Magnolia (D. magnolia), Yellow-rumped [Myrtle] (D. coronata), Black-throated Green (D. virens), and Bay-breasted (D. castanea) warblers — was observed in the boreal mixedwood forest of Prince Albert National Park in central Saskatchewan. Birds segregated their habitat use by preferentially foraging in different tree species, and through preferential use of different foraging locations (height and position) within trees.White Spruce (Picea glauca) was used more than expected by Yellow-rumped Warblers, and Golden-crowned and Ruby-crowned kinglets. Tennessee and Magnolia warblers used White Birch (Betula papyrifera), more than expected and Boreal Chickadees and Blue-headed Vireos used Balsam Fir (Abies balsamea) more than expected. Boreal Chickadees, Ruby-crowned Kinglets, and Tennessee, Blackburnian and Yellow-rumped warblers all used the bottom part of trees less than expected, while Blueheaded Vireos foraged near the top of trees less than expected. Large inner branches were avoided by Tennessee, Blackburnian and Yellow-rumped warblers, while Bay-breasted Warblers and Blue-headed Vireos avoided small outer twigs. In conifers, Blackburnian Warblers foraged significantly higher in the trees than all other species except Black-throated Green and Baybreasted warblers. Blackburnian Warblers also foraged significantly higher than Blue-headed Vireos and Magnolia Warblers in deciduous trees.

1990 ◽  
Vol 68 (11) ◽  
pp. 2235-2242 ◽  
Author(s):  
Rhonda L. Millikin

The impact of fenitrothion on the arthropod food of songbirds was measured using white birch (Betula papyrifera Marsh.) and balsam fir (Abies balsamea (L.) Mill.) branch sample and drop trays. Following ground application of fenitrothion at 293 g active ingredient/ha, there was a significant decrease in the biomass of arthropods as determined using branch samples from both tree species, but not until 5 days after the application (29% reduction for balsam fir, 35% for white birch). Samples from drop trays indicated an immediate kill of arthropods not associated with the tree. Most remaining arthropods on treated balsam fir trees were dead. These dead arthropods would not be suitable food for birds that require movement to detect their prey. There was no significant relationship between amount of deposit (treated trees only) and the reduction of arthropods for either tree species.


2012 ◽  
Vol 144 (3) ◽  
pp. 447-457 ◽  
Author(s):  
Garrett Brodersen ◽  
Rob Johns ◽  
Renée Lapointe ◽  
David Thumbi ◽  
Graham Thurston ◽  
...  

AbstractFood quality can influence the performance of immature insects and their interactions with pathogens, such as viruses. In manipulative field studies, virus-free caterpillars of the whitemarked tussock moth (WMTM) (Orgyia leucostigma (Smith)) had higher survival, more female-biased sex ratios, and were larger when feeding on white birch (Betula papyrifera Marshall) versus balsam fir (Abies balsamea (Linnaeus) Miller) or red spruce (Picea rubens Sargent). Subsequent laboratory studies with two nucleopolyhedroviruses, derived from WMTMs and Douglas-fir tussock moths, indicated that caterpillars fed high quality food (i.e., artificial diet) prior to infection had less mortality associated with virus infection than those feeding on lower quality foliage (i.e., birch). In field studies, caterpillars fed birch following infection had significantly lower mortality than those feeding on relatively lower quality foliage (i.e., balsam fir). We postulate that higher nutritional quality in artificial diet relative to birch (previrus-ingestion nutrition) and in birch relative to balsam fir foliage (postvirus-ingestion nutrition) has a positive effect on the ability of tussock moth caterpillars to resist or recover from viral infections, although the specific mechanisms responsible for observed resistance remain unclear.


2011 ◽  
Vol 35 (3) ◽  
pp. 345-359 ◽  
Author(s):  
Claude Labelle ◽  
Pierre J.H. Richard

L’analyse pollinique des sédiments de trois lacs situés au sud-est du parc des Laurentides a permis de retracer les étapes de la recolonisation végétale post-wisconsinienne. Celle-ci s’est effectuée selon un schéma assez constant à travers le secteur à l’étude. Au début, la végétation était très ouverte, mais tout de même relativement riche en taxons herbacés et arbustifs. Cette phase initiale de végétation (sous-zone la) fut suivie, après une période de transition (sous-zone 1b), par une végétation luxuriante de type toundra (sous-zone 1c). Celle-ci fut à son tour remplacée par une végétation de type toundra arbustive (sous-zone 1d) où l’on voit s’accroître l’importance de Betula glandulosa et d’autres éléments arbustifs. Avec un certain métachronisme entre les sites, l’afforestation s’est amorcée par l’installation du Populus cf. tremuloïdes (sous-zone 2a) et s’est poursuivie par l’arrivée de Picea mariana (fin de la sous-zone 2a) puis, par celle d’une série d’arbres tels Betula papyrifera, Pinus cf. divaricata, Abies balsamea, Picea glauca et Larix laricina (sous-zone 2b). Pendant cette dernière phase de l’afforestation, l’abondance du pollen d’Alnus cf. crispa dans les spectres est maximale. Il semble qu’au moins mille ans se soient écoulés avant l’arrivée des arbres autres que le Populus cf. tremuloïdes. Par la suite, l’histoire de la végétation forestière (zone 3) a été plutôt monotone. Bien que les diagrammes révèlent des périodes de plus grande abondance de certains taxons (Pinus strobus, Picea mariana, Pinus et. divaricata), la majorité des arbres, présents actuellement dans la région, ont migré très tôt à l’Holocène.


2020 ◽  
Vol 96 (01) ◽  
pp. 27-35
Author(s):  
Myriam Delmaire ◽  
Nelson Thiffault ◽  
Evelyne Thiffault ◽  
Julie Bouliane

Ecosystem-based management aims to maintain the natural proportion of native species over a given landscape. White spruce (Picea glauca (Moench) Voss) is a species sensitive to environmental conditions; it is especially demanding in terms of nutrients and its regeneration is negatively affected by clearcut harvesting. Its proportion is now significantly lower than what it was in the preindustrial forests of Québec (Canada). As a native species in boreal Québec, efforts to maintain its proportion in the landscape are undertaken for white spruce, but little is known about the best practices to maximize establishment success of seedlings planted in the balsam fir (Abies balsamea)–white birch (Betula papyrifera) bioclimatic domain. Our general objective was to identify planting practices as related to microsite treatment that favour white spruce sapling survival and size after 11 growing seasons following enrichment planting of sites harvested by mechanized careful logging in an ecosystem-based management context. We also aimed at comparing white spruce performance with that of black spruce (Picea mariana (Mill.) BSP), a native species that is less sensitive to abiotic stress. Finally, we wanted to assess stand composition at this juvenile stage, as a function of microsite treatment and planted species. Localized site preparation did not significantly affect growth or survival for white spruce compared to control conditions. Furthermore, localized site preparation did not increase the proportion of white and black spruce, as evaluated by basal area. Our results suggest that white spruce can be successfully established in enrichment planting in fir-dominated boreal forests, without site preparation.


1983 ◽  
Vol 59 (4) ◽  
pp. 177-183 ◽  
Author(s):  
D. A. MacLean ◽  
M. G. Morgan

Long-term growth responses from manually and chemically releasing balsam fir (Abies balsamea (L.) Mill.) seedlings from shrub competition were examined on five 0.4-ha plots in northwestern New Brunswick. Manually releasing seedlings from mountain maple (Acer spicatum Lam.) competition by clearing a 1-m radius circle around each seedling in one plot resulted in increases of 64% for total fir volume, 36% for mean dbh, and 22% for mean height, in comparison with a control plot, 32 years later. Application of a 2,4-D — 2,4,5-T mixture to two plots resulted in 265 and 157% greater fir volume than the control plot 28 years later. Herbicide treatment dramatically changed the species composition of the treated plots, favoring fir and spruce (Picea sp.) over pin cherry (Prunus pensylvanica L.f.) and white birch (Betula papyrifera Marsh.), but had lesser effects on individual-tree growth rates.


2007 ◽  
Vol 24 (2) ◽  
pp. 138-145 ◽  
Author(s):  
Chris Richard Hennigar ◽  
David A. MacLean ◽  
Chris James Norfolk

Abstract The first major European gypsy moth (Lymantria dispar L.) outbreak occurred in central New Brunswick, Canada, on over 3,000 ha of forestland, from 2001ߝ2003. The outbreak was severe enough to result in considerable landowner concern and a privately funded aerial insecticide spray program to protect trees. Defoliation was unexpectedly severe on several tree species thought to be resistant or immune, as indicated from studies in the northeastern United States. Fifty plots (564 trees) were established and measured for standard mensurational characteristics, defoliation, and annual tree mortality, and after the cessation of defoliation, 44 trees were destructively stem analyzed to determine growth patterns. Balsam fir (Abies balsamea [L.] Mill.) with defoliation of more than 75% sustained specific volume increment reduction averaging 55% and 25% mortality after 2 years of severe defoliation. Red oak (Quercus rubra L.) sustained about 40% growth reduction, similar to results of previous studies. However, white birch (Betula papyrifera Marsh.) and trembling aspen (Populus tremuloides Michx.), with more than 75% defoliation for 2 years, sustained 43ߝ48% growth reduction, higher than in previous studies, and 4ߝ12% mortality. The gypsy moth range in Canada appears to be gradually expanding beyond previous climatic (cold winter temperature) limitations, and these results will help to predict future impacts.


2011 ◽  
Vol 41 (11) ◽  
pp. 2176-2192 ◽  
Author(s):  
C. Eiry Spence ◽  
David A. MacLean

Many current forest management regimes stress emulation of natural disturbance events, e.g., spruce budworm (SBW; Choristoneura fumiferana (Clemens)) outbreaks in a balsam fir (Abies balsamea (L.) Mill.) dominated forest, as the preferred method for ensuring sustainability of forest ecosystems. This study compared a SBW-inspired harvest treatment in 25 plots in northern New Brunswick with an uncontrolled SBW outbreak in 30 plots in the Cape Breton Highlands, Nova Scotia. Stand-level measurements before, during, and after each disturbance indicated similar reduction of living stand volume (70% reduction in emulation harvest versus 83% in SBW outbreak), mortality patterns, and lengths of disturbance (4 years of >10% mortality by density of predisturbance stand). Differences for the harvest treatment included higher cumulative postdisturbance blowdown (43% versus 8% of postdisturbance stand density), conversion to hardwood-dominated stands immediately after the disturbance, and faster growth response (immediate release of all species in the harvest treatment versus decreased balsam fir and white spruce (Picea glauca [Moench] Voss) growth and increased white birch (Betula papyrifera Marshall) growth in the SBW outbreak). There were significant differences in stand dynamics following the two disturbances. Results suggest that instead of emulating SBW disturbances, forest managers should be inspired by the spatial and temporal characteristics of SBW-defoliated stands and use significant key features of them to design harvest plans that satisfy management goals.


1979 ◽  
Vol 111 (8) ◽  
pp. 875-882
Author(s):  
A. G. Raske ◽  
M. Alvo

AbstractSample sizes needed to measure population levels of the birch casebearer, Coleophora fuscedinella Zeller, and its damage to white birch, Betula papyrifera Marsh, were calculated for various degrees of confidence and assurance. Both a non-destructive and a destructive sampling plan are presented and a new method to classify the damage level of a stand. This method uses a maximum likelihood technique to estimate the proportion of trees of various damage classes.


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