Owl winter irruptions as an indicator of small mammal population cycles in the boreal forest of eastern North America

Oikos ◽  
2004 ◽  
Vol 107 (1) ◽  
pp. 190-198 ◽  
Author(s):  
Marianne Cheveau ◽  
Pierre Drapeau ◽  
Louis Imbeau ◽  
Yves Bergeron
The Holocene ◽  
2015 ◽  
Vol 25 (12) ◽  
pp. 1912-1922 ◽  
Author(s):  
Mathieu Frégeau ◽  
Serge Payette ◽  
Pierre Grondin

2014 ◽  
Vol 26 (3) ◽  
pp. 588-602 ◽  
Author(s):  
Aurélie Terrier ◽  
Martin P. Girardin ◽  
Alan Cantin ◽  
William J. de Groot ◽  
Kenneth Agbesi Anyomi ◽  
...  

2021 ◽  
Vol 485 ◽  
pp. 118954
Author(s):  
Pierre-Luc Couillard ◽  
Serge Payette ◽  
Martin Lavoie ◽  
Mathieu Frégeau

1973 ◽  
Vol 3 (4) ◽  
pp. 621-631 ◽  
Author(s):  
Donald R. Whitehead

AbstractRecent pollen and macrofossil data from the Southeast is consistent with a displacement of boreal forest species by over 1000 km during full-glacial time. Data from west of the Appalachians suggests a displacement of some 600 km. Thus boreal forests were developed in a broad area south of the ice margin. Few deciduous forest elements persisted in that region. The displacement appears to have been azonal. There is good evidence to suggest a significant mid-Wisconsin interstadial (23,000-36,000 BP) characterized by a more temperate biota.


1975 ◽  
Vol 5 (3) ◽  
pp. 395-434 ◽  
Author(s):  
Ronald B. Davis ◽  
Thompson Webb

By mapping and summarizing 478 pollen counts from surface samples at 406 locations in eastern North America, this study documents the relationships between the distributions of pollen and vegetation on a continental scale. The most common pollen types in this region are pine, birch, oak, and spruce. Maps showing isopercentage contours or isopolls for 13 important pollen types reflect the general N-S zonation of the vegetation. The maps and tabulations of average pollen spectra for the six major vegetational regions indicate high values for the following pollen types in each region: (1) tundra-nonarboreal birch, sedge, and alder; (2) forest/tundra-spruce, nonarboreal birch and alder; (3) boreal forest-spruce, jack pine (type), and arboreal birch with fir in the southeastern part; (4) conifer/hardwood forest-white pine, arboreal birch, and hemlock with beech, maple, and oak in the southern part; (5) deciduous forest-oak, pine, hickory, and elm, with beech and maple in the northern part, and highest values of oak and hickory west of the Appalachian crest; and (6) southeastern forest-pine, oak, hickory, tupelo, and Myricaceae. In some cases, less abundant pollen types are diagnostic for the region, e.g., bald cypress in the southeast. In the conifer-hardwood region and southward, pollen of weeds associated with deforestation and agriculture is abundant. The maps also show that much of southeastern U.S. and the area just to the east of Hudson Bay are in need of additional sampling. At 51 of the sites, absolute pollen frequencies (APF; grains/ml lake sediment) were obtained. These confirm the major conclusions from the percentage data, but differences are evident, e.g., the percentages of alder pollen peak in the tundra whereas alder APFs peak in the boreal forest, and spruce percentages peak in the forest-tundra whereas spruce APFs peak in the boreal forest. Because the APF data reflect the patterns of absolute abundance of individual taxa in the vegetation as well as the overall forest densities, future counts of modern pollen should include APF determinations. The effects of sedimentation processes on APF quantities indicate that APF samples should be obtained from moderate size lakes of similar morphology and hydrology and that, in each lake, several samples from the profundal zone should be pooled to create a sample representative of that lake.


2009 ◽  
Vol 39 (11) ◽  
pp. 2021-2032 ◽  
Author(s):  
Fang Ye ◽  
Philip G. Comeau

Vertical and horizontal patterns of light within gaps and expansion of trees into gaps were examined in young stands dominated by trembling aspen ( Populus tremuloides Michx.) in northeastern British Columbia and northwestern Alberta. Lateral growth of branches of aspen edge trees averaged 15.2 cm/year and was similar to crown expansion rates reported for edge trees in eastern North America. Branches growing into gaps were significantly longer than those growing away from gaps and are likely to lead to gap shrinkage and reductions in light within gaps. However, height growth of edge trees was not significantly different from that of trees within the surrounding stands. Models describing relationships between diffuse transmittance and locations within gaps and surrounding stand height were developed in this paper. Sky view angle (SVA) was found to be effective for predicting transmittance to different locations within gaps. When SVA values exceed 1.2 (at the B.C. sites), white spruce ( Picea glauca (Moench) Voss) will receive <40% of full sunlight, which is less than optimal for spruce height growth.


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