High-Latitude Yukon Boreal-Cordilleran Grassland Plant Communities

High-latitude (61.9˚ – 62.8˚ N) graminoid plant communities located near the northern limit of boreal forest occurrence in the Carmacks – Pelly Crossing area of Yukon were sampled and classified, and four sociations were recognized: Calamagrostis purpurascens (purple reedgrass), Hesperostipa comata...

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Bibliographic Details
Published in:ARCTIC
Main Author: Strong, Wayne L
Format: Article in Journal/Newspaper
Language:English
Published: The Arctic Institute of North America 2015
Subjects:
Online Access:https://journalhosting.ucalgary.ca/index.php/arctic/article/view/67495
Description
Summary:High-latitude (61.9˚ – 62.8˚ N) graminoid plant communities located near the northern limit of boreal forest occurrence in the Carmacks – Pelly Crossing area of Yukon were sampled and classified, and four sociations were recognized: Calamagrostis purpurascens (purple reedgrass), Hesperostipa comata (needle-and-thread grass), Poa glauca – Artemisia frigida (glaucous bluegrass – pasture sagewort), and Pseudoroegneria spicata – Artemisia frigida (bluebunch wheatgrass – pasture sagewort). These plant communities occurred primarily on south – southwest slopes (180˚ – 230˚) with 45% – 75% gradients. Relative to southern Canada mixedgrass prairie, Yukon grasslands were likely species poor, had less total canopy cover, and produced less than half as much aboveground herb biomass (typically 200 – 300 kg/ha). The distribution of the sociations appeared limited to ~60˚ – 65˚ N latitude in the Yukon-Alaska region. Calamagrostis was the most abundant and widespread grassland sociation in the study area. The four sociations occupied less than 4% of the Carmacks – Pelly Crossing landscape, although they represented the most extensive high-latitude boreal grassland vegetation in Canada (≥ 2600 ha) and they were among the most northerly in North America. Les communautés de plantes graminoïdes en haute latitude (61,9˚ – 62,8˚ N) situées près de la limite nord du milieu de forêt boréale dans la région de Carmacks – Pelly Crossing, au Yukon, ont fait l’objet d’un échantillonnage et d’un classement. Cela a permis de reconnaître quatre sociations : Calamagrostis purpurascens (calamagrostis pourpre), Hesperostipa comata (stipe comateuse), Poa glauca – Artemisia frigida (pâturin glauque – armoise douce) et Pseudoroegneria spicata – Artemisia frigida (agropyre à épi – armoise douce). Ces communautés de plantes se manifestaient surtout sur les versants du sud et du sud-ouest (180˚ – 230˚) comportant des gradients variant entre 45 % et 75 %. Comparativement à la prairie mixte du sud du Canada, les herbages du Yukon comportaient vraisemblablement peu d’espèces et un moins grand couvert au total, et ils produisaient moins de la moitié de biomasse épigée (généralement entre 200 et 300 kg/ha). La répartition des sociations semblait limitée à la latitude ~60˚ – 65˚ N de la région du Yukon-Alaska. Dans l’aire visée par l’étude, Calamagrostis était la sociation d’herbage la plus abondante et la plus généralisée. Les quatre sociations occupaient moins de 4 % du paysage de Carmacks – Pelly Crossing, même si elles représentaient la végétation d’herbage boréal la plus vaste en haute latitude au Canada (≥ 2600 ha) et qu’elles figuraient parmi les sociations les plus au nord de l’Amérique du Nord.