Distribution patterns of American Arctic lichens

• Published in: Canadian Journal of Botany
• Main Author: Thomson, John W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1972
• Subjects: Plant Science; Arctic; Pacific; Arctic lichen; Siberia
• Online Access: http://dx.doi.org/10.1139/b72-138; http://www.nrcresearchpress.com/doi/pdf/10.1139/b72-138

Maps showing typical American Arctic lichen distribution patterns are given, including broad ranging circumpolar, boreal forest outlier, Appalachian extensions, arcto-Pacific (Beringian), amphi-Atlantic, American Arctic endemic, Great Plains and Arctic, and western states and eastern arctic disjuncts. Discussion of dispersion mechanisms suggests wind over snow cover as most important. The origin of the arctic lichens is suggested as being in tectonic uplifts of the Miocene giving alpine tundras from which spread into arctic tundras occurred in pre-Pleistocene and subsequently. Possible sites of origin are the Rocky Mountains and the mountains of eastern Siberia. The question is posed of whether the distribution patterns reflect equiformal spread from centers of origin or if they reflect patterns of distribution of environmental conditions.