Bryology in arctic and boreal North America and Greenland

Abstract

Bryological research in boreal and arctic North America is in very preliminary stages. Although the flora is moderately well documented, details are lacking in much of the region. Greenland, Alaska, and Ellesmere Island are better understood than the rest of the area. Much of the information has been accumulated as casual collections and observations and incidental to other research. Bryophyte cover in arctic regions is less than that of vascular plants; in boreal regions wetlands are often dominated by bryophytes and open forests have extensive moss carpets. Turfs dominate the growth forms in the arctic while in boreal regions whorled-branched turfs, wefts, and compact mats become the predominant growth forms. Bryophytes are important in plant community structure and dynamics of both boreal and arctic regions, but detailed studies are few. Cytology of arctic and boreal bryophytes in North America rests on a single paper, thus any generalizations are hazardous. Physiology of bryophytes in northern North America has been inadequately documented. The sexuality, reproductive cycles, growth rates, and metabolic activities of bryophytes are areas that could yield intriguing results. Reproduction in bryophytes in northern regions appears not to be greatly different from that of more southern regions. In spite of the shorter growing season and the terrain and climate favoring wind dispersal, this had not led to an increase in the incidence of asexual reproduction in spite of the fact that more than 60% of the bryophytes are dioicous. Bryogeographic patterns are similar to those of the vascular flora but the presence of western North American taxa in the easternmost arctic and their absence in intervening areas is highly suggestive of eastern refugia. Glacial refugia are supported by the bryophyte distributions; their presence in unglaciated Alaska–Yukon, Ellesmere Island, and parts of Greenland seems best documented. Thirty-six maps are given showing bryophyte distribution patterns in the region under discussion.