Plant communities on the surficial materials of north-central District of Keewatin, Northwest Territories

Abstract

A reconnaissance study of the vegetation of north-central District of Keewatin was undertaken in order to gain a better understanding of the relationships between the nature and distribution of plant communities and the surficial materials on which they grow. The four types of surficial materials studied - bedrock, glacial deposits, marine deposits, and actively aggrading and eroding deposits - each support a suite of plant communities that naturally segregate on the basis of moisture regime. Bedrock supports solely cryptogamic communities. Glacial deposits, commonly moderately to well drained, have lichen-heath and lichen-Hierochloe tundra; imperfectly and poorly drained glacial deposits have cryptogam-monocot tundra and wet sedge meadows. Marine silts and clays, generally moderately to poorly drained, support cottongrass tusscock tundra and wet sedge meadows. The driest aspects are unvegetated or have sparse grass barrens. Marine sand and gravel are generally moderately to well drained and have shrub-monocot tundra or shrub-monocot barrens. Locally where poorly drained, wet sedge meadows occur. Communities growing on actively aggrading and eroding postglacial fluvial and eolian deposits are generally in early stages of succession. Differences in species occurrence, abundance, and diversity, related to altitudinal and to some extent latitudinal changes, allow a bioclimatic subdivision of the Low Arctic ecosystem in the map area. This zonation is most obvious in the changes from Zone I where there is a variety of heath species, a dominance of dwarf shrubs, and the regular occurrence of erect shrubs, to Zone III where lichens and masses are dominant and the importance of shrub species is reduced, particularly the absence of erect shrubs and the reduction of heath species to two major ones. The removal or disruption of plant communities due to man's activities can lead to destruction of unique or botanically significant communities or species, alteration of drainage, accelerated geomorphic processes, and erosion. Such activities can also lead to the destruction of important feeding and breeding habitats for de pendent fauna. Communities on imperfectly and poorly drained materials are the most vulnerable to disruption.

Hierarchical subdivision of Arctic tundra based on vegetation response to climate, parent material and topography

“…A notable exception is Edlund 1990) map of the Queen Elizabeth Islands in the Canadian Archipelago. Limestone and dolomite deposits in this region are highly alkaline and coarse textured and support sparsely vegetated barrens (Edlund 1982a,b; Edlund & Alt 1989). Edlund's map portrays the differences of vegetation on acidic and alkaline substrates.…”

“…Vegetation patterns related to parent‐material differences are extensive and therefore important to global‐ and regional‐scale modelling efforts. There is a rich literature describing the peculiarities of floras and vegetation on carbonate and ultramafic rocks, saline soils, and fine‐ vs. coarse‐textured soils in the Arctic and sub‐Arctic (see for example, Edlund 1982a; Elvebakk 1982; Cooper 1986; Edlund & Alt 1989; Walker & Everett 1991). Unfortunately, the effects of parent material on Arctic vegetation have rarely been mapped.…”

Biological diversity of peatlands in Canada

“…Total number of common plant species in natural Canadian peatlands. Data were obtained from Damman (1977), Wells (1981), Edlund (1982), Sims et al (1982), Karlin and Bliss (1984), Banner et al (1987), Chee (1988), , Vitt and Chee (1990), Gignac et al (1991), Jeglum and He (1995), Wells (1996), Beilman (2001), Asada et al (2003b), and Belland and Vitt (N. D.). Taxonomy follows that of Stotler and Crandall-Stotler (1977), Scoggan (1978aScoggan ( , 1978bScoggan ( , 1979, Anderson (1990), Anderson et al (1990), and Esslinger and Egan (1995).…”

Stratigraphy and Paleoecology of Quaternary Sediments Along Pasley River, Boothia Peninsula, Central Canadian Arctic

“…The present northern limit of shrub birches is several hundred kilometres to the south (Fig. 2c) (EDLUND, 1982(EDLUND, , 1983. Although rare outliers may occur somewhat closer at favourable sites, it can be confidently assumed that shrub birches do not occur anywhere within tundra Zone 2.…”