MARSH AND BOG VEGETATION IN NORTHWESTERN ALBERTA

Swamp, marsh, wet meadow, saline meadow, Drepanocladus bog, and Sphagnum bog are characterized and related aquatic vegetation is described briefly. There is succession from different kinds of swamp and marsh, through wet meadow, to Agropyron–Carex grassland and to various wooded communities, and also of marsh, through Drepanocladus–Carex bog to a Larix laricina association. The main bog sere of the region is initiated by some kind of aquatic or marsh phase and passes through Sphagnum bog stages to bog forest (Picea mariana) climax. Ecological aspects of Sphagnum species are considered in relation to succession and a regeneration cycle. Retrogression caused by burning is described for marshes, bogs, and bog forests. Many bogs in the northern part of the region have large mounds and ridges that retain frozen peat below the surface mantle during the summer. The significance of these permafrost areas is discussed. Brief consideration is given to phytogeographical features of the region.