Classification of Wetlands and Deepwater Habitats of the United States
Definition. The Moss-Lichen Wetland Class includes areas where
mosses or lichens cover substrates other than rock and where
emergents, shrubs, or trees make up less than 30% of the areal
cover. The only water regime is saturated.
Description. Mosses and lichens are important components of the
flora in many wetlands, especially in the north, but these plants
usually form a ground cover under a dominant layer of trees,
shrubs, or emergents. In some instances higher plants are uncommon
and mosses or lichens dominate the flora. Such Moss-Lichen
Wetlands are not common, even in the northern United States where
they occur most frequently.
Subclasses and Dominance Types.
Moss. -- Moss Wetlands are most abundant in the far north. Areas
covered with peat mosses (Sphagnum spp.) are usually called bogs
(Golet and Larson 1974; Jeglum et al. 1974; Zoltai et al. 1975),
whether Sphagnum or higher plants are dominant. In Alaska,
Drepanocladus and the liverwort Chiloscyphus fragilis may dominate
shallow pools with impermanent water; peat moss and other mosses
(Campylium stellatum, Aulacomnium palustre, and Oncophorus
wahlenbergii) are typical of wet soil in this region (Britton
1957; Drury 1962).
Lichen. -- Lichen Wetlands are also a northern Subclass. Reindeer
moss (Cladina rangiferina) forms the most important Dominance
Type. Pollett and Bridgewater (1973) described areas with mosses
and lichens as bogs or fens, the distinction being based on the
availability of nutrients and the particular plant species
present. The presence of Lichen Wetlands has been noted in the
Hudson Bay Lowlands (Sjörs 1959) and in Ontario (Jeglum et al.
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