The Alaska Vegetation Classification - Alaska Geobotany Center ...

Marsh-(1) A periodically wet or continually flooded nonpeat-forming ecosystemwhere the surface is not deeply submerged and supports sedges, cattails, andrushes or other hygrophytic plants. Subclasses include freshwater and saltwatermarshes. Less acid and less continuously flooded than a bog, often only intermittentlyflooded. (2) In Alaska, sites are characteristically flooded with 15 centimeters(6 in) or more of water; may have no standing water late in the summer butsoils remain saturated. Vegetation usually is dominated by emergent herbaceousplants. Typical species are Arctophila fulva, Scifpus spp., Equisetum fluviatile, andEleochafispalustfis. Woody plants, lichens, and sphagnum are absent or rare.Sa/tmarsh--Similar to a fresh marsh, but adjacent to the sea and inundatedperiodically (tidally or seasonally) with saline water.Tidal marsMow marsh lands traversed by interlacing channels and sloughsand subject to tidal inundation. Usually the vegetation is composed of salt-tolerant(halophytic) grasses and sedges.Meadow-Closed herbaceous vegetation, commonly in stands of limited extent.Often used to denote stands of grasses and sedges.Brackish marsh meadow-Coastal flats and lower beach habitats regularlyinundated by tides. Soils are mineral, sometimes overlain by a tough sod ofroots and rhizomes or by shallow (up to 20 centimeters [8 in]) peat.Fresh marsh meadow-Fresh or essentially fresh community types predominatelyon mineral soils or less than 30 centimeters (12 in) of peat. Where peat ispresent, it usually is sedge peat.Sedge meadow4 vegetation unit (usually in wet situations) consisting of lowgrasslike plants belonging to Cyperaceae; for example, cottongrass.Wet meadow-In Alaska, sites characterized by saturated soils or by flooding todepths of less than 15 centimeters (6 in) and vegetation dominated by herbaceousspecies, usually graminoids. Moss cover varies but generally is low. Soils aremineral but may be overlain by a shallow organic layer.Mesic-Refers to sites of habitats characterized by intermediate moisture conditions;that is, neither decidedly wet (hygric) nor decidedly dry (xeric).Mesophyte-A plant whose normal habitat is neither very wet nor very dry; forexample, paper birch.Metamorphic rock-Rock of any origin altered in mineralogical composition,chemical composition, or structure by heat and pressure. Nearly all such rocksare crystalline.Microrelief-Small-scale local differences in topography, including mounds, swales,and pits that are only a few feet in diameter and height.Microsere-A time sequence of communities, of small areal extent, that may beobserved even in climax stands. Microseres involve such processes as thereplacement of a large individual plant after it dies, the sequence of decomposersthat follow each other in a unit of litter, and the development of vegetation on anabandoned ant nest.Mineral soil-Soil that is mainly mineral material and low in organic material (usuallyless than 20 percent). Its bulk density is greater than that of organic soil.267