The Alaska Vegetation Classification - Alaska Geobotany Center ...

Communities of the second phase are commonly dominated by Carexpluriflora inthe south and C. rariflora in the north. Low shrubs may be present, but mosses andlichens are absent. Plant cover is usually complete or nearly so and plant height isgenerally 20 to 40 centimeters (8 to 16 in).Distribution and site characterlstics-The coarse sedge communities of the firstphase are common throughout the State along borders of brackish ponds, drainageways,and tidal flats. Areas tend to be quite small in northern Alaska, where tidalfluctuation is small and coastal erosion is intense. Frequency of tidal inundationranges from several times per month to once per summer. Soils consist of silts andclays, without microtopography, that often overlay sand or gravel. Water quickly runsoff most of the seaward sites after flooding, which allows the surface centimeter ortwo of soil to dry. Soil salinity ranges from 6 to 12 parts per thousand. Soil reaction iscircumneutral to slightly acid.Communities of the second phase occur inland from those of the first phase andform a broad ecotone with freshwater wetlands. The substrate is a saturated hummockypeat, often with a few centimeters of water in the depressions. Soil salinity isgenerally between 0 and 6 parts per thousand; soil reaction ranges from slightly acidto as low as pH 4.4.Successional status-Succession depends primarily on whether the coastline isprograding (as on deltas), subsiding, or stable. The successional trend on a progradingmarsh would be from halophytic forb or halophytic grass to halophytic sedgephase one to halophytic sedge phase two to various freshwater wetland types.Where the coastline is subsiding, the successional trend would be reversed.Closely related types-Seaward edges of communities of the first phase commonlyborder abruptly on halophytic grass wet meadow communities. The sedge communitiesare substantially taller and denser than the grass communities. Communities ofthe second phase frequently grade inland into fresh wet meadows or bogs. They areespecially similar to subarctic lowland sedge-bog meadows, but the latter are fartherfrom the sea (never tidally inundated) and support mosses and a greater diversity ofsedges. With increasing shrubs, these inland halophytic sedge meadows may gradeinland into sweetgale, willow ten, or shrubby bog communities. Communities dominatedby Neocharispalusfris are similar to certain fresh sedge marshes but areexposed to periodic flooding by tidewater.Photographs-Batten and others 1978, figure 9; Neiland 1971b, figures 12 and 13;Racine and Anderson 1979, figure 22; figure 67, this publication.Primary relerence&el Moral and Watson 1978, Frohne 1953, Jefferies 1977,Meyers 1985, Stephens and Billings 1967, Vince and Snow 1984.Communities-Carex subspafbacea (Hanson 1951, 1953; Meyers 1985). Carexsubspafbacea-Puccinelliaphryganodes (Bergman and others 1977, Byrd and Ronsse1983, Nodler and others 1978, Webber and others 1978). Carex ursina (Jefferies1977). Carex mackenziei(Byrd and Ronsse 1983. Ritchie and others 1981). Carexramenskii(6atten and others 1978, Hanson 1951, Jefferies 1977, Neiland 1971b,Quimby 1972, Vince and Snow 1984). Carex ramenskii-Potentilla egedii (Byrd andRonsse 1983, George and others 1977, Rosenberg 1986). Carex ramenskii-Triglochinmarifimum-Pofenfilla egedii (Hanson 1951, Ritchie and others 1981). Carex lyngbyaei(Batten and others 1978; Craighead and others 1988; Crow 1968, 1977b; Crow and