The Alaska Vegetation Classification - Alaska Geobotany Center ...

Distribution and site characteristics-Fresh herb marshes occur in permanentlyflooded sites (usually with 15 to 100 centimeters [6 to 40 in] of water), includingsloughs, oxbow lakes, sluggish rivers, and lake margins, in and near the forestedparts of the State. Soils may be mineral silts or sands or welldecomposed organicmucks.Successional status-These are early successional communities in aquatic seres;they replace open water or aquatic communities. As sedimentation and organic matteraccumulation gradually build up the soil to near the water level, these communitiesprobably will be replaced by graminoid wet meadows. They also can be replaced bylaterally expanding floating bog mats.Closely related types-Fresh herb marshes are similar to graminoid marshes inthat they consist of tall emergent plants in deep water. The former are dominated,however, by nongraminoid emergents, typically Equisetum fluviatile.Fresh herb marshes also are similar to subarctic lowland herb wet meadows and bogmeadows. Many of the common secondary species of marshes are codominant inherb wet meadows or herb bog meadows. Wet meadows are flooded with much lesswater than marshes or have no standing water at all. Herb bog meadows often occurin shallower water than herb marshes but sometimes are in fairly deep water or onfloating mats submerged slightly below the surface that sink when walked on. Thesubstrate of the bog meadows is peat. in contrast to the mineral or well-decomposedorganic substrate of marshes. Neither herb wet meadows nor herb bog meadows aredominated by €quiseturn fluviatile.Primary references-Racine 1976, Ritchie and others 1981.Cornmunitie~-Equisefum fluviatile (Craighead and others 1988, Racine 1976,Ritchie and others 1981). Equisetum fluviatile-Menyanfhes trifoliafa (Hulten 1966.Racine 1978b, Ritchie and others 1981, Rosenberg 1986). Equisetum fluviatile-Polygonum amphibium (Young and Racine 1976).llJ.B.3.b. Subarctic Lowland Herb Wet MeadowDescriptlon-Herb wet meadows are dominated by herbs or nonwoody plants otherthan grasses and sedges, commonly Equisetum arvense, E. variegatum, Calfhapalustris, and Juncus arcticus. Scattered grasses and sedges may be present.Nonsphagnaceous mosses may be common or absent. Lichens and woody plantsare rare or absent. Cover usually is less than complete.Distribution and site characteristics-Herb wet meadows are found in seepageareas, pools, pond margins, and marsh edges throughout most of the State, especiallythe southern two-thirds. Stands usuaiiy are quite small and widely scattered.They occur on saturated or shallowly flooded soils. If standing water is present, itusually is less than 15 centimeters (6 in) deep. Soils usually are mineral silts orsometimes sands; often they have a few centimeters of well-decomposed organicmuck at the surface. Soil reaction is circumneutral to acid but not extremely acid; pHvalues of 6.1 to 7.0 have been reported, but some herb meadows probably occur onmore acidic substrates.Successional status-As soil development proceeds, adjacent wet sedge meadowsmay expand into and ovewhelm many of these communities, which eventuallyevolve to bog or scrub communities.196