The Alaska Vegetation Classification - Alaska Geobotany Center ...

Closely related types-These communities are similar to other aquatic communitiesbut are dominated by four-leaf marestail. They are especially similar to commonmarestail communities, which occur exclusively in fresh water, but are dominated byfour-leaf marestail instead of common marestail and occur in brackish, coastalsettings. Four-leaf marestail may be common in the understory of the wetter parts ofsome halophytic sedge wet meadow communities, but emergent plants are lackingfrom four-leaf marestail communities.Primary references-Batten and others 1978, del Moral and Watson 1978.Communities-Hippuris tetraphylla (Potter 1972). Hippuris tetraphylla-Potamogetonpectinatus (Batten and others 1978). Hippuris tetraphylla-Pofamogeton filiformis-Myriophyllumspicatum (Crow 1968, lsleib and Kessel 1973). Hippuris fetraphylla-Pofamogeton filiformis (del Moral and Watson 1978, Thomas 1957).lll.D.2.b. Bracklsh PondweedDescription-These communities are dominated by species of pondweed thattolerate brackish water, primarily Potamogeton pectinatus and P. filiformis.Wigeongrass (Ruppia spiralis) and horned pondweed (Zannichellia palustris)communities also are included. Hippuris tetraphylla may be present. Emergentplants are absent or rare.Dlstributlon and site characteristics-Brackish pondweed communities occupyshallow (10 to 50 centimeters [4 to 20 in] deep) brackish ponds in coastal marshesthroughout Alaska, except for the Chukchi and Beauforl seacoasts. These pondsare tidally inundated several times each summer and have salinities of roughly 1 to10 parts per thousand. The substrate consists of tidally deposited silts and clays.Successional status-Most ponds containing brackish pondweed communities arereplaced eventually by halophytic sedge wet meadows.Closely related types-These communities are similar to fresh pondweed communities,and most of the dominant species also grow in fresh water. The brackishpondweed communities occur, however, only within or at the edges of coastalmarshes and may include Hippuris tetraphylla or other salt-tolerant species as minorconstituents. Pondweed species with broad leaves (such as Potamogetongramineusand P. perfoliatus) never dominate brackish communities.Primary references-Neiland 1971 b, Palmer 1942.Communities-~yriophyllum spicafum-Potamogeton filiformis (Crow 1968).Pofamogeton filiformis (Crow 1968). Potamogefonspp. (Neiland 1971b, Palmer1942). Potamogetonspp.-Zanniche/liapalustris (Rosenberg 1986).111.0.3. Marine Aquatic HerbaceousThis unit includes communities in the ocean.21 0