Name:
Lemna spp. Western North American Aquatic Vegetation
Reference:
NatureServe Biotics 2019
Description:
This aquatic association of floating vegetation is known to occur throughout western North America. <i>Lemna</i> spp. typically dominate but may be mixed with other plant taxa floating on the water surface. <i>Lemna</i>-dominated aquatic vegetation occupies wetlands that are permanently, semipermanently or seasonally flooded. These small plants may float on the water's surface or become stranded and possibly rooted during drawdown periods. Water chemistry is fresh. The standing water habitat is relatively shallow, generally less than 2-4 m (6.6-13.1 feet) and occurs as ponds, lakes, ditches, stock ponds, and backwater sloughs of river and stream channels. Standing water for much or most of the growing season is characteristic. Depth of the water is of no consequence to floating plants; they occur where the wind pushes them. The composition of examples varies across this wide distributional range. <i>Lemna</i> taxa that may be present in Western North America include <i>Lemna aequinoctialis</i> (southwest only as well as southeast U.S.), <i>Lemna gibba</i> (mostly southwestern U.S. and southward), <i>Lemna minor</i> (widespread across temperate North America), <i>Lemna minuta</i> (widespread across southern U.S.), <i>Lemna trisulca</i> (widespread temperate and boreal, but not southeast U.S.), and <i>Lemna turionifera</i> (widespread temperate and boreal, but not southeast U.S.). Other species present may include <i>Spirodela polyrrhiza</i> (widespread temperate U.S.), <i>Azolla microphylla, Azolla filiculoides, Wolffiella lingulata</i> (rare), <i>Wolffiella oblonga</i> (extreme southwest and southeast U.S.), and <i>Wolffia borealis</i> (west coast temperate and eastern temperate U.S., but not coastal plain), as well as <i>Riccia</i> spp. (aquatic liverworts). <i>Potamogeton</i> spp., <i>Sagittaria</i> spp., or <i>Polygonum</i> spp. may also be present in Rocky Mountain ponds. While these latter species are rooted submerged species, and technically not part of the strictly floating community, they do intermingle. Community composition may change hour to hour, yet the environment (only the top few centimeters of water) is homogeneous. Biomass can be abundant under eutrophic conditions.
Accession Code:
urn:lsid:vegbank.org:commConcept:34209-{2BD367A3-1739-47DF-9EAC-04187B30E5A4}
Plot-observations of this Community Concept:
0
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