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CEGL005450 Lemna spp. Western North American Aquatic Vegetation
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: Duckweed species Western North America Aquatic Vegetation
Colloquial Name: Western North America Duckweed Pond
Hierarchy Level: Association
Type Concept: This aquatic association of floating vegetation is known to occur throughout western North America. Lemna spp. typically dominate but may be mixed with other plant taxa floating on the water surface. Lemna-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. Lemna taxa that may be present in Western North America include Lemna aequinoctialis (southwest only as well as southeast U.S.), Lemna gibba (mostly southwestern U.S. and southward), Lemna minor (widespread across temperate North America), Lemna minuta (widespread across southern U.S.), Lemna trisulca (widespread temperate and boreal, but not southeast U.S.), and Lemna turionifera (widespread temperate and boreal, but not southeast U.S.). Other species present may include Spirodela polyrrhiza (widespread temperate U.S.), Azolla microphylla, Azolla filiculoides, Wolffiella lingulata (rare), Wolffiella oblonga (extreme southwest and southeast U.S.), and Wolffia borealis (west coast temperate and eastern temperate U.S., but not coastal plain), as well as Riccia spp. (aquatic liverworts). Potamogeton spp., Sagittaria spp., or Polygonum 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.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: Lemna spp. and other characteristic wetland taxa that comprise floating, submerged and aquatic rooted associations are not well-reported in the literature, but they are known to occur in the field. Lemna and Azolla will be easy to distinguish from each other; some Lemna taxa may be less easy to distinguish from Spirodela, Wolffiella, and Wolffia.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available
Floristics: The composition of examples varies across the wide distributional range of this community. Lemna taxa that may be present in Western North America include Lemna aequinoctialis (southwest only as well as southeast U.S.), Lemna gibba (mostly southwestern U.S. and southward), Lemna minor (widespread across temperate North America), Lemna minuta (widespread across southern U.S.), Lemna trisulca (widespread temperate and boreal, but not southeast U.S.), and Lemna turionifera (widespread temperate and boreal, but not southeast U.S.). Other species present may include Spirodela polyrrhiza (widespread temperate U.S.), Azolla microphylla (= Azolla mexicana), Azolla filiculoides, Wolffiella lingulata (rare), Wolffiella oblonga (extreme southwest and southeast U.S.), and Wolffia borealis (west coast temperate and eastern temperate U.S., but not coastal plain), as well as Riccia spp. (aquatic liverworts). Potamogeton spp., Sagittaria spp., or Polygonum 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. Ponds in California may also include Spirodela spp., Azolla spp., and Wolffiella spp. (Windell et al. 1986).
Dynamics: Because the biomass of floating organisms is generally not great, they do not have an important influence on the accumulation of organic matter on the pond bottom. However, a study comparing Rocky Mountain with Illinois pond communities found that similar types in Illinois ponds have twice the number of species and biomass found in Colorado ponds (Fuller 1930).
Environmental Description: Lemna-dominated aquatic vegetation occupies wetlands that are permanently flooded, semi-permanently flooded to seasonally flooded. 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. 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.
Geographic Range: This type is found throughout the western temperate region of the United States.
Nations: US
States/Provinces: AZ, CA, CO, ID, MT, ND, NE, NM, NV, OK, OR, SD, TX, UT, WA, WY
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.894143
Confidence Level: Low - Poorly Documented
Confidence Level Comments: No Data Available
Grank: G5
Greasons: No Data Available
| Type | Name | Database Code | Classification Code |
|---|---|---|---|
| Class | 5 Aquatic Vegetation Class | C05 | 5 |
| Subclass | 5.B Freshwater Aquatic Vegetation Subclass | S13 | 5.B |
| Formation | 5.B.2 Temperate to Polar Freshwater Aquatic Vegetation Formation | F057 | 5.B.2 |
| Division | 5.B.2.Na North American Freshwater Aquatic Vegetation Division | D049 | 5.B.2.Na |
| Macrogroup | 5.B.2.Na.2 Rocky Mountain Pond-lily - Pacific Mosquito Fern - Western Waterweed Western North American Freshwater Aquatic Vegetation Macrogroup | M109 | 5.B.2.Na.2 |
| Group | 5.B.2.Na.2.a Pond-lily species - Pondweed species - Duckweed species Freshwater Aquatic Vegetation Group | G544 | 5.B.2.Na.2.a |
| Alliance | A1747 Common Duckweed - Northern Watermeal - Columbian Watermeal Aquatic Vegetation Alliance | A1747 | 5.B.2.Na.2.a |
| Association | CEGL005450 Duckweed species Western North America Aquatic Vegetation | CEGL005450 | 5.B.2.Na.2.a |
Concept Lineage: CEGL003059 split by region into CEGL005450, CEGL005451, CEGL005452 (DFL 7-13).
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: No Data Available
- Fuller, G. D. 1930. A comparison of certain Rocky Mountain grasslands with the prairie of Illinois. Transactions of the Illinois Academy of Science 8:121-130.
- Owns, T., project coordinator, et al. 2004. U.S. Geological Survey and National Park Service Vegetation Mapping Program: Florissant Fossil Beds National Monument. U.S. Geological Survey and National Park Service. 390 pp.
- Sawyer, J. O., and T. Keeler-Wolf. 1995. A manual of California vegetation. California Native Plant Society, Sacramento. 471 pp.
- Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.
- Windell, J. T., B. E. Willard, D. J. Cooper, S. Q. Foster, C. F. Knud-Hansen, L. P. Rink, and G. N. Kiladis. 1986. An ecological characterization of Rocky Mountain montane and subalpine wetlands. USDI Fish and Wildlife Service Biological Report 86(11). 298 pp.