Invalid Unit Specified
M401 Eichhornia crassipes - Egeria densa - Alternanthera philoxeroides Ruderal Aquatic Vegetation Macrogroup

The U.S. National
Vegetation Classification
Type Concept Sentence: This ruderal aquatic vegetation occurs in freshwater semipermanently or permanently flooded wetlands of lakes, rivers, and ponds dominated by floating or submerged herbaceous vegetation.
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Common (Translated Scientific) Name: Common Water-hyacinth - Brazilian Waterweed - Alligator-weed Ruderal Aquatic Vegetation Macrogroup
Colloquial Name: North American Temperate Ruderal Aquatic Vegetation
Hierarchy Level: Macrogroup
Type Concept: This ruderal aquatic vegetation occurs in freshwater wetlands of lakes, rivers, and ponds, in areas which are permanently or semipermanently flooded. The dominant growth forms are floating, rooting and submerged aquatic vegetation. The most common species include the exotics Alternanthera philoxeroides, Egeria densa, Eichhornia crassipes, Ludwigia peploides, Pistia stratiotes, and Salvinia molesta. In cool temperate regions, Hydrocharis morsus-ranae, Myriophyllum spicatum, and Trapa natans are locally common. These exotic species can spread vigorously and form extensive mats that cover the surface or submersed areas of the water.
Diagnostic Characteristics: Floating aquatic vegetation dominated by ruderal species such as Alternanthera philoxeroides, Egeria densa, Eichhornia crassipes, Hydrilla verticillata, Ludwigia peploides, Myriophyllum spicatum, and Pistia stratiotes are typical. Other species that could be included are Salvinia molesta or Trapa natans (in cool temperate areas).
Rationale for Nominal Species or Physiognomic Features: The three nominal species, Eichhornia crassipes, Egeria densa, and Alternanthera philoxeroides, may be the most frequent and widespread exotic species in this macrogroup, though they are more common in warm temperate and tropical areas rather than cool temperate ones.
Classification Comments: There are some differences in dominant species between cold-temperate and warm-temperate areas but probably not enough to warrant separate macrogroups. Possibly the difference could be recognized at the group level.
Similar NVC Types:
M109 Western North American Freshwater Aquatic Vegetation, note:
M108 Eastern North American Freshwater Aquatic Vegetation, note:
M871 Boreal Freshwater Aquatic Vegetation, note:
Physiognomy and Structure: Floating-leaved or submerged herbaceous aquatic plants dominate. They can have sparse to dense cover.
Floristics: In the warm temperate region, Alternanthera philoxeroides, Eichhornia crassipes, Ludwigia peploides, and Pistia stratiotes are common aquatic exotic species. They can occur further north in limited amounts. Other species include Egeria densa, Hydrilla verticillata, Myriophyllum aquaticum, Myriophyllum spicatum, Najas minor, Nymphoides peltata, Nymphoides cristata, Potamogeton crispus, Salvinia minima, Salvinia natans, and Salvinia molesta. In the cool temperate region, Hydrocharis morsus-ranae, Myriophyllum spicatum, and Trapa natans are locally common exotic invasive plants.
Dynamics: In the warm temperate region, cold temperatures can cause damage to certain of these plants, and probably limits their ranges to the north. After flooding events, these plants can establish in new areas where the floodwater has carried them. Many of these plants can also be spread to new areas by boats. Various control methods have been used to reduce nuisance infestations (Gettys et al. 2009).
Environmental Description: Climate: This aquatic vegetation occurs in both warm temperate and tropical areas, which have a humid climate, and in cool temperate regions. Soil/substrate/hydrology: This aquatic vegetation occurs in freshwater wetlands that are permanently or semipermanently flooded. Areas may be impounded, natural lakes, or low-gradient flowing streams and rivers. Often patches of this vegetation will occur in the more slowly flowing sections of rivers and streams.
Geographic Range: This macrogroup is found in eastern Canada, the eastern, midwestern, and southeastern United States, Texas, eastern Mexico, and the Caribbean.
Nations: CA, MX, US
States/Provinces: AL, AR, CT, DE, FL, GA, IA, IL, IN, KS, KY, LA, MA, ME, MI, MN, MO, MS, ND, NE, NH, NJ, NY, OH, OK, ON, PA, QC, SC, TN, TX, VA, VT, WI, WV
US Forest Service Ecoregions (2007)
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Plot Analysis Summary:
Confidence Level: Moderate
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Grank: GNA
Concept Lineage:
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Synonomy: < Aquatic Bed, Permanently Flooded and Semipermanently Flooded (Cowardin et al. 1979)
> Floating mats of water hyacinth (Kushlan 1990)
< Freshwater marsh (Kushlan 1990)
Concept Author(s): Faber-Langendoen et al. (2014)
Author of Description: C. Nordman
Version Date: 15Oct2014
  • Cowardin, L. M., V. Carter, F. C. Golet, and E. T. LaRoe. 1979. Classification of wetlands and deepwater habitats of the United States. FWS/OBS-79/31. USDI Fish & Wildlife Service, Office of Biological Services, Washington, DC. 103 pp.
  • Faber-Langendoen, D., J. Drake, S. Gawler, M. Hall, C. Josse, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, L. Sneddon, K. Schulz, J. Teague, M. Russo, K. Snow, and P. Comer, editors. 2010-2019a. Divisions, Macrogroups and Groups for the Revised U.S. National Vegetation Classification. NatureServe, Arlington, VA. plus appendices. [in preparation]
  • Gettys, L. A., W. T. Haller, and M. Bellaud, editors. 2009. Biology and control of aquatic plants: A best management practices handbook. Aquatic Ecosystem Restoration Foundation, Marietta GA. 210 pp. []
  • Kushlan, J. A. 1990. Freshwater marshes. Pages 324-363 in: R. L. Myers and J. J. Ewel, editors. Ecosystems of Florida. University of Central Florida Press, Orlando.
  • Lui, K., M. Butler, M. Allen, J. da Silva, and B. Brownson. 2008. Field guide to aquatic invasive species: Identification, collection and reporting of aquatic invasive species in Ontario waters. Queen's Printer for Ontario. MNR # 52089. []
  • Morris, T. L. 1974. Water hyacinth Eichhornia crassipes (Mart.) Solms: Its ability to invade aquatic ecosystems of Paynes Prairie Preserve. M.S. thesis, University of Florida, Gainesville.