Common (Translated Scientific) Name: Hornwort species - Pond-lily species - Pondweed species Eastern North American Freshwater Aquatic Vegetation Macrogroup
Colloquial Name: Eastern North American Freshwater Aquatic Vegetation
Hierarchy Level: Macrogroup
Type Concept: Aquatic beds can be found across a large part of North America, ranging from boreal, interior Canada (Saskatchewan, Manitoba, Ontario) south through the Great Plains to the Gulf Coastal Plain in Texas and east to the Atlantic. Stands in this macrogroup have rooted aquatic herbaceous vegetation, are permanently flooded with water generally less than 2 m deep, and are subject to low to moderate waves and currents. Emergent vegetation has <10% total cover. Common aquatic plant species include Brasenia schreberi, Ceratophyllum demersum, Eleocharis robbinsii, Elodea canadensis, Eriocaulon aquaticum, Heteranthera dubia, Heteranthera reniformis, Bidens beckii, Myriophyllum spp., Najas flexilis, Nuphar advena, Nuphar microphylla, Nuphar variegata, Nymphaea odorata, Nymphaea tetragona (in central Canada), Nymphoides aquatica, Nymphoides cordata, Potamogeton amplifolius, Potamogeton epihydrus, Potamogeton friesii, Potamogeton gramineus, Potamogeton natans, Potamogeton perfoliatus, Potamogeton nodosus, Potamogeton richardsonii, Potamogeton zosteriformis, Ruppia maritima, Stuckenia pectinata, Utricularia spp., and Vallisneria americana. Zannichellia palustris is a common component in the Great Plains. Alkaline sites may contain Chara spp. Water salinity varies from fresh to saline, with the saline and brackish sites tending to occur in the Great Plains.
Diagnostic Characteristics: These aquatic beds are characterized by permanently flooded sites in inland areas or coastal fresh to oligohaline areas with water usually 0.3 to 2 m deep, vegetation dominated by submerged or floating-leaved herbaceous plants, and few to no emergent plants. Except for some sites in the Great Plains, composition is generally of species that do not tolerate moderate (>5 ppt) to high (18 ppt) water salinities.
Rationale for Nominal Species or Physiognomic Features:
Classification Comments: This widely distributed macrogroup should be reviewed to verify that it is internally consistent. Particularly, whether there is enough difference in brackish/saline communities in the Great Plains or the freshwater tidal aquatic marshes to warrant separate macrogroups, parallel to the emergent marshes. Coastal saline aquatic (subtidal) aquatic marshes (e.g., seagrass beds) are in separate macrogroups, Temperate Eel-grass Vegetation Macrogroup (M183) and Temperate Pacific Seagrass Intertidal Vegetation Macrogroup (M184) or Ditchgrass Saline Aquatic Vegetation Macrogroup (M186).
Similar NVC Types:
M401 North American Temperate Ruderal Aquatic Vegetation, note: is dominated by ruderal and exotic species and can be similar to degraded examples of M108.
M067 Atlantic & Gulf Coastal Plain Wet Prairie & Marsh, note: "has >10% emergent vegetation, so aquatic vegetation can be a typical component."
M071 Great Plains Marsh, Wet Meadow, Shrubland & Playa, note: "has >10% emergent vegetation, so aquatic vegetation can be a typical component."
M109 Western North American Freshwater Aquatic Vegetation, note:
M069 Eastern North American Marsh, Wet Meadow & Shrubland, note: "has >10% emergent vegetation, so aquatic vegetation can be a typical component."
M066 Atlantic & Gulf Coastal Fresh-Oligohaline Tidal Marsh, note: "has >10% emergent vegetation, so aquatic vegetation can be a typical component."
M186 Ditchgrass Saline Aquatic Vegetation, note: "is currently restricted to coastal, saline habitats."
Physiognomy and Structure: The physiognomy of these aquatic beds is fairly simple. Submerged and floating-leaved herbaceous plants dominate. They can have sparse to dense cover. Emergent plants are scattered to absent in the core of these communities but often become more common along the drier edges. Emergent woody vegetation is very rare and, when present, is generally limited to the drier parts of these submergent marshes.
Floristics: A variety of submergent or floating-leaved herbaceous plants may dominate this aquatic vegetation. Common dominant species include Brasenia schreberi, Ceratophyllum demersum, Eleocharis robbinsii, Elodea canadensis, Eriocaulon aquaticum, Heteranthera dubia, Heteranthera reniformis, Bidens beckii (= Megalodonta beckii), Myriophyllum spp., Najas flexilis, Nuphar advena, Nuphar microphylla, Nuphar variegata, Nymphaea odorata, Nymphaea tetragona (in central Canada), Nymphoides aquatica, Nymphoides cordata, Potamogeton amplifolius, Potamogeton epihydrus, Potamogeton friesii, Potamogeton gramineus, Potamogeton natans, Potamogeton perfoliatus, Potamogeton nodosus, Potamogeton richardsonii, Potamogeton zosteriformis, Ruppia maritima, Stuckenia pectinata, Utricularia spp., and Vallisneria americana. Other species likely to occur are Azolla caroliniana, Bacopa caroliniana, Gratiola brevifolia, Lemna spp., Peltandra virginica, and Spirodela spp. Taller emergent species are frequently found in small amounts in these aquatic beds, particularly along the shallower edges. Zannichellia palustris is a common component in the Great Plains. Alkaline sites may contain Chara spp.
Dynamics: These aquatic beds are typically part of a complex of wetland communities. They tend to be stable if hydrologic conditions remain stable. Examples in the Great Plains, where evaporation rates are higher and precipitation can be lower than in the eastern United States, are greatly affected by multi-year changes in precipitation patterns. When precipitation decreases, they can dry out and disappear for years until precipitation increases, flooding the basins again, and allowing the species of this macrogroup to sprout from the seed bed (Stewart and Kantrud 1971) or from persistent rhizomes or tubers. Emergent marsh, shrub wetlands, and/or wet meadows are typically on the upland side of these communities. Aquatic beds may form the center (deepest part) of wetlands. Other communities not typically part of terrestrial vegetation classifications tend to occur in deeper or higher energy settings.
Environmental Description: Climate: This aquatic vegetation can be found from boreal, through cool-temperate, to warm-temperate climates. Soil/substrate/hydrology: Aquatic beds can be found in lakes, ponds, low-gradient river channels, and oxbows and backwaters of rivers or streams. This includes the shoreline and estuaries along the Great Lakes and fresh tidal portions of coastal estuaries. Surface soils are typically muck (well-composed peat) in richer sites, but there is substantial variance across the range of this macrogroup. Muck can be over nearly any material, including bedrock. Submerged or floating-leaved vegetation can also root in mineral soils. Most sites have freshwater, but in closed basins in the Great Plains where evaporation is high and soils or groundwater contains salts, the water can be brackish (5-18 ppt) or even saline (>18 ppt). Nearly all stands of aquatic beds are flooded in all but the driest years. Water depth varies from several centimeters to 2 m. A few stands in the Great Plains dry out for part of most years, but water is present long enough to support the characteristic species. Aquatic vegetation occurs where wave and current action is minor to moderate. Frequent fast water or heavy waves prevent these vegetation communities from persisting. Except for higher saline inland sites, salinity is low; most sites are in freshwater or (in coastal areas) in very mildly oligohaline settings (e.g., salinity <1 ppt).
Geographic Range: These aquatic beds can be found across a large part of eastern North America, ranging from boreal, interior Canada (Saskatchewan, Manitoba, Ontario) south through the Great Plains to the Gulf Coast and east to the Atlantic. Stands occur from near sea level to 1525 m (5000 feet) elevation in the Great Plains.
Nations: CA, MX?, US
States/Provinces: AB, AL?, AR, CT, DE, GA?, IA, IL, IN, KS, KY, MA, MB, MD, ME, MI, MN, MO, MS?, MT, NC, ND, NE, NH, NJ, NY, OH, OK, ON, PA, QC, RI, SC, SD, SK, TN, TX, VA, VT, WI, WV, WY
|US Forest Service Ecoregions (2007)|
Confidence Level: Low
Confidence Level Comments:
Synonomy: = Freshwater Marsh - Euhydrophyte (Mitsch et al. 2009) [Concept is equivalent in the U.S. east of the Rocky Mountains.]
= Submerged and Floating Aquatic Vegetation (Stewart and Kantrud 1971) [Concept is equivalent in North Dakota.]
= Submergent Marsh (Kost et al. 2007) [Concept is equivalent within Michigan.]
Concept Author(s): Faber-Langendoen et al. (2014)
Author of Description: J. Drake
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]
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- Mitsch, W. J., J. G. Gosselink, C. J. Anderson, and L. Zhang. 2009. Wetland Ecosystems. John Wiley & Sons, Inc., New York. 295 pp.
- Stewart, R. E., and H. A. Kantrud. 1971. Classification of natural ponds and lakes in the glaciated prairie region. USDI Bureau of Sport Fisheries and Wildlife Resources, Publication 92. Washington, DC. 77 pp.