Print Report

G387 Ascophyllum nodosum - Ulva lactuca Intertidal Algal Flat Group

Type Concept Sentence: This group houses intertidal Atlantic shores of various substrates ranging from rock to mud; macroalgae are the dominant lifeform.

Common (Translated Scientific) Name: Yellow Tang - Sea-lettuce Intertidal Algal Flat Group

Colloquial Name: North American North Atlantic Intertidal Shore

Hierarchy Level:  Group

Type Concept: This group encompasses North American North Atlantic intertidal zones dominated by macroalgae. The substrate may be solid rock, mud, sand, and/or silt, with rock or coarse substrates generally marking the more exposed habitats that can experience extremes of exposure to winds, waves, currents, and ice-scour. Diagnostic species on rocky substrates include Chondrus crispus, Fucus vesiculosus, Fucus evanescens, Fucus spiralis, Ascophyllum nodosum, and Laminaria spp. Sandflats and mudflats are usually located in quiet pockets of bays and protected by headlands. Sand-sized particles are mixed with silt and clay. In the summer, Enteromorpha intestinalis can cover these mudflats. Other characteristic species include Enteromorpha prolifera, Ulva lactuca, Rhizoclonium riparium, Ruppia maritima, and Zostera marina. Mudflats and sandflats tend to be more sparsely vegetated than the rocky intertidal habitats.

Diagnostic Characteristics: Tidal shores and flats with algal communities exposed twice daily at low tide.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: The group is documented to range south to the Carolinas, but the description is based on sources from the northern part of the range.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: The vegetation ranges from patchy to continuous. Macroalgae are the dominant, and often the only, plants. Mudflats and sandflats may have only very sparse vegetation.

Floristics: Diagnostic species on rocky substrates include Ascophyllum nodosum, Ceramium rubrum, Chondrus crispus, Chorda filum, Fucus evanescens, Fucus spiralis, Fucus vesiculosus, Laminaria agardhii, and Punctaria latifolia. On sandflats and mudflats, Enteromorpha intestinalis, Enteromorpha prolifera, and Ulva lactuca are characteristic; Rhizoclonium riparium, Ruppia maritima, and Zostera marina may be present. Other species include Ceramium strictum, Dasya elegans, Grinnellia americana, and others (Conard 1935).

Dynamics:  Regular tidal flooding alternately exposes and inundates this vegetation; macroalgae are attached to rock surfaces with holdfasts. Wave exposure, battering by flood debris, and desiccation all have varying effects on community composition and structure. Overturning of boulders by wave action are re-colonized by vegetative regrowth or by spore dispersal (Sousa 1979). Severe ice-scouring also acts to remove vegetation from rocky shores (McCook and Chapman 1997).
Environmental Description:  Saltwater intertidal habitats on the North Atlantic shores of North America. Tidal amplitude varies with location, as does the degree of exposure to winds, waves, currents, and ice-scour. Climate: Temperate to sub-boreal oceanic.
Geographic Range: Vegetation in this group ranges from North Carolina north into Canada.

Nations: CA,US

States/Provinces:  CT, DE, LB, MA, MD, ME, NB, NC, NF, NH, NJ, NS, NY, RI, VA


Confidence Level: Moderate

Confidence Level Comments: No Data Available
Grank: GNR

Greasons: No Data Available
Type Name Database Code Classification Code
Class 5 Aquatic Vegetation Class C05 5
Subclass 5.A Saltwater Aquatic Vegetation Subclass S09 5.A
Formation 5.A.2 Benthic Macroalgae Saltwater Vegetation Formation F053 5.A.2
Division 5.A.2.Wb Temperate Intertidal Shore Division D047 5.A.2.Wb
Macrogroup 5.A.2.Wb.1 Temperate Atlantic Intertidal Shore Macrogroup M104 5.A.2.Wb.1
Group 5.A.2.Wb.1.a Yellow Tang - Sea-lettuce Intertidal Algal Flat Group G387 5.A.2.Wb.1.a
Alliance A4132 North Atlantic Intertidal Mudflat Alliance A4132 5.A.2.Wb.1.a
Alliance A4133 North Atlantic Tidal Rocky Shore Alliance A4133 5.A.2.Wb.1.a
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: < Ahnfeldtia association (Conard 1935)
< Chondrus - Ceramium rubrum association (Conard 1935)
< Fucus - Ascophyllum association (Batchelder 1926)
< Laminarietum association (Conard 1935)
= Marine Intertidal Subsystem (Brown 1993a)
Concept Author(s): B. Brown (1993a); H.S. Conard (1935)

Author of Description: S.C. Gawler and L.A. Sneddon

Acknowledgements: No Data Available

Version Date: 05-08-15
  • Batchelder, C. H. 1926. An ecological study of a brackish water stream. Ecology 7:55-71.
  • Brown, B. 1993a. A classification of marine and estuarine habitats in Maine: An ecosystem approach to habitats. Part I: Benthic habitats. First iteration. Maine Natural Areas Program, Department of Economic and Community Development, Augusta, ME. 51 pp. plus appendix.
  • Conard, H. S. 1935. The plant associations of central Long Island. The American Midland Naturalist 16:433-516.
  • 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]
  • McCook, L. J., and A. R. O. Chapman. 1997. Patterns and variations in natural succession following massive ice-scour of a rocky intertidal shore. Journal of Experimental Marine Biology and Ecology 214:121-147.
  • Olivero, A. 2006. North Atlantic Coast Ecoregion - Rocky Shore Ecosystems. GIS map and data. [http://gis.tnc.org/data/MapbookWebsite/map_page.php?map_id=273] (accessed 28 September 2008).
  • Sousa, W. P. 1979. Experimental investigations of disturbance and ecological succession in a rocky intertidal algal community. Ecological Monographs 49:227-254.