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G494 Morella cerifera - Uniola paniculata - Schizachyrium littorale Dune & Grassland Group

Type Concept Sentence: This vegetation of sandy coastlines and barrier islands ranges along the Atlantic and Gulf coasts from North Carolina south to Texas. It includes somewhat sparse herbaceous dune vegetation, backdune shrublands and shrub-herb patchworks, non-tidal maritime grasslands, and temporarily flooded interdunal swales. Possible dominants include Uniola paniculata and Panicum amarum on the foredunes and Spartina patens and Schizachyrium littorale on the older dunes and sand flats, as well as many other species.

Common (Translated Scientific) Name: Wax-myrtle - Sea-oats - Shore Little Bluestem Dune & Grassland Group

Colloquial Name: South Atlantic & Gulf Coastal Dune & Grassland

Hierarchy Level:  Group

Type Concept: This group encompasses vegetation of sandy coastlines and barrier islands, ranging from northernmost North Carolina south along the Atlantic Coast and around the coast of the Gulf of Mexico to Texas. A range of physiognomies may be present, from somewhat sparse herbaceous dune vegetation with Uniola paniculata diagnostic, to backdune shrublands and shrub-herb patchworks, non-tidal maritime grasslands, and temporarily flooded interdunal swales. Characteristic species of the dunes include Uniola paniculata and Panicum amarum on the foredunes, and Spartina patens and Schizachyrium littorale on the older dunes and sand flats. Iva imbricata is a characteristic shrub. On the northern Gulf Coast, this group includes a number of diagnostic and endemic plant species, including Ceratiola ericoides, Chrysoma pauciflosculosa, Schizachyrium maritimum, Paronychia erecta, and Helianthemum arenicola. On the western Gulf Coast, this group includes vegetation of eolian deposits of the South Texas Sand Sheet, with ridges dominated by Schizachyrium littorale and a mixture of forbs, and swales dominated by Paspalum monostachyum, Andropogon gerardii, Muhlenbergia capillaris, and Sorghastrum nutans. Dominant ecological processes are those associated with the maritime environment, including frequent salt spray, saltwater overwash, and sand movement, that can be severe enough to limit tree growth. The environment of this group is highly dynamic. Reworking of sand by storms or by slower eolian processes may completely change the local environment in a short time, and portions of the group may occupy sites fairly early in the process of primary succession.

Diagnostic Characteristics: This is distinctive vegetation of sandy coastlines and barrier islands from North Carolina south to Texas containing or dominated by Uniola paniculata and Panicum amarum on the foredunes and Spartina patens and Schizachyrium littorale on the older dunes and sand flats.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This group shares physiognomic character and some species with the North Atlantic Coast analog ~North Atlantic Coastal Dune & Grassland Group (G493)$$, but treating the two as one group results in one that ranges from Maine to Texas with almost no species in common at the extremes. The separation of the groups parallels broad-scale biogeographic and climatic differences believed to be important in this environment, and occurs more-or-less in the southern part of the Virginian Province (as labeled by Cowardin et al. 1979) as it transitions to the Carolinian Province around Cape Hatteras. A useful vegetation indicator of this transition is the shift in herbaceous dominance on the dunes from Ammophila breviligulata in the present group to Uniola paniculata in the south. Although the location of this shift itself is somewhat imprecise because of widespread planting of both species on artificially enhanced dunes, this boundary appears to be well approximated by Omernik Ecoregion 63g vs. 63d (EPA 2004).

North Atlantic versus South Atlantic meet in central Virginia (south of the James River - the cut-off line between Chesapeake Bay and Mid-Atlantic ecoregions). This is where Uniola and Quercus virginiana start up, and Ammophila drops out. Prunus maritima drops out in Maryland, a little farther north. (L. Sneddon pers. comm. 2012, but G. Fleming suggests this may be a line of convenience, and need further review). For more information on diagnostic criteria for the range limits of this group, see information in ~Uniola paniculata - Panicum amarum Dune Grassland Alliance (A1199)$$.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: The cover and structure of this vegetation is highly variable both in space and in time. It includes herb-dominated, mixed shrub-herb, and shrub-dominated vegetation with total cover ranging from sparse to nearly complete. Shrubs may be of various heights.

Floristics: Characteristic species of the dunes include Uniola paniculata and Panicum amarum on the foredunes, and Spartina patens (= var. monogyna) and Schizachyrium littorale on the older dunes and sand flats. Iva imbricata is a characteristic shrub. On the northern Gulf Coast, this group includes a number of diagnostic and endemic plant species, including Ceratiola ericoides, Chrysoma pauciflosculosa, Schizachyrium maritimum, Paronychia erecta, and Helianthemum arenicola. On the western Gulf Coast, this group includes vegetation of eolian deposits of the South Texas Sand Sheet, with ridges dominated by Schizachyrium littorale and a mixture of forbs, and swales dominated by Paspalum monostachyum, Andropogon gerardii, Muhlenbergia capillaris, and Sorghastrum nutans. Other common herbs there include Eragrostis spp., Paspalum plicatulum, Acalypha radians, Argythamnia mercurialina var. pilosissima, Chamaecrista flexuosa var. texana, Cnidoscolus texanus, Croton argyranthemus, Dalea phleoides, Froelichia floridana, Galactia canescens, Gaura mckelveyae, Helianthemum georgianum, Monarda fruticulosa (= Monarda punctata var. fruticulosa), Phlox cuspidata, Rhynchosia americana, Stillingia sylvatica, and Thelesperma nuecense.

Dynamics:  The environment of this group is one of the most dynamic in existence for terrestrial vegetation. Reworking of sand by storms or by slower eolian processes may completely change the local environment in a short time, changing one association to another. Many of these sites are fairly early in the process of primary succession on recent surfaces. Chronic salt spray is an ongoing stress. Overwash and extreme salt spray from storms are frequent disturbances. Vegetation interacts strongly with geologic processes; the presence of grass is an important factor in the development of new dunes. Alteration of dynamic processes, such as artificial enhancement of dunes by planting or sand fencing, can have drastic effects on this vegetation, causing large areas to succeed to woody vegetation. Maritime grasslands on barrier islands and mainland areas near the coast of southern Texas, including grasslands of primary and secondary dunes, interdune swales, and barrier flats, naturally occurred as an open matrix of midgrass species within native mesquite - acacia shrublands dominated by Acacia farnesiana, Acacia rigidula, and Prosopis glandulosa but have become shrub-dominated due to a lack of fire. In many areas this vegetation has been virtually eliminated due to conversion to tame pasture, cropland, or due to lack of burning.
Environmental Description:  Soil/substrate/hydrology: These are generally upland plant communities and less commonly non-flooded dune swale wetlands. Strong salt spray is an important influence on vegetation in many parts of the range. Overwash by seawater during storms is important on sand flats not protected by continuous dunes. On dunes, present or recent sand movement is an important factor. The combination of these factors prevents the dominance of woody vegetation. Sites may be either dry or saturated by freshwater from rainfall and the local water table. Areas connected to tidal influence and areas with ponded freshwater are placed in other systems. Soils are sandy, with little organic matter and little or no horizon development. Soils may be excessively drained on the higher dunes. Soils are low in nutrient-holding capacity, but aerosol input of sea salt provides a continuous source of nutrients. There is variation in vegetation patterns and patch size with the aspect of the barrier island.
Geographic Range: This group ranges on the Atlantic Coast from northern North Carolina (around Cape Hatteras) to central Florida, becoming sporadic around southern Florida, and then along the Gulf Coast west to Texas.

Nations: MX,US

States/Provinces:  AL, FL, GA, LA, MS, MXTAM, NC, SC, TX, VA


Confidence Level: Moderate

Confidence Level Comments: No Data Available
Grank: GNR

Greasons: No Data Available
Type Name Database Code Classification Code
Class 2 Shrub & Herb Vegetation Class C02 2
Subclass 2.B Temperate & Boreal Grassland & Shrubland Subclass S18 2.B
Formation 2.B.4 Temperate to Polar Scrub & Herb Coastal Vegetation Formation F005 2.B.4
Division 2.B.4.Na Eastern North American Coastal Scrub & Herb Vegetation Division D026 2.B.4.Na
Macrogroup 2.B.4.Na.2 American Beachgrass - Sea-oats - Seaside Goldenrod Dune & Grassland Macrogroup M057 2.B.4.Na.2
Group 2.B.4.Na.2.a Wax-myrtle - Sea-oats - Shore Little Bluestem Dune & Grassland Group G494 2.B.4.Na.2.a
Alliance A1029 Sweet Acacia - Spiny Florida Prickly-pear - Gulf Coast Wolfberry Dune Scrub Alliance A1029 2.B.4.Na.2.a
Alliance A1061 Woody-goldenrod - Gulf Bluestem Dune Scrub Alliance A1061 2.B.4.Na.2.a
Alliance A1199 Sea-oats - Bitter Panicgrass Dune Grassland Alliance A1199 2.B.4.Na.2.a
Alliance A1200 Shore Little Bluestem - Gulfdune Crowngrass - Bitter Panicgrass Texas Coastal Grassland Alliance A1200 2.B.4.Na.2.a
Alliance A1222 Gulf Bluestem - Camphorweed Dune Grassland Alliance A1222 2.B.4.Na.2.a
Alliance A3687 Chalky Bluestem - Bluejoint Panicgrass - Wright''s Rosette Grass Wet Grassland Alliance A3687 2.B.4.Na.2.a
Alliance A3688 Southern Hairgrass - Saltmeadow Cordgrass Dune Grassland Alliance A3688 2.B.4.Na.2.a
Alliance A3689 Sand Live Oak - Myrtle Oak Dune Shrubland Alliance A3689 2.B.4.Na.2.a
Alliance A3690 Live Oak - Yaupon - Wax-myrtle Shrubland Alliance A3690 2.B.4.Na.2.a
Alliance A3693 Sea-oats - Southern Hairgrass - Coughbush Subtropical Dune Grassland Alliance A3693 2.B.4.Na.2.a
Alliance A4061 Gulf Cordgrass - Little Bluestem - Bracted Blazingstar Saline Coastal Prairie Alliance A4061 2.B.4.Na.2.a
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: >< Beach Dune (FNAI 1990)
>< Coastal Grassland (FNAI 1990)
Concept Author(s): H.J. Oosting and W.D. Billings (1942)

Author of Description: S.C. Gawler

Acknowledgements: Sean Basquill

Version Date: 05-05-15
  • 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.
  • EPA [Environmental Protection Agency]. 2004. Level III and IV Ecoregions of EPA Region 4. U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Western Ecology Division, Corvallis, OR. Scale 1:2,000,000.
  • FNAI [Florida Natural Areas Inventory]. 1990. Guide to the natural communities of Florida. Florida Natural Areas Inventory and Florida Department of Natural Resources, Tallahassee. 111 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]
  • Judd, F. W., R. I. Lonard, and S. L. Sides. 1977. The vegetation of South Padre Island in relation to topography. Southwest Naturalist 22(1):31-48.
  • Oosting, H. J., and W. D. Billings. 1942. Factors affecting vegetational zonation on coastal dunes. Ecology 23:131-142.
  • Pinson, Jr., J. N. 1973. A floristic analysis of open dunes in South Carolina. Ph.D. dissertation, University of South Carolina, Columbia. 82 pp.
  • Stalter, R. 1974. Vegetation in coastal dunes of South Carolina. Castanea 39:95-103.
  • van der Valk, A. G. 1975b. The floristic composition and structure of foredune plant communities of Cape Hatteras National Seashore. Chesapeake Science 16:115-126.