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CEGL006491 (Hypericum prolificum, Eubotrys racemosa) / Schizachyrium scoparium - Solidago simplex var. racemosa - Ionactis linariifolius Riverscour Sparse Vegetation
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: (Shrubby St. John''s-wort, Swamp Doghobble) / Little Bluestem - Sticky Goldenrod - Flaxleaf Whitetop Aster Riverscour Sparse Vegetation
Colloquial Name: Potomac Gorge Riverside Outcrop Barrens
Hierarchy Level: Association
Type Concept: This sparse outcrop vegetation of the Potomac Gorge in Virginia and Maryland occurs on metasedimentary and intrusive igneous rock exposures that are catastrophically flood-scoured. The habitat is variable, with small pools interspersed among shaded microhabitats and exposed xeric microhabitats. The vascular vegetation generally covers <5% of a given area and consists of scattered herbs and dwarfed shrubs. The most characteristic species are Schizachyrium scoparium, Solidago simplex var. racemosa, Dichanthelium acuminatum var. acuminatum, Ionactis linariifolius, and the shrubs Eubotrys racemosa and Hypericum prolificum. Other minor, inconstant species include Andropogon gerardii, Gaylussacia baccata, Juncus dichotomus, Phlox subulata, Veronicastrum virginicum, Hypericum gentianoides, Amelanchier nantucketensis, and Sporobolus clandestinus. Small pools and potholes support inclusions of wetland species, including Ludwigia alternifolia, Scirpus cyperinus, Cephalanthus occidentalis, and Ludwigia palustris. Lichens, especially Xanthoparmelia conspersa, have very high cover on the rock surfaces. The bryophyte Grimmia laevigata is also important in areas with ephemeral seepage or surface water. This association is apparently endemic to the Potomac Gorge.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: Classification of this type is supported by analysis of a 1250-plot regional dataset assembled for the NCR parks vegetation mapping project. This association is represented by 17 Maryland and Virginia plots from the Potomac Gorge.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available
Floristics: The vascular vegetation generally covers <5% of a given area and consists of scattered herbs and dwarfed shrubs. The most characteristic species are Schizachyrium scoparium, Solidago simplex var. racemosa (= Solidago racemosa), Dichanthelium acuminatum var. acuminatum, Ionactis linariifolius, and the shrubs Eubotrys racemosa (= Leucothoe racemosa) and Hypericum prolificum. Other minor, inconstant species include Andropogon gerardii, Gaylussacia baccata, Juncus dichotomus, Phlox subulata, Veronicastrum virginicum, Euphorbia corollata, Hypericum gentianoides, Amelanchier nantucketensis, and Sporobolus clandestinus. Small pools and potholes support inclusions of wetland species, including Ludwigia alternifolia, Scirpus cyperinus, Cephalanthus occidentalis, and Ludwigia palustris. Lichens, especially Xanthoparmelia conspersa, have very high cover on the rock surfaces. The bryophyte Grimmia laevigata is also important in areas with ephemeral seepage or surface water. Mean species richness of 17 plot-sampled stands was 23 taxa per 100 m2 (range 12 to 36 taxa).
Dynamics: The community is patchy, occurring in narrow, discontinuous strips bordering the river in a roughly 2 mile long river corridor.
Environmental Description: This sparse outcrop vegetation occurs on metasedimentary and intrusive igneous rock exposures that are catastrophically flood-scoured. Most of the global range is on exposed cliffs, ledges, and crags of the massive bedrock terraces that flank Great Falls and Mather Gorge for several miles below the falls. A few patches occur on exposed shoreline outcrops downstream of Mather Gorge. The habitat is variable, with small pools interspersed among shaded microhabitats and exposed xeric microhabitats. No extractable mineral soil is present in this environment, and plants are rooted in crevices, gravel and organic deposits, and bryophyte mats. According to Lea (2000, 2004), the mean flood-return interval varies from less than one year to about 10 years, and the substrate is violently scoured by larger floods.
Geographic Range: This community is endemic to a 15-km stretch of the Potomac River valley in Maryland and Virginia.
Nations: US
States/Provinces: MD, VA
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.802098
Confidence Level: Moderate
Confidence Level Comments: No Data Available
Grank: G2
Greasons: No Data Available
| Type | Name | Database Code | Classification Code |
|---|---|---|---|
| Class | 2 Shrub & Herb Vegetation Class | C02 | 2 |
| Subclass | 2.C Shrub & Herb Wetland Subclass | S44 | 2.C |
| Formation | 2.C.4 Temperate to Polar Freshwater Marsh, Wet Meadow & Shrubland Formation | F013 | 2.C.4 |
| Division | 2.C.4.Nd Eastern North American Temperate Freshwater Marsh, Wet Meadow & Shrubland Division | D323 | 2.C.4.Nd |
| Macrogroup | 2.C.4.Nd.4 Eastern North American Riverscour Vegetation Macrogroup | M881 | 2.C.4.Nd.4 |
| Group | 2.C.4.Nd.4.a Central Interior-Appalachian Riverscour Barrens & Prairie Group | G753 | 2.C.4.Nd.4.a |
| Alliance | A2069 Big Bluestem - Indiangrass Appalachian Gravel Riverscour Alliance | A2069 | 2.C.4.Nd.4.a |
| Association | CEGL006491 (Shrubby St. John''s-wort, Swamp Doghobble) / Little Bluestem - Sticky Goldenrod - Flaxleaf Whitetop Aster Riverscour Sparse Vegetation | CEGL006491 | 2.C.4.Nd.4.a |
Concept Lineage: Concept change when type was moved to sparsely vegetated alliance.
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: = (Hypericum prolificum, Leucothoe racemosa) / Schizachyrium scoparium - Solidago racemosa - Ionactis linariifolius Herbaceous Vegetation (Fleming et al. 2007b)
= Leucothoe racemosa / Schizachyrium scoparium - Solidago racemosa - Ionactis linariifolius Herbaceous Vegetation (Fleming and Patterson 2003)
= Leucothoe racemosa / Schizachyrium scoparium - Solidago racemosa - Ionactis linariifolius Herbaceous Vegetation (Fleming and Patterson 2003)
- Eastern Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boston, MA.
- Fleming, G. P. 2007. Ecological communities of the Potomac Gorge in Virginia: Composition, floristics, and environmental dynamics. Natural Heritage Technical Report 07-12. Unpublished report submitted to the National Park Service. Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond. 341 pp. plus appendices.
- Fleming, G. P., K. D. Patterson, and K. Taverna. 2017. The natural communities of Virginia: A classification of ecological community groups and community types. Third approximation. Version 3.0. Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond, VA. [http://www.dcr.virginia.gov/natural-heritage/natural-communities/]
- Fleming, G. P., K. Taverna, and P. P. Coulling. 2007b. Vegetation classification for the National Capitol Region parks, eastern region. Regional (VA-MD-DC) analysis prepared for NatureServe and USGS-NPS Vegetation Mapping Program, March 2007. Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond.
- Fleming, G. P., and K. D. Patterson. 2003. Preliminary vegetation classification for the National Capitol Region parks. Regional (VA-WVA-MD-DC) analysis prepared for NatureServe and USGS-NPS Vegetation Mapping Program, March 2003. Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond.
- Fleming, Gary P. Personal communication. Ecologist, Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond, VA.
- Grossman, D. H., K. Lemon Goodin, and C. L. Reuss, editors. 1994. Rare plant communities of the conterminous United States: An initial survey. The Nature Conservancy. Arlington, VA. 620 pp.
- Harrison, J. W. 2011. The natural communities of Maryland: 2011 working list of ecological community groups and community types. Unpublished report. Maryland Department of Natural Resources, Wildlife and Heritage Service, Natural Heritage Program, Annapolis. 33 pp.
- Harrison, J. W., and P. Stango, III. 2003. Shrubland tidal wetland communities of Maryland''s Eastern Shore: Identification, assessment and monitoring. Maryland Natural Heritage Program, Maryland Department of Natural Resources, Annapolis. 118 pp.
- Harrison, J. W., compiler. 2004. Classification of vegetation communities of Maryland: First iteration. A subset of the International Classification of Ecological Communities: Terrestrial Vegetation of the United States, NatureServe. Maryland Natural Heritage Program, Maryland Department of Natural Resources, Annapolis. 243 pp.
- Lea, C. 2000. Plant communities of the Potomac Gorge and their relationship to fluvial factors. M.S. thesis, George Mason University. Fairfax, VA. 219 pp.
- Southworth, S., and D. Denenny. 2006. Geologic map of the national parks in the National Capital Region, Washington, D.C., Virginia, Maryland, and West Virginia: U.S. Geological Survey Open-File Report 2005-1331. [http://pubs.usgs.gov/of/2005/1331/]