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CEGL006484 Carpinus caroliniana - Ilex decidua Wet Shrubland
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: American Hornbeam - Possum-haw Wet Shrubland
Colloquial Name: Piedmont Riverscour Shrubland
Hierarchy Level: Association
Type Concept: This association has been documented only in the eastern Piedmont region of Maryland and Virginia, where it is restricted to high-gradient stretches of the Potomac and Rappahannock rivers. It occupies protected areas (eroding draws, ravines, downstream sides of large outcrops) on the flanks of rocky bluffs and bedrock terraces that are periodically scoured by powerful floods, and occasionally occurs on sand- and boulder-covered flats on the active channel shelf. The vegetation is characterized by partially open to dense thickets of shrubs and shrubby trees generally less than 6 m tall. The species richness of the woody layers is high. Carpinus caroliniana and Ilex decidua are both present and usually codominant. Fraxinus pennsylvanica, Fraxinus americana, Robinia pseudoacacia, Diospyros virginiana, Viburnum prunifolium, Hypericum prolificum, Quercus rubra, and Nyssa sylvatica are also frequent. Less constant shrubs and small trees that occasionally achieve moderate cover include Ilex verticillata, Ostrya virginiana, Physocarpus opulifolius, and Viburnum dentatum. Vines are common, with Campsis radicans, Toxicodendron radicans, and/or Parthenocissus quinquefolia often present. The herbaceous layer is species-rich and variable, with a more diverse assemblage of species present at low cover where soils are shallow over rocks, and dominance by a more limited number of species, particularly Chasmanthium latifolium, Dichanthelium clandestinum, Elymus virginicus, and Cerastium arvense, where soils are deep. Lonicera japonica, as well as the exotic herbs Saponaria officinalis and Lespedeza cuneata, can be invasive.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: Classification of this type is based partly on analysis of data from seven plot samples collected along the Potomac (5 plots) and Rappahannock (2 plots) rivers. Composition of this group of plots is quite heterogeneous but strongly united by similar habitats, comparable physiognomy, and a suite of 26 species (mostly woody) with >70% constancy. Although associated with very specialized habitats and potentially very rare, the fact that this vegetation has been documented from two different mid-Atlantic river systems argues for recognition as an USNVC association.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available
Floristics: The type is characterized by partially open to dense thickets of shrubs and shrubby trees generally less than 6 m tall. The species richness of the woody layers is high. Carpinus caroliniana and Ilex decidua are both present and usually codominant. Fraxinus pennsylvanica, Fraxinus americana, Robinia pseudoacacia, Diospyros virginiana, Viburnum prunifolium, Hypericum prolificum, Quercus rubra, and Nyssa sylvatica are also frequent. Less constant shrubs and small trees that occasionally achieve moderate cover include Ilex verticillata, Ostrya virginiana, Physocarpus opulifolius, and Viburnum dentatum. Vines are common, with Campsis radicans, Toxicodendron radicans, and/or Parthenocissus quinquefolia often present. The herbaceous layer is species-rich and variable, with a more diverse assemblage of species present at low cover where soils are shallow over rocks, and dominance by a more limited number of species, particularly Chasmanthium latifolium, Dichanthelium clandestinum, Elymus virginicus, and Cerastium arvense, where soils are deep. Lonicera japonica, as well as the exotic herbs Saponaria officinalis and Lespedeza cuneata, can be invasive.
Dynamics: No Data Available
Environmental Description: The community occupies protected areas (eroding draws, ravines, downstream sides of large outcrops) in the bedrock-controlled channel of Potomac River in Mather Gorge (reach about 5 km immediately below Great Falls on the Maryland side), where shallow to deep coarse sands are deposited during large floods. Traces of this vegetation were observed along a somewhat lower gradient (but also bedrock-controlled) reach just downstream from Violette''s Lock, about 11 km upstream from Great Falls. Some occurrences are located in infrequently flooded, rocky drainage channels that are moist enough and protected enough to allow woody vegetation to persist, but that experience tree-damaging flood debris regularly enough to produce thicket-like growths of shrubs and trees. A single stand documented on the Virginia side of Mather Gorge occupies a linear ecotonal area at the foot of a massive bluff, on periodically scoured outcrops between the river and the forested slope above. Stands along the Rappahannock River in Fauquier and Culpeper counties, Virginia, occur on a bouldery slope with some diabase outcrops at the foot of a bluff bordering the river, as well as on sand- and boulder-covered flats on the active channel shelf. Flooding regime is temporarily flooded, with a probable mean return interval of from 1 to 15 years. Sites can be seasonally somewhat dry.
Geographic Range: This association has been documented only in the eastern Piedmont region of Maryland and Virginia, where it is restricted to high-gradient stretches of the Potomac and Rappahannock rivers.
Nations: US
States/Provinces: MD, VA
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.802033
Confidence Level: Moderate
Confidence Level Comments: No Data Available
Grank: G1?
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.3 Eastern North American Wet Shoreline Vegetation Macrogroup | M880 | 2.C.4.Nd.3 |
| Group | 2.C.4.Nd.3.a Eastern North American Riverine Wetland Vegetation Group | G755 | 2.C.4.Nd.3.a |
| Alliance | A0948 Black Willow Sand-Gravel Floodplain Scrub Alliance | A0948 | 2.C.4.Nd.3.a |
| Association | CEGL006484 American Hornbeam - Possum-haw Wet Shrubland | CEGL006484 | 2.C.4.Nd.3.a |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: = Carpinus caroliniana - Ilex decidua - Fraxinus pennsylvanica Shrubland (Lea 2000)
= Carpinus caroliniana - Ilex decidua Shrubland (Fleming and Taverna 2006)
= Carpinus caroliniana - Ilex decidua Shrubland (Fleming and Taverna 2006)
- 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., and K. Taverna. 2006. Vegetation classification for the National Capitol Region parks, western region. Regional (VA-WVA-MD-DC) analysis prepared for NatureServe and USGS-NPS Vegetation Mapping Program, March 2006. Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond.
- 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., 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.
- Lea, C. 2004. Draft vegetation types in National Capital Region Parks. Edited by S.C. Gawler and J. Teague. Working draft for review by NatureServe, Virginia Natural Heritage, West Virginia Natural Heritage, Maryland Natural Heritage, and National Park Service. July 2004. 157 pp.