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CEGL003891 Alnus viridis ssp. crispa / Carex pensylvanica Shrubland
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: Mountain Alder / Pennsylvania Sedge Shrubland
Colloquial Name: Southern Appalachian Alder Grassy Bald
Hierarchy Level: Association
Type Concept: This mainly deciduous shrubland occurs at the highest elevations, greater than 1750 m (5800 feet) in the southern Appalachian Mountains on summit ridges of the Roan Mountain massif. It is dominated by Alnus viridis ssp. crispa, typically 1.5-2 m in height, rarely producing a closed canopy but typically occurring as uniformly spaced clumps about 1 m apart. Rubus allegheniensis is often a codominant with Alnus viridis ssp. crispa. Other shrub species occur with low coverage and include Rhododendron catawbiense, Vaccinium corymbosum, and Crataegus spp. Openings in the shrub canopy are dominated by herbs, mainly Carex pensylvanica and Carex debilis var. rudgei but also may include Danthonia compressa, Deschampsia flexuosa, Viola blanda, Rumex acetosella (exotic), and Athyrium filix-femina ssp. asplenioides. In moister areas, bryophyte cover can be up to 75%, with Polytrichum commune typical. This community can grade into or occur adjacent to high-elevation rock outcrop communities, montane grass-dominated communities, high-elevation herbaceous seeps, or forests dominated by stunted Fagus grandifolia. It may expand into montane grass-dominated communities and may eventually succeed to ~Rhododendron catawbiense Shrubland (CEGL003818)$$.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: Other communities dominated by Alnus viridis ssp. crispa may occur in the western and northeastern United States as well as in Canada. This community occurs as disconnected patches on summit ridges, interrupted by grass-dominated vegetation such as ~Danthonia compressa - (Sibbaldiopsis tridentata) Grassland (CEGL004242)$$ or ~Carex pensylvanica Grassland (CEGL004094)$$. Additionally, this community can grade into or occur adjacent to high-elevation rock outcrop communities, high-elevation herbaceous seeps, or forests dominated by stunted Fagus grandifolia.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available
Floristics: These montane, mainly deciduous shrublands are dominated by Alnus viridis typically 1.5-2 m in height, rarely producing a closed canopy but typically occurring as uniformly spaced clumps about 1 m apart. Rubus allegheniensis is often a codominant with Alnus viridis ssp. crispa. Other shrub species occur with low coverage and include Rhododendron catawbiense, Vaccinium corymbosum, and Crataegus spp. Openings in the shrub canopy are dominated by herbs, mainly Carex pensylvanica and Carex debilis var. rudgei but also may include Athyrium filix-femina ssp. asplenioides, Danthonia compressa, Deschampsia flexuosa, Viola blanda, Rumex acetosella (exotic). In moister areas, bryophyte cover can be up to 75%, with Polytrichum commune typical.
Dynamics: This community may be damaged by lightning-caused fire or defoliating insects (Brown 1941). It is unclear if Alnus viridis ssp. crispa is able to expand into adjacent grassy balds or not. This shrubland may experience invasion by Rhododendron catawbiense, Abies fraseri, and Picea rubens and may succeed to vegetation dominated by these species.
Environmental Description: This community occurs on ridges and exposed slopes at elevations of 1770-1800 m (5800-5900 feet). Slope gradients range from 8-15°. Extreme cold, high precipitation, frequent fog, and desiccating winds in combination with the shallow, nutrient-poor soils are the key environmental factors influencing this community. This community occurs as disconnected patches on summit ridges, interrupted by grass-dominated vegetation. It can grade into or occur adjacent to high-elevation rock outcrop communities, montane grass-dominated communities, high-elevation herbaceous seeps, or forests dominated by stunted Fagus grandifolia. It often invades montane grass-dominated communities and may eventually succeed to ~Rhododendron catawbiense Shrubland (CEGL003818)$$.
Geographic Range: This community occurs only in the Roan Mountain massif of the Southern Blue Ridge of North Carolina and Tennessee.
Nations: US
States/Provinces: NC, TN
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.684436
Confidence Level: Low
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.B Temperate & Boreal Grassland & Shrubland Subclass | S18 | 2.B |
| Formation | 2.B.2 Temperate Grassland & Shrubland Formation | F012 | 2.B.2 |
| Division | 2.B.2.Nc Eastern North American Grassland & Shrubland Division | D024 | 2.B.2.Nc |
| Macrogroup | 2.B.2.Nc.1 Catawba Rosebay / Michaux''s Saxifrage - Flattened Oatgrass Felsic & Mafic Scrub & Grassland Macrogroup | M506 | 2.B.2.Nc.1 |
| Group | 2.B.2.Nc.1.b Pennsylvania Sedge - Flattened Oatgrass - Shrubby Fivefingers Southern Appalachian Grass Bald Group | G657 | 2.B.2.Nc.1.b |
| Alliance | A2026 Pennsylvania Sedge - Flattened Oatgrass - Blue Ridge St. John''s-wort Grass Bald Alliance | A2026 | 2.B.2.Nc.1.b |
| Association | CEGL003891 Mountain Alder / Pennsylvania Sedge Shrubland | CEGL003891 | 2.B.2.Nc.1.b |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: < IC4a. Heath Bald Shrubland (Allard 1990)
- Allard, D. J. 1990. Southeastern United States ecological community classification. Interim report, Version 1.2. The Nature Conservancy, Southeast Regional Office, Chapel Hill, NC. 96 pp.
- Anderson, L. E., H. A. Crum, and W. R. Buck. 1990. List of mosses of North America north of Mexico. The Bryologist 93:448-499.
- Brown, D. M. 1941. Vegetation of Roan Mountain: A phytosociological and successional study. Ecological Monographs 11:61-97.
- Schafale, M. P. 2012. Classification of the natural communities of North Carolina, 4th Approximation. North Carolina Department of Environment, Health, and Natural Resources, Division of Parks and Recreation, Natural Heritage Program, Raleigh.
- Schafale, M. P., and A. S. Weakley. 1990. Classification of the natural communities of North Carolina. Third approximation. North Carolina Department of Environment, Health, and Natural Resources, Division of Parks and Recreation, Natural Heritage Program, Raleigh. 325 pp.
- Southeastern Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Durham, NC.