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A3994 Appalachian Mafic - Circumneutral Cliff Alliance

Type Concept Sentence: This alliance is made up of sparse or patchy vegetation of mafic or circumneutral rock cliffs in which Physocarpus opulifolius or Rhus aromatica are usually present, but species composition and structure is highly variable among sites. It occurs in the Piedmont, Interior Low Plateau, and Southern Blue Ridge.


Common (Translated Scientific) Name: Appalachian Mafic - Circumneutral Cliff Alliance

Colloquial Name: Appalachian Mafic - Circumneutral Cliff

Hierarchy Level:  Alliance

Type Concept: This alliance is made up of sparse or patchy vegetation of mafic or circumneutral rock cliffs in which Physocarpus opulifolius or Rhus aromatica are usually present, but species composition and structure are highly variable among sites. On calcareous substrates, stands are characterized by Rhus aromatica and Celtis tenuifolia, with Carex eburnea as a characteristic herb; Quercus muehlenbergii is often present as a tall shrub or tree. Other shrubs which may be present include Frangula caroliniana, Paxistima canbyi, Philadelphus hirsutus, Physocarpus opulifolius, Ptelea trifoliata, Viburnum prunifolium, and Zanthoxylum americanum. Rhus aromatica and Physocarpus opulifolius also occur on mafic cliffs, along with some basophilic species such as Aquilegia canadensis, Arabis spp., Sanguinaria canadensis, and others. Schizachyrium scoparium and Asplenium spp. occur with some frequency, but species composition is highly variable in this alliance, supporting flora that is a mix of drought-tolerant, shade-intolerant species such as Campanula divaricata, Cheilanthes lanosa, Cheilanthes tomentosa, Danthonia spicata, Hieracium venosum, Opuntia humifusa, Packera plattensis, Phlox subulata ssp. subulata, Pleopeltis polypodioides, Tephrosia virginiana, Tradescantia subaspera, Tsuga caroliniana, and others. This alliance occurs in the Piedmont, Interior Low Plateau, and Southern Blue Ridge on steep to vertical outcrops of mafic igneous or metamorphic rocks, including gabbro, amphibolite, greenstone, basalt, and sometimes andesite and diorite.

Diagnostic Characteristics: Calcareous or mafic cliff of the Piedmont, Interior Low Plateau, or Southern Blue Ridge, characterized by sparse or patchy Rhus aromatica, Physocarpus opulifolius, and dry-site herbs.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This alliance requires further data; it is defined largely by geography and rock chemistry. ~Piedmont Mafic Cliff Sparse Vegetation (CEGL003982)$$ may reach greater than 25% vascular cover, and may be re-evaluated for placement elsewhere.

Similar NVC Types: No Data Available
note: No Data Available

Physiognomy and Structure: This vegetation is variable in structure, ranging from patches of sparse woodland with low trees, to patchy herbaceous vegetation, to sparse vascular and/or nonvascular vegetation confined to cracks and crevices.

Floristics: On calcareous substrates, stands are characterized by Rhus aromatica and Celtis tenuifolia, with Carex eburnea as a characteristic herb; Quercus muehlenbergii is often present tall shrub or tree. Other shrubs which may be present include Frangula caroliniana, Paxistima canbyi, Philadelphus hirsutus, Physocarpus opulifolius, Ptelea trifoliata, Viburnum prunifolium, and Zanthoxylum americanum. Rhus aromatica and Physocarpus opulifolius also occur on mafic cliffs, along with some basophilic species such as Aquilegia canadensis, Arabis spp., Sanguinaria canadensis, and others. Schizachyrium scoparium and Asplenium spp. occur with some frequency, but species composition is highly variable in this alliance, supporting flora that is a mix of drought-tolerant, shade-intolerant species such as Campanula divaricata, Cheilanthes lanosa, Cheilanthes tomentosa, Danthonia spicata, Hieracium venosum, Opuntia humifusa, Packera plattensis (= Senecio plattensis), Phlox subulata ssp. subulata, Pleopeltis polypodioides (= Polypodium polypodioides), Tephrosia virginiana, Tradescantia subaspera, Tsuga caroliniana, and others.

Dynamics:  No Data Available

Environmental Description:  This alliance occurs on vertical or near-vertical exposures of mafic or ultramafic rocks, such as amphibolite, hornblende gneiss, and others, as well as calcareous substrates. Surfaces are usually steep to nearly vertical, with little soil accumulation that is largely restricted to cracks and crevices.

Geographic Range: This alliance occurs in the Piedmont, Interior Low Plateau, and Southern Blue Ridge of the southeastern U.S.

Nations: US

States/Provinces:  AL?, GA, KY, NC, SC, TN, VA?




Confidence Level: Low

Confidence Level Comments: No Data Available

Grank: GNR

Greasons: No Data Available


Concept Lineage: One association each from A.1049, A.1836, A.1837

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available

Synonomy: No Data Available

Concept Author(s): L. Sneddon, in Faber-Langendoen et al. (2013)

Author of Description: L. Sneddon

Acknowledgements: No Data Available

Version Date: 12-18-14

  • Faber-Langendoen, D., J. Drake, M. Hall, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, M. Russo, K. Schulz, L. Sneddon, K. Snow, and J. Teague. 2013-2019b. Screening alliances for induction into the U.S. National Vegetation Classification: Part 1 - Alliance concept review. NatureServe, Arlington, VA.
  • 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.