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A2070 Panicum virgatum - Andropogon gerardii Interior Gravel Riverscour Prairie Alliance
Type Concept Sentence: This alliance includes scoured riverbank "prairies" of the Interior regions of the United States, including the Interior Low Plateau, Ozarks, and Ouachitas. These may locally be called "riverside prairies," "linear prairies," "rivershore grasslands," "scoured riverine prairies," or other local names. These grasslands may be associated with dry cobble or gravel riverbanks, as well as flood-scoured, acidic or calcareous bedrock exposures associated with major rivers. Examples typically contain Andropogon gerardii, Chasmanthium latifolium, Panicum virgatum, Schizachyrium scoparium, and/or Sorghastrum nutans, any of which could be locally dominant.
Common (Translated Scientific) Name: Big Bluestem - Switchgrass Interior Gravel Riverscour Prairie Alliance
Colloquial Name: Interior Riverine Gravel Wash Prairie
Hierarchy Level: Alliance
Type Concept: This alliance includes scoured riverbank "prairies" of the Interior regions of the United States, including the Interior Low Plateau, Ozarks, and Ouachitas. These may locally be called "riverside prairies," "linear prairies," "rivershore grasslands," "scoured riverine prairies," or other local names. These grasslands may be associated with dry cobble or gravel riverbanks, as well as flood-scoured, acidic or calcareous bedrock exposures associated with major rivers. This includes riverine gravel/cobble bar "prairies" along the upper Cumberland River in Kentucky and Tennessee, as well as scour areas along high-gradient sections of major rivers, such as the Duck River of Tennessee, the Kentucky and Green rivers of Kentucky, the Glover and Kiamichi rivers of Oklahoma, and the Cossatot River of Arkansas. Examples typically contain Andropogon gerardii, Chasmanthium latifolium, Panicum virgatum, Schizachyrium scoparium, and/or Sorghastrum nutans, any of which could be locally dominant. Examples of this alliance have mixed shrub and herbaceous physiognomy and may include a few taller trees. Trees are characteristically less than 5 m tall (but scattered individuals may approach 10 m), and canopy cover characteristically ranges from 0 to 10% (but in intervals between flood events may locally approach 30%).
Diagnostic Characteristics: This alliance contains riverine riverwash and riverscour patch prairies and related vegetation from the Appalachian regions of the south-central United States.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: No Data Available
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Examples of this alliance have mixed shrub and herbaceous physiognomy and may include a few taller trees. Trees are characteristically less than 5 m tall (but scattered individuals may approach 10 m) and canopy cover characteristically ranges from 0 to 10% (but in intervals between flood events may locally approach 30%).
Floristics: Species composition is variable depending in part on size of river and width of riverbank. Stands are typically dominated by some combination of Panicum virgatum, Andropogon gerardii, and/or Sorghastrum nutans, as well as Schizachyrium scoparium and/or Chasmanthium latifolium, any of which could be locally dominant (collectively up to 40% total cover in some examples). Some associations contain Calamovilfa arcuata. Other common herbaceous species may include Baptisia sphaerocarpa, Boltonia diffusa, Coreopsis tripteris, Euphorbia corollata, Conoclinium coelestinum (= Eupatorium coelestinum), Eupatorium serotinum, Ludwigia alternifolia, Panicum rigidulum, Rhexia mariana, Silphium laciniatum, Symphyotrichum dumosum, Trachelospermum difforme, Tradescantia ohiensis, Tridens flavus, Tripsacum dactyloides, and others. Commonly occurring woody species include Acer rubrum var. trilobum, Alnus serrulata, Amorpha fruticosa, Betula nigra, Cornus obliqua (= Cornus amomum ssp. obliqua), Diospyros virginiana, Hamamelis vernalis (in the Ozarks and Ouachitas), Hypericum lobocarpum, Hypericum prolificum, Ilex decidua, Ilex vomitoria, Liquidambar styraciflua, Nyssa sylvatica, Platanus occidentalis, and others. Additional species may include Camassia scilloides, Carex crinita, Dichanthelium acuminatum var. lindheimeri, Houstonia purpurea, Juncus coriaceus, Liatris squarrosa, Mecardonia acuminata, Parthenium integrifolium, Physostegia intermedia, Rhynchospora glomerata, Trepocarpus aethusae, and Valerianella radiata. Woody plants (which may be twisted and contorted, bearing testimony to adverse abrasion properties associated with flooding) may include Betula nigra, Cephalanthus occidentalis, Cornus obliqua, Fraxinus pennsylvanica, Hypericum prolificum, Phyllanthopsis phyllanthoides (= Leptopus phyllanthoides), Salix caroliniana, and Salix nigra. Common vines include Nekemias arborea (= Ampelopsis arborea) and Bignonia capreolata, often trailing along the ground surface. This vegetation is maintained by the scouring of floods in relatively high-gradient flashy rivers. Where river size is too small, scouring is not intense enough to remove shrubs which then come to dominate the site. Where the river is too large or becomes low-gradient, the plant community shifts to riparian forest vegetation. Hydrological alteration degrades and eliminates this community.
Dynamics: This vegetation is maintained by the scouring of floods in relatively high-gradient flashy rivers. These sites receive water input from the rivers during flood events, becoming dry during rainless intervals. Where river size is too small, scouring is not intense enough to remove shrubs which then come to dominate the site. Where the river is too large or becomes low-gradient, the plant community shifts to riparian forest vegetation. Hydrological alteration degrades and eliminates this community.
Environmental Description: Stands may be found on both gravel and bedrock substrates that are scoured by spring floods. Examples occupy high-gradient sections of rivers, often in conjunction with exposed substrates composed of limestone, sandstone, siltstone and, to a lesser extent, shale that are seasonally scoured by floodwaters. Cobbles are abundant, generally mixed with sandy silt that nurtures a luxuriant suite of plants.
Geographic Range: Examples of this interior riverscour alliance are found in the central United States from Illinois and Indiana south through Tennessee (and presumably Kentucky), to Alabama, as well as in Arkansas and Oklahoma. The Alabama association is technically located in the East Gulf Coastal Plain, but this location (in Bibb County, Alabama) is actually underlain by limestones of the Ridge and Valley.
Nations: US
States/Provinces: AL, AR, IL, IN, KY, OK, TN, WV?
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.878797
Confidence Level: Low
Confidence Level Comments: No Data Available
Grank: GNR
Greasons: No Data Available
Concept Lineage: A2069 and A2070 represent a split-up and reconfiguration of parts of A.1337, A.1343, and A.1843 (MP 9-12). This alliance (A2070) has members from A.1337 (3/10) & A.1343 (1/5).
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: ? P5A4aI2a. Panicum virgatum (Foti et al. 1994)
- Campbell, Julian J. N. Personal communication. Kentucky Field Office, The Nature Conservancy.
- Evans, Marc. Personal communication. Ecologist. Kentucky Natural Heritage Program, Kentucky State Nature Preserves Commission, Frankfort.
- 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.
- Faber-Langendoen, D., and Midwest State Natural Heritage Program Ecologists. 1996. Terrestrial vegetation of the midwest United States. International classification of ecological communities: Terrestrial vegetation of the United States. The Nature Conservancy, Arlington, VA.
- Foti, T., M. Blaney, X. Li, and K. G. Smith. 1994. A classification system for the natural vegetation of Arkansas. Proceedings of the Arkansas Academy of Science 48:50-53.
- Pyne, M., and D. I. Withers. 1996. Terrestrial and subterranean natural heritage survey of TVA Columbia Project lands. DNH Report No. 96-001. Tennessee Department of Conservation, Division of Natural Heritage. Nashville.
- Smith, T. L. 1991. Natural ecological communities of Pennsylvania. First revision. Unpublished report. Pennsylvania Science Office of The Nature Conservancy, Middletown, PA. 111 pp.
- Zollner, Douglas. Personal communication. Ecologist, The Nature Conservancy, Arkansas Field Office, Little Rock.