Print Report
A1384 Rhynchospora spp. - Panicum rigidulum - Panicum verrucosum Pondshore Marsh Alliance
Type Concept Sentence: These herbaceous graminoid depression ponds are dominated by Panicum rigidulum, Panicum verrucosum, Rhexia virginica, Rhynchospora spp., and Saccharum giganteum, occurring on the Atlantic Coastal Plain from Nova Scotia south to Virginia, and disjunct in the Great Lakes area, the Great Valley of Virginia, northern Alabama, and central Tennessee.
Common (Translated Scientific) Name: Beaksedge species - Redtop Panicgrass - Warty Panicgrass Pondshore Marsh Alliance
Colloquial Name: Northern Coastal Beaksedge - Panicgrass Sandplain Pondshore Marsh
Hierarchy Level: Alliance
Type Concept: This alliance accommodates a variety of seasonally flooded vegetation of pondshore and lakeshore environments. Occurrences of this alliance are usually small and dominated by herbaceous graminoid species such as Panicum rigidulum, Panicum verrucosum, Rhexia virginica, Rhynchospora spp., and Saccharum giganteum. Many other graminoid species are common in these depressions. Some associations may include a zone dominated by taller graminoids, including Saccharum spp. or Scirpus cyperinus. Many species are annual or short-lived perennial plants. They persist for years in the seedbank until the hydrologic conditions are right for germination. Thus, species composition of particular stands may change from year to year. In interior stations of this alliance, many of these seedbank plants are species significantly disjunct from their main range on the Atlantic Coastal Plain. There are two major vegetation zones that occur in this environment: Zone 1 is a seasonally flooded zone of sparse cover by graminoids; and Zone 2 is a saturated zone of dense graminoid cover. These ponds have a pronounced seasonal fluctuation in water level, filling in the winter and drying in the summer. The water table fluctuates seasonally and yearly. It is highest in late winter and spring, and during years of high precipitation. The soils are derived mainly from sand, which is poor in nutrients and is acidic, with pH ranging from 4.4-7.0. These conditions inhibit microbial decomposition and considerable organic material accumulates as peat. This alliance occurs primarily along the Atlantic Coastal Plain from Nova Scotia, Canada, south to Virginia, with inland stations in the central Great Lakes area, the Great Valley of Virginia, northern Alabama, and central Tennessee.
Diagnostic Characteristics: Herbaceous graminoid ponds; most associations occur in the Northern Coastal Plain. Dominant species may include Panicum rigidulum, Panicum verrucosum, Rhexia virginica, Rhynchospora spp., and Saccharum giganteum.
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: Vegetation is dominated by graminoid herbs; some forbs and shrubs are present but sparse.
Floristics: Occurrences of this alliance are usually small depressions dominated by herbaceous graminoid species such as Panicum rigidulum, Panicum verrucosum, Rhexia virginica, Rhynchospora spp., and Saccharum giganteum. Many species are annuals which persist for years in the seedbank until the hydrologic conditions are right for germination. Thus, species composition may change through the seasons or from year to year. In the Great Lakes region, many of these seedbank plants are species disjunct from their main range on the Atlantic Coastal Plain (Brodowicz 1989, Keddy and Sharp 1989). There are two major vegetation zones that occur in this environment: Zone 1 is a seasonally flooded zone of sparse cover by graminoid herbs; Zone 2 is a saturated zone of dense graminoid herb cover. Some associations may include a zone dominated by taller graminoids, including Saccharum spp. or Scirpus cyperinus. These zones remain largely intact, but a succession of wet or dry years can cause them to shift slightly up or down slope. Abundant species in this alliance include the graminoid herbs Calamagrostis canadensis, Carex spp., Carex scoparia, Cladium mariscoides, Eleocharis melanocarpa, Fimbristylis autumnalis, Juncus spp., Rhynchospora capitellata, Rhynchospora scirpoides (= Psilocarya scirpoides), and Schoenoplectiella hallii (= Scirpus hallii), and the forb Rhexia virginica. Other species that may occur are the graminoid herbs Dulichium arundinaceum, Eleocharis melanocarpa, Eleocharis obtusa, Eleocharis palustris (= Eleocharis smallii), Fimbristylis autumnalis, Fuirena squarrosa, Juncus effusus, Juncus spp., Rhynchospora macrostachya, Scirpus cyperinus, and Xyris difformis, and the forbs Agalinis purpurea, Eupatorium perfoliatum, Euthamia caroliniana (= Euthamia tenuifolia), Hypericum boreale, Rotala ramosior, Stachys hyssopifolia, Triadenum virginicum, and Viola lanceolata, and the shrubs Spiraea alba, and Spiraea tomentosa.
Central Tennessee examples contain patches of the graminoid herbs Andropogon virginicus, Calamagrostis coarctata, and Saccharum baldwinii, with a more-or-less distinct zone of mixed graminoids such as Carex bullata, Dichanthelium dichotomum, Juncus acuminatus, Juncus dichotomus, Juncus effusus, Juncus marginatus, Juncus scirpoides, Panicum rigidulum var. rigidulum, Panicum verrucosum, Rhynchospora capitellata, Rhynchospora glomerata, and Xyris torta. Also present are the forbs Lobelia canbyi, Ludwigia linearis, and Rhexia mariana. The mosses Polytrichum commune and Sphagnum spp. may also be present.
The northern Alabama example contains Carex glaucescens, Dichanthelium dichotomum, Eleocharis acicularis, Panicum verrucosum, and Sphagnum sp., with Liquidambar styraciflua (ALNHP unpubl. data 2017).
Central Tennessee examples contain patches of the graminoid herbs Andropogon virginicus, Calamagrostis coarctata, and Saccharum baldwinii, with a more-or-less distinct zone of mixed graminoids such as Carex bullata, Dichanthelium dichotomum, Juncus acuminatus, Juncus dichotomus, Juncus effusus, Juncus marginatus, Juncus scirpoides, Panicum rigidulum var. rigidulum, Panicum verrucosum, Rhynchospora capitellata, Rhynchospora glomerata, and Xyris torta. Also present are the forbs Lobelia canbyi, Ludwigia linearis, and Rhexia mariana. The mosses Polytrichum commune and Sphagnum spp. may also be present.
The northern Alabama example contains Carex glaucescens, Dichanthelium dichotomum, Eleocharis acicularis, Panicum verrucosum, and Sphagnum sp., with Liquidambar styraciflua (ALNHP unpubl. data 2017).
Dynamics: These depression wetlands occur in shallow basins with no outlets and sometimes no inlets. The water table fluctuates seasonally and yearly. It is highest in late winter and spring, and during years of high precipitation. The soils are derived mainly from sand. The sand is poor in nutrients and is acidic, with pH ranging from 4.4-7.0. These conditions inhibit microbial decomposition and considerable organic material accumulates as peat. The peat mixes with sand or forms more-or-less pure deposits. In some basins, an impermeable layer of clay develops 2-5 m below the surface. This layer may hold the local water table above the regional water table for long periods.
In central Tennessee (Interior Low Plateau; southeastern Highland Rim), vegetation of this alliance is found in depression ponds which have a pronounced seasonal fluctuation in water level, filling in the winter and often drying completely in the summer (Russo 1997). In these upland depressions, water is ponded by an impermeable substrate (e.g., Guthrie silt loam soils with fragipans, also Holston loam). The variation in amount and duration of flooding may promote herb dominance while restricting the number of trees and shrubs that can survive. In the past, fire may have been another natural disturbance favoring graminoid herbs rather than trees and shrubs.
In central Tennessee (Interior Low Plateau; southeastern Highland Rim), vegetation of this alliance is found in depression ponds which have a pronounced seasonal fluctuation in water level, filling in the winter and often drying completely in the summer (Russo 1997). In these upland depressions, water is ponded by an impermeable substrate (e.g., Guthrie silt loam soils with fragipans, also Holston loam). The variation in amount and duration of flooding may promote herb dominance while restricting the number of trees and shrubs that can survive. In the past, fire may have been another natural disturbance favoring graminoid herbs rather than trees and shrubs.
Environmental Description: In the Great Lakes area, stands of this alliance are found on sandy pitted outwash plains and glacial lakeplains. The level topography of these plains produces gently sloping, shallow basins with no outlets and sometimes no inlets. The water table fluctuates seasonally and yearly. It is highest in late winter and spring and during years of high precipitation. The soils are derived mainly from sand. The sand is poor in nutrients and is acidic, with pH ranging from 4.4-7.0. These conditions inhibit microbial decomposition and considerable organic material accumulates as peat. The peat mixes with sand or forms more-or-less pure deposits. Basin shorelines typically have stretches of pure sand in areas where wave action is greatest, pure peat in protected areas, and a mixture of the two substrates in other areas. In some basins, an impermeable layer of clay develops 2-5 m below the surface. This layer may hold the local water table above the regional water table for long periods. In the South, this alliance is found in upland depression ponds of the Interior Low Plateau (Eastern Highland Rim) of Tennessee (Russo 1997), and seasonally flooded depressions in the Atlantic Coastal Plain of Virginia north to southern Ontario and possibly Nova Scotia.
Geographic Range: This alliance is found in New England, including Massachusetts, Rhode Island, New Jersey, New York, Maryland, Virginia, northern Alabama (ALNHP unpubl. data 2017), Tennessee (Russo 1997), and possibly Kentucky. It also occurs in Canada in southern Ontario (Keddy and Sharp 1989) and possibly Nova Scotia and is disjunct in the Great Lakes area (Brodowicz 1989).
Nations: CA,US
States/Provinces: AL, CT, DE, IN, KY?, MA, MD, ME, MI, NH, NJ, NS?, NY, ON, RI, TN, VA, VT, WI
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.899125
Confidence Level: Low
Confidence Level Comments: No Data Available
Grank: GNR
Greasons: No Data Available
Concept Lineage: includes many association from A.1384, but not all of them (has been pasted in from A.1384 with edits in track changes).
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: No Data Available
- Brodowicz, W. W. 1989. Report on the Coastal Plain flora of the Great Lakes region. Prepared for the Michigan Natural Features Inventory.
- 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.
- Keddy, C. J., and M. J. Sharp. 1989. Atlantic coastal plain flora conservation in Ontario. Prepared for the Natural Heritage League and World Wildlife Fund.
- Kost, M. A., and M. R. Penskar. 2000. Natural community abstract for coastal plain marsh. Michigan Natural Features Inventory, Lansing, MI. 6 pp.
- Russo, M. J. 1997. Arnold Engineering Development Center preliminary community classification. Appendix to draft report to The Nature Conservancy, Tennessee Field Office, Nashville. 23 pp.