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CEGL006219 Nyssa sylvatica - Magnolia virginiana / Rhododendron viscosum - Toxicodendron vernix / Smilax pseudochina Swamp Woodland
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: Blackgum - Sweetbay / Swamp Azalea - Poison-sumac / Bamboovine Swamp Woodland
Colloquial Name: Fall-line Terrace Gravel Magnolia Bog
Hierarchy Level: Association
Type Concept: This saturated woodland is known from a limited area at and just east of the Fall Line in Maryland, the District of Columbia, and northern Virginia. It occurs on saturated toeslopes of fluvial-estuarine terraces where sands and gravels of the Cretaceous-aged Potomac Formation are exposed. Irregular microtopography with abundant groundwater seepage forming braided channels, Sphagnum-covered hummocks, and mucky depressions are characteristic. Historic accounts of this vegetation describe these areas as "bogs" with Magnolia virginiana and various shrubs fringing and forming clumps within a more open center dominated by herbaceous plants. Historic vegetation included Nyssa sylvatica, Toxicodendron vernix (abundant), Gaylussacia frondosa, Viburnum nudum var. nudum, Pinus rigida, and Eriocaulon decangulare (abundant), Lycopodiella appressa, Carex bullata, Asclepias rubra, Helianthus angustifolius, Rhynchospora gracilenta, Xyris torta, Pogonia ophioglossoides, and Utricularia spp. Today, remaining examples exist mostly as open woodlands with very dense shrubs (averaging 80% cover) and very small, scattered herbaceous patches. Nyssa sylvatica is the most dominant species, followed by Magnolia virginiana, Acer rubrum, Liriodendron tulipifera, and Ilex opaca var. opaca. Shrub cover includes Rhododendron viscosum, Vaccinium spp., Smilax rotundifolia, Gaylussacia frondosa, Viburnum nudum var. nudum, Eubotrys racemosa, Aronia arbutifolia, Ilex verticillata, Amelanchier canadensis, Ilex laevigata, and Toxicodendron vernix. The only herbs that have significant cover are Osmunda cinnamomea and Dichanthelium dichotomum var. dichotomum, while many others have low cover. Regionally uncommon or rare "bog" species persisting at one or a few sites include Solidago uliginosa var. uliginosa, Eurybia radula, Eriocaulon decangulare, Juncus longii, Drosera intermedia, Asclepias rubra, and Kalmia angustifolia. Historically, fire may have been an important factor in maintaining herbaceous patches and limiting the growth of shrubs and trees, but the geohydrologic conditions and effects of permanently saturated soils ("root pruning") that cause blowdowns of large trees (except Pinus rigida and Nyssa sylvatica) have also been observed to be prominent factors. Ice storms, which are frequent over time in the natural range of this community, also maintain an open mosaic in these wetlands. This community has always had a limited distribution in the Mid-Atlantic fall-line zone and has probably always been rare. Today, less than 20 sites remain in very small patches degraded by hydrologic disturbance, non-native invasive plants, woody succession, fire exclusion, and various anthropogenic impacts. This community has similarities with the bog vegetation of the New Jersey Pine Barren region, but is likely distinguished by species with southern affinities.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: Data have been collected by Rod Simmons et al. from 14 plot samples representing this type. These data were used (in combination with historical data) during the NCR National Capital Parks project (Phase I, regional vegetation analysis and final NCR East Region analysis) to produce this classification.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available
Floristics: McAtee (1918) originally described these "bogs" as having a physiognomic zonation, with Magnolia virginiana and various shrubs fringing and forming clumps within a more open center dominated by herbaceous plants. Exceptionally clear historical photographs taken by McAtee in 1909 show the more open condition of one of the bogs. The following species are clearly identifiable in the photos: Nyssa sylvatica, Toxicodendron vernix (abundant), Gaylussacia cf. frondosa (abundant), Viburnum nudum var. nudum, Pinus rigida, and Eriocaulon decangulare (abundant). Herbaceous species mentioned by McAtee (1918) as characteristic of many historical bogs include Lycopodiella appressa, Carex bullata, Asclepias rubra, Helianthus angustifolius, Rhynchospora gracilenta, Xyris torta, Pogonia ophioglossoides, and Utricularia spp. Except where open conditions have been artificially maintained by powerline rights-of-way, the physiognomy of remnant patches of this community is that of an open woodland with a very dense shrub layer and very small, scattered herbaceous patches. In 11 analyzed plot samples, Nyssa sylvatica has the highest mean tree cover, followed by Magnolia virginiana, Acer rubrum, Liriodendron tulipifera, and Ilex opaca var. opaca. Pinus rigida occurs in about half the plots, sometimes with significant cover. Shrub cover usually averages about 80%, most of it contributed by the following species in rough descending order of importance: Rhododendron viscosum, Vaccinium corymbosum, Smilax rotundifolia, Gaylussacia frondosa, Viburnum nudum var. nudum, Eubotrys racemosa, Aronia arbutifolia, Ilex verticillata, Amelanchier canadensis, Ilex laevigata, and Toxicodendron vernix. Rubus hispidus is a creeping shrub common in most occurrences. The only herbs that achieve significant mean cover are Osmunda cinnamomea and Dichanthelium dichotomum var. dichotomum. Low-cover herbs occurring in >50% of the plots are Mitchella repens, Smilax pseudochina, Dioscorea villosa, Solidago rugosa, Dichanthelium dichotomum var. ensifolium, Rhynchospora capitellata, Viola x primulifolia, Medeola virginiana, Lycopus virginicus, Chasmanthium laxum, Glyceria striata, and Leersia virginica. Regionally uncommon or rare "bog" species persisting at one or a few sites include Solidago uliginosa var. uliginosa, Eurybia radula, Eriocaulon decangulare, Juncus longii, Drosera intermedia, Asclepias rubra, and Kalmia angustifolia.
Dynamics: This community occurs in small patches adjacent to dry to mesic, acidic upland forests dominated by oaks and/or pines (McAtee 1918) and was possibly impacted by occasional wildfires. The historical abundance of Pinus rigida in the vicinity of these bogs (McAtee 1918) and its persistence in some of the surviving remnants may also suggest a history of fire. Remnant stands appear to have become more closed and densely shrubby, which could be attributed to a number of factors, including a post-successional period following widespread clearing throughout the region, fire exclusion, and others.
Environmental Description: This community type usually occurs on saturated toeslopes at bases of highly weathered, highly acidic, fluvial-estuarine terrace gravel deposits of Cretaceous or Tertiary age. Irregular microtopography with abundant groundwater seepage forming braided channels, Sphagnum-covered hummocks, and mucky depressions is characteristic. Soils consist mostly of coarse gravel and sand, with large cobbles often abundantly exposed at the surface. Soil samples collected from plots were extremely acidic, low in organic matter content, and low in base status.
Geographic Range: This community is known from a limited area at and just east of the Fall Line in Howard, Montgomery, Prince George''s, and Charles counties, Maryland; the District of Columbia; and the City of Alexandria and Arlington, Fairfax, Prince William, and Stafford counties, Virginia.
Nations: US
States/Provinces: DC, MD, VA
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.732427
Confidence Level: Moderate
Confidence Level Comments: No Data Available
Grank: G1
Greasons: No Data Available
| Type | Name | Database Code | Classification Code |
|---|---|---|---|
| Class | 1 Forest & Woodland Class | C01 | 1 |
| Subclass | 1.B Temperate & Boreal Forest & Woodland Subclass | S15 | 1.B |
| Formation | 1.B.3 Temperate Flooded & Swamp Forest Formation | F026 | 1.B.3 |
| Division | 1.B.3.Nb Southeastern North American Flooded & Swamp Forest Division | D062 | 1.B.3.Nb |
| Macrogroup | 1.B.3.Nb.3 Sweetbay - Swamp Bay - Pond Pine Swamp Forest Macrogroup | M032 | 1.B.3.Nb.3 |
| Group | 1.B.3.Nb.3.b Atlantic White-cedar - Pitch Pine Swamp Group | G039 | 1.B.3.Nb.3.b |
| Alliance | A2058 Red Maple - Blackgum Swamp Forest Alliance | A2058 | 1.B.3.Nb.3.b |
| Association | CEGL006219 Blackgum - Sweetbay / Swamp Azalea - Poison-sumac / Bamboovine Swamp Woodland | CEGL006219 | 1.B.3.Nb.3.b |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: = Nyssa sylvatica - Magnolia virginiana - (Pinus rigida) / Rhododendron viscosum - Gaylussacia frondosa / Smilax pseudochina Woodland (Fleming and Patterson 2003)
= Nyssa sylvatica - Magnolia virginiana - (Pinus rigida) / Rhododendron viscosum - Toxicodendron vernix / Smilax pseudochina Woodland (Fleming et al. 2007b)
< Coastal Plain / Piedmont Seepage Bog (Fleming and Patterson 2004)
= Magnolia Bog (McAtee 1918)
= Nyssa sylvatica - Magnolia virginiana - (Pinus rigida) / Rhododendron viscosum - Toxicodendron vernix / Smilax pseudochina Woodland (Fleming et al. 2007b)
< Coastal Plain / Piedmont Seepage Bog (Fleming and Patterson 2004)
= Magnolia Bog (McAtee 1918)
- Eastern Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boston, MA.
- Fleming, A. H. 2009. Hydrogeologic setting of a floristically distinctive ground-water slope wetland along the fall zone in northern Virginia. PowerPoint Presentation. The Flora Project, Horticulture and Natural Resources Section, Department of Recreation, Parks and Cultural Activities, City of Alexandria, VA. [http://alexandriava.gov/22560]
- 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., K. Taverna, and P. P. Coulling. 2007b. Vegetation classification for the National Capitol Region parks, eastern region. Regional (VA-MD-DC) analysis prepared for NatureServe and USGS-NPS Vegetation Mapping Program, March 2007. Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond.
- Fleming, G. P., and K. D. Patterson. 2003. Preliminary vegetation classification for the National Capitol Region parks. Regional (VA-WVA-MD-DC) analysis prepared for NatureServe and USGS-NPS Vegetation Mapping Program, March 2003. Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond.
- Fleming, G. P., and K. D. Patterson. 2004. Natural community inventory of selected areas in the Northern Virginia Culpeper Basin, Fairfax, Loudoun, Prince William, Fauquier, and Culpeper counties. Unpublished report submitted to the Virginia Native Plant Society, Potowmack Chapter. Natural Heritage Technical Report 04-07. Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond. 21 pp. plus appendices.
- 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.
- Harshberger, J. W. 1916. The vegetation of the New Jersey Pine Barrens. Reprinted 1970. Dover Publications, Inc., New York. 329 pp.
- Hitchcock, A. S., and P. Standley. 1919. Flora of the District of Columbia and vicinity. Contributions to the U.S. National Herbarium 21:1-329.
- McAtee, W. L. 1918. A sketch of the natural history of the District of Columbia together with an indexed edition of the U.S. Geological Survey''s 1917 map of Washington and vicinity. Bulletin of the Biological Society of Washington. 142 pp.
- Simmons, R. H. 2013a. Beatley Bog. Pages 23-25 in: Remnant natural areas in parks, waterways, and undeveloped sites in the City of Alexandria, Virginia: Seminary Hill area. Department Recreation, Parks, and Cultural Activities, City of Alexandria, VA. [http://alexandriava.gov/48838]
- Simmons, R. H. 2013b. Magnolia bogs of the fall line: Three centuries of botanical exploration and diversity. PowerPoint Presentation.
- Simmons, R. H., J. M. Parrish, M. D. Tice, and M. T. Strong. 2008. Conservation priorities and selected natural communities of the upper Anacostia watershed. Marilandica 12:1-22.
- Simmons, R. H., and M. T. Strong. 2001. Araby Bog: A globally rare Magnolia bog in Charles County, Maryland. Marilandica 9:6-9.