Classification of Vegetation Communities of Maryland: First Iteration
A Subset of the International Classification of Ecological
Concept: This alliance, found in the upper midwestern and eastern regions of the United States as well as parts of adjacent Canada, contains communities known as 'calcareous seepage swamps,' 'hardwood swamps,' and 'red maple - black ash swamps' in which Acer rubrum and Fraxinus nigra are dominant or prominent canopy members. Total canopy cover ranges from nearly closed to open. Where the tree canopy is open, the understory vegetation is patchy, ranging from shrub-dominated patches to minerotrophic sedge meadows. Associated canopy trees are Betula alleghaniensis, Ulmus rubra, Ulmus americana, and Pinus strobus. In the northern parts of the range, Larix laricina, Thuja occidentalis, and Abies balsamea are sometimes present. Lindera benzoin (east), Toxicodendron vernix, Alnus incana (north), Salix spp., and Rhamnus alnifolia often occur in the shrub layer. The herbaceous layer is often quite diverse, supporting such species as Carex leptalea, Carex bromoides ssp. bromoides, Caltha palustris, Veratrum viride, Platanthera grandiflora, Geum rivale (north), Symplocarpus foetidus, Trollius laxus (north), Cypripedium reginae, Cypripedium parviflorum (= Cypripedium calceolus), Osmunda cinnamomea, Impatiens capensis, Cardamine bulbosa, Saxifraga pensylvanica, Dryopteris cristata, and Carex lacustris.
Stands are typically found in poorly drained depressions (sometimes as narrow zones or small inclusions in wetland complexes, sometimes as large swamps), and occasionally in seepage zones at the base of river terraces or draws. Soils are generally muck and, although Sphagnum spp. may occur, there is generally not substantial peat development. Stands often occur in areas where there is influence by calcareous bedrock, and soil pH is generally higher than that of other alliances containing Acer rubrum.
Range: This alliance is found in Connecticut, Maine, Massachusetts, Maryland, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, Virginia, West Virginia, Indiana, Illinois, Michigan, Minnesota, Missouri, North Dakota, and Wisconsin; and in Canada in Manitoba and Ontario. Present in Garrett County, Maryland.
States/Provinces: CT IL IN? MA MB MD MI MN MO ND NH NJ NY ON PA RI VA VT WI WV
TNC Ecoregions: 35:C, 36:C, 38:C, 45:P, 46:C, 47:C, 48:C, 57:C, 58:C, 59:C, 60:C, 61:C, 62:C, 63:C, 64:C
USFS Ecoregions: 212Ea:CPP, 212Eb:CPP, 212Ec:CPP, 212Ed:CP?, 212Fa:CCC, 212Fb:CCC, 212Fc:CCC, 212Fd:CCC, 212Ga:CPP, 212Gb:CP?, 212Ha:CCP, 212Hb:CCP, 212Hd:CCC, 212He:CCP, 212Hh:CCP, 212Hi:CCP, 212Hj:CCP, 212Hk:CCP, 212Hl:CCP, 212Hm:CCC, 212Hn:CCP, 212Ho:CCP, 212Hp:CCP, 212Hq:CCP, 212Hr:CCP, 212Hs:CCP, 212Ht:CCP, 212Hu:CCP, 212Hv:CCC, 212Hw:CCP, 212Hx:CCP, 212Hy:CCP, 212Ib:CCC, 212Ja:CCP, 212Jb:CCC, 212Jc:CCC, 212Jd:CCC, 212Je:CCP, 212Jf:CCP, 212Jj:CCP, 212Jk:CCP, 212Jl:CCP, 212Jm:CCC, 212Jn:CCP, 212Jo:CCP, 212Jr:CCP, 212Ka:CCC, 212Kb:CCC, 212La:CCC, 212Lb:CCP, 212Lc:CCP, 212Ld:CCP, 212Ma:CCP, 212Mb:CCC, 212Na:CCC, 212Nb:CCP, 212Nc:CCC, 212Nd:CCP, 212Oa:CCC, 221Ad:CCP, 221Ae:CCC, 221Af:CCC, 221Ag:CCP, 221Ah:CCP, 221Ai:CCP, 221Al:CCP, 221Am:CCP, 221Ba:CCC, 221Bb:CCP, 221Bc:CCP, 221Bd:CCC, 221Da:CPP, 221Db:CPP, 221Dc:CPP, 221Ea:CP?, 221Eb:CP?, 221Fa:CCP, 222Aa:CCC, 222Ad:CC?, 222Ae:CC?, 222Af:CCC, 222Al:CCC, 222Ia:CPP, 222Ib:CPP, 222Ic:CPP, 222Id:CPP, 222Ie:CPP, 222If:CPP, 222Jc:CCC, 222Jg:CCC, 222Ke:CCC, 222Kf:CCC, 222Kg:CCC, 222Lc:CCC, 222Ld:CCC, 222Lf:CCC, 222Mc:CCC, 222Md:CCC, 222Na:CCC, 232A:CC, 232Br:CCC, 251Aa:CCC, 251Dc:CCC, M212Ad:CP?, M212Ba:CCC, M212Bb:CCP, M212Bc:CCP, M212Bd:CCP, M212Ca:CCP, M212Cb:CCP, M212Cc:CCP, M212Cd:CCP, M212Da:CPP, M212Db:CPP, M212Dc:CPP, M212Ea:CCC, M212Eb:CCC, M212Fa:CPP, M212Fb:CPP, M221Aa:CCC, M221Ab:CCC, M221Ac:CCC, M221Ad:CCC, M221Ba:CCC, M221Bb:CCC, M221Bd:CC?, M221Be:CC?, M221C:CP, M221Da:CCC
Federal Lands: NPS (Colonial, Isle Royale, Voyageurs); USFS (George Washington, Jefferson, Huron-Manistee)
Synonymy: Black Ash - American Elm - Red Maple: 39, in part (Eyre 1980); Ulmus - Fraxinus wetland forest (No. 25), in part (Vankat 1990); Black Ash-Red Maple-Tamarack Calcareous Seepage Swamp (Swain and Kearsley 2001); Red maple - black ash palustrine forest (Fike 1999); Red maple - mixed shrub palustrine woodland (Fike 1999); Eastern Calcareous Seepage Swamp (Smith 1991); Circumneutral Shrub Swamp, in part (Smith 1991)
References: Eyre 1980, Faber-Langendoen et al. 1996, Fike 1999, MNNHP 1993, Smith 1991, Swain and Kearsley 2001, Vankat 1990
Authors: ECS, RW, Midwest Identifier: A.347
ACER RUBRUM - FRAXINUS PENNSYLVANICA / BIDENS LAEVIS - PILEA FONTANA FOREST
Red Maple - Green Ash / Smooth Beggarticks - Lesser Clearweed Forest
Coastal Plain Calcareous Seepage Swamp G? (00-11-15)
Ecological Group (SCS;MCS): Northern Coastal Plain Calcareous Seepage Swamp Forests (360-17; n/a)
Concept: This calcareous seepage swamp occurs on the Virginia Coastal Plain on groundwater-saturated stream bottoms in ravines that have cut into Tertiary shell deposits or limesands. Braided streams and hummock-and-hollow microtopography are characteristic of the environmental setting. The tree canopy is characterized by Fraxinus pennsylvanica, Acer rubrum, Liquidambar styraciflua, and others. The shrub layer is comprised of Lindera benzoin, Morella cerifera (= Myrica cerifera) and Cornus foemina. Vines are abundant, characterized by Decumaria barbara. The herbaceous layer is characterized by Caltha palustris, Carex bromoides, Packera aurea (= Senecio aureus), Scirpus lineatus, Thelypteris palustris, Pedicularis lanceolata, Carex tetanica, Liparis loeselii, and Carex granularis on drier hummocks, and Saururus cernuus, Bidens laevis, Pilea fontana, Glyceria striata, and Impatiens capensis in wetter hollows and seepage rivulets.
Comments: Although Fraxinus pennsylvanica rather than Fraxinus nigra characterizes the canopy of this type, it is placed in the Fraxinus nigra - Acer rubrum Saturated Forest Alliance (A.347) because of the calcareous environmental setting and presence of calciphitic species.
Range: This calcareous seepage swamp occurs on the Virginia Coastal Plain.
States/Provinces: MD?, VA:S?
TNC Ecoregions: 57:C, 58:C
USFS Ecoregions: 232Br:CCC
Federal Lands: NPS (Colonial)
Synonymy: Acer rubrum - Fraxinus pennsylvanica / Bidens laevis - Pilea fontana - (Scirpus lineatus) Saturated Forest [Provisional] (Fleming 2001)
References: Fleming 2001, Fleming et al. 2001
Authors: Chesapeake Bay Ecology Group, mod.
L.A. Sneddon, ECS Confidence: 3 Identifier: CEGL006413
FRAXINUS NIGRA - ACER RUBRUM / CAREX LEPTALEA SATURATED FOREST
Black Ash - Red Maple / Little Bog Sedge Saturated Forest
Red Maple - Black Ash Swamp G? (97-12-01)
Ecological Group (SCS;MCS): Northern Swamp Forests (490-16; n/a)
Concept: Closed-canopy deciduous swamp forest of poorly drained depressions or seepage zones in the unglaciated portions of Lower New England/Northern Piedmont, High Allegheny Plateau, and Central Appalachians. This forest can occur as narrow zones to small inclusions to large swamps. Soils are generally mucky and without substantial peat development. It often occurs in areas of calcareous bedrock. The canopy is codominated by Acer rubrum and Fraxinus nigra with associates such as Betula alleghaniensis, Ulmus rubra, Ulmus americana, and Pinus strobus. The understory is patchy, ranging from shrub-dominated to sedge-dominated. Shrubs include Lindera benzoin, Toxicodendron vernix, Alnus incana, Salix spp., and Rhamnus alnifolia. The herb layer is diverse with Carex leptalea, Carex bromoides, Caltha palustris, Veratrum viride, Platanthera grandiflora, Geum rivale, Symplocarpus foetidus, Cypripedium reginae, Trollius laxus, Osmunda cinnamomea, Impatiens capensis, Cardamine bulbosa, Saxifraga pensylvanica, Dryopteris cristata, Carex lacustris, and Symplocarpus foetidus.
States/Provinces: MD:S?, NY:S4S5, PA:S?, WV:S?
TNC Ecoregions: 59:C, 60:C, 61:C
USFS Ecoregions: 212Fb:CCC, 212Fd:CCC, 221E:CP, M221Aa:CCC, M221Ac:CCC, M221Ad:CCC, M221Ba:CCC, M221Bb:CCC, M221Da:CCC
Synonymy: Red maple-black ash swamp (CAP pers. comm. 1998)
References: CAP pers. comm. 1998, Edinger et al. 2002, Fike 1999
Authors: S.L. Neid, ECS Confidence: 3 Identifier: CEGL007441
FRAXINUS NIGRA - LIRIODENDRON TULIPIFERA - ACER RUBRUM / CALTHA PALUSTRIS - CAREX BROMOIDES FOREST
Black Ash - Tuliptree - Red Maple / Yellow Marsh-marigold - Brome-like Sedge Forest
Montane Black Ash Seepage Swamp G3 (00-04-17)
Ecological Group (SCS;MCS): Appalachian Highlands Forested Fens and Calcareous Seeps (470-50; n/a)
Concept: This community type occupies groundwater-saturated stream headwaters, large spring seeps and runs, and lateral areas in ravine and stream bottoms where groundwater emerges at the base of slopes. Overstory composition is mixed, with Liriodendron tulipifera, Acer rubrum, and Fraxinus americana the most abundant species. Frequent associates are Fraxinus nigra, Betula lenta, and Tilia americana. Fraxinus nigra is more abundant and sometimes dominant in the understory, along with Acer rubrum and Fraxinus americana. Canopy closure is often incomplete (mean stratum cover = 60-80%), most evidently because of blowdowns. Very wet microhabitats that impede the establishment and firm rooting of trees may also contribute to a somewhat open canopy. Shrub stratum diversity is moderately high; Lindera benzoin is usually the most abundant species, and considerable stratum cover is contributed by tree saplings. Other frequently occurring true shrubs are Alnus serrulata, Carpinus caroliniana, Hamamelis virginiana, Ilex verticillata, and Sambucus canadensis. Except in local areas where shrubs are dense, herbaceous cover is high (mean stratum cover = 90%). One or both of the early-maturing forbs, Symplocarpus foetidus and Veratrum viride, are usually dominant over substantial areas. Because of microtopographic diversity (see below), herbaceous patch-mosaics are typical in this vegetation. More-or-less constant (50% constancy), sometimes locally abundant species include Eurybia schreberi (= Aster schreberi), Caltha palustris, Carex bromoides, Carex gynandra, Carex prasina, Chelone glabra, Chrysosplenium americanum, Cinna arundinacea, Dryopteris carthusiana, Dryopteris goldiana, Glyceria striata, Impatiens capensis, Osmunda cinnamomea, Osmunda regalis var. spectabilis, Ranunculus recurvatus, Saxifraga pensylvanica, Packera aurea (= Senecio aureus), Sphenopholis pensylvanica, Thalictrum pubescens, and Viola cucullata. Moss cover is often significant, but only rarely includes Sphagnum spp. (not recorded in the plots analyzed here). Typical upland mesophytes commonly occur in well-drained hummock microhabitats and contribute to relatively high species richness values for this type of wetland.
Comments: This type needs additional resolution relative to Fraxinus nigra - Acer rubrum / Carex leptalea Saturated Forest (CEGL007441). Liriodendron tulipifera was added to the name to help distinguish this type from more northern and boreal associations in the alliance. Environmentally, this community type is distinguished from other montane wetlands by its saturated or seasonally saturated habitats that are influenced by more-or-less calcareous substrates. Floristically, it is distinguished from calcareous fens and seeps by its forest physiognomy and the absence or scarcity of light-demanding plants. This unit is most similar to forested, acidic seepage wetlands that are situated on soils derived from acidic sandstones, quartzites, and other oligotrophic substrates. These environmentally disparate swamps share a surprising number of prominent species including Acer rubrum, Symplocarpus foetidus, Veratrum viride, Osmunda cinnamomea, Osmunda regalis var. spectabilis, Carex leptalea, etc. Mean species richness of stands analyzed in this study (n=52.2), however, is much higher than that of 23 acidic swamps in Augusta County, Virginia (n=27.7; DCR-DNH unpublished data). Distinct floristic features of calcareous seepage swamps include the prevalence of Fraxinus spp. (especially Fraxinus nigra), and nutrient-demanding species, among the most diagnostic of which are Caltha palustris, Carex bromoides, Carex laevivaginata, Pilea fontana, Poa paludigena, Ranunculus hispidus var. caricetorum, Saxifraga pensylvanica, and Trillium cernuum. These communities lack the Sphagnum mosses that characterize acidic groundwater wetlands. Moreover, many vascular plants that are common in or diagnostic of acidic seepage swamps are absent or unimportant, e.g., Pinus rigida, Nyssa sylvatica, Viburnum nudum var. nudum, Parnassia asarifolia, Platanthera ciliaris, Platanthera clavellata, Rubus hispidus, Lycopodium obscurum, Carex debilis var. debilis, and Carex folliculata (Fleming and Van Alstine 1999). Observations suggest, however, that the sharp distinctions that can now be drawn from limited existing data may be somewhat illusory, as the two putative "types" of seepage swamp are most likely confluent along a continuum of pH and trophic gradients.
Range: The probable range of this community type encompasses the Central Appalachian region of Pennsylvania, Maryland, Virginia, and West Virginia. In Virginia it is found primarily in the northern half of the mountains, apparently reaching its southern limits in Giles County. The majority of occurrences are on the Northern Blue Ridge, but the type is also scattered in suitable habitats of the Ridge and Valley province.
States/Provinces: MD?, VA:S?, WV?
TNC Ecoregions: 58:C, 59:C
USFS Ecoregions: M221Aa:CCC, M221Ab:CCC, M221Bd:C??, M221Da:CCC
Federal Lands: USFS (George Washington, Jefferson)
Synonymy: Acer rubrum - Fraxinus nigra / Caltha palustris - Carex bromoides Forest (Fleming 1999), Acer rubrum - Fraxinus americana - Fraxinus nigra / Carex bromoides - Carex prasina - (Caltha palustris) Forest (Fleming and Coulling 2001), Black Ash - American Elm - Red Maple: 39 (Eyre 1980) B
References: Eyre 1980, Fleming 1999, Fleming and Coulling 2001, Fleming and Van Alstine 1999, Fleming et al. 2001, Golet et al. 1993, Ludwig et al. 1993
Authors: G.P. Fleming, SCS Confidence: 2 Identifier: CEGL008416
- Maryland Vegetation Classification Subset Report I.B. Deciduous forest
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