Common (Translated Scientific) Name: Little Bluestem - Poverty Oatgrass - Michaux's Saxifrage Grassland & Shrubland Division
Colloquial Name: Eastern North American Grassland & Shrubland
Hierarchy Level: Division
Type Concept: This division encompasses a variety of grass- and shrub-dominated vegetation types in the northern and central regions of eastern Canada and the United States, often on somewhat droughty or fire-dependent sites as compared to the surrounding forest and woodland matrix. Within a given area, both physiognomic types can be interspersed, or solely dominated by one or the other. In open tall prairie vegetation, such as in the barrens of Kentucky, Andropogon gerardii, Andropogon ternarius, Panicum anceps, Panicum spp., Schizachyrium scoparium, Sorghastrum nutans, and Sporobolus spp. are predominant. Common forb species include Helianthus mollis, Helianthus occidentalis, Helianthus silphioides, Silphium terebinthinaceum, and Silphium trifoliatum. Shrublands are composed of Cercis canadensis, Forestiera ligustrina, Hypericum spp., Juniperus virginiana var. virginiana, and Rhus aromatica. The species composition and stature of shrublands exhibit a great degree of variability. The woody species composition of some communities consists predominantly of ericaceous shrubs (Arctostaphylos uva-ursi, Corema conradii, Gaultheria procumbens, Gaylussacia baccata, Kalmia angustifolia, Leiophyllum buxifolium, Pyxidanthera barbulata, Vaccinium angustifolium, Vaccinium myrtilloides, Vaccinium pallidum) with scrub or stunted oak species (Quercus ilicifolia, Quercus prinoides, or Quercus rubra). In the case of Appalachian balds, composition varies with elevation, with communities of Danthonia spicata, Dichanthelium spp., and Pinus virginiana, Quercus montana, Quercus stellata, Quercus velutina, and Schizachyrium scoparium, at lower elevation yielding to Carex pensylvanica, Danthonia compressa, Rhododendron catawbiense, and Sibbaldiopsis tridentata at higher elevations. Alvar vegetation contains a mix of eastern prairie peninsula tallgrass prairie elements and eastern subboreal elements. The division occurs within two climate types (sensu Trewartha): Temperate Continental and Subtropical humid. The substrates are granite or rhyolite, limestone, metamorphic, sandstone, or serpentine. As a result, pH ranges from very acidic to basic. Soils range in depth from very deep to shallow or absent. Texture also is variable, from fine loamy to coarse soils. Vegetation on shallow soils is subject to extremely xeric conditions in the summer months, whereas those in regions with cold winters and moist soils experience frost-heaving. Species composition and dynamics in this division are influenced by fire frequency, land-use history, and herbivory, whether browsing by deer and grazing by cattle. Distinct from these natural conditions are ruderal grasslands and shrublands that typically occur on sites that have been cleared and plowed (for farming or development) and then abandoned, and are now dominated by weedy or generalist native and exotic forbs, grasses, ferns, and shrubs.
Diagnostic Characteristics: A diverse number of soil and substrate types are attribute to this division, making it difficult to find a diagnostic category related to abiotic conditions. Vegetation structure ranges from densely growing eastern tall prairie species, similar to the tallgrass prairie region in the prairie peninsula, to sparsely vegetated rock outcrops. Some taxa shared among macrogroups include Danthonia spp., Juniperus horizontalis, Juniperus virginiana, Quercus montana, Quercus stellata, Schizachyrium scoparium, and Sporobolus spp.
Rationale for Nominal Species or Physiognomic Features:
Classification Comments: Although some vegetation types within this division are well document (i.e., alvar), the need for additional analysis to resolve issues of vegetation composition and substrate relationships, as in the case of serpentine, do exist. There is a great variety in abiotic substrates, and a corresponding heterogeneity in vegetation. That said, a number of wide-ranging dominants are found in many of the stands, including Juniperus virginiana, Danthonia sericea, Danthonia spicata, and Schizachyrium scoparium.
Similar NVC Types:
D042 Eastern North American Alpine Tundra, note:
D026 Eastern North American Coastal Scrub & Herb Vegetation, note:
D023 Central North American Grassland & Shrubland, note: "contains many of the same dominant grasses as are found in D024, particularly for ~Central Lowlands-West Gulf Coastal Tallgrass Prairie Macrogroup (M054)$$."
D025 North American Boreal Grassland & Shrubland, note:
D323 Eastern North American Temperate & Boreal Freshwater Marsh, Wet Meadow & Shrubland, note:
Physiognomy and Structure: This division consists of diverse physiognomic types, ranging from patchy vegetation (vascular and/or nonvascular) on rock outcrops, open grasslands, to sparsely treed vegetation, with a combination of grasses and shrubs in the understory, and dense shrublands, often predominated by ericaceous species. Vegetation associated with rock outcrops experience xeric conditions, often producing stunted growth form in woody plants.
Floristics: There is considerable variation in floristic composition, a product of regional and latitudinal environmental gradients, variation in soil type and depth and elevation. Key grass species include Andropogon gerardii, Andropogon ternarius, Andropogon virginicus, Chasmanthium laxum, Danthonia sericea, Danthonia spicata, Deschampsia cespitosa, Deschampsia flexuosa, Dichanthelium acuminatum, Dichanthelium aciculare, Dichanthelium dichotomum, Dichanthelium linearifolium, Dichanthelium scoparium, Dichanthelium sphaerocarpon, Elymus hystrix, Panicum anceps, Panicum rigidulum, Panicum verrucosum, Panicum virgatum, Poa compressa, Schizachyrium scoparium, Sorghastrum nutans, Sporobolus clandestinus, Sporobolus heterolepis, Sporobolus neglectus, Sporobolus vaginiflorus, and Tripsacum dactyloides.
Herbaceous species include Aletris farinosa, Asclepias syriaca, Baptisia australis, Coreopsis major, Coreopsis tripteris, Doellingeria umbellata, Eupatorium perfoliatum, Eupatorium pilosum, Eupatorium rotundifolium, Eurybia hemispherica, Euthamia graminifolia, Eutrochium fistulosum, Fragaria virginiana, Helianthus angustifolius, Helianthus hirsutus, Helianthus mollis, Helianthus occidentalis, Helianthus silphioides, Lobelia puberula, Minuartia spp., Oenothera biennis, Packera tomentosa, Pityopsis graminifolia, Pteridium aquilinum, Potentilla simplex, Rudbeckia hirta, Sedum nuttallianum, Silphium laciniatum, Silphium terebinthinaceum, Silphium trifoliatum, Solidago altissima, Solidago canadensis, Solidago gigantea, Solidago nemoralis, Solidago rugosa, Symphyotrichum dumosum, Symphyotrichum lateriflorum, Symphyotrichum novae-angliae, and Symphyotrichum patens. Croton michauxii var. ellipticus (= Croton willdenowii), Portulaca pilosa, Sedum nuttallianum, and Selaginella rupestris are present in communities on shallow soils and rock outcrops.
Woody species may consist of true shrubs or trees in a "dwarfed" or stunted condition and include Abies balsamea, Amelanchier spp., Arctostaphylos uva-ursi, Cercis canadensis, Cornus racemosa, Cornus sericea, Crataegus spp., Fraxinus americana, Gaylussacia baccata, Juniperus horizontalis, Juniperus virginiana, Kalmia angustifolia, Kalmia latifolia, Larix laricina, Picea glauca, Pinus rigida, Pinus strobus, Prunus virginiana, Prunus americana, Quercus alba, Quercus montana (= Quercus prinus), Quercus stellata, Quercus marilandica, Rhus aromatica, Rhus glabra, Rhus typhina, Rubus spp., Thuja occidentalis, Ulmus alata, Vaccinium angustifolium, Vaccinium arboreum, Vaccinium corymbosum, Vaccinium myrtilloides, Vaccinium pallidum, Viburnum lentago, and Viburnum recognitum, Viburnum rufidulum.
Nonvascular plant species, such as the moss genera Dicranum and Polytrichum, and the lichen genus Cladonia, are common in shallow soil and rock outcrop sites.
Eastern ruderal grasslands and shrublands encompass sites in the northern and central regions of the eastern United States that have been cleared and plowed (for farming or development) and then abandoned, and are now dominated by weedy or generalist native and exotic forbs, grasses, ferns, and shrubs. Open old-field meadows have characteristic forbs that include Asclepias syriaca, Centaurea stoebe ssp. micranthos (= Centaurea maculosa), Cerastium arvense, Daucus carota, Euthamia graminifolia, Fragaria virginiana, Oenothera biennis, Picris hieracioides, Potentilla simplex, Rudbeckia hirta, Solidago altissima, Solidago canadensis, Solidago juncea, Solidago nemoralis, Solidago rugosa, Symphyotrichum lateriflorum (= Aster lateriflorus), and Symphyotrichum novae-angliae (= Aster novae-angliae). Common grasses include Anthoxanthum odoratum, Bromus inermis, Dactylis glomerata, Elymus repens (= Agropyron repens), Lolium spp., Phleum pratense, Poa compressa, and Poa pratensis. Shrubs may be present, but collectively they have less than 25% cover. The mesic old-field shrublands are typically dominated by Amelanchier spp., Cornus racemosa (= Swida racemosa), Cornus sericea (= Swida sericea), Crataegus spp., Juniperus virginiana, Prunus americana, Prunus virginiana, Rhus glabra, Rhus typhina, Rubus spp., Rubus spp., Viburnum lentago, and Viburnum recognitum (= Viburnum dentatum var. lucidum). The exotic shrubs Elaeagnus angustifolia, Lonicera spp., and Rosa multiflora may be invasive in some areas. Dry old-field grassland and shrublands are found on sandy or rocky substrates and is typically dominated by Andropogon virginicus, Poa compressa, Schizachyrium scoparium, Solidago nemoralis, and an assortment of dry weedy species such as the exotic Centaurea stoebe ssp. micranthos. Scattered native or exotic trees may be present, including Acer rubrum, Fraxinus pennsylvanica, Pinus rigida, Pinus strobus, Pinus sylvestris, and Populus deltoides.
Dynamics: Species composition and dynamics in this division are influenced by fire frequency, land-use history, and herbivory, whether browsing by deer and grazing by cattle. Vegetation on shallow soils, exposed rock, or in rock crevices, is affected by hydrology and soil moisture. Low soil moisture on rock outcrops results in sparse vegetation and dwarf of stunted woody plant growth forms.
Geographic Range: Occurrences of this division can be found from the eastern seaboard of Atlantic Canada west to eastern Minnesota, south to the Ouachita Mountains and Ozark Plateau, and east to the Interior Low Plateaus, Appalachia Mountains, Piedmont and Atlantic Coast.
Nations: CA, US
States/Provinces: AL, AR, CT, GA, IA, IL, IN, KS, KY, LA, MA, MB, MD, ME, MI, MN, MO, NB, NC, ND, NE, NH, NJ, NS, NY, OH, OK, ON, PA, PE, QC, RI, SC, SD, TN, VA, VT, WI, WV
|US Forest Service Ecoregions (2007)|