Common (Translated Scientific) Name: Little Bluestem - Silky Oatgrass Acidic Scrub & Grassland Macrogroup
Colloquial Name: Central Interior Acidic Scrub & Grassland
Hierarchy Level: Macrogroup
Type Concept: This macrogroup represents grasslands, shrublands, and scattered trees, often co-occurring in a mosaic with woodlands on quartzite, sandstone or other outcrops of acidic rock and associated thin-soil areas, primarily in unglaciated regions. The acidic soils are typically dry during the summer and autumn, becoming saturated during the winter and spring. Grasses such as Schizachyrium scoparium and Sorghastrum nutans dominate this macrogroup. Other characteristic grasses include Danthonia sericea and Danthonia spicata. Shrubs such as Vaccinium spp. and/or Gaylussacia spp. are common, as are scattered trees of Pinus virginiana, Pinus rigida, Pinus echinata, Quercus montana, Quercus stellata, and Quercus marilandica. Trees may be stunted. Juniperus virginiana var. virginiana can be present and often increases in the absence of fire. Herbaceous plants, including Diamorpha smallii and Minuartia glabra, are found on some of these outcrops on the Cumberland Plateau in Tennessee. Fruticose lichens such as Cladonia spp. may be prominent in some examples. Examples of the macrogroup are influenced by drought and infrequent to occasional fires. Prescribed fires can help maintain an open grassland or woodland structure. Examples of this macrogroup are primarily found in the Interior Highlands (Ozarks, Ouachita Mountains, Interior Low Plateau, and Cumberland Plateau regions) with rare and limited occurrences north and south of this range.
Diagnostic Characteristics: These are open grasslands with scattered trees and small rock outcrops which are on thin-soil acidic glades in the central and south-central United States. Schizachyrium scoparium, Danthonia sericea, and Danthonia spicata are common dominants. Dichanthelium acuminatum, Dichanthelium linearifolium, and Dichanthelium sphaerocarpon are common associates on these acidic glades. Shrubs which favor acidic soils such as Vaccinium spp. and/or Gaylussacia spp. are common, as are widely scattered trees of Pinus virginiana, Pinus rigida, Pinus echinata, Quercus montana, Quercus stellata, Quercus marilandica, and Ulmus alata. Herbaceous plants, including Diamorpha smallii and Minuartia glabra, are typical of these outcrops on the Cumberland Plateau in Tennessee. A diverse set of graminoid and forb species occurs on these glades, but rangewide review is needed to identify the diagnostic species.
Rationale for Nominal Species or Physiognomic Features: Schizachyrium scoparium and Danthonia sericea are characteristic grasses of these rocky acidic glades in the southeastern United States. While Schizachyrium scoparium has a wide range in the eastern and central United States, Danthonia sericea is limited to the southeastern United States, and may be rare or absent in some areas where this macrogroup occurs, such as in the Ozarks and Ouachita Highlands.
Classification Comments: No Data Available
Similar NVC Types:
M012 Central Midwest Oak Forest, Woodland & Savanna, note:
M016 Southern & South-Central Oak - Pine Forest & Woodland, note:
M505 Laurentian-Acadian Acidic Rocky Scrub & Grassland, note: "occurs further north and northeast, in northeastern West Virginia and in Virginia in the Blue Ridge of the Central Appalachian area."
M506 Appalachian Rocky Felsic & Mafic Scrub & Grassland, note:
M508 Central Interior Calcareous Scrub & Grassland, note:
Physiognomy and Structure: The vegetation encompasses a complex of sparsely vegetated rock outcrops, perennial grasslands, and scattered heath shrubs and trees on shallow soils.
Floristics: Grasses such as Schizachyrium scoparium and Sorghastrum nutans dominate these stands, with scattered stunted oak species, including Quercus montana (= Quercus prinus), Quercus stellata, and Quercus marilandica, other shrubby trees such as Celtis tenuifolia and Juniperus virginiana, and shrub species such as Vaccinium spp. (including Vaccinium arboreum) and Gaylussacia spp. Other herbaceous plants that may be associated with these glades include Andropogon ternarius, Coreopsis grandiflora, Coreopsis lanceolata, Croton michauxii var. ellipticus (= Croton willdenowii), Danthonia sericea, Danthonia spicata, Dichanthelium acuminatum, Dichanthelium linearifolium, Dichanthelium sphaerocarpon, Pityopsis graminifolia var. latifolia, Portulaca pilosa, Sedum nuttallianum, Selaginella rupestris, Silene regia, Silene rotundifolia, and Symphyotrichum patens var. patentissimum (Nelson 2005). Herbaceous plants, including Diamorpha smallii and Minuartia glabra, are typical of the outcrops on the Cumberland Plateau in Tennessee. Pinus virginiana and Acer rubrum are typical of the current condition of many of the woodlands surrounding these outcrops on the Cumberland Plateau; Pinus rigida and/or Pinus echinata may also occur. Moss and lichen cover and diversity can be high (Nelson 2005). A fuller description of the characteristic species combination of vascular and nonvascular plants is needed for this macrogroup (Winterringer and Vestal 1956, Voigt and Mohlenbrock 1964, Baskin and Baskin 1988, Quarterman et al. 1993, Heikens and Robertson 1995, Taft 1997b, Nelson 2005).
Dynamics: Examples of this macrogroup are influenced by drought and infrequent to occasional fires. Prescribed fires can be helpful for managing stands of this macrogroup by promoting an open glade structure. Droughts and deer browse may currently interact to keep these glades open. Historically, the surrounding matrix of dry oak woodlands may have been more likely to burn, and those fires and the more open canopy could have spread into the glades (West and Welsh 1998). These glades are thought to be more environmentally controlled, by shallow soils, which suggest that soil depth and the historic extent of the glade community may be related.
Environmental Description: Climate: Humid cool temperate. In summer, glades may become extremely hot, and in the most exposed situations support only the most heat- and drought-tolerant taxa. Soil/substrate/hydrology: This macrogroup occurs on flat outcrops of sandstone rock and along moderate to steep slopes or valley walls of rivers along most aspects. Parent material is sandstone, but also includes chert, shale, quartzite or rhyolite, novaculite, igneous quartzite or nepheline syenite bedrock with well- to excessively well-drained, shallow soils interspersed with rock and boulders. Substrates include quartzite or sandstone or other outcrops of acidic rock and associated thin-soil areas over these types of rock. Some areas are really prone to wetness in the winter and spring.
Geographic Range: This macrogroup occurs west of the Blue Ridge, in the central states. Examples of this macrogroup are found in the Interior Highlands of the Ozark, Ouachita, and Interior Low Plateau regions, as well on the Cumberland Plateau of Kentucky, Tennessee, Alabama, Georgia, Virginia, and likely West Virginia, with rare and limited occurrences in the Baraboo Hills of Wisconsin.
States/Provinces: AL, AR, GA, IL, IN, KY, MO, OH, OK, TN, VA, WV
|US Forest Service Ecoregions (2007)|
Southeastern Mixed Forest Province
Confident or certain
Southern Unglaciated Allegheny Plateau Section
Confident or certain
Omernik Ecoregions: 35:C, 35a:C, 35e:C, 36:C, 38:C, 39:C, 68:C
Confidence Level: High
Confidence Level Comments:
Synonomy: = Sandstone Glade (Nelson 2005)
= Sandstone Glades (Baskin and Baskin 1988)
= Sandstone Outcrops (Glades) (Quarterman et al. 1993)
Concept Author(s): E. Quarterman, M.P. Burbank, and D.J. Shure (1993)
Author of Description: C.W. Nordman
Version Date: 15Oct2014
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