Interior Low Plateau
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The Interior Low Plateaus are a physiographic region in eastern United States. It consists of a diverse landscape that extends from north Alabama across central Tennessee and Kentucky into southern Illinois, Indiana, and Ohio. Its natural communities are a matrix of
temperate In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...
forest A forest is an ecosystem characterized by a dense ecological community, community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, ...
s,
woodland A woodland () is, in the broad sense, land covered with woody plants (trees and shrubs), or in a narrow sense, synonymous with wood (or in the U.S., the '' plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunli ...
s, and
prairie Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the ...
s.


Setting

This is a region of rolling plains and eroded plateaus, with a
humid subtropical climate A humid subtropical climate is a subtropical -temperate climate type, characterized by long and hot summers, and cool to mild winters. These climates normally lie on the southeast side of all continents (except Antarctica), generally between ...
in the south and
humid continental climate A humid continental climate is a climatic region defined by Russo-German climatologist Wladimir Köppen in 1900, typified by four distinct seasons and large seasonal temperature differences, with warm to hot (and often humid) summers, and cold ...
in the north. It is notable for its extensive karst limestone, which comprise the caves at
Mammoth Cave National Park Mammoth Cave National Park is a national park of the United States in south-central Kentucky. It encompasses portions of Mammoth Cave, the longest known cave system in the world. The park's are located primarily in Edmonson County, with sma ...
. This region includes a portion of what the U.S. Forest service calls the "Central Hardwood Forest". The region extends from southern
Ohio Ohio ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the ...
,
Indiana Indiana ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Michigan to the northwest, Michigan to the north and northeast, Ohio to the east, the Ohio River and Kentucky to the s ...
and
Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. It borders on Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash River, Wabash and Ohio River, Ohio rivers to its ...
through
Tennessee Tennessee (, ), officially the State of Tennessee, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Kentucky to the north, Virginia to the northeast, North Carolina t ...
and central
Kentucky Kentucky (, ), officially the Commonwealth of Kentucky, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Illinois, Indiana, and Ohio to the north, West Virginia to the ...
and into northern
Alabama Alabama ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South, Deep Southern regions of the United States. It borders Tennessee to the north, Georgia (U.S. state), Georgia to the east, Florida and the Gu ...
. Nearly 65% of Kentucky's territory is within the Interior Low Plateaus region, which encompasses an area from the western Appalachian Plateaus to the
Tennessee River The Tennessee River is a long river located in the Southern United States, southeastern United States in the Tennessee Valley. Flowing through the states of Tennessee, Alabama, Mississippi, and Kentucky, it begins at the confluence of Fren ...
. It includes the Kentucky Bluegrass and
Knobs region The Knobs Region or ''The Knobs'' is located in the US state of Kentucky. It is a narrow, arc-shaped region consisting of hundreds of isolated hills. The region wraps around the southern and eastern parts of the Bluegrass region in the north ce ...
s, the
Highland Rim The Highland Rim is a geographic term for the area in Tennessee, North Alabama, and Kentucky which surrounds the Central Basin. The Central Basin is a geological dome which has subsequently fractured and eroded to produce a basin. The Highland R ...
and the
Shawnee Hills The Shawnee Hills are a region within the larger Interior Low Plateaus physiographic province located in southern Illinois, southern Indiana, and western Kentucky. In Illinois it rests mainly in an east–west arc roughly following the outline ...
.


Geology

The underlying bedrock of the Interior Low Plateaus consists of sedimentary rocks such as limestone, sandstone, and shale. These date from the
Ordovician period The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era, and the second of twelve periods of the Phanerozoic Eon. The Ordovician spans 41.6 million years from the end of the Cambrian Period Ma (mill ...
in the
Nashville Basin The Nashville Basin, also known as the Central Basin, is a term often used to describe the area surrounding Murfreesboro, Tennessee, in which Nashville is located. The Central Basin was caused by an uplifting which produced a dome known as the ...
and
Bluegrass region The Bluegrass region is a geographic region in the U.S. state of Kentucky. It makes up the central and northern part of the state, roughly bounded by the cities of Frankfort, Kentucky, Frankfort, Paris, Kentucky, Paris, Richmond, Kentucky, Ric ...
, up to the
Carboniferous Period The Carboniferous ( ) is a geologic period and system of the Paleozoic era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the Permian Period, Ma. It is the fifth and penultimate perio ...
in the
Shawnee Hills The Shawnee Hills are a region within the larger Interior Low Plateaus physiographic province located in southern Illinois, southern Indiana, and western Kentucky. In Illinois it rests mainly in an east–west arc roughly following the outline ...
. The Interior Low Plateaus lie at the southern edge of the glacial boundary. Unlike the
till plain Till plains are an extensive flat plain of glacial till that forms when a sheet of ice becomes detached from the main body of a glacier and melts in place, depositing the sediments it carried. Ground moraines are formed with melts out of the glac ...
to the north, the underlying bedrock is generally close to the surface, and the topography of an area depends on how resistant the underlying bedrock is to erosion. More resistant sandstones have resulted in hillier areas such as the Norman Upland and Crawford Upland in Southern Indiana, while softer limestones have already eroded down to gently rolling plains, like the Scottsburg Lowlands and Wabash Lowlands of southeast and southwest Indiana. The hillier parts of the Interior Low Plateaus are not mountain ranges, but
dissected plateau A dissected plateau is a plateau area that has been severely eroded, and the relief is sharp. Such an area may be referred to as mountainous, but dissected plateaus are distinguishable from orogenic mountain belts by the lack of fold (geology), ...
s.


Natural Communities

The natural communities in this region are a matrix of forest, woodlands, and prairie. Today, much of the open prairie and savanna communities have been lost due to fire suppression and agriculture. However, oak-hickory woodlands remain relatively common, and mesic forest is abundant along riparian areas.


Woodlands

Oak-hickory woodland is the most common natural community in the Interior Low Plateaus. It is the dominant natural community for many areas of rolling hills, including the Western Highland Rim, Shawnee Hills, and Outer Bluegrass. These woodlands represent an intermediate state between a forest and a savanna. Common trees in this community include post oak (''
Quercus stellata ''Quercus stellata'', the post oak or iron oak, is a North American species of oak in the white oak section. It is a slow-growing oak that lives in dry areas on the edges of fields, tops of ridges, and also grows in poor soils, and is resistan ...
''), white oak (''
Quercus alba ''Quercus alba'', the white oak, is one of the preeminent hardwoods of eastern and central North America. It is a long-lived oak, native to eastern and central North America and found from Minnesota, Ontario, Quebec, and southern Maine south as ...
''), southern red oak ('' Quercus falcata''), black oak (''
Quercus velutina ''Quercus velutina'' (Latin 'velutina', "velvety") , the black oak, is a species of oak in the red oak group (''Quercus'' sect. ''Lobatae''), native and widespread in eastern and central North America. It is sometimes called the eastern black oak ...
''), and pignut hickory (''
Carya glabra ''Carya glabra'', the pignut hickory, is a common, but not abundant species of hickory in the oak-hickory forest association in the Eastern United States and Canada. Other common names are pignut, sweet pignut, coast pignut hickory, smoothbark ...
''). In more calcareous areas, common woodland trees include Shumard oak (''
Quercus shumardii ''Quercus shumardii'', the Shumard oak, spotted oak, Schneck oak, Shumard red oak, or swamp red oak, is one of the largest of the oak species in the red oak group (''Quercus'' section ''Lobatae''). It is closely related to '' Quercus buckleyi'' ...
''), Chinquapin oak (''
Quercus muhlenbergii ''Quercus muehlenbergii'', the chinquapin (or chinkapin) oak, is a deciduous species of tree in the white oak group (''Quercus'' sect. ''Quercus''). The species was often called ''Quercus acuminata'' in older literature. ''Quercus muehlenbergii'' ...
''), and Carolina shagbark ('' Carya carolinae-septentrionalis''). In more acidic dry woodlands there are stands of chestnut oak (''
Quercus montana ''Quercus montana'', the chestnut oak, is a species of oak in the white oak group, ''Quercus'' sect. ''Quercus''. It is native to the eastern United States, where it is one of the most important ridgetop trees from southern Maine southwest to ...
'') and Virginia pine (''
Pinus virginiana ''Pinus virginiana'', the Virginia pine, scrub pine, Jersey pine, possum pine, is a medium-sized tree, often found on poorer soils from Long Island in southern New York south through the Appalachian Mountains to western Tennessee and Alabama. Th ...
''). In swampy fragipan flats, woodlands consist of willow oak (''
Quercus phellos ''Quercus phellos'', the willow oak, is a North American species of a deciduous tree in the red oak group of oaks. It is native to the south-central and eastern United States. Description It is a medium-sized tree growing to tall (exceptiona ...
''), overcup oak (''
Quercus lyrata ''Quercus lyrata'', the overcup oak, is an oak in the white oak group (''Quercus'' sect. ''Quercus''). The common name, overcup oak, refers to its acorns that are mostly enclosed within the acorn cup. It is native to lowland wetlands in the east ...
''), pin oak (''
Quercus palustris ''Quercus palustris'', also called pin oak, swamp oak, or swamp Spanish oak, is a tree in the red oak section (''Quercus'' sect. ''Lobatae'') of the genus ''Quercus''. Pin oak is one of the most commonly used landscaping oaks in its native rang ...
''), sweetgum (''
Liquidambar styraciflua ''Liquidambar styraciflua'', commonly known as the American sweetgum among other names, is a deciduous tree in the genus ''Liquidambar'' native to warm temperate areas of eastern North America and tropical montane regions of Mexico and Central A ...
''), and blackgum (''
Nyssa sylvatica ''Nyssa sylvatica'', commonly known as tupelo, black tupelo, black gum or sour gum, is a medium-sized deciduous tree native to eastern North America from the coastal Northeastern United States and southern Ontario south to central Florida and ea ...
''). The woodlands in this region contain a rich sun-loving herbaceous layer, with many species of goldenrod (''
Solidago ''Solidago'', commonly called goldenrods, is a genus of about 100 to 120''Solidago''.
F ...
''), sunflower (''
Helianthus ''Helianthus'' () is a genus comprising around 70 species of annual and perennial flowering plants in the daisy family Asteraceae commonly known as sunflowers. Except for three South American species, the species of ''Helianthus'' are native to ...
''), and aster (''
Symphyotrichum ''Symphyotrichum'' () is a genus of over 100 species and naturally occurring hybrids of herbaceous annual and perennial plants in the composite family, Asteraceae, most which were formerly treated within the genus '' Aster''. The majority are ...
''). Image:Oak woodland Hoosier National Forest.jpg, Oak-hickory woodland in the Hoosier National Forest, Indiana Image:Pennyroyal Plain Flatwoods (montgomery co).JPG, Wet oak
flatwoods Flatwoods, pineywoods, pine savannas and longleaf pine–wiregrass ecosystem are terms that refer to an ecological community in the southeastern coastal plain of North America. Flatwoods are an ecosystem maintained by wildfire or prescribed fir ...
in the Pennyroyal Plain, Tennessee


Prairie and Savanna

The flat surfaces of the Interior Low Plateaus historically contained extensive areas of open prairie. This community was concentrated in the areas of the Mitchell Plain and
Pennyroyal Plain The Pennyroyal Plateau or Pennyroyal Region, often spelled Pennyrile, is a large physiographic region of Kentucky that features rolling hills, caves, and karst topography in general. It is named for ''Hedeoma pulegioides'' (the American pennyroyal ...
with smaller areas of prairie in the
Nashville Basin The Nashville Basin, also known as the Central Basin, is a term often used to describe the area surrounding Murfreesboro, Tennessee, in which Nashville is located. The Central Basin was caused by an uplifting which produced a dome known as the ...
and
Highland Rim The Highland Rim is a geographic term for the area in Tennessee, North Alabama, and Kentucky which surrounds the Central Basin. The Central Basin is a geological dome which has subsequently fractured and eroded to produce a basin. The Highland R ...
. Early settlers describe these areas as nearly treeless expanses, containing
Greater prairie chicken The greater prairie-chicken or pinnated grouse (''Tympanuchus cupido''), sometimes called a boomer,Friederici, Peter (July 20, 1989)"The Last Prairie Chickens" ''Chicago Reader''. Retrieved August 27, 2014.(Chinese 中文:帕艺明彩大凤 ...
and herds of Bison. Today, some prairie remains in areas that are managed by controlled burns, or other forms of tree removal such as powerline and roadside clearings. Dry prairies are the most common remnant in this region, due to their unsuitability for agriculture and resistance to succession. They are dominated by ''
Schizachyrium scoparium ''Schizachyrium scoparium'', commonly known as little bluestem or beard grass, is a species of North American prairie grass native to most of the contiguous United States (except California, Nevada, and Oregon) as well as a small area north of t ...
'' (little bluestem) and ''
Aristida purpurascens ''Aristida purpurascens'' is a species of grass known by the common name arrowfeather threeawn. It is native to eastern North America. One of the three varieties has a distribution extending south into Honduras. Description ''A. purpurascens'' t ...
'' (three-awn grass). Mesic prairies are rarer, and are dominated by very tall grasses such as Indian grass (''
Sorghastrum nutans ''Sorghastrum nutans'', known as Indiangrass, is a North American prairie grass found in the United States and Canada, especially in the Great Plains and tallgrass prairies. It is sometimes called Indian grass, yellow Indian-grass, or wood gras ...
''), big bluestem (''
Andropogon gerardi ''Andropogon gerardi'', commonly known as big bluestem, is a species of tall grass native to much of the Great Plains and grassland regions of central and eastern North America. It is also known as tall bluestem, bluejoint, and turkeyfoot. Taxon ...
''), and plume grass ('' Erianthus alopecuroides''). Wet prairies are the rarest and most poorly-documented grassland type in this region. The few existing remnants have species such as gamagrass (''
Tripsacum dactyloides ''Tripsacum dactyloides'', commonly called eastern gamagrass, or Fakahatchee grass, is a warm-season, sod-forming bunch grass. It is widespread in the Western Hemisphere, native from the eastern United States to northern South America.
''), prairie cordgrass ('' Spartina pectinata''), and many rushes (''
Juncus ''Juncus'' is a genus of monocotyledonous flowering plants, commonly known as rushes. It is the largest genus in the family Juncaceae, containing around 300 species. Description Rushes of the genus ''Juncus'' are herbaceous plants that superfici ...
'') and sedges (''
Carex ''Carex'' is a vast genus of over 2,000 species of grass-like plants in the family (biology), family Cyperaceae, commonly known as sedges (or seg, in older books). Other members of the family Cyperaceae are also called sedges, however those of ge ...
''). Significant prairie remnants now remain at
Ft. Campbell Fort Campbell is a United States Army installation located astride the Kentucky–Tennessee border between Hopkinsville, Kentucky and Clarksville, Tennessee (post address is located in Kentucky). Fort Campbell is home to the 101st Airborne Divi ...
and
Arnold Air Force Base Arnold Air Force Base (Arnold AFB) is a United States Air Force base located in Coffee County, Tennessee, Coffee and Franklin County, Tennessee, Franklin counties, Tennessee, adjacent to the city of Tullahoma, Tennessee, Tullahoma. It is named ...
, as well as in a few small nature preserves. Blackjack oak (''
Quercus marilandica ''Quercus marilandica'', the blackjack oak, is a small oak, one of the red oak group ''Quercus'' sect. ''Lobatae''. It is native to the eastern and central United States. Description ''Quercus marilandica'' is a small deciduous tree growing to ...
'') was reportedly one of the few trees that could occasionally survive the annual wildfires in the prairies. Image:Pennyroyal Plain mesic priaire at clarksville, November.jpg, Mesic prairie remnant in the Pennyroyal Plain, Tennessee Image:Inner Nashville Basin savanna with Ast bibulatus.jpg, Dry oak savanna in the Inner Nashville Basin, Tennessee


Forests

Closed-canopy forests in this region are also naturally found in many areas, such as riparian zones, river bottoms, and dissected terrain. Mesic forests are often found in narrow stream gorges. These forests have a particularly rich diversity in spring wildflowers. They are dominated by sugar maple (''
Acer saccharum ''Acer saccharum'', the sugar maple, is a species of flowering plant in the soapberry and lychee family Sapindaceae. It is native to the hardwood forests of eastern Canada and the eastern United States. Sugar maple is best known for being the p ...
''), beech (''
Fagus grandifolia Beech (genus ''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to subtropical (accessory forest element) and temperate (as dominant element of mesophytic forests) Eurasia and North America. There are 14 accepted species i ...
''), basswood (''
Tilia americana ''Tilia americana'' is a species of tree in the family Malvaceae, native to eastern North America, from southeast Manitoba east to New Brunswick, southwest to northeast Oklahoma, southeast to South Carolina, and west along the Niobrara River to ...
''), northern red oak (''
Quercus rubra ''Quercus rubra'', the northern red oak, is an oak tree in the red oak group (''Quercus'' section ''Lobatae''). It is a native of North America, in the eastern and central United States and southeast and south-central Canada. It has been intro ...
''), and tuliptree (''
Liriodendron tulipifera ''Liriodendron tulipifera''—known as the tulip tree, American tulip tree, tulipwood, tuliptree, tulip poplar, whitewood, fiddletree, lynn-tree, hickory-poplar, and yellow-poplar—is the North American representative of the two-species genus ...
''). In the Eastern Highland Rim, at the edge of the Cumberland Plateau, these forests develop a more Appalachian character, and contain species such as eastern hemlock (''
Tsuga canadensis ''Tsuga canadensis'', also known as eastern hemlock, eastern hemlock-spruce, or Canadian hemlock, and in the French-speaking regions of Canada as ''pruche du Canada'', is a Pinophyta, coniferous tree native plant, native to eastern North America. ...
''), yellow buckeye (''
Aesculus flava ''Aesculus flava'', also known commonly as the common buckeye, the sweet buckeye, and the yellow buckeye, is a species of deciduous tree in the subfamily Hippocastanoideae of the family Sapindaceae. The species is native to the Ohio Valley and ...
''), and cucumber magnolia ('' Magnolia tripetala''). Acidic sandstone cove forests in the Shawnee Hills also contain more typically Appalachian species such as yellow birch (''
Betula alleghaniensis ''Betula alleghaniensis'', the yellow birch, golden birch, or swamp birch, is a large tree and an important lumber species of birch native to northeastern North America. Its vernacular names refer to the golden color of the tree's bark. In the pa ...
'') and umbrella magnolia ('' Magnolia tripetala''). Floodplain forests in the Interior Low Plateau remain relatively common, although many areas have been converted to agriculture. These forests are dominated by sugarberry (''
Celtis laevigata ''Celtis laevigata'' is a medium-sized tree native to North America. Common names include sugarberry, southern hackberry, or in the southern U.S. sugar hackberry or just hackberry. Sugarberry is easily confused with common hackberry ('' C. occ ...
''), boxelder (''
Acer negundo ''Acer negundo'', also known as the box elder, boxelder maple, Manitoba maple or ash-leaved maple, is a species of maple native to North America from Canada to Honduras. It is a fast-growing, short-lived tree with opposite, ash-like compound l ...
''), silver maple (''
Acer saccharinum ''Acer saccharinum'', commonly known as silver maple, creek maple, silverleaf maple, soft maple, large maple, water maple, swamp maple, or white maple, is a species of maple native to the eastern and central United States and southeastern Canad ...
''), and sycamore (''
Platanus occidentalis ''Platanus occidentalis'', also known as American sycamore, American planetree, western plane, occidental plane, buttonwood, and water beech, is a species of ''Platanus'' native to the eastern and central United States, the mountains of northeast ...
''). Forests were particularly common in the uplands of the Inner Bluegrass region of Kentucky, which has naturally mesic conditions. These forests were dominated by sugar maple (''
Acer saccharum ''Acer saccharum'', the sugar maple, is a species of flowering plant in the soapberry and lychee family Sapindaceae. It is native to the hardwood forests of eastern Canada and the eastern United States. Sugar maple is best known for being the p ...
''), bitternut hickory (''
Carya cordiformis ''Carya cordiformis'', the bitternut hickory, also called bitternut, yellowbud hickory, or swamp hickory, is a large hickory species native to the eastern United States and adjacent Canada. Notable for its unique sulphur-yellow buds, it is one ...
''), Ohio buckleye (''
Aesculus glabra ''Aesculus glabra'', commonly known as Ohio buckeye,''Aesculus ...
''), blue ash (''
Fraxinus quadrangulata ''Fraxinus quadrangulata'', the blue ash, is a species of ash native primarily to the Midwestern United States from Oklahoma to Michigan, as well as the Bluegrass region of Kentucky and the Nashville Basin region of Tennessee. Isolated popula ...
''), and chinquapin oak (''
Quercus muhlenbergii ''Quercus muehlenbergii'', the chinquapin (or chinkapin) oak, is a deciduous species of tree in the white oak group (''Quercus'' sect. ''Quercus''). The species was often called ''Quercus acuminata'' in older literature. ''Quercus muehlenbergii'' ...
''). This community is now quite rare in the Inner Bluegrass due to logging by early European settlers. Its destruction was so rapid and complete, that mid-20th century ecologists mistook the successional state of the Bluegrass as its natural condition. Sun-loving species such as hackberry (''
Celtis occidentalis ''Celtis occidentalis'', commonly known as the common hackberry, is a large deciduous tree native to North America. It is also known as the nettletree, beaverwood, northern hackberry, and American hackberry. It is a moderately long-lived hardwoo ...
''), black cherry (''
Prunus serotina ''Prunus serotina'', commonly called black cherry,World Economic Plants: A Standard Reference, Second Edition'. CRC Press; 19 April 2016. . p. 833–. wild black cherry, rum cherry, or mountain black cherry, is a deciduous tree or shrub in the r ...
''), black walnut (''
Juglans nigra ''Juglans nigra'', the eastern American black walnut, is a species of deciduous tree in the walnut family, Juglandaceae, native to central and eastern North America, growing mostly in riparian zones. Black walnut is susceptible to thousand can ...
''), and white ash (''
Fraxinus americana ''Fraxinus americana'', the white ash or American ash, is a fast-growing species of ash tree native to eastern and central North America. White ash trees are threatened by the invasive emerald ash borer. The tree is highly valued as lumber. ...
'') now dominate much of the Bluegrass region. Image:Pennyroyal Plain riparian forest (Christian co).JPG, Bottomland forest in the Pennyroyal Plain, Kentucky Image:TN calcareous riparian forest.jpg, Calcareous riparian forest in the Western Highland Rim, Tennessee


Barrens and Glades

Barrens are open treeless areas on slopes, often with shallow soil. These are found sporadically in the Outer Bluegrass, Inner Nashville Basin, Shawnee Hills, and in parts of the Highland Rim. It is unclear whether these communities rely on fire for their openness, or are maintained by soil conditions alone. They are usually dominated by short grasses such as little bluestem (''
Schizachyrium scoparium ''Schizachyrium scoparium'', commonly known as little bluestem or beard grass, is a species of North American prairie grass native to most of the contiguous United States (except California, Nevada, and Oregon) as well as a small area north of t ...
''), and large showy forbs such as prairie dock ('' Silphium terebinthinaceum'') and blazing star (''
Liatris ''Liatris'' (), commonly known as gayfeather and blazing star is a genus of flowering plants in the tribe Eupatorieae within the family Asteraceae native to North America (Canada, United States, Mexico and the Bahamas). Some species are used ...
''). Barrens are particularity abundant and well-preserved in the area of Adams County, Ohio, which includes Adams Lake Prairie,
Lynx Prairie Lynx Prairie is a nature preserve located in Adams County, Ohio, United States, near the community of Lynx. The preserve features a group of cedar glades which harbor rare prairie species, surrounded by forests on all sides. The prairie speci ...
, Chaparral Prairie, and others. Glades are areas of flat rock exposures of bedrock. In the Nashville Basin, glades are most often found in areas that were a matrix of barren and woodland communities. Although historically with a more open grassland border, many are now surrounded by dense thickets of redcedar (''
Juniperus virginiana ''Juniperus virginiana'', also known as eastern redcedar, red cedar, Virginian juniper, eastern juniper, red juniper, and other local names, is a species of juniper native to eastern North America from southeastern Canada to the Gulf of Mexico an ...
'') and redbud (''
Cercis canadensis ''Cercis canadensis'', the eastern redbud, is a large deciduous shrub or small tree, native to eastern North America from southern Michigan south to central Mexico, west to New Mexico. Species thrive as far west as California and as far north as ...
''). Glades are most common the Nashville Basin, although there are rare examples found in the Mitchell Plain, Pennyroyal Plain and Outer Bluegrass. Glades have a flora adapted to extreme dry conditions in the summer, and standing water in the spring. The glades of the Nashville Basin and Moulton Valley are considered a center endemism due to their large number of restricted species. Characteristic species of the Nashville Basin glades include Nashville glade cress ('' Leavenworthia stylosa''), limestone fame-flower (''
Phemeranthus calcaricus ''Phemeranthus'' (fameflower) is a genus of flowering plants in the miner's lettuce family, Montiaceae, native to the Americas. It was formerly placed in Portulacaceae. The name is derived from the Greek words εφήμερος (''ephemeros''), ...
''), Nashville breadroot (''
Pediomelum subacaule ''Pediomelum'' is a genus of legumes known as Indian breadroots. These are glandular perennial plants with palmately-arranged leaves. They have a main erect stem with inflorescences of blue or purple flowers and produce hairy legume pods containi ...
''), Gattinger's prairie clover (''
Dalea gattingeri ''Dalea'' is a genus of flowering plants in the legume family, Fabaceae. Members of the genus are commonly known as prairie clover or indigo bush. Its name honors English apothecary Samuel Dale (1659–1739). They are native to the Western hemi ...
''), and Tennessee milk-vetch ('' Astragalus tennesseensis''). Glades in other regions contain less endemism, and are characterized by species such as widow's-cross stonecrop ('' Sedum pulchellum''), limestone skullcap ('' Scutellaria parvula''), glade violet ('' Viola egglestonii''), one-flower gladecress ('' Leavenworthia uniflora''), and poverty dropseed ('' Sporobolus vaginiflorus''). Glade remnants are common and well-preserved due to their undesirability for agriculture, and their largely edaphic nature. Many examples exist in
Cedars of Lebanon State Park Cedars of Lebanon State Park is a state park in Wilson County, Tennessee, in the southeastern United States. It consists of situated amidst the Cedars of Lebanon State Forest. The park and forest are approximately south of Lebanon, Tennessee ...
, as well as numerous other natural areas. Image:Couchville glade.jpg, Limestone glade in the Inner Nashville Basin, Tennessee Image:Outer Bluegrass dolomite barren (Lewis co).JPG, Dolomite barren in the Outer Bluegrass, Kentucky


Wetlands

The Interior Low Plateau has an abundance of sinkhole ponds in the karst regions of the Mitchell Plain, Pennyroyal Plain, and Highland Rim. These isolated communities were historically found within a matrix of wet prairie. These communities are often covered in swamp forest, and are dominated by swamp cottonwood (''
Populus heterophylla ''Populus heterophylla'', also known as downy poplar, swamp poplar and swamp cottonwood, is a large deciduous poplar belonging to the ''Populus'' genus of the family ''Salicaceae''. This species can grow on sites that have too much water for oth ...
'') and red maple (''
Acer rubrum ''Acer rubrum'', the red maple, also known as swamp maple, water maple, or soft maple, is one of the most common and widespread deciduous trees of eastern and central North America. The U.S. Forest Service recognizes it as the most abundant nati ...
''). High-quality herbaceous examples have species with coastal plain affinities. Many of these communities have been destroyed due to drainage for agriculture. Emergent shrub sloughs are found along the bottoms of major rivers, such as the Cumberland River and Tennessee River. These are dominated by buttonbush (''
Cephalanthus occidentalis ''Cephalanthus occidentalis'' is a species of flowering plant in the family Rubiaceae that is native to eastern and southern North America. Common names include buttonbush, common buttonbush, button-willow, buck brush, and honey-bells. Descripti ...
''), and along the Tennessee River contain bald-cypress (''
Taxodium distichum ''Taxodium distichum'' (baldcypress, bald-cypress, bald cypress, swamp cypress; ; ''cipre'' in Louisiana) is a deciduous conifer in the family Cupressaceae. It is native to the southeastern United States. Hardy and tough, this tree adapts to a ...
''). These sloughs were historically widespread, but dam construction and agricultural activity have destroyed most of them. A rare wetland type in this region is the calcareous seepage fen. These are found sparingly in the Highland Rim, and are dominated by grass of Parnassus (''
Parnassia grandifolia ''Parnassia grandifolia'', also known as bigleaf grass of Parnassus, is a flowering herbaceous plant of the family Celastraceae. It is native to the southeastern United States, where it has a spotty distribution. Its primary habitat is open wet ...
'') and contain the federally-endangered Tennessee yellow-eyed grass ('' Xyris tennesseensis''). Calcareous seeps are also found near glades in the Inner Nashville Basin. These communities often have extensive stands of sunnybells ('' Schoenolirion croceum'') and other rare species. Calcareous seeps and swamp forest are also found sparingly in the Bluegrass region. These contain trees such as green ash (''
Fraxinus pennsylvanica ''Fraxinus'' (), commonly called ash, is a genus of plants in the olive and lilac family, Oleaceae, and comprises 45–65 species of usually medium-to-large trees, most of which are deciduous trees, although some subtropical species are ever ...
'') and swamp white oak (''
Quercus bicolor ''Quercus bicolor'', the swamp white oak, is a North American species of medium-sized trees in the beech family. It is a common element of America's north central and northeastern mixed forests. It can survive in a variety of habitats. It forms ...
''), along with many herbaceous plants that are considered regionally rare. Image:Nashville Basin fen.jpg, Calcareous seepage fen in the Inner Nashville Basin, Tennessee Image:Western Highland Rim- Bottomland Emergent Marsh, (Marks Slough).jpg, Emergent slough along the Cumberland River, Tennessee


Fauna

This region contains the richest diversity of freshwater animals in North America. In particular, the Duck River in Tennessee is considered one of the top three most biologically rich rivers in the world, containing over 150 species of fish, 60 species of freshwater mussels, and 22 species of aquatic snails. The Green River in this region also harbors diversity of a similar scale. This high amount of freshwater mussel diversity is due to the limestone bedrock underlying much of the region. The limestone creates calcareous water that acts as a buffer against acidity, which helps the mussels in shell-building. Birds of the woodlands include
vireo The vireos make up a family, Vireonidae, of small to medium-sized passerine birds found in the New World (Canada to Argentina, including Bermuda and the West Indies) and Southeast Asia. The family contains 62 species and is divided into eight ...
s and
tanager The tanagers (singular ) comprise the bird family (biology), family Thraupidae, in the order Passeriformes. The family has a Neotropical distribution and is the second-largest family of birds. It represents about 4% of all avian species and 12 ...
s while mammals include Eastern gray squirrels,
chipmunk Chipmunks are small, striped rodents of subtribe Tamiina. Chipmunks are found in North America, with the exception of the Siberian chipmunk which is found primarily in Asia. Taxonomy and systematics Chipmunks are classified as four genera: '' ...
s,
raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the North American, northern or common raccoon (also spelled racoon) to distinguish it from Procyonina, other species of raccoon, is a mammal native to North America. It is the largest ...
s and
opossum Opossums () are members of the marsupial order Didelphimorphia () endemic to the Americas. The largest order of marsupials in the Western Hemisphere, it comprises 126 species in 18 genera. Opossums originated in South America and entered North A ...
s.


Threats

The dominance of oak in this part of the
pre-Columbian savannas of North America Pre-Columbian woodlands of North America, consisting of a mixed woodland-grassland ecosystem, were maintained by both natural lightning fires and by Native Americans before the significant arrival of Europeans. Although decimated by widespread ...
was due to frequent fires. The
fire suppression Fire suppression may refer to: * Firefighting * Fire suppression systems * Wildfire suppression Wildfire suppression is a range of firefighting tactics used to suppress wildfires. Firefighting efforts depend on many factors such as the availabl ...
policies since the 1930s have been a significant forest disturbance. Today there is very little intact habitat in this ecoregion, with a reduction of
bottomland hardwood forest Bottomland forest is woodland on lowland alluvial floodplains or lower terraces of rivers and streams. Bottomland forest is very rare in Europe. The bottomland hardwood forest is a type of deciduous and evergreen hardwood forest found in broad low ...
s by 70–95%, and only 0.02 percent of the original oak savannas remain. Although much of the area is forested, these forests tend to be highly fragmented and significantly altered by development, agriculture, and fire suppression. The forests are dominated primarily by oak and hickory species, but
succession Succession is the act or process of following in order or sequence. Governance and politics *Order of succession, in politics, the ascension to power by one ruler, official, or monarch after the death, resignation, or removal from office of ...
has filled the understory with
maple ''Acer'' is a genus of trees and shrubs commonly known as maples. The genus is placed in the soapberry family Sapindaceae.Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 9, June 2008 nd more or less continuously updated si ...
s and
yellow poplar ''Liriodendron tulipifera''—known as the tulip tree, American tulip tree, tulipwood, tuliptree, tulip poplar, whitewood, fiddletree, lynn-tree, hickory-poplar, and yellow-poplar—is the North American representative of the two-species genus ...
and blocking oak regeneration. In some areas, habitat is threatened by urbanization and invasive species such as non-native
privet A privet is a flowering plant in the genus ''Ligustrum''. The genus contains about 50 species of erect, deciduous or evergreen shrubs or trees, with a native distribution from Europe to tropical and subtropical Asia, and with one species each ...
,
honeysuckle Honeysuckles are arching shrubs or Vine#Twining vines, twining vines in the genus ''Lonicera'' () of the family Caprifoliaceae. The genus includes 158 species native to northern latitudes in North America, Eurasia, and North Africa. Widely kno ...
,
garlic mustard ''Alliaria petiolata'', or garlic mustard, is a biennial flowering plant in the mustard family (Brassicaceae). It is native to Europe, western and central Asia, north-western Africa, Morocco, Iberia and the British Isles, north to northern S ...
and
kudzu Kudzu (), also called Japanese arrowroot or Chinese arrowroot, is a group of climbing, coiling, and trailing deciduous perennial vines native to much of East Asia, Southeast Asia, and some Pacific islands. It is invasive species, invasive in ...
.


Protected Land

Significant natural areas in the ecoregion include: Mammoth Cave National Park; the Land Between the Lakes National Recreation Area of Tennessee and Kentucky;
Hoosier National Forest The Hoosier National Forest is a property managed by the United States Forest Service in the hills of Southern Indiana, southern Indiana. Composed of four separate sections, it has a total area of . Hoosier National Forest's headquarters are loc ...
and
Yellowwood State Forest Yellowwood State Forest, originally Beanblossom Land Utilization Project, is a state forest located in Brown County, Indiana, near the more famous Brown County State Park. The forest features seventeen different areas within Brown County, com ...
in southern
Indiana Indiana ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Michigan to the northwest, Michigan to the north and northeast, Ohio to the east, the Ohio River and Kentucky to the s ...
; the Edge of Appalachia Preserve in
Ohio Ohio ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the ...
; and the
Shawnee Hills The Shawnee Hills are a region within the larger Interior Low Plateaus physiographic province located in southern Illinois, southern Indiana, and western Kentucky. In Illinois it rests mainly in an east–west arc roughly following the outline ...
in southern
Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. It borders on Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash River, Wabash and Ohio River, Ohio rivers to its ...
.


See also

*
Physiographic regions of the world Physiographic regions are a means of defining Earth's landforms into independently distinct, mutually exclusive areas, independent of political boundaries. It is based upon the classic three-tiered approach by Nevin M. Fenneman in 1916, that separ ...
*
List of ecoregions in the United States (EPA) This list provides an overview of United States ecoregions designated by the U.S. Environmental Protection Agency (EPA) and the Commission for Environmental Cooperation (CEC). The CEC was established in 1994 by the member states of Canada, Mex ...
the USEPA uses the designation, and assigns to it, number 71 *
List of ecoregions in the United States (WWF) The following is a list of United States ecoregions as identified by the World Wide Fund for Nature (WWF). The United States is a megadiverse country with a high level of endemism across a wide variety of ecosystems. Terrestrial ecoregions The ...
, the WWF provides an alternate classification and includes this region in primarily its Central U.S. hardwood forests designation


References


External links

* * {{NatGeo ecoregion, id=na0404, name=Central U.S. hardwood forests
Central U.S. hardwood forests images at bioimages.vanderbilt.edu
Temperate broadleaf and mixed forests in the United States Ecoregions of the United States Plant communities of Alabama Plant communities of Indiana Plant communities of Kentucky Plant communities of Ohio Plant communities of Tennessee Forests of the United States Geomorphology Ecoregions of Indiana