ML18026B253

USGS-1998 - Tn 5159 - USGS 1998 Eco Tn

ML18026B253
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Site:	Clinch River
Issue date:	01/26/2018
From:	State of TN, Dept of Environment & Conservation, US Dept of Interior, Geological Survey (USGS)
To:	Office of New Reactors
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90° 89° 88° 87° Ecoregions of Tennessee 86° 85° 84° 83° 82° 70 Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental 71 68 67 resources; they are designed to serve as a spatial framework for the research, assessment, management, and monitoring 69 KENTUCKY of ecosystems and ecosystem components. Ecoregions are directly applicable to the immediate needs of state VIRGINIA 74 agencies, such as the Tennessee Department of Environment and Conservation (TDEC), for selecting regional stream 68c 67 i reference sites and identifying high-quality waters, developing ecoregion-specific chemical and biological water KY Lake 71e 71g R iv er 67hRiver 66f quality criteria and standards, and augmenting TDECs watershed management approach. Ecoregion frameworks are Barkley l er el inc h R iv g also relevant to integrated ecosystem management, an ultimate goal of most federal and state resource management Clarksville Dale Hollow ow Cl on 67 P lst Reelfoot Lake Ho f agencies.

h Lake Kentucky 69d 67f 67h 67 66 The approach used to compile this map is based on the premise that ecological regions can be identified through the 74a Lake Old Hickory analysis of the patterns and the composition of biotic and abiotic phenomena that affect or reflect differences in r Norris Johnson Lake iv e nd R Lake City ecosystem quality and integrity (Wiken 1986; Omernik 1987, 1995). These phenomena include geology, Cumb b e r la 67f Riv er erla C um physiography, vegetation, climate, soils, land use, wildlife, and hydrology. The relative importance of each io n nd Ob Ri characteristic varies from one ecological region to another regardless of the hierarchical level. A Roman numeral ve Cherokee Lake Ri 66d hierarchical scheme has been adopted for different levels of ecological regions. Level I is the coarsest level, dividing r

71h ver 66e iv e r y North America into 15 ecological regions, with level II dividing the continent into 52 regions. At level III, the iR 68c ck hu i

67 li c continental United States contains 99 regions (United States Environmental Protection Agency [USEPA] 1997). Level ssiss 74a Nashville No ipp IV is a further subdivision of level III ecoregions. Explanations of the methods used to define USEPAs ecoregions 36° MISSOURI Mi 67g 36° are given in Omernik (1995), Griffith et al. (1994, 1997), and Gallant et al. (1989).

Middl Center Hill ARKANSAS 73a iver eF Lake Oak g g 66d ed Dee rR o J Percy 68a Ridge 67 67 Douglas 66g This level III and IV ecoregion map was compiled at a scale of 1:250,000; it depicts revisions and subdivisions of Fork Priest Lake e

earlier level III ecoregions that were originally compiled at a smaller scale (USEPA 1996; Omernik 1987). The poster rk Fork Lake Knoxville 73 Sparta Crossville 71f is part of a collaborative project primarily between the USEPA National Health and Environmental Effects Research d D e er Ri Fort Loudoun 66e Laboratory - Corvallis, OR., and TDECs Division of Water Pollution Control. Collaboration and consultation also 74b Lake h ver 67 74a Murfreesboro occurred with the United States Department of Agriculture - Natural Resources Conservation Service (NRCS), the S 66e United States Department of Agriculture - Forest Service (USFS), USEPA Region IV, and with other State of ou th 65e 71i Tennessee agencies.

74a Fo rk Forked 71g e Fr en c h De This project is associated with an interagency effort to develop a common framework of ecological regions. Reaching Little Te n n er R iver Duc McMinnville Watts Bar 67f 66f kR Lake that objective requires recognition of the differences in the conceptual approaches and mapping methodologies that Jackson ive iv er r have been used to develop the most commonly used existing ecoregion-type frameworks, including those developed Broad R Columbia er ver ss eR by the USFS (Bailey et al. 1994), the USEPA (Omernik 1987, 1995), and the NRCS (U.S. Department of Agriculture iv Ri e

ie R ee iv e r 66g 66 1981). As each of these frameworks is further developed, the differences between them lessen. Regional 74a atc Tenn collaborative projects such as this one in Tennessee, where some agreement can be reached among multiple resource 71h h ess o River Fontana management agencies, is a step in the direction of attaining commonality and consistency in ecoregion frameworks for Buffal qu Se Lake Ha h the entire nation.

67 tchie 67i r 67 R ive Rive r ch i Literature Cited:

Loo sahat ie b Lit tl e 68 Te Bailey, R.G., Avers, P.E., King, T., and McNab, W.H., eds., 1994, Ecoregions and subregions of the United States (map)

Chickamauga nn r Tims Ford Lake e s N O R T H C A R O L IN A (supplementary table of map unit descriptions compiled and edited by McNab, W.H. and Bailey, R.G.): Washington, D.C., U.S.

Lawrenceburg Ten nessee Riv e see Riv er W Lake Hiw S O U T H C A R O L IN A Department of Agriculture - Forest Service, scale 1:7,500,000.

olf 67g assee R ive r Memphis Ri ve r 67h Gallant, A.L., Whittier, T.R., Larsen, D.P., Omernik, J.M., and Hughes, R.M., 1989, Regionalization as a tool for managing Elk River 67f e 66 environmental resources: Corvallis, Oregon, U.S. Environmental Protection Agency EPA/600/3-89/060, 152 p.

65j 45 65b 65a Griffith, G.E., Omernik, J.M., Wilton, T.F., and Pierson, S.M., 1994, Ecoregions and subregions of Iowa - a framework for water Pickwick 35° Lake 67g 35° quality assessment and management: The Journal of the Iowa Academy of Science, v. 101, no. 1, p. 5-13.

MISSISSIPPI 65i 68c Chattanooga 68c Griffith, G.E., Omernik, J.M., and Azevedo, S.H., 1997, Ecoregions of Tennessee: Corvallis, Oregon, U.S. Environmental AL ABAMA GEORGIA Protection Agency EPA/600R-97/022, 51 p.

74 65 71 66 68 67 Omernik, J.M., 1987, Ecoregions of the conterminous United States (map supplement): Annals of the Association of American 68 Geographers, v. 77, no. 1, p. 118-125, scale 1:7,500,000.

INTERIORGEOLOGICAL SURVEY, RESTON, VIRGINIA1998 90° 89° 88° 87° 86° 85° 84° 83° 82° Omernik, J.M., 1995, Ecoregions - a framework for environmental management, in Davis, W.S. and Simon, T.P., eds., Biological assessment and criteria - tools for water resource planning and decision making: Boca Raton, Florida, Lewis Publishers, p. 49-62.

Level III Ecoregions of the Conterminous United States 1 Coast Range 2 Puget Lowland 27 Central Great Plains 28 Flint Hills 54 Central Corn Belt Plains 55 Eastern Corn Belt Plains U.S. Department of Agriculture - Soil Conservation Service, 1981, Land resource regions and major land resource areas of the 1 2 77 3 Willamette Valley 29 Central Oklahoma/Texas Plains 56 Southern Michigan/Northern Indiana United States: Agriculture Handbook 296, 156 p.

41 42 4 Cascades 5 Sierra Nevada 30 Edwards Plateau 31 Southern Texas Plains Drift Plains 65 Southeastern Plains 67 Ridge and Valley 69 Central Appalachians 73 Mississippi Alluvial Plain SCALE 1:940 000 10 49 58 57 Huron/Erie Lake Plains U.S. Environmental Protection Agency, 1997, Level III ecoregions of the continental United States (revision of Omernik, 1987):

1 3 15 16 48 6 Southern and Central California Chaparral and Oak Woodlands 32 Texas Blackland Prairies 58 Northeastern Highlands 65a Blackland Prairie 67f Southern Limestone/Dolomite 69d Cumberland Mountains 73a Northern Mississippi Alluvial Plain 10 0 20 40 mi Corvallis, Oregon, U.S. Environmental Protection Agency - National Health and Environmental Effects Research Laboratory Map 11 33 East Central Texas Plains 59 Northeastern Coastal Zone 4 15 16 17 16 17 43 51 50 51 50 58 7 Central California Valley 34 Western Gulf Coastal Plain 60 Northern Appalachian Plateau 65b Flatwoods/Alluvial Prairie Margins Valleys and Low Rolling Hills M-1, various scales.

9 46 8 Southern California Mountains 35 South Central Plains and Uplands 20 0 40 80 km 78 12 17 57 60 62 59 9 Eastern Cascades Slopes and 36 Ouachita Mountains 61 Erie/Ontario Drift and Lake Plains 65e Southeastern Plains and Hills 67g Southern Shale Valleys 71 Interior Plateau 74 Mississippi Valley Loess Plains Wiken, E., 1986, Terrestrial ecozones of Canada: Ottawa, Environment Canada, Ecological Land Classification Series no. 19, 26 p.

52 53 Foothills 37 Arkansas Valley Albers equal area projection 18 44 47 56 57 61 62 67 10 Columbia Plateau 38 Boston Mountains 62 North Central Appalachians 63 Middle Atlantic Coastal Plain 65i Fall Line Hills 67h Southern Sandstone Ridges 71e Western Pennyroyal Karst 74a Bluff Hills Standard parallels 35° 20' N and 36° 15' N 19 64 63 11 Blue Mountains 39 Ozark Highlands 1

5 13 25 54 55 70 12 Snake River Basin/High Desert 40 Central Irregular Plains 64 Northern Piedmont 65 Southeastern Plains 65j Transition Hills 67i Southern Dissected Ridges and 71f Western Highland Rim 74b Loess Plains 7 13 Northern Basin and Range 41 Canadian Rockies*

8 20 21 27 28 40 69 14 Southern Basin and Range 42 Northwestern Glaciated Plains 66 Blue Ridge Mountains 67 Ridge and Valley Knobs 71g Eastern Highland Rim 6 72 15 Northern Rockies PRINCIPAL AUTHORS: Glenn Griffith (USEPA), James Omernik (USEPA) and 8 22 39 71 67 45 16 Montana Valley and Foothill 43 Northwestern Great Plains 44 Nebraska Sand Hills 68 Southwestern Appalachians 69 Central Appalachians 66 Blue Ridge Mountains 71h Outer Nashville Basin Sandra Azevedo (OAO Corporation).

14 26 6 37 38 66 63 Prairies 45 Piedmont*

46 Northern Glaciated Plains 70 Western Allegheny Plateau 66d Southern Igneous Ridges and Mountains 68 Southwestern Appalachians 71i Inner Nashville Basin 17 Middle Rockies 71 Interior Plateau 23 25 36 73 68 18 Wyoming Basin 47 Western Corn Belt Plains 72 Interior River Lowland 66e Southern Sedimentary Ridges 68a Cumberland Plateau Level III ecoregion COLLABORATORS AND CONTRIBUTORS: John Jenkins (NRCS), Richard 23 19 Wasatch and Uinta Mountains 48 Lake Agassiz Plain 73 Mississippi Alluvial Plain 79 29 32 35 74 65 20 Colorado Plateaus 49 Northern Minnesota Wetlands 74 Mississippi Valley Loess Plains 66f Limestone Valleys and Coves 68b Sequatchie Valley Level IV ecoregion Livingston (NRCS), James Keys (USFS); Phil Stewart (TDEC), Greg Russell 21 Southern Rockies 50 Northern Lakes and Forests (TDEC), Alan Woods (Dynamac Corporation), Joy Broach (TDEC), Linda 24 30 33 22 Arizona/New Mexico Plateau 51 North Central Hardwood 75 Southern Coastal Plain 76 Southern Florida Coastal Plain 66g Southern Metasedimentary Mountains 68c Plateau Escarpment County boundary Cartwright (TDEC), Debbie Arnwine (Tennessee Department of Health), and USDA Natural Resources 32 Forests Tennessee Department of 34 75 23 Arizona/New Mexico Mountains 24 Southern Deserts 52 Driftless Area 77 North Cascades*

78 Klamath Mountains*

State boundary Thomas Loveland (USGS). Environment and Conservation Conservation Service 31 25 Western High Plains 53 Southeastern Wisconsin Till 79 Madrean Archipelago*

76 26 Southwestern Tablelands Plains

• Level III ecoregions identified in the ecoregion revision and subdivision process subsequent to the original map compilation (Omernik 1987).

65. Southeastern Plains These irregular plains have a mosaic of cropland, pasture, woodland, and oak-hickory-pine forest. The Cretaceous or Tertiary-age sands, silts, and clays of the region contrast geologically with the older limestone, chert, and shale found in the Interior Plateau (71). Elevations and relief are greater than the loess plains of Ecoregion 74 to the west, but generally less than the Coal mining in the Cumberland Mountains (69d).

Interior Plateau (71) to the east. Streams in this area are relatively low-gradient and sandy-bottomed.

The Blackland Prairie, extending north from Mississippi, is a flat to undulating elevations reaching over 650 feet, and more rolling topography and more relief than the 69. Central Appalachians 65a lowland region covering only a small portion of McNairy County, Tennessee. Loess Plains (74b) to the west, streams have increased gradient, generally sandy substrates, The Central Appalachian ecoregion, stretching from northern Tennessee to central Pennsylvania, is primarily a high, dissected, rugged plateau composed of sandstone, shale, conglomerate, Although there is some of the Cretaceous-age chalk, marl, and calcareous clay that and distinctive faunal characteristics for west Tennessee. The natural vegetation type is and coal. The rugged terrain, cool climate, and infertile soils limit agriculture, resulting in a mostly forested landcover. The high hills and low mountains are covered by a mixed mesophytic characterizes the region in Mississippi and Alabama, the northern extent of the Blackland oak-hickory forest, grading into oak-hickory-pine to the south. forest with areas of Appalachian oak and northern hardwoods forest. Bituminous coal mines are common, and have caused the siltation and acidification of streams.

Pasture with some cropland is common on Clearcut on commercial forest land in Prairie in Tennessee is not distinct. To the south, the natural vegetation had dominant trees of sweetgum, post oak, and red cedar, along with patches of bluestem prairie. Today, the 65i The Fall Line Hills ecoregion, comprising the Tennessee or Tombigbee Hills in Mississippi and the Fall Line Hills in Alabama, is composed primarily of the better-drained land of the Flatwoods/

Alluvial Prairie Margins (65b).

Ecoregion 65e.

The Cumberland Mountains, in contrast to the sandstone-dominated Cumberland well-drained, loamy, and acidic, with low fertility. The natural vegetation is a mixed area is mostly in cropland and pasture, with small patches of mixed hardwoods. Cretaceous-age coastal plain sandy sediments. The sand and chert gravel surficial materials 69d Plateau (68a) to the west and southwest, are more highly dissected, with narrow- mesophytic forest, although composition and abundance vary greatly depending on aspect, are covered by sandy loam topsoils. It is mostly forested terrain of oak-hickory-pine on crested steep slopes, and younger Pennsylvanian-age shales, sandstones, siltstones, and slope position, and degree of shading from adjacent land masses. Large tracts of land are The Flatwoods/Alluvial Prairie Margins extend north from Mississippi, but the 65b distinctiveness of this narrow ecoregion belt fades quickly from Ripley, Mississippi open hills with 100-200 feet of relief. Elevations in the small Tennessee portion, roughly coal. Narrow, winding valleys separate the mountain ridges, and relief is often 2000 feet. owned by lumber and coal companies, and there are many areas of stripmining.

north into Tennessee. In Mississippi and Alabama, this is a transition region between the between Chambers Creek and Pickwick Lake in Hardin County, are 450-685 feet. Cross Mountain, west of Lake City, reaches 3534 feet in elevation. Soils are generally White-tail deer populations have increased Blackland Prairie and the more forested plains and hills. Some areas, as the Flatwoods The Transition Hills have the highest elevations in Ecoregion 65, and contain in many Tennessee ecoregions in recent name implies, are heavily forested, but the prairie and alluvial areas now have significant 65j characteristics of both the Southeastern Plains and the Interior Plateau (71) decades.

amounts of cropland and pasture. In Tennessee, the small region stands out as lower, less ecoregions. Many streams of this transition area have cut down into the Mississippian, The rugged Cumberland Mountains of the Frozen Head State Natural Area also contain hilly agricultural land compared to the forested Southeastern Plains and Hills (65e) that Devonian, and Silurian-age rocks and may look similar to those of the Interior Plateau (71). 120 species of spring wildflowers.

surround it. Cretaceous-age coastal plain deposits of silt, sand, clay, and gravel, however, overlie the View of Ecoregion 65es rolling plains and hills from Natchez Trace State Park and The Tennessee River is impounded by Beaver are common in Ecoregion 65 and Forest. The Southeastern Plains and Hills contain several north-south trending bands of older limestone, shale, and chert. It is a mostly forested region of oak-hickory-pine, and has Pickwick Landing Dam in the Transition are increasing in numbers in many of 65e sand and clay formations. Tertiary-age sand, clay, and lignite are to the west, and had pine plantation activities associated with pulp and paper operations. Hills (65j). Tennessees ecoregions.

Cretaceous-age fine sand, fossiliferous micaceous sand, and silty clays are to the east. With

71. Interior Plateau The Interior Plateau is a diverse ecoregion extending from southern Indiana and Ohio to northern Alabama. Rock types are distinctly different from the coastal plain sands of western Tennessee ecoregions, and elevations are lower than the Appalachian ecoregions to the east. Mississippian to Ordovician-age limestone, chert, sandstone, siltstone and shale compose the landforms of open hills, irregular plains, and tablelands. The natural vegetation is primarily oak-hickory forest, with some areas of bluestem prairie and cedar glades. The region has the

66. Blue Ridge Mountains most diverse fish fauna in Tennessee.

The Blue Ridge Mountains of Tennessee are characterized by forested slopes, high gradient, cool, clear streams, and rugged terrain on a mix of igneous, metamorphic, and sedimentary geology. Annual precipitation of nearly 80 inches can occur on the well-exposed high peaks of the Great Smoky Mountains that reach over 6000 feet. The southern Blue Ridge is one of and the mixed mesophytic forests of the Appalachian ecoregions (68, 69) to the east.

the richest centers of biodiversity in the eastern U.S. It is the most floristically diverse ecoregion of the state, and includes Appalachian oak forests, northern hardwoods, and Southeastern 71e The Western Pennyroyal Karst is a flatter area of irregular plains, with fewer perennial streams, compared to the open hills of the Western Highland Rim (71f). Bottomland hardwoods forests were once abundant in some areas, although much of the spruce-fir forests. Shrub, grass, and heath balds, hemlock, cove hardwoods, and oak-pine communities are also significant. Small sinkholes and depressions are common. The productive soils of this notable original bottomland forest has been inundated by several large impoundments. Barrens and agricultural area are formed mostly from a thin loess mantle over residuum of former prairie areas are now mostly oak thickets or pasture and cropland.

The Southern Igneous Ridges and Mountains occur in Tennessees northeastern west. In places, the Precambrian rocks have eroded through to Cambrian or Ordovician-age Mississippian-age limestones. Most of the region is cultivated or in pasture; tobacco and 66d limestones, as seen especially in isolated, deep cove areas that are surrounded by steep The Outer Nashville Basin is a more heterogeneous region than the Inner Nashville 71h Basin (71i), with more rolling and hilly topography and slightly higher elevations.

Blue Ridge near the North Carolina border, primarily on Precambrian-age igneous livestock are the principal agricultural products, with some corn, soybeans, and small and high-grade metamorphic rocks. The typical crystalline rock types include granite, mountains. The main areas of limestone include the Mountain City lowland area and Shady Roan Mountain rhododendrons in the Blue Ridge streams have a distinct fish Strip-cropping on Western Pennyroyal Tobacco is grown in large areas of 71e, grains. The natural vegetation consisted of oak-hickory forest with mosaics of bluestem The region encompasses most all of the outer areas of the generally non-cherty Ordovician gneiss, schist, and metavolcanics, covered by well-drained, acidic brown loamy soils. Valley in the north; and Wear Cove, Tuckaleechee Cove, and Cades Cove of the Great Southern Igneous Ridges and Mountains fauna, with some containing brook trout, Karst (71e) agricultural land. and in smaller plots like this in the more prairie. The barrens of Kentucky that extended south into Stewart, Montgomery, and limestone bedrock. The higher hills and knobs are capped by the more cherty Mississippian-(66d). the only salmonid native to Tennessee. hilly ecoregions of the Interior Plateau Elevations of this rough, dissected region range from 2000-6200 feet, with Roan Mountain Smoky Mountains in the south. Hay and pasture, with some tobacco patches on small (71f, 71h). Robertson counties, were once some of the largest natural grasslands in Tennessee. age formations, and some Devonian-age Chattanooga shale, remnants of the Highland Rim.

reaching 6286 feet. Although there are a few small areas of pasture and apple orchards, the farms, are typical land uses. The regions limestone rocks and soils are high in phosphorus, and commercial phosphate is The mixed forests of The Western Highland Rim is characterized by dissected, rolling terrain of open region is mostly forested; Appalachian oak and northern hardwoods forests predominate. 71f hills, with elevations of 400-1000 feet. The geologic base of Mississippian-age 66g The Southern Metasedimentary Mountains are steep, dissected, biologically-diverse mountains that include Clingmans Dome (6643 feet), the highest point in Chilhowee Mountain in Ecoregion 66e have a mined. Deciduous forest with pasture and cropland are the dominant land covers. Streams The Southern Sedimentary Ridges in Tennessee include some of the westernmost limestone, chert, and shale is covered by soils that tend to be cherty, acid, and low to are low to moderate gradient, with productive, nutrient-rich waters, resulting in algae, rooted 66e foothill areas of the Blue Ridge Mountains ecoregion, such as the Bean, Starr, Tennessee. The Precambrian-age metamorphic and sedimentary geologic materials are history of disturbance by vegetation, and occasionally high densities of fish. The Nashville Basin as a whole has a Indians, settlers, loggers, moderate in fertility. Streams are characterized by coarse chert gravel and sand substrates Chilhowee, English, Stone, Bald and Iron Mountain areas. Slopes are steep, and elevations generally older and more metamorphosed than the Southern Sedimentary Ridges (66e) to and fire. with areas of bedrock, moderate gradients, and relatively clear water. The oak-hickory distinctive fish fauna, notable for fish that avoid the region, as well as those that are present.

are generally 1000-4500 feet. The rocks are primarily Cambrian-age sedimentary (shale, the west and north. The Appalachian oak forests and, at higher elevations, the northern natural vegetation was mostly deforested in the mid to late 1800s, in conjunction with the The Inner Nashville Basin is less hilly and lower than the Outer Nashville Basin sandstone, siltstone, quartzite, conglomerate), although some lower stream reaches occur on hardwoods forests include a variety of oaks and pines, as well as silverbell, hemlock, iron-ore related mining and smelting of the mineral limonite, but now the region is again 71i (71h), outcrops of the Ordovician-age limestone are common, and the generally limestone. Soils are predominantly friable loams and fine sandy loams with variable yellow poplar, basswood, buckeye, yellow birch, and beech. Spruce-fir forests, found heavily forested. Some agriculture occurs on the flatter interfluves and in the stream and shallow soils are redder and lower in phosphorus than those of the outer basin. Streams are Cades Cove in Ecoregion 66f and the Great Smoky Mountains of Ecoregion 66g. amounts of sandstone rock fragments, and support mostly mixed oak and oak-pine forests. generally above 5500 feet, have been affected greatly over the past twenty-five years by the river valleys: mostly hay, pasture, and cattle, with some cultivation of corn and tobacco. lower gradient than surrounding regions, often flowing over large expanses of limestone balsam woolly aphid. The Copper Basin, in the southeast corner of Tennessee, was the site Most all of Tennessees The regions of the Interior Plateau in Tennessee are remnants of a huge geological 66f Limestone Valleys and Coves are small but distinct lowland areas of the Blue Ridge, with elevations mostly between 1500 and 2500 feet. About 450 million years of copper mining and smelting from the 1850s to 1987, and once left more than fifty black bears are found in Cropland, pasture, and an extensive Woodland and pasture on the rolling hills The Eastern Highland Rim has more level terrain than the Western Highland Rim 71g (71f), with landforms characterized as tablelands of moderate relief and irregular bedrock. The most characteristic hardwoods within the inner basin are a maple-oak-hickory-ash association. The limestone cedar glades of Tennessee, a unique mixed grassland/forest structure, the Nashville Dome, that fractured and eroded away, leaving a crater-like the Blue Ridge central basin.

ago, older Blue Ridge rocks to the east were forced up and over younger rocks to the square miles of eroded bare earth. ornamental nursery industry are found on of the Outer Nashville Basin (71h).

cedar glades vegetation type with many endemic species, are located primarily on the Mountains (66). the more level terrain of the Eastern plains. Mississippian-age limestone, chert, shale, and dolomite predominate, and karst Highland Rim (71g). terrain sinkholes and depressions are especially noticeable between Sparta and limestones of the Inner Nashville Basin. The more xeric, open characteristics and shallow McMinnville. Numerous springs and spring-associated fish fauna also typify the region. soils of the cedar glades also result in a distinct distribution of amphibian and reptile species.

Natural vegetation for the region is transitional between the oak-hickory type to the west Urban, suburban, and industrial land use in the region is increasing.

67. Ridge and Valley Also known as the Great Valley of East Tennessee, this is a relatively low-lying region between the Blue Ridge Mountains to the east and the Cumberland Plateau on the west. As a result of extreme folding and faulting events, the roughly parallel ridges and valleys come in a variety of widths, heights, and geologic materials, including limestone, dolomite, shale, siltstone, sandstone, chert, mudstone, and marble. Springs and caves are relatively numerous. Present-day forests cover about 50% of the region. The ecoregion has great aquatic habitat diversity in Reelfoot Lake, created Tennessee and supports a diverse fish fauna rivaled only by that of the Highland Rim. by earthquakes in 1811 and 1812, provides The Southern Limestone/Dolomite Valleys and Low Rolling Hills form a ridges have narrow crests, and the soils are typically stony, sandy, and of low fertility. The important habitat for fish 67fheterogeneous region composed predominantly of limestone and cherty dolomite. chemistry of streams flowing down the ridges can vary greatly depending on the geologic and birds.

Landforms are mostly low rolling ridges and valleys, and the soils vary in their material. The higher elevation ridges are in the north, including Wallen Ridge, Powell Livestock, dairy, hay, corn, small grain, Urban, industrial, and agricultural productivity. Landcover includes intensive agriculture, urban and industrial, or areas of Mountain, Clinch Mountain and Bays Mountain. White Oak Mountain in the south has vegetables, and tobacco are the typical activities are common in the valleys of thick forest. White oak forests, bottomland oak forests, and sycamore-ash-elm riparian some sandstone on the west side, but abundant shale and limestone as well. Grindstone farm products of the Ridge and Valley Ecoregion 67f.

(67).

forests are the common forest types, and grassland barrens intermixed with cedar-pine Mountain, capped by the Gizzard Group sandstone, is the only remnant of Pennsylvanian-glades also occur here. age strata in the Ridge and Valley of Tennessee. Free-flowing aquatic 73. Mississippi Alluvial Plain habitats have been This riverine ecoregion extends from southern Illinois, at the confluence of the Ohio River with the Mississippi River, south to the Gulf of Mexico. It is mostly a flat, broad floodplain with The Southern Shale Valleys consist of lowlands, rolling valleys, and slopes and The Southern Dissected Ridges and Knobs contain more crenulated, broken, or greatly reduced by 67g hilly areas that are dominated by shale materials. The northern areas are associated 67i hummocky ridges, compared to the smoother, more sharply pointed sandstone impoundments on the river terraces and levees providing the main elements of relief. Regionally, the soils tend to be poorly drained, although locally some sandy soils are well-drained. Winters are mild and Tennessee River and all Fields and forest along the summers are hot, with temperatures and precipitation increasing from north to south. Bottomland deciduous forest vegetation covered the region before clearance for cultivation.

with Ordovician-age calcareous shale, and the well-drained soils are often slightly acid to ridges of Ecoregion 67h. Although shale is common, there is a mixture and interbedding of of its major tributaries. lower Forked Deer River.

neutral. In the south, the shale valleys are associated with Cambrian-age shales that contain geologic materials. The ridges on the east side of Tennessees Ridge and Valley tend to be the main crops. The natural vegetation consists of Southern floodplain forest (oak, tupelo, some narrow bands of limestone, but the soils tend to be strongly acid. Small farms and associated with the Ordovician-age Sevier shale, Athens shale, and Holston and Lenoir 73a The Northern Mississippi Alluvial Plain within Tennessee is a relatively flat region of Quaternary alluvial deposits of sand, silt, clay, and gravel. It is bounded bald cypress). The two main distinctions in the Tennessee portion of the ecoregion are rural residences subdivide the land. The steeper slopes are used for pasture or have reverted limestones. These can include calcareous shale, limestone, siltstone, sandstone, and The largest known distinctly on the east by the Bluff Hills (74a), and on the west by the Mississippi River. between areas of loamy, silty, and sandy soils with better drainage, and areas of more clayey Landscape patterns of Ecoregions 67f and 67i include forested ridges, low rolling hills, to brush and forested land, while small fields of hay, corn, tobacco, and garden crops are conglomerate. In the central and western part of Ecoregion 67, the shale ridges are population of tall larkspur, Average elevations are 200-300 feet with little relief. Most of the region is in cropland, soils of poor drainage that may contain wooded swamp-land and oxbow lakes. Waterfowl, and agricultural valleys. associated with the Cambrian-age Rome Formation: shale and siltstone with beds of an endangered plant species grown on the foot slopes and bottom land. associated with cedar with some areas of deciduous forest. Soybeans, cotton, corn, sorghum, and vegetables are raptors, and migratory songbirds are relatively abundant in the region.

The Southern Sandstone Ridges ecoregion encompasses the major sandstone sandstone. Chestnut oak forests and pine forests are typical for the higher elevations of the barrens of the Ridge and 67h ridges, but these ridges also have areas of shale and siltstone. The steep, forested ridges, with areas of white oak, mixed mesophytic forest, and tulip poplar on the lower Valley, is found on federal slopes, knobs, and draws. land near Oak Ridge.

Barges on the meandering Mississippi River.

Bald eagle populations have increased, The banded water snake in Tennessee is but are still threatened by habitat loss and found primarily in the Mississippi Alluvial environmental contaminants. Plain (73).

68. Southwestern Appalachians Stretching from Kentucky to Alabama, these open low mountains contain a mosaic of forest and woodland with some cropland and pasture. The eastern boundary of the ecoregion in Tennessee, along the more abrupt escarpment where it meets the Ridge and Valley (67), is relatively smooth and only slightly notched by small eastward flowing stream drainages. The western boundary, next to the Interior Plateaus Eastern Highland Rim (71g), is more crenulated with a rougher escarpment that is more deeply incised. The mixed mesophytic forest is 74. Mississippi Valley Loess Plains restricted mostly to the deeper ravines and escarpment slopes, and the upland forests are dominated by mixed oaks with shortleaf pine. This ecoregion stretches from near the Ohio River in western Kentucky to Louisiana. It consists primarily of irregular plains, with oak-hickory and oak-hickory-pine natural vegetation.

Thick loess tends to be the distinguishing characteristic. With flatter topography than the Southeastern Plains (65) to the east, streams tend to have less gradient and more silty substrates. In and east valleys of Mississippian to Ordovician-age limestones, dolomites, and shales. Sequatchie Valley (68b) and Plateau Many waterfalls occur near the boundary The Cumberland Plateaus tablelands and open low mountains are about 1000 feet of Ecoregions 68a and 68c where softer Tennessee, agriculture is the dominant land use.

68a higher than the Eastern Highland Rim (71g) to the west, and receive slightly more Similar to parts of the Ridge and Valley (67), this is an agriculturally productive region, Escarpment (68c).

rocks erode under the sandstone cap.

precipitation with cooler annual temperatures than the surrounding lower-elevation with areas of pasture, hay, soybeans, small grain, corn, and tobacco. The Bluff Hills consist of sand, clay, silt, and lignite, and are capped by loess The Loess Plains are gently rolling, irregular plains, 250-500 feet in elevation, with ecoregions. The plateau surface is less dissected with lower relief compared to the Forest, pasture, and The Bluff Hills (74a) form a distinct 74a greater than 60 feet deep. The disjunct region in Tennessee encompasses those 74b loess up to 50 feet thick. The region is a productive agricultural area of soybeans, Cumberland Mountains (69d) or the Plateau Escarpment (68c). Elevations are generally 68c The Plateau Escarpment is characterized by steep, forested slopes and high velocity, high gradient streams. Local relief is often 1000 feet or more. The clearcut landscape mosaic of the Cumberland boundary where they meet the level cropland thick loess areas that are generally the steepest, most dissected, and forested. The carved cotton, corn, milo, and sorghum crops, along with livestock and poultry. Soil erosion can be Plateau (68a). of the Mississippi Alluvial Plain (73).

1200-2000 feet, with the Crab Orchard Mountains reaching over 3000 feet. Pennsylvanian- geologic strata include Mississippian-age limestone, sandstone, shale, and siltstone, and loess has a mosaic of microenvironments, including dry slopes and ridges, moist slopes, a problem on the steeper, upland Alfisol soils; bottom soils are mostly silty Entisols. Oak-age conglomerate, sandstone, siltstone, and shale is covered by mostly well-drained, acid Pennsylvanian-age shale, siltstone, sandstone, and conglomerate. Streams have cut down Most streams in 74b have been ravines, bottomland areas, and small cypress swamps. While oak-hickory is the general hickory and southern flooplain forests are the natural vegetation types, although most of the soils of low fertility. The region is forested, with some agriculture and coal mining into the limestone, but the gorge talus slopes are composed of colluvium with huge angular, channelized. The Hatchie River remains forest type, some of the undisturbed bluff vegetation is rich in mesophytes, such as beech forest cover has been removed for cropland. Some less-disturbed bottomland forest and activities. slabby blocks of sandstone. Vegetation community types in the ravines and gorges include relatively unaltered, and its bottomland and sugar maple, with similarities to hardwood forests of eastern Tennessee. Smaller cypress-gum swamp habitats still remain. Several large river systems with wide floodplains, forest provides important wildlife habitat.

The Sequatchie Valley is structurally associated with an anticline, where erosion of mixed oak and chestnut oak on the upper slopes, more mesic forests on the middle and streams of the Bluff Hills have localized reaches of increased gradient and small areas of the Obion, Forked Deer, Hatchie, Loosahatchie, and Wolf, cross the region. Streams are low-68b broken rock to the south of the Crab Orchard Mountains scooped out the linear lower slopes (beech-tulip poplar, sugar maple-basswood-ash-buckeye), with hemlock along The deeper ravines and gravel substrate that create aquatic habitats that are distinct from those of the Loess Plains gradient and murky with silt and sand bottoms, and most have been channelized.

gorges of Ecoregion 68c The Plateau Escarpment (68c) of the Tennessee River Gorge. valley. The open, rolling, valley floor, 600-1000 feet in elevation, is generally 1000 feet rocky streamsides and river birch along floodplain terraces. provide wet and cool (74b) to the east. Unique, isolated fish assemblages more typical of upland habitats can be below the top of the Cumberland Plateau. A low, central, cherty ridge separates the west environments that can found in these stream reaches. Gravels are also exposed in places at the base of the bluffs.

harbor distinct plant Rolling pasture land occurs in some Agricultural landscape of the Loess Plains (74b) near Dyer.

communities. eastern areas of the Bluff Hills (74a).