Chapter 17
Ecological Subregions of the United States

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Eastern Broadleaf Forest (Continental)

Thirteen Sections have been delineated in this Province:

These Sections are located in the central conterminous States, including parts of Arkansas, Missouri, Tennessee, Kentucky, Illinois, Indiana, Ohio, New York, Michigan, Wisconsin, Iowa, and Minnesota. The area of these Sections is about 270,000 mi2 (699,300 km2).

Section 222A--Ozark Highlands

Geomorphology. This Section is part of the Ozark Plateaus geomorphic province. It is a maturely dissected high plateau with dendritic and radial drainage patterns. Most of the Section is equally divided between steep hills with local relief up to 1,000 ft (300 m) and rolling hills with local relief between 200 and 500 ft (60 to 150 m). There are also gently rolling plains with local relief of less than 200 ft; also present is the flat, 6-mile (10-km) wide Mississippi River flood plain, composed of broad bottomlands with associated terraces, ox-bows, and meander scars. Current geomorphic processes are fluvial erosion, transport and deposition, and mass wasting. Widespread karst features include caves, sinkholes, and springs. Elevation ranges from 300 to 1,800 ft (100 to 600 m).

Lithology and Stratigraphy. Quaternary loess deposits (unconsolidated aeolian silt) are widespread on the uplands; areas without loess cover have moderately thick residuum. Lower slopes are covered with Quaternary colluvium; valley bottoms are characterized by alluvial material. The Mississippi's flood plain has up to 150 ft (45 m) of unconsolidated Tertiary and Quaternary alluvium (gravel, sand, silt, and clay) overlying bedrock. Bedrock consists of lower Ordovician dolomite and sandstone, with lesser amounts of Silurian, Devonian, Mississippian, and Pennsylvanian rocks (limestone, chert, sandstone, and shale) around the Section's margins. The oldest bedrock units, near the center of the Section and forming the highest hills, are Proterozoic igneous rocks, volcanics ranging from rhyolite to andesite, some gabbro, and a large granitic pluton.

Soil Taxa. There are Udalfs and Udults, with mesic temperature regime and udic moisture regime. The soils are mostly cherty, developed in loess mantle. Minerology is siliceous or mixed. Soils are generally old, shallow, stony, and acidic, except on broad ridges and bottomlands.

Potential Natural Vegetation. K\"uchler vegetation types are mapped as oak-hickory forest, oak-hickory-pine forest, mosaic of bluestem prairie and oak-hickory forest, and cedar glades. Dry upland sites include post oak-blackjack oak-black hickory with lichen-moss ground cover, and shortleaf pine-oak in areas of sandstone bedrock. Mesic slopes sites have white oak-northern red oak-bitternut hickory-flowering dogwood. Riparian sites have river birch-silver maple. Glades have little bluestem-baldgrass; eastern redcedar has invaded these prairie sites as a result of fire suppression. The current trend is to characterize Ozark's landscapes as "woodland" or "savanna" rather than "forest," in recognition of the role of frequent, low-intensity fire.

Fauna. Major ungulates are white-tailed deer and cattle (elk and bison were extirpated). The major predator is the coyote (the red wolf, timber wolf, and cougar were extirpated). The mink, otter, beaver, black bear, fox, and bobcat had declined but are recovering. The Section supports opossum and some threatened and endangered bats; armadillo recently began invading. Bird species total 143, including bald eagle and other raptors, turkey, various owls, wood duck, roadrunner, kingfisher, various woodpeckers, and various songbirds (many warblers). Habitat diversity (glades, sinkholes, and caves) contributes to rich herpetofauna, including rattlesnakes, copperheads, turtles, and many salamanders. The richness of fish species is great, including 18 endemics and some relics. Introduced trout and carp are thriving. Crustaceans (19 endemic crayfish) and molluscs (seven endemics) include some threatened and endangered species. Insects, spiders, and ticks are very abundant; the gypsy moth had not been established as of August 1995.

Climate. Mean annual precipitation is 40 to 48 in (1,020 to 1,220 mm) from northwest to southeast. Snow averages about 10 in (240 mm). Mean annual temperature is 55 to 60 oF (13 to 16 oC). The growing season lasts 180 to 200 days. Frost pockets are common.

Surface Water Characteristics. Clear, cold spring-fed streams characterize the Ozarks. Karst topography influences surface water, producing losing streams, springs (some large) and spring-fed streams, seeps, and fens. Small sinkhole ponds exist but few natural lakes; however, several large rivers have been dammed to create reservoirs. There is a moderate density of small intermittent drainages, and small to medium-sized perennial streams, most with low to moderate rates of flow.

Disturbance Regimes. Frequent, low intensity, widespread fire occurred prior to European settlement. Fire suppression led to changes in community type and species composition. Closed-canopy forests replaced many woodlands; pastures replaced prairies, glades, and bottomland forests. Climatic influences include occasional summer droughts, winter ice storms, and tornadoes.

Land Use. Forestry, tourism, hunting and fishing, grazing, and lead mining dominate.

Cultural Ecology. Fourteen thousand years ago, small, highly mobile groups of people followed now-extinct Pleistocene game animals such as mammoth and mastodon into the region. The land was covered by late-glacial forests of oak, ash, jack pine, and spruce. Ten thousand years ago the climate became warmer and drier, and prairie, oak savannas, and oak-hickory and pine forests dominated. An abundance of resources supported increasingly larger, denser human populations. One thousand years ago intensive horticultural practices began. Three hundred years ago, the Osage continued seasonal exploitation of the Ozark's resources. Two hundred and fifty years ago French explorers arrived and soon began lead, iron and barite mining activities. Until the mid-1800's the region remained an agricultural frontier, populated principally by yeoman farmers who supplemented their diet with wild resources. Intensive harvesting of pine and oak forests occurred between 1850 and 1915. Poor timber harvesting and farming practices, in combination with frequent fires and floods, left the land bare. In 1933 land management activities emphasizing resource protection and rehabilitation were started by public agencies. At the same time, provisions were made for recreation developments since hundreds of thousands of people were within a day's drive of public lands.

Compiled by Eastern Region, Missouri Department of Conservation, University of Missouri-Columbia, and Natural Resources Conservation Service.

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222C--Upper Gulf Coastal Plain

Geomorphology. This Section is in the Coastal Plains geomorphic province. The predominant landforms are irregular, shallow to moderately dissected plains of alluvial origin formed by deposition of continental sediments onto a submerged, shallow continental shelf, which was later exposed by sea level subsidence. Geomorphic processes currently active include gentle-gradient valley stream erosion, transport and deposition. Elevation ranges from 80 to 330 ft (25 to 100 m). Local relief seldom exceeds 100 ft (30 m).

Lithology and Stratigraphy. Unconsolidated sediments in this Section formed during the Mesozoic (15 percent) and Cenozoic (85 percent) Eras. Mesozoic strata consist of Cretaceous marine sediments (sandstone, and limestone). Cenozoic strata consists of Tertiary marine sediments.

Soil Taxa. Soils are mostly Udalfs. Uplands are dominated by well drained Hapludalfs. Fragiudalfs occur on moderately well drained side slopes and terraces. Paleudalfs, Fragiudalfs and Hapludults have formed where the mantle of loess is thin. Dystrochrepts, Udifluvents, and Fluvaquents are present on flood plains. These soils have a thermic temperature regime, an udic moisture regime, and mixed mineralogy. Soils are generally deep, medium textured, and have adequate moisture supply for use by vegetation during the growing season.

Potential Natural Vegetation. K\"uchler classifies vegetation as oak-hickory forest, blackbelt, and a mosaic of bluestem prairie and oak-hickory forest. The predominant vegetation form is temperate lowland and submontane broad-leaved cold-deciduous forest and cold-deciduous alluvial forest. The oak-hickory forest cover type dominates this Section. The oaks on drier sites include post, southern red, scarlet, chestnut and blackjack; on moister, sites white, southern red, and black oaks predominate. Shortleaf pine is usually present. Hickories, including pignut, mockernut, shagbark, and bitternut, form a common, but minor component. Bottom land hardwoods occupy recent alluvium along major rivers. Many young stands are dominated by eastern cottonwood and black willow. Older stands include a mixture of species, including hackberry, sugarberry, American elm, boxelder, overcup oak, water hickory, and green ash.

Fauna. Among the fauna in this Section are white-tailed deer, black bear, bobcat, gray fox, raccoon, gray squirrel, fox squirrel, eastern chipmunk, white-footed mouse, pine vole, short-tailed shrew, and cotton mouse. The turkey, ruffed grouse, bobwhite, and mourning dove are game birds in various parts of this Section. Songbirds include the red-eyed vireo, cardinal, tufted titmouse, wood thrush, summer tanager, blue-gray gnatcatcher, hooded warbler, and Carolina wren. The herpetofauna include the box turtle, common garter snake, and timber rattlesnake. Endemics to this Section include Sequoyah slimy salamander, Kiamichi slimy salamander, goldstripe darter, and blackspot shiner. Threatened and endangered species are bald eagle, American alligator, and American burying beetle. Species extirpated or extinct are red wolf, ivory-billed woodpecker, Bachman's warbler, passenger pigeon, and the Carolina parakeet.

Climate. Average annual precipitation averages 48 to 52 in (1,200 to 1,320 mm). Average temperature ranges from 61 to 68oF (16 to 20 oC). The growing season lasts 200 to 280 days.

Surface Water Characteristics. There is a moderate density of small to medium perennial streams and associated rivers, most with moderate volume of water at low velocity. A dendritic drainage pattern has developed on this moderately dissected plateau. The largest rivers are the Obion and Hatchie.

Disturbance Regimes. Fire has probably been the principal historical disturbance. Climatic influences include winter ice storms and periodic flooding along major rivers.

Land Use. Natural vegetation has been cleared for agriculture on much of the area.

Cultural Ecology. Reserved.

Compiled by Southern Region and Southeastern Forest Experiment Station.

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222D--Interior Low Plateau, Shawnee Hills

Geomorphology. This Section is part of the Interior Low Plateaus geomorphic province. Extensive sandstone bluffs, cuestas, rise up to 100 ft (30 m) above the terrain in front of them and dip gently down the back slope. Other landforms include steep-sided ridges and hills, gentler hills and broader valleys, karst terrain, gently rolling lowland plains, and bottom lands along major rivers, with associated terraces and meander scars. A notable but very minor landform is anthropogenic. lands that have been strip-mined exhibit humocky or ridge-swale topography. Current geomorphic processes are fluvial erosion, transport and deposition; mass-wasting; and karst solution. Elevation ranges from 325 to 1,060 ft (100 to 325 m). Lowest elevations occur along the Ohio Rive, the highest at Williams Hill in Illinois.

Lithology and Stratigraphy. Bedrock under about 50 percent of this Section consists primarily of flat-lying Pennsylvanian sandstones (bluff formers), with minor amounts of siltstone, shale, and coal. Interbedded Mississippian limestones, shales, and sandstones are bedrock in most of the remainder of the Section. In the Illinois portion of the Section, at its southern margin, thick, relatively homogeneous Mississippian limestones form the bedrock. At the geographic center of the Section, bracketing the Ohio River in Illinois and Kentucky, the flat-lying attitude of the bedrock has been radically altered or displaced by intense faulting, which has affected local topography.

Soil Taxa. These soils formed under deciduous forests from loess, residuum, and alluvium. The Section is dominated by Ultisol and Alfisol soil orders. However, recent investigations indicate inclusions of the Inceptisol order. Soils are generally well drained to moderately well drained; the drainage for a few soils varies in degree but is generally poor. They have a mesic temperature regime, and predominantly a udic moisture regime.

Potential Natural Vegetation. K\"uchler vegetational types include oak-hickory forest in the uplands of Illinois and Kentucky, and joined by maple-beech-birch in Indiana; oak-gum-cypress forest occupies the bottom lands throughout the Section. Uplands are dominated by the white oak, black oak, shagbark hickory community; the black jack oak, scarlet oak, pignut hickory community occupies drier sites; the beech, tuliptree, bitternut hickory, sugar maple, white ash community occupies deep, mesic ravines. The southern flood plains along the Ohio and Wabash rivers are dominated by the sycamore, Kentucky cofftree, sugarberry, and honey locust community, with local tupelo and cypress swamp communities.

Fauna. Eastern gray squirrel and white-tailed deer are common. In the early 1700's, bison roamed the wood lands. The marsh rice rat, cotton mouse, golden mouse, and Rafinesque's big-eared bat seem to be restricted to this Section. Canada geese and other waterfowl winter in large concentrations in the broader valleys and flat low lands of the region. Wintering populations of Ring-billed gulls are unique. Forest-interior birds such as the Cerulean warbler and the wood thrush live in the forested uplands, while the Swainson's warbler nests in the bottom land forests. The central newt, zigzag salamander, eastern mud turtle, and worm snake are prevalent present-day herptofauna. The clear rocky creeks are habitat for the least brook lamprey, black spottedtop minnow, and the spottail darter.

Climate. The mean annual precipitation is 45 in (1,140 mm) in Illinois and 44 in (1,120 mm) in Kentucky and Indiana. The average annual temperature ranges from 57 oF (14 oC) in Illinois to 55 oF (13 oC) in Kentucky and southern Indiana. Frost free days average about 190 in Illinois and 185 in Indiana.

Surface Water Characteristics. There is a moderate density of medium to large perennial streams and associated rivers, most with moderate volume of water at low velocity. Dendritic drainage has developed on a maturely dissected plateau, essentially without bedrock structural control, except where intense faulting occurs. There are few natural lakes except along the Ohio River, where oxbow lakes occur in flood plains. Uplands have some clear, rocky streams and creeks. Streambank and channel erosion and mass wasting can be observed along segments of some streams.

Disturbance Regimes. The natural communities in this Section were influenced by large herbivores such as elk, by insects and tree diseases, by windstorms, and by drought and fire. Drastic environmental influences on the generally forested hills discouraged trees and maintained openings, glades, on slopes; extensive, bushy grasslands, called barrens, occur on some of the drier sites. Large herbivores, drought, windstorms, insects, and tree diseases kept the forest canopy open and similar to a savanna on ridges. Occasional wildfires helped to maintain the hill-prairies, glades, and barrens. Most communities were affected by mass wasting, due to shale bedrock outcrops, thin soils, and frequent freeze-thaw conditions. Beaver affected timber in narrow flood plains. Anthropogenic disturbances dominate today (see below).

Land Use. Prehistoric Native American activities had little effect on the Section. After 1800, approximately 50 percent of the landscape was cleared and most wetlands drained by Euro-Americans for farming. Fires became more frequent during this period, as did erosion, as the hillslopes were denuded for timber and fuel. The landscape is now a patchwork of forest and agricultural lands, the former used for recreation, ecosystem maintenance, and wood-fiber production, the latter for grazing and row crops. Energy and mineral production have affected and continue to affect small portions of the landscape; coal, iron, lead, zinc, fluorite, limestone, sand, and gravel have been mined in the Section, beginning in the mid-1800's. Oil and gas production began in the early 1900's.

Cultural Ecology. The earliest inhabitants of the Section (around 10,000 to 8,000 B.C.) were restricted to the higher elevations surrounding the remnants of the glacial lakes. Later prehistoric populations roamed across the Shawnee Hills, seasonally collecting plant foods such as nuts, seeds, fresh greens, and tubers, exploiting a rich faunal resource, and utilizing local minerals (ochre, clay, salt, chert, and fluorite). Due to agricultural innovations, latest prehistoric populations (900 to 1400 A.D.) largely inhabited the bottom lands of the Mississippi and Ohio Rivers (Sections 222C and 234A), although they continued to exploit the mineral, floral, and faunal resources of the interior hill region (Section 222D). Earliest Euro-American settlements (about 1700-1830) were generally located along the major transportation routes, including both overland trails and river corridors. Later settlers were attracted by the wooded hills of southern Illinois. The area was visually very similar to the lands they were migrating from, uplands of the southeastern United States. Their technology relied heavily on wood. forested areas were necessary for housing, tools, food, fodder, and fuel, both for personal use and to supply charcoal to local iron works. This and their diversified agricultural methods created eroded hillsides characteristic of the early 20th century Shawnee Hills. As the population increased and the amount of arable land decreased, the ridgetops and hillsides were increasingly cleared for agriculture. This continued until the land was so depleted it was not possible to produce a viable crop.

Compiled by Eastern Region and The Nature Conservancy.

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Section 222E--Interior Low Plateau, Highland Rim

Geomorphology. This Section is in the Interior Low Plateau geomorphic province. Landforms were formed by platform deposition of continental sediments into a shallow inland sea, followed by uplifting to form a level-bedded plateau, which has been shaped by differential erosion to form a moderate to deeply dissected surface. Landforms on about 70 percent of the Section consist of about equal areas of open hills and irregular plains. About 20 percent consists of tablelands. Elevation rages from 650 to 990 ft (200 to 300 m). Local relief ranges from 100 to 300 ft (30 to 100 m) on irregular plains and from 300 to 600 ft (100 to 200 m) on tablelands.

Lithology and Stratigraphy. Rock units formed during the Paleozoic Era. Strata consist of 10 percent Ordovician marine sediments (limestones), 10 percent Silurian marine sediments (limestone and shale), 10 percent Devonian marine sediments (sandstones and shale), and 60 percent Mississippian marine sediments (sandstone, limestone, and shale). The remaining 10 percent of strata are early to mid Paleozoic Era in age.

Soil Taxa. Soils south of the Kentucky and Tennessee border are mainly Udults that have a thermic temperature regime. In Kentucky and Indiana, Udalfs and Udulfs are dominant and have a mesic temperature regime. Moisture regimes are udic and mineralogy is siliceous and kaolinitic. In the southern part, Paleudults are on hillsides and Fragiudults are on upland flats. Fragiaquults and Dystrochrepts are present in lower areas. In the northern area, Paleudults, Paleudalfs, Fragiudults, and Fragiudalfs are on upland areas. Hapludolls and Eutrochrepts are on bottom lands. The soils are deep, have a subsoil high in clay content, and have an adequate supply of moisture for use by vegetation during the growing season.

The Nashville Basin is a distinct, 6,000 mi2 (15,600 km2) area in central Tennessee. Landforms around the outer edge of the basin are deeply dissected and toward the center are undulating. Soils, which consist mostly of Udalfs and Udults, are similar to those in other parts of the Section. A small area consists of Rendolls, which are dominated by redcedar forest or redcedar-deciduous brush communities.

Potential Natural Vegetation. K\"uchler classifies vegetation as oak-hickory forest, cedar glades, and a mosaic of bluestem prairie and oak-hickory forest. The predominant vegetation form is temperate low land and submontane broad-leaved cold-deciduous forest. The oak-hickory forest cover type dominates this Section. The oaks on drier sites include post, southern red, scarlet, chestnut, and blackjack; on moister sites, white and black oaks predominate. Shortleaf pine is usually present. Hickories, including pignut, mockernut, shagbark, and bitternut, form a common but minor component.

Fauna. Among the fauna in this Section are white-tailed deer, black bear, bobcat, gray fox, raccoon, gray squirrel, fox squirrel, eastern chipmunk, white-footed mouse, pine vole, short-tailed shrew, and cotton mouse. The turkey, ruffed grouse, bobwhite, and mourning dove are game birds in various parts of this Section. Songbirds include the red-eyed vireo, cardinal, tufted titmouse, wood thrush, summer tanager, blue-gray gnatcatcher, hooded warbler, and Carolina wren. The herpetofauna include the box turtle, common garter snake, and timber rattlesnake. Endemics to this Section include Sequoyah slimy salamander, Kiamichi slimy salamander, goldstripe darter, and blackspot shiner. Threatened and endangered species are bald eagle, American alligator, and American burying beetle. Species extirpated or extinct from this Section are red wolf, ivory-billed woodpecker, Bachman's warbler, passenger pigeon, and the Carolina parakeet.

Climate. Annual precipitation averages 44 to 54 in (1,120 to 1,370 mm). Temperature averages 55 to 61 oF (13 to 16 oC). The growing season lasts 180 to 205 days.

Surface Water Characteristics. This Section has a moderate density of small to medium intermittent and perennial streams and associated rivers, most with moderate volume of water at low velocity. A dendritic drainage pattern has developed on a deeply dissected plateau, with some influence from the underlying bedrock. The largest rivers include the Cumberland and Tennessee.

Disturbance Regimes. Fire has probably been the principal historical disturbance, previously burning over moderate-size areas between natural barriers with low frequency and low intensity.

Land Use. Natural vegetation from much of the area has been cleared for agriculture.

Cultural Ecology. Reserved.

Compiled by Southeastern Forest Experiment Station and Southern Region.

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Section 222F--Interior Low Plateau, Bluegrass

Geomorphology. This Section is in the Interior Low Plateaus geomorphic province. Platform deposition of continental sediments into a shallow inland sea was followed by uplifting to form a level-bedded plateau, which has been shaped by differential erosion to form a moderately to deeply dissected surface. Landforms on about 90 percent of the Section consist of about equal amounts of irregular plains and open hills. A small area consists of smooth plains. Elevation ranges from 650 to 1,000 ft (200 to 300 m). Local relief ranges from 100 to 500 ft (30 to 150 m) in the open hills. In the smooth plains, relief is 100 to 300 ft (30 to 100 m).

Lithology and Stratigraphy. Rock units formed during the Paleozoic Era. Strata consist of 70 percent Ordovician marine deposits (limestone, shale, and calcareous siltstone); 10 percent Silurian marine deposits (limestone, and shale); and 20 percent Devonian marine shale deposits.

Soil Taxa. Soils are mainly Udalfs, except in the "Knobs" area. Hapludalfs, Paleudalfs, Fragiudalfs, and Hapludolls are typical on uplands. Hapludolls, Eutrochrepts, Fluvaquents, Hapludalfs, and Fragiudalfs are on bottom lands and flood plains. These soils have a mesic temperature regime, udic moisture regime, and mixed mineralogy. These soils are fine textured and most are deep.

Potential Natural Vegetation. The predominant vegetation form is temperate lowland and submontane broad-leaved, cold-deciduous forest, while cold-deciduous alluvial forest occurs along the major rivers. Major species in the oak-hickory cover type includes white, black, and northern red oaks. Other important species include sugar maple, beech, black walnut, and yellow-poplar. Bitternut, pignut, or shagbark hickories may also be present. Sycamore, silver maple, boxelder, willow, and American elm are common species along major river bottom lands.

Fauna. The primary game animals and furbearers of the region are the white-tailed deer, gray fox, red fox, raccoon, opossum, striped skunk, mink, muskrat, eastern cottontail, fox squirrel, and gray squirrel. Common small mammals of forested habitats include the short-tailed shrew, white-footed mouse, and pine vole. In more open areas, the least shrew, prairie deer mouse, prairie vole, meadow vole, and, occasionally, the meadow jumping mouse occur. The bobwhite and mourning dove are the principal game birds of the Section; some common and characteristic songbirds include the warbling vireo, loggerhead shrike, mockingbird, eastern kingbird, eastern meadowlark, red-winged blackbird, indigo bunting, dickcissel, and brown-headed cowbird. The reptile fauna is less varied here than in other Sections; the eastern garter snake, queen snake, black rat snake, black racer, eastern milk snake, red-eared slider, and common snapping turtle are frequently seen. Common amphibian species are the cave salamander, ravine salamander, Jefferson salamander, streamside salamander (nearly endemic), Cope's gray tree frog, American toad, green frog, bullfrog, and pickerel frog.

The small mammal, amphibian, and reptile fauna of the Ordovician limestone portion of the Bluegrass Section is quite distinctive and differs greatly from that of the Devonian shale portion. Numerous species of otherwise common animals are nearly or completely absent from the limestone region: a few examples include the golden mouse; longtail, seal, northern dusky, four-toed, and northern red salamanders; wood and southern leopard frogs; upland and mountain chorus frogs; five-lined and ground skinks; black kingsnake, timber rattlesnake, and brown and northern redbelly snakes. The fauna of the Devonian shale portion closely resembles that of the adjacent Cumberland Plateau, and for that aspect would be better lumped with that Section.

The paddlefish and sturgeon have been greatly impeded from their migration in these waters by locks, dams, and impoundments along the Ohio River and its major tributaries. Other fauna in these waters are common throughout the State. Uniquely noticeable mussel fauna within this Section are the elktoe, snuffbox, rabbitsboot, and salamander mussels. Populations and habitat being hindered by impoundments.

Climate. Precipitation averages 44 in (1,120 mm); an average of 14 in (370 mm) of snow falls annually. Annual temperature averages 55 oF (13 oC). The growing season lasts 180 days.

Surface Water Characteristics. There is a moderate density of medium to large perennial streams and associated rivers, most with moderate volume of water at low velocity. A dendritic drainage pattern has developed, with some influence from the underlying bedrock. Major rivers include the Kentucky and Licking.

Disturbance Regimes. Fire has probably been the principal historical disturbance, previously burning over moderate-size areas between natural barriers with low frequency and low intensity. Climatic influences include occasional summer droughts and tornadoes.

Land Use. Native vegetation has been cleared for agriculture on much of the area.

Cultural Ecology. Reserved.

Compiled by Southern Region, Southern Research Station, Kentucky Natural Heritage, Kentucky Nature Perserves Commission.

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Section 222G--Central Till Plains, Oak-Hickory

Geomorphology. This Section forms part of the Central low lands geomorphic province. The northern half is characterized by relative flatness and shallow entrenchment of drainages due to thick till deposits (50 to 100 ft, 15 to 30 m) that mask the topographic expression of the bedrock. Till is thinner (6 to 50 ft, 2 to 15 m) in the southern half, allowing the topography to be controlled by the relief on the deeply eroded bedrock. The dominant geomorphic process operating in the Section are fluvial erosion, transport and deposition. A notable but very minor landform is anthropogenic. lands that have been strip-mined exhibit humocky or ridge-swale topography. Elevation ranges from 330 to 985 ft (100 to 300 m).

Lithology and Stratigraphy. The greatest part of this Section is covered by Pleistocene (Illinoisan) till, ranging from more than 100 ft (30 m) thick in the north to a feather-edge at the southern boundary. Pleistocene (Wisconsinan) loess blankets most uneroded surfaces. There are significant areas of Wisconsinan slackwater-lake deposits (stratified silt, clay, and muck) along major rivers and tributaries. Mississippian limestones and sandstones are exposed above the Mississippi River's flood plain. Erosional "windows" through the till-plains expose Pennsylvanian sandstones and shales.

Soil Taxa. The soils on uplands are light colored and strongly developed, with poor internal drainage. The soils, developed from thin loess and till, support forest and prairie vegetation. Fragipan and claypan layers are characteristic in the upland soils. Prairie soils with a high sodium content are locally called "akaline slicks." Alfisols and Mollisols are the dominant soil orders. They are deep and medium textured with a mesic temperature regime, and an aquic or udic moisture regime. Inceptisols are a minor soil order.

Potential Natural Vegetation. K\"uchler indicates that the uplands support oak-hickory forest. bottom lands along the Ohio and lower Wabash support oak-gum-cypress; elm-ash-cottonwood forest grows along the upper Wabash and its major Indiana tributaries. Historically, 40 percent of uplands in the Section were tall-grass prairie, not forest. The dominant forest community is post oak, black oak, shingle oak, mockernut hickory, and shagbark hickory. Forests on the drier southern and western slopes are of the white oak, shingle oak, and black oak community; the white oak, white ash, basswood, sugar maple, and slippery elm community dominates more mesic sites. The flat woods community is post oak, swamp white oak, blackjack oak, and pin oak. Forests in the broad flood plains are dominantly silver maple, willow, sycamore, and American elm nearest the rivers, with pin oak, white oak, hickory, ash, hackberry, and honeylocust on heavier soils farther from the river banks. Pin oak occasionally grows in pure stands.

Fauna. Large carnivores including the mountain lion and black bear were gone from this area by the mid 1800's. The thirteen-lined ground squirrel and Franklin's ground squirrel occur at the southern edge of their range. The least weasel and badger are found here. The Carolina chickadee and greater prairie chicken are found in this Section. The crawfish frog, two-lined skink, redback salamander, fence swift, eastern box turtle, and rough green snake are common herpetofauna. Several darters, including the eastern sand, the dusky, and harlequin, are unique to this Section. The common stoneroller, spotted bass, mosquitofish, and Johnny darter are characteristic of the perennial streams and rivers.

Climate. The mean annual precipitation ranges from 45 in (1,140 mm) in the south to 44 in (1,120 mm) in the north. The average temperature ranges from 57 oF (14 oC) in the south to 55 oF (13 oC) in the northern part of this Section. Frost free days average from 180 to 190.

Surface Water Characteristics. This Section has a moderate density of medium to large perennial streams, most with moderate volume of water at low velocity. Dendritic drainage pattern has developed on submaturely dissected plateau, largely without bedrock structural control. There are few natural lakes except oxbows along the Kaskaskia, Big Muddy, and Wabash river flood plains. The Kaskaskia River Basin overall use (aquatic life) rating is full support. The Big Muddy and Wabash River Basins overall use (aquatic life) rating is partial support to minor impairment. The aquatic habitats consist of rivers, creeks, and oxbows.

Disturbance Regimes. Fire, both natural and human-caused, has probably been the principal historical source of disturbance, burning over moderate-size areas between natural barriers with moderate frequency and low intensity. Besides fire, grazing ungulates, insects and tree diseases, windstorms, drought, and ice were the major disturbances during presettlement times. They generally discouraged woody vegetation and encouraged grasslands on the flatter upland divides between forested drainages, and opened the canopy in the ravines and on slopes. Beaver dams occasionally created temporary ponds large enough to kill large stands of timber in the ravines and bottom lands. Over a period of years these ponds became filled with silt and became shallow wooded swamps or, on some sites, wet sedge meadows. Land use since settlement has caused conversion from forest, prairie, and wetland to agriculture on at least 80 percent of the area.

Land Use. The dominant land use is agriculture. About 90 percent of the original native vegetative cover has been replaced by cultivated crops, meadows, towns, or roads. Either or both plowing and livestock grazing have eliminated natural prairies. Of the forested areas, the remnants are on the steepest slopes, poorest soils, or in flood plains too low and wet for cultivation. Coal strip-mining has and continues to affect a portion of the landscape.

Cultural Ecology. Early prehistoric, nomadic Native American populations had access to very rich and diverse faunal and floral resources in the Section. The most recent prehistoric groups settled near the prairie-forest margin because that environment offered well-timbered tracts for wood, food, and forage, as well as easily cleared and tillable prairie soils. Likewise, the Euro-American settlers initially occupied areas known as "points" at the head of river and creek valleys where the timber adjoins the prairie. This arrangement also afforded access to both prairie and forested environments. During the early years of the 19th century Euro-American settlers began to drain, clear, and plow the prairies and wood lands for agriculture; underground coal mining began soon thereafter. Although the soils of this region are not as fertile as those that underlie Section 251D, they are much less erodable than the soils in Section 222D, so this region has been more productive and economically stable. Currently the Section is dominated by typical rural agricultural activities and by coal mining and oil production.

Compiled by Eastern Region and The Nature Conservancy, Illinois Chapter.

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Section 222H--Central Till Plains, Beech-Maple

Geomorphology. This Section is part of the Central Lowlands geomorphic province. It is characterized by its flatness and by shallow entrenchment of its drainages. This is a level to gently rolling till-plain (glacial ground moraine), with broad bottom lands along the few major river valleys. The plain is overlain by a series of low ridges (glacial end moraines) generally trending west to east in an undulating pattern. Drainage is dendritic with only minor entrenchment. The dominant geomorphic process operating in the Section is fluvial erosion, transport and deposition. Elevation ranges from 650 to 1,000 ft (200 to 300 m). Local relief is mainly a few meters, but in places, hills rise as much as 80 ft (25 m).

Lithology and Stratigraphy. The greatest part of this Section is covered by Pleistocene (Wisconsinan) till, ranging from 50 to more than 200 ft (15 to more than 60 m) thick. This material comprises both the ground and end moraines. Some small areas of Wisconsinan slack-water lake deposits (stratified silt, clay, and muck) also occur. Pennsylvanian, Mississippian, Devonian, Silurian, and Ordovician sedimentary rocks form bedrock under the till, and are exposed (youngest to oldest, west to east) in major drainages where erosion has removed the unconsolidated cover.

Soil Taxa. Most of the soils are Udalfs and Aqualfs and have udic and aquic moisture regimes and a mixed or illitic mineralology. They formed in calcareous loamy glacial till, which is mantled by loess in the southern part of the Section.

Potential Natural Vegetation. K\"uchler type is beech-maple forest over most of the Section, with a significant amount of oak-hickory forest mapped in the southeast portion, and a few patches mapped as mosaic of bluestem prairie and oak-hickory forest.

Fauna. Small mammals that characterize this Section include the Franklin's ground squirrel, Rafinesque's big-eared bat, cotton rats, cottontail rabbits, and shrews. Examples of larger mammals currently using this Section include the whitetail deer, coyote, and red and gray foxes. Historically, this Section was once characterized by woods and plains bison, elk, black bears, mountain lions, and wolves. These species were gone by the mid-1800's. Section 222H has few characteristic amphibians and retiles, although the smallmouth salamander and Kirtland's water snake are as plentiful here as in any adjacent Sections. This Section is within the migratory route for many songbirds. The western portion of Section 222H is in the flyway for sandhill cranes and was likely the historic route for this species.

Climate. Precipitation average 35 to 40 in (900 to 1,030 mm). Half or more of this precipitation occurs during freeze-free periods. The low precipitation in winter is mostly snow. Annual temperature averages 50 to 55 oF (10 to 13 oC). The growing season lasts 155 to 180 days.

Surface Water Characteristics. A major water divide occurs in this Section, separating water flowing to the Gulf of St. Lawrence from water flowing to the Gulf of Mexico. Once abundant, but now occurring as remnants, some bog ponds and pothole lakes, plus springs lie along this divide. Low gradient streams and rivers are predominant, except along the glacial boundary where moderate and high gradient streams do occur. The bottoms of streams are composed of sand, gravel, bedrock, and boulders. There is moderate to high stream density.

Disturbance Regimes. Disturbance from fire is uncommon, scattered, and small. By far the largest disturbance effect is from land use. Climatic-influenced disturbances include winter ice storms, occasional tornadoes, and periodic flooding along major river flood plains.

Land Use. Most of the Section is under heavy developmental pressures from urban development and agriculture. Most forested tracts are now second growth wood lots, less than 250 acres in size.

Cultural Ecology. Twelve thousand years of human habitation is represented. Archaic occupants broadly adapted to the general landscape, with earlier interaction near valley edges. Woodland ceremonial sites of the Hopewell tradition are the most dramatic prehistoric cultural expression, representing vast trade networks of various local and exotic natural resource materials. The epicenter of the Hopewell Interaction Sphere lies in the Scioto River Valley. With the exception of steep side slopes of stream valleys, the entire area was cultivated historically. Europeans reached the area around 1650 A.D. Settlement consisted of farming communities; later, extractive industries, such as coal, iron ore, clay, oil and gas, and sandstone gained importance. Most of the Section is currently under developmental pressures from both agriculture and urban expansion.

Compiled by Eastern Region.

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Section 222I--Erie and Ontario Lake Plain

Geomorphology. This Section is part of the Central low lands geomorphic province. It is characterized by its flatness and by shallow entrenchment of its drainages. This is a combination of level to gently rolling till-plain (glacial ground moraine), and flat lake plain. There are a few areas with broad, low ridges (glacial end moraines) generally trending parallel to the lakes' shorelines. The eastern end of the Section, in New York State, includes either or both moderately dissected till and drumlin plains on three low but notable "stairstep" escarpments, parallel to and below the northern margin of the Allegheny Plateau. Geomorphic processes operating in the Section include: fluvial erosion, transport and deposition; lakeshore erosion and deposition; and minor dune construction. Elevations range from 245 ft (75 m), which is the mean elevation of the surface of Lake Ontario, and extend up to 1,000 ft (300 m) along the Appalachian Plateau border. Most of the land is under 800 ft (240 m) in elevation. Local relief ranges between 0 to 300 ft (0 to 90 m). Gentle slopes cover 50 to 80 percent of the area, 50 to 75 percent occur on low lands.

Lithology and Stratigraphy. The moraines, covering about half this Section, are composed of Pleistocene (Wisconsinan) till. The rest, the Maumee basin and along the margins of Lakes Erie and Ontario, is composed of Wisconsinan lacustrine deposits (stratified clay, silt, marl, peat, and muck), with sand forming prehistoric beach ridges and dunes. These glacial deposits range from 50 to about 200 ft (15 to 60 m) thick. Ordovician, Silurian, and Devonian sedimentary rocks form bedrock under the till and lake deposits, and are exposed intermittently along the lakesshores.

Soil Taxa. Soils are predominantly Udalfs and Aqulafs. Ochrepts and Aquepts are more common near the shore of Lake Ontario. Udipsamments predominate around Lake Oneida and in the eastern Mohawk Valley. Notable areas of medisaprist soils occur in the central part of the Section in New York. Soil temperature regime is mesic; soil moisture regimes are dominantly udic and aquic.

Potential Natural Vegetation. K\"uchler vegetation types include northern hardwood forest, beech-maple forest, and elm-ash forest. Other, regionally-defined important vegetation types include beech-maple mesic forest in the east, maple-basswood forest, hemlock-northern hardwood forest, oak openings, and pitch pine-heath barrens.

Fauna. Current mammal populations are typified by the masked shrew, cottontail rabbit, eastern chipmunk, woodchuck, southern flying squirrel, white-footed mouse, raccoon, long-tailed weasel, striped skunk, and white-tailed deer. Common birds in this Section today include the green-backed heron, mallard, American kestrel, American woodcock, mourning dove, downy woodpecker, eastern wood-peewee, red-eyed vireo, common yellowthroat, rose-breasted grosbeak, song sparrow, northern oriole. Some amphibians and reptiles which are characteristic of this Section include the American toad, leopard frog, snapping turtle, painted turtle, northern water snake, garter snake, and milk snake. Habitats in this Section have been greatly modified by modern man-- wetlands drained, forests cleared, large urban areas developed. The bison, elk, black bear, mountain lion, timber wolf, and massasauga were all fairly common historically but have since been extirpated (except for the black bear and massasauga, which continue to occur in small numbers). The bobcat and porcupine, also common in the past, were extirpated from the west portion but still occur in the east. The white-tailed deer, bald eagle, and wood duck are three animals which have made respectable recoveries in the 20th century after being extirpated (or nearly so) in the past.

This Section has a great diversity of aquatic habitats and fishes. Species like the lake sturgeon, lake trout, cisco, lake whitefish, blue pike, and Great Lakes muskellunge were once commercially important species in Lakes Erie and Ontario. The blue pike is considered extinct, and the other species have seen a dramatic decline in numbers. Unplanned introductions of species like the sea lamprey, and planned introductions of coho and chinook salmon, have created changes in the Erie and Ontario fisheries over time. The largemouth and smallmouth bass, walleye, yellow perch, northern pike, and emerald shiner are commonly found in the quiet shoreline areas of Erie and Ontario, and in the inland natural lakes. Warm water streams in this Section provide habitat for black bass, sunfish, walleye, mudminnows, and other species. Brown trout, brook trout, coho salmon, and chinook salmon can be found in the colder streams in this Section.

Climate. Precipitation averages 27 to 45 in (700 to 1,150 mm), increasing from west to east. Precipitation is distributed evenly throughout the year. Immediately adjacent to Lake Erie, snowfall averages 40 to 60 in (1,020 to 1,520 mm); in the remainder of the zone, it ranges from 60 to 80 in (1,520 to 2,030 mm). Mean annual temperature ranges from 45o to 52 oF (7o to 11 oC). The growing season lasts 140 to 160 days, but ranges to 180 days in a narrow belt along Lake Ontario.

Surface Water Characteristics. Abundant water resources include perennial streams, inland lakes, canals, reservoirs, and wetlands. Lake Erie, Lake Ontario, and the St. Lawrence River border this U.S. Section on the north. The Mohawk River and Blackhawk River are large streams of regional importance. Streams tend to be shallowly entrenched and have low gradients. Low gradient streams with deranged drainage patterns are common due to topography and glacial influence. Moderate gradient streams occur in the foothills and Mohawk Valley. Large lakes include the Finger Lakes. Seneca (67 mi2, 174 km2), Cayuga (66 mi2, 172 km2), Owasco (10 mi2, 26 km2), Skaneateles (14 mi2, 36 km2), and Canandaigua (17 mi2, 44 km2) all of which were developed through glacial scouring; and Oneida Lake (80 mi2, 208 km2). Average annual runoff ranges from 16 to 20 in (410 to 510 mm) and approaches 30 in (760 mm) adjacent to the Tug Hill Plateau.

Disturbance Regimes. Climatic-induced disturbances include winter ice storms and occasional tornadoes. Presettlement swamp forests, wet prairies, and marshes, were flooded during several months of the year. Natural disturbance regimes now affecting the streams and rivers are floods and droughts. Anthropogenic disturbance to aquatic systems includes channelization, ditching, and input of industrial waste, sewage, and soil. Insect and disease disturbances have resulted from Dutch elm disease, chestnut blight, and ash dieback among others. Occasional fire disturbances are small and scattered.

Land Use. The dominant land use in this area is agriculture, accounting for about 50 percent of total acreage in this Section. Forest land, mostly in farm woodlots, occupies 30 percent of the area. The remaining land is in residential and urban use.

Cultural Ecology. There have been 10,000 years of human occupation in this area, which was the historic home of the Miami, Erie, and Iroquois Tribal groups. Occupation was predominantly sedentary, with subisistence based on hunting, gathering, fishing, and later farming. Euro-American settlement began during the latter 18th to early 19th centuries, with the exploitation of a variety of natural resources and development of large population centers such as Detroit, Cleveland, and Buffalo. Today the area relies upon shipping, agriculture, and a variety of industrial economic activities.

Compiled by Northeastern Forest Experiment Station, Northeastern Area State and Private Forestry, and the Eastern Region.

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Section 222J--South Central Great Lakes

Geomorphology. This Section is part of the Central low lands geomorphic province. It is a combination of a level to gently rolling low land (glacial ground moraine) and flat outwash or lacustrine plains. Dune fields are present along Lake Michigan. Cropping out of the plains are partially buried end moraine ridges and mounded ice-contact hills. Three glacial lobes converged in southern Michigan, and morainal ridges are arranged in roughly parallel arcs along the paths of glacial retreat. Glacial outwash plains and deltas are found along major drainages. Drainage is dendritic with pronounced terracing. Geomorphic processes operating in the Section include: fluvial erosion, transport, and deposition; lakeshore erosion and deposition; and minor dune construction. Elevation ranges from 580 to 1,280 ft (175 to 396 m), mostly below 1,000 ft (300 m). Local relief is primarily 6 to 200 ft (2 to 60 m).

Lithology and Stratigraphy. This Section is covered by Pleistocene (Wisconsinan) glacial drift, including till, lake sediments, and outwash, ranging up to about 1,300 ft (396 m) thick over bedrock. Extensive areas near Lake Huron are underlain by lacustrine deposits, mainly stratified clay and silt, overlain by sand prehistoric-beach ridges. Pleistocene and Holocene sand dunes lie along Lake Michigan. Devonian, Mississippian, Pennsylvanian, and Jurassic sedimentary rocks underlie the drift. Bedrock is exposed along Huron's shores and occasionally inland.

Soil Taxa. Udalfs, Aqualfs, Aquolls, Rendolls, and Udolls occur on loamy moraines and till plains. Fluvents are in flood plains. Psamments and Orthods are on outwash and ice-contact sands. Histosols are in low-lying areas; many are artificially drained. Moisture regime is mostly udic, with some aquic and xeric. Temperature regime is Mesic.

Potential Natural Vegetation. K\"uchler vegetation types are oak-hickory forest, dominating sandy sites and beech-maple forest on loamy soils.

Fauna. Historically, the caribou, elk, and moose were common large mammals in the Section, along with the wolf. These species have been extirpated, with the exception of a small population of wolves. Currently, whitetail deer are common, along with beaver, muskrat, raccoon, skunk, and coyote. Birds include hawks, eagles, peregrine falcons, sandhill cranes, ducks, quail, grouse, and songbirds. Gulls, terns, sandpipers, and cormorants are found near the Great Lakes. Anadromous fish, such as steelhead, brown trout, and chinook and coho salmon, run up rivers and streams from the Great Lakes. Resident fish are brook and rainbow trout; in lakes, there are walleye, northern pike, smallmouth and largemouth bass, and a variety of panfish. Endangered species include the bald eagle, wolf, Piping plover, Karner blue butterfly, American burying beetle, and Hungerford's crawling water beetle.

Climate. Precipitation averates 29 to 36 in (750 to 930 mm). Temperature averages 45 to 50 oF (7 to 10 oC). The growing season lasts mainly 140 to 160 days, but up to 180 days near Lake Michigan's shoreline.

Surface Water Characteristics. Low-gradient streams and rivers drain mostly into the Great Lakes, but those in the southern extremity of the Section drain into the Mississippi-Ohio Rivers drainage system. Lakes that are small to medium--size are present, but not abundant. Wetlands, many seasonally flooded, formed in extensive low-lying areas in former glacial lakebeds; many are now artifically drained.

Disturbance Regimes. Fire was the dominant natural disturbance in the oak-hickory forest. Tornadoes and windshear events, together with gaps in the overstory, were responsible for regenerating the beech-sugar maple forests.

Land Use. Much of the land was cleared and drained for agriculture during the 19th century. Current land use is predominantly for agriculture, secondarily for urban and industrial development, with only a minor amount remaining in forest vegetation. Gas and oil development occurs in some of the area.

Cultural Ecology. Native peoples utilized the area extensively for fishing, gathering, farming, and hunting. They used fire to manage vegetation, especially in the oak-hickory forest, often creating barrens. During this century, the Section has been been dominantly occupied by industrial workers, many of whom moved from Appalachia and economically depressed southern states. In recent years, the economy has diversified and a cross-Section of service and professional workers now occupies the several large metropolitan areas of this Section. Agriculture, while a major land use, employs relatively few people. Conflicts develop among residents who wish to preserve remnants of natural ecosystems, and those who advocate further development. There is very little publicly owned land.

Compiled by Eastern Region.

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Section 222K--Southwestern Great Lakes Morainal

Geomorphology. This Section is part of the Central Lowland geomorphic province. It is characterized by flat to undulating topography resulting from glaciation:plains composed of till, outwash, and lacustrine; drumlin fields and morainal ridges; and local occurrences of other features (kames, eskers, kettles, etc.). Drainage is dendritic with only minor entrenchment. Geomorphic processes operating in the Section include: are fluvial erosion, transport and deposition; lakeshore erosion and deposition; and minor dune construction. Elevation ranges from about 570 to 1,650 ft (175 to 500 m). Local relief ranges from a few feet on plains to about 300 ft (90 m) in some places, such as interlobate moraines and a few bedrock escarpments.

Lithology and Stratigraphy. Section 222K is covered by Pleistocene (Wisconsinan) glacial drift. till, lacustrine sand-silt-clay-peat-muck, and either or both outwash sands and gravels, ranging in thickness up to about 400 ft (120 m). Bedrock beneath the drift is composed primarily of Ordovician and Silurian dolomite and minor sandstone; some Cambrian sandstone occurs in the northernmost part, and Mississippian shale underlies the southeastern corner. Bedrock is exposed intermittently, mostly in the northern and western portions of the Section where the drift is thinnest.

Soil Taxa. Mostly Alfisols predominates. A few large outwash plains in the northwestern part of the Section are dominated by sandy Entisols. Mollisols occur extensively in the Till Plains and dominant in the southeastern portion of the Section, and in some lacustrine plains. There is also a significant occurrence of Histosols, largely coincidental with bogs. Moisture regimes are mostly Udic, with occurrences of aquic and xeric regimes. Temperature regime is Mesic, except for the northwestern extremity, which is currently considered to be in the frigid zone.

Potential Natural Vegetation. K\"uchler vegetation types are primarily oak savanna, with a lesser extent of maple-basswood forest, and some small areas of bluestem prairie.

Fauna. Large mammals historically found in this Section were the bison and elk, which occurred in large numbers. The whitetail deer was common but apparently not numerous. The major predator was the wolf. Smaller mammals and birds were characterized by the prairie chicken (open areas), sharptail grouse, long-billed curlew, Franklin's ground squirrel, and many species adapted to a mixture of prairie, oak savanna, and forested conditions. The passenger pigeon occurred in vast numbers, as did many species of both nesting and migrating waterfowl. Today the dominant large mammal is the whitetail deer, which has extended its range into this Section from the north in the past 25 years. The elk and wolf were extirpated by the early to mid-1800's. Dominant smaller animals today are the introduced ringneck pheasant, and the red fox, coyote, raccoon, and both red and gray squirrels. The wild turkey has recently been reintroduced and has rapidly expanded into all parts of this Section. Most waterfowl species are far less numerous today, except for Canada geese and the sandhill crane, which appear to be benefitting from waste grain in agricultural operations.

Common fish species today are the largemouth bass, perch, crappie, northern pike, and walleye. The Lake Michigan fishery has been substantially altered by the invasion of non-native species such as the alewife, zebra mussell, and spiny water flea. Coho and chinook salmon and steelhead trout have been introduced and have established runs up many streams draining into Lake Michigan.

Climate. Precipitation averages 29 to 35 in (750 to 900 mm). Two-thirds of this amount falls during the growing season. Winter precipitation is mostly snow. Temperature averages 43 to 52 oF (6 to 11 oC). The growing season lasts 125 to 160 days (180 days in a narrow band along Lake Michigan).

Surface Water Characteristics. This is a relatively young landscape with a relatively low to medium density of streams, which tend to be low gradient and slow flowing. Surface drainage networks are fairly well developed except in end moraines, interlobate moraines, and large outwash plains. There is a relatively high occurrence of lakes created by glacial action. Drainage is into the Upper Mississippi Basin, mostly via the Wisconsin, Rock, and Illinois River systems, and into Lake Michigan.

Disturbance Regimes. Fire was apparently important in maintaining the oak Savannas and prairies. Windthrow ocurred in some localized areas.

Land Use. Most of the area is used for agriculture. There is a heavy concentration of urbanization along much of the Lake Michigan shoreline (including the cities of Chicago and Milwaukee); urban development is also dominant in the Lake Winnebago and Madison areas of Wisconsin. Outdoor recreation is an important category of land use, and is largely associated with the many inland lakes, as well as the Lake Michigan shoreline.

Cultural Ecology. Native American occupation and ecological exploitation began as early as 10,000 years ago. These early inhabitants evolved from mobile, nomadic hunting groups to more sedentary groups adapting to subsistence based on farming and hunting. Historically, the area encompasses the Illinois and Winnebago Tribal Territory. European exploration occurred between 1620 and 1665. From 1665 to 1828, fur trade was predominant in the area. Large metropolitan cities such as Chicago and Milwaukee developed in the latter 19th and early 20th centuries and prospered as a result of natural resource exploitation and utilization. Today, a vast number of industries provide employment for the area's dense population.

Compiled by Eastern Region.

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Section 222L--North-Central U.S. Driftless and Escarpment

Geomorphology. This Section is part of the Central low lands Geomorphic Province. It is bisected by the Mississippi River flood plain. The Section is a maturely dissected, upland plateau where broad, steep-sided bedrock ridges and "mounds" up to 500 ft (150 m) high are separated by wide, flat-bottomed drainages in the southern portion of the Section, and by narrow, V-shaped valleys farther north. Current geomorphic processes include: fluvial erosion, transport and deposition; masswasting; and karst solution. Elevation ranges from 650 to 1,300 ft (200 to 400 m). Local relief ranges from 100 to 600 ft (30 to 180 m).

Lithology and Stratigraphy. Much of the upland area is blanketed with Pleistocene loess, Kansan west of the Mississippi and Wisconsinan to the east. Residuum and colluvium mantle most slopes, and alluvium occupies larger valleys. Beneath this unconsolidated material, bedrock consists of Cambrian sandstone and dolomite, Ordovician dolomite, shale and sandstone, and Silurian dolomite, with a local occurrence of Proterozoic quartzite. Small, isolated outliers of Cretaceous sandstone and shale overlie the Paleozoic rocks at the western edge. Ridges and "mounds" are capped with the resistant dolomites and quartzite. Broader drainages are underlain by Ordovician shale. Bedrock is heavily jointed, with much evidence of solution in the carbonates.

Soil Taxa. Dominant types are mostly Udalfs. Udolls occur on benches, some broad ridgetops, and steep slopes bordering major valleys. Fluvents and Psamments occur locally along streams on flood plains and stream terraces. Mesic temperature and udic moisture regimes dominate.

Potential Natural Vegetation. K\"uchler types are oak savanna and maple-basswood forest, with some northern flood plain forest along some of the major rivers.

Fauna. This Section was characterized by bison, antelope and prairie chicken on the open prairies, and elk and bison in the oak savannas and bottom land forests along major rivers. Whitetail deer and sharptail and ruffed grouse occupied the early and mid-successional vegetation stages common in this Section as a result of fire and wind. Large predators were the wolf and black bear. The passenger pigeon was common throughout all forested sites, including the oak savanna. Waterfowl were largely restricted to the Mississippi River and adjacent riparian habitats, which hosted large migratory populations in the spring and fall. Today the elk, bison, and wolf have been extirpated, and the very abundant whitetail deer is the dominant large mammal. The sharptail grouse and prairie chicken have disappeared, but the ruffed grouse is common. The introduced ringneck pheasant is found in moderate numbers and the reintroduced wild turkey has rapidly expanded its range to all parts of the Section. Gray and red squirrels are common, along with the cottontail rabbit; but waterfowl populations are greatly reduced, with the exception of Canada geese and sandhill cranes. Great blue herons and cormorants are common along the Mississippi. Fish habitat consists mostly of large and small river systems which contain the northern pike, catfish, largemouth bass, walleye, carp and sucker.

Climate. Precipitation averages 29 to 35 in (740 to 890 mm). About 40 to 45 percent falls during the growing season. Average annual temperature is 45 to 50 oF (7 to 10 oC). The growing season lasts for 136 to 160 days.

Surface Water Characteristics. This is a maturely dissected landscape with a fairly high density of perennial and intermittent streams. The drainage pattern is mostly dendritic; however, many streams and valleys exhibit abrupt turns caused by joints in bedrock. Valleys are deeply incised. Natural lakes are rare or nonexistent. This Section is dissected by the Mississippi River.

Disturbance Regimes. Fire was historically important on the upland prairie and oak dominated ecosystems. Recent records of tornadoes and ice storms indicate that they locally impacted forest vegetation.

Land Use. The current dominant land use is agriculture; about 30 to 40 percent is in crop land. Most of the steeper side slopes remain wooded.

Cultural Ecology. There have been 10,000 years of human occupation in this part of the Upper Mississippi Valley cultural area. The Native American lifestyle was predominantly sedentary. The primary occupation was subsistence-based hunting; later farming gained importance. This area was home to the historic Illinois tribal group. Euro-American settlement began during the latter 18th to early 19th centuries, with exploitation of a variety of natural resources (forests and wildlife). Dairy farming became the major economic activity during the latter 19th and early 20th centuries.

Compiled by Eastern Region.

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Section 222M--Minnesota and Northeastern Iowa Morainal

Geomorphology. This Section is part of the Central Lowland geomorphic province. It is characterized by level plains and low, irregular hills resulting from glaciation: till and outwash plains; drumlin fields and morainal ridges; and local occurrences of other features (e.g., kames, eskers, and kettles). Poor to unintegrated (chaotic) drainage is common in the northern portion of the Section; to the south, drainage is dendritic with only minor entrenchment. Geomorphic processes operating in the Section are fluvial erosion, transport and deposition. Elevation ranges from 1,000 to 1,600 ft (300 to 485 m). Local relief is generally less than 100 ft (30 m).

Lithology and Stratigraphy. This Section is covered by Pleistocene (Wisconsinan in the north half, Illinoisan-Kansan in the south) glacial drift; till and outwash sands and gravels, ranging in thickness from 30 to 500 ft (9-150 m), thinning toward the south. A thin, discontinuous mantle of loess overlies a pre-Illinoisan landscape in the southern part of the Section. Bedrock is composed of Archaean granite, greenstone, and metasediments in the northern half of the Section, with Cambrian sandstone, Ordovician shale, dolomite and sandstone, and Silurian dolomite in the southern half. Bedrock is exposed intermittently, mostly in the southern and eastern portions of the Section where the drift is thinnest.

Soil Taxa. Dominant types include Mollisols, Alfisols, and Entisols. Moisture regime is dominantly mesic; some areas are xeric and some are aquic. Temperature regime is dominantly mesic, but ranges to frigid in the northern extremity.

Potential Natural Vegetation. K\"uchler's map shows mostly bluestem prairie with significant maple-basswood forest and lesser amounts of oak savannah, oak-hickory forest, and northern flood plain forest. Other investigators indicate bluestem prairie may be a more minor component, with greater dominance of oak savannah and oak wood lands.

Fauna. This Section represents the meeting of the plains of the west and the wood lands of the upper midwest. It contained large and diverse populations of wildlife. Bison were common, and this may have been optimum North American habitat for the elk. The dominant large predator was the wolf. Prairie chicken, sharptail grouse, passenger pigeon, jack rabbit, coyote, and fox were common. The bison, elk, and wolf were extirpated, but the coyote and fox remain numerous. The prairie chicken and sharptail grouse survive in isolated habitats throughout the Section. Waterfowl populations are greatly reduced (except for the Canada goose and sandhill crane), although wetland habitat restoration efforts appear to be helping to stabilize numbers.

Climate. Precipitation averages 25 to 33 in (650 to 850 mm); 35-45 percent falls during the growing season. Temperature averages 39 to 48 oF (4 to 9 oC). The growing season lasts 120 to 160 days.

Surface Water Characteristics. Most of the Section is characterized by a scarcity of natural lakes and wetlands; there are fairly well developed drainage networks with relatively slow-flowing streams. The exception is approximately the northern one-fourth to one-fifth of the Section, where several natural lakes, common wetlands, and undeveloped surface drainage networks are associated with end moraines.

Disturbance Regimes. Fire was historically important in oak savanna development. Windthrow was common in the sugar maple-basswood forests. tornadoes and other high wind events and floods also created natural disturbances. Major anthropogenic disturbances during the past 100 to 150 years have included logging and clearing for agriculture.

Land Use. Agriculture is currently the major land use. Some forest land, used primarily for wildlife habitat and recreation, remains on steep landscapes and adjacent to streams and lakes. Major urban and industrial development is associated mainly with the Minneapolis-St. Paul, Minnesota metropolitan area.

Cultural Ecology. Humans have occupied the area for at least 10,000 years, adapting their ways of life in a variety of changing environments. Conditions have varied from cool, wet, tundra supporting herds of open land grazing animals such as bison and caribou; through a warm, dry savanna period when availability of water and aquatic resources was drastically altered; to the hardwood forest and tall grass prairie of the present. People lived in small nomadic groups and larger villages, changing their hunting, fishing, and gathering methods as environmental conditions changed, to allow for the most efficient resource use. Horticulture has been practiced for about 1,000 years. Within the last 300 years, the near extinction of some species of fur-bearing mammals for the fur trade, the cutting of the "Big Woods" forests by logging, and cultivation of the land have significantly altered the environment. Farming, industrialization, concentrated human settlement, and recreation are the major human activities affecting the ecosystem today.

Compiled by Eastern Region and Minnesota Department of Natural Resources.

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Section 222N--Lake Agassiz, Aspen Parklands

Geomorphology. This Section is part of the Central Lowlands geomorphic province. It forms the southeastern margin of a large, level lake plain (created by glacial Lake Agassiz) that extends far to the north and west into Manitoba, Saskatchewan, and Alberta. Low dunes and wet swales mark the Section's western edge; prominent beach and morainal ridges cross the Section in several places. Drainage is dendritic, with only minor entrenchment. Geomorphic processes operating in the Section are fluvial erosion, transport and deposition. Elevation ranges from 900 to 1,250 ft (270 to 380 m). Local relief is low; most areas are nearly level. The western edge has up to 50 to 150 ft (15 to 45 m) of local relief along beach ridges.

Lithology and Stratigraphy. This Section is covered by Pleistocene (Wisconsinan) glacial drift, ranging in thickness from 100 to 400 ft (30 to 120 m): calcareous tills, lacustrine silt-clay-peat-muck, and beach sands. Holocene peats cover some of the Pleistocene deposits. Bedrock beneath the drift and peat is composed of Archaean granite, greenstone, and metasediments. Bedrock is not exposed.

Soil Taxa. The dominant soil orders are Entisols, Histosols, and Mollisols, with frigid temperature regime and dominantly aquic moisture regime.

Potential Natural Community. K\"uchler mapped this area as bluestem prairie and oak savann, with a minor component of maple-basswood forest. Local investigators indicate the pre-European settlement vegetation was primarily aspen savanna, with significant components of tallgrass prairie, wet prairie, and dry gravel prairie (on gravelly beach ridges.)

Fauna. This Section represents the meeting of the northern plains of the west and the northern hardwoods of the upper midwest; it contained diverse populations of wildlife. Bison and elk were common. The dominant large predator was the wolf. Prairie chicken, sharptail grouse, jack rabbit, coyote, and fox were common. The bison and elk were extirpated, but the wolf may range into the Section from the northeastern Minnesota area. Coyote and fox are numerous, and the prairie chicken and sharptail grouse survive in isolated habitats throughout the Section. Waterfowl populations are greatly reduced (except for the Canada goose and sandhill crane), although wetland habitat restoration efforts appear to be helping to stabilize numbers.
Climate. Precipitation averages 20 to 22 in (510 to 560 mm). About 40 percent falls during the growing season. Snowfall is 40 to 50 in (1,000 to 1,270 mm). Temperature averages 37 to 41 oF (3 to 5 oC). The growing season lasts about 120 days.

Surface Water Characteristics. Drainage network is not well developed. Streams meander and flow slowly. Flooding is common. Drainage is to the north and west, to Hudson Bay. The major drainage is the Roseau River.

Disturbance Regimes. Fire was the most common natural disturbance, followed by floods and tornadoes. Fire frequency and intensity were reduced by the natural barrier of low dunes, beach ridges, and wet swales that mark the western edge of the Section.

Land Use. Agriculture is the current dominant land use, including extensive areas recently cleared for farming.

Cultural Ecology. Humans have occupied the area for at least 10,000 years, adapting their ways of life in a variety of changing environments. Conditions have varied from cool, wet tundra supporting herds of open land grazing animals such as bison and caribou; through a warm, dry savanna period when availability of water and aquatic resources was drastically altered; to the mixed deciduous-coniferous forests of the present. People lived in small nomadic groups and larger villages, changing their hunting, fishing, and gathering methods as environmental conditions changed, to enable the most efficient resource use. Within the last 300 years, the near extinction of some species of fur-bearing mammals for the fur trade, the cutting of the pine forests by logging, and cultivation of the land have significantly altered the environment. Today, farming, logging, and recreation are the major human activities affecting the ecosystem.

Compiled by Eastern Region and Minnesota Department of Natural Resources.

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