**Alabama Ecoregion Descriptions**

**August, 2001**

**45. Piedmont**

Considered the nonmountainous portion of the old Appalachians Highland
by physiographers, the northeast-southwest trending Piedmont ecoregion
comprises a transitional area between the mostly mountainous ecoregions
of the Appalachians to the northwest and the relatively flat coastal
plain to the southeast. It is a complex mosaic of Precambrian and
Paleozoic metamorphic and igneous rocks with moderately dissected
irregular plains and some hills. Once largely cultivated, much of this
region has reverted to pine and hardwood woodlands. The soils tend to be
finer-textured than in coastal plain regions.

45a. The **Southern Inner Piedmont** is mostly higher in elevation with
more relief than 45b, but is generally lower and has less relief and
contains different rocks and soils than 45d. Covering most of the
Ashland Plateau, the rolling to hilly, well-dissected upland contains
mostly schist, gneiss, and granite bedrock. Madison soils are typical
over the more micaceous saprolite and rocks, and these soils are more
common in 45a than in 45b. This ecoregion is drained mostly by the
Tallapoosa River, and in the west, by tributaries to the lower Coosa
River. The region is mostly forested, with major forest types of
oak-pine and oak-hickory. Native pines include loblolly, shortleaf, and
some longleaf. Open areas are mostly in pasture, although there are some
small areas of cropland. Hay, cattle, and poultry are the main
agricultural products.

45b. The **Southern Outer Piedmont** ecoregion in Alabama is a
triangular shaped area sometimes referred to as the Opelika Plateau. It
has lower elevations, less relief, and slightly less precipitation than
45a. Oak-hickory and oak-pine are the major forest types, with slightly
more loblolly-shortleaf pine forest than in 45a. Schist and gneiss are
the dominant rock types, covered with saprolite and mostly red, clayey
subsoils. Kanhapludults are the typical soils, such as the Cecil,
Appling, Gwinnett, and Pacolet series. The southern boundary of the
ecoregion occurs at the Fall Line, where unconsolidated coastal plain
sediments are deposited over the Piedmont metamorphic and igneous rocks.
The dissected irregular plains are drained by tributaries of the
Tallapoosa and Chattahoochee rivers.

45d. The **Talladega Upland** contains the higher elevations of the
Alabama Piedmont, and tends to be more mountainous, dissected, and
heavily forested than 45a and 45b. The geology is also distinctive,
consisting of mostly Silurian to Devonian age phyllite, quartzite,
slate, metasiltstone, and metaconglomerate, in contrast to the
high-grade metamorphic and intrusive igneous rocks of 45a and 45b. The
more mountainous parts of the region, with ridges formed from quartzite,
sandstone, and metaconglomerate, contain Alabama's highest point,
2407-foot Cheaha Mountain. The climate of 45d is slightly cooler and
wetter than the other ecoregions (45a, b) of the Alabama Piedmont.
Oak-hickory-pine is the natural vegetation type, and the region once
contained some unique montane longleaf pine communities. Public land
(Talladega National Forest) comprises a large portion of the region.

**65. Southeastern Plains**

These irregular plains with broad interstream areas have a mosaic of
cropland, pasture, woodland, and forest. Natural vegetation is mostly
oak-hickory-pine and Southern mixed forest. The Cretaceous or
Tertiary-age sands, silts, and clays of the region contrast geologically
with the Paleozoic limestone, shale and sandstone of ecoregions 67, 68,
and 71 or with the even older metamorphic and igneous rocks of the
Piedmont (45). Elevations and relief are greater than in the Southern
Coastal Plain (75), but generally less than in much of the Piedmont.
Streams in this area are relatively low-gradient and sandy-bottomed.

65a. The flat to undulating **Blackland Prairie** region has distinctive
Cretaceous-age chalk, marl, and calcareous clay. Soils are generally
clayey and tend to shrink and crack when dry and swell when wet. Streams
have a high variability in flow and affect some fish species
distributions. The natural vegetation had dominant trees of sweetgum,
post oak, and red cedar, along with patches of bluestem prairie. Today,
the area is mostly cropland and pasture, with small patches of mixed
hardwoods. Pond-raised catfish aquaculture has increased in recent
years.

65b. The **Flatwoods/Blackland Prairie Margins** combines two slightly
different areas. The flatwoods are comprised of a mostly forested
lowland area of little relief, formed primarily on dark, massive marine
clay of the Porters Creek Formation. Soils, such as Wilcox and Mayhew,
are deep, clayey, somewhat poorly to poorly drained, and acidic. The
Blackland Prairie Margins are undulating, irregular plains, with
slightly more relief than the Flatwoods, but also tend to have heavy
clay soils that are sticky when wet, hard and cracked when dry, with
generally poor drainage.

65d. The dissected irregular plains and gently rolling low hills of the
**Southern Hilly Gulf Coastal Plain** ecoregion developed over diverse
east-west trending bands of sand, clay, and marl formations. Broad
cuestas with gentle south slopes and steeper north-facing slopes are
common, and the heterogeneous region has a mix of clayey, loamy, and
sandy soils. It has more rolling topography, higher elevations, and more
relief than 65a, 65b, 65f, 65g, and streams have increased gradient. The
natural vegetation of oak-hickory-pine forest grades into southern mixed
forest to the south. Land cover is mostly forest and woodland, with some
cropland and pasture.

65f. The **Southern Pine Plains and Hills** have a different mix of
vegetation and land use compared to 65d, and streams tend to be darker
tea-colored and more acidic as one moves south. The oak-hickory-pine
forest of the north in 65d grades into Southern mixed forest and
longleaf pine forest in this region. The longleaf pine forest provided
habitat for now rare or endangered species such as the red-cockaded
woodpecker, gopher tortoise, eastern indigo snake, and Florida pine
snake. Loblolly and slash pine plantations now cover wide areas. The
hill summits and higher elevations are composed of the Citronelle
formation, generally sandy, gravelly, and porous, and more resistent to
erosion than the older underlying Miocene sandstones.

65g. The **Dougherty Plain** is mostly flat to gently rolling and
influenced by the near-surface limestone. The karst topography contains
sinkholes, springs, and fewer streams in the flatter part of the plain.
The western and northern boundaries are gradational, as more gentle
slopes, lower relief, and more cultivation are found towards the
southeast. Crops such as peanuts, cotton, soybeans, and melons are
common, along with poultry production. Many of the limesink ponds,
marshes, and forested riparian areas act as biological oases in the
mostly agricultural landscape.

65i. The **Fall Line Hills** are composed primarily of Cretaceous-age
loamy and sandy sediments. It is mostly forested terrain of
oak-hickory-pine on hills with 200-400 feet of relief. Elevations range
from 200-1000 feet. Longleaf pine is being reintroduced in many parts of
the region, and the area around the Talladega National Forest in west
Alabama provides a major stronghold for the endangered red-cockaded
woodpecker.

65j. The **Transition Hills** contain characteristics of both the
Southeastern Plains (65) and the Interior Plateau (71) ecoregions. Many
streams in this transition area have cut down into the Mississippian,
Devonian, and Silurian-age rocks and can look similar to those of the
Interior Plateau. Cretaceous-age coastal plain deposits of silt, sand,
clay, and gravel, however, overlie the older limestone, shale, and
chert. It is a mostly forested region of oak-hickory-pine, with small
areas of cropland and pasture in narrow valley bottoms and on gently
sloping ridges. Elevations are some of the highest in ecoregion 65,
mostly between 420 and 980 feet.

65p. **Southeastern Floodplains and Low Terraces** comprise a riverine
ecoregion of large sluggish rivers and backwaters with ponds, swamps,
and oxbow lakes. It includes the larger river systems, the Coosa,
Tallapoosa, Black Warrior, Tombigbee, Alabama, Chattahoochee, and
Conecuh. River swamp forests of bald cypress and water tupelo and
oak-dominated bottomland hardwood forests provide important wildlife
corridors and habitat. While hardwood forests cover much of the
floodplains, cropland is typical on the higher, better-drained terraces.

65q. The **Buhrstone/Lime Hills** region has some of the most rugged
terrain of the Alabama coastal plain. The rough, hilly topography is
attributed to the hardened beds of claystone and sandstone in the
Tallahatta Formation and resistant limestones of other Eocene and
Oligocene deposits. While 65q is more hilly than surrounding regions,
its stream characteristics also differ from those in 65d and 65f. Many
of the streams have relatively high gradients and hard-rock bottoms.
Some fish species that are generally found above the Fall Line, such as
the banded sculpin, southern studfish, Alabama shiner, rainbow shiner,
and burrhead shiner, are also found in this region because of its
streams with upland characteristics. The Red Hills salamander, a
federally-listed threatened species, is also found mostly within this
region on cool, shady, moist ravines and bluff sites located on the
claystones and sandstones of the Tallahatta and Hatchetigbee Formations.

**67. Ridge and Valley**

Stretching from Pennsylvania to Alabama, this is a relatively low-lying
region between the Blue Ridge (66) to the east (or Piedmont in Alabama)
and the Southwestern Appalachians (68) 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. Land
cover is mixed and present-day forests cover about 50% of the region.
The ecoregion has great aquatic habitat diversity and supports a diverse
fish fauna.

67f. The **Southern Limestone/Dolomite Valleys and Low Rolling Hills**
form a heterogeneous region composed predominantly of limestone and
cherty dolomite. Landforms are mostly undulating valleys and rounded
ridges and hills, with many caves and springs. Soils vary in their
productivity, and land cover includes oak-hickory and oak-pine forests,
pasture, intensive agriculture, and urban and industrial. Along the
Coosa River floodplain, biota more typical of coastal plain regions can
be found due to the valley and riverine connection to ecoregion 65.

67g. The **Southern Shale Valleys** consist of undulating to rolling
valleys and some low, rounded hills and knobs that are dominated by
shale. The soils formed in materials weathered from shale, shaly
limestone, and clayey sediments, and tend to be deep, acidic, moderately
well-drained, and slowly permeable. The steeper slopes are used for
pasture or have reverted to brush and mixed forest land. Small fields of
hay, corn, soybeans, tobacco, and garden crops are grown on the foot
slopes and bottom land.

67h. The **Southern Sandstone Ridges** region encompasses the major
sandstone ridges, but these ridges also have areas of shale, siltstone,
and conglomerate. The steep, forested ridges tend to have narrow crests,
and the soils are typically stony, sandy, and of low fertility. The
chemistry of streams flowing down the ridges can vary greatly depending
on the geologic material. In Georgia and Tennessee, most of the
sandstone ridges are relatively narrow, but in Alabama, the region also
includes the Coosa and Cahaba ridges that are broader and of younger
Pennsylvanian-age sandstone and shale, with similarities to 68f.

67i. The **Southern Dissected Ridges and Knobs** contain more
crenulated, broken, or hummocky ridges, compared to the smoother, more
sharply crested sandstone ridges of 67h. Although shale is common, there
is a mixture and interbedding of geologic materials, including cherts,
siltstone, sandstone, quartzose limestone, and in Alabama, some slate,
quartzite, and metasiltstone. Oak forests and pine forests are typical
for the higher elevations of the ridges, with oak-hickory and a number
of more mesic forest species on the lower slopes, knobs, and draws.

**68. Southwestern Appalachians**

Stretching from Kentucky to Alabama, these low mountains contain a
mosaic of forest and woodland with some cropland and pasture. The
eastern boundary of the ecoregion, along the abrupt escarpment next to
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 Plateau's Eastern Highland Rim (71g), is
more crenulated with a rougher escarpment that is more deeply incised.
The mixed mesophytic forest is restricted mostly to the deeper ravines
and escarpment slopes, and the summit or tableland forests are dominated
by mixed oaks with shortleaf pine.

68a. The **Cumberland Plateau**'s tablelands are about 1000 feet higher
than the Eastern Highland Rim (71g) to the west, and receive slightly
more precipitation with cooler annual temperatures than the surrounding
lower-elevation ecoregions. Similar to 68d, the plateau surface has less
dissection and relief compared to the Plateau Escarpment (68c).
Elevations of the region in Alabama are generally 1500-1700 feet.
Pennsylvanian-age sandstone, conglomerate, siltstone, and shale is
covered by mostly well-drained, acid soils of low fertility. The region
is mostly forested or in pasture, with some cropland in the lower
elevation section to the south.

68b. From the Tennessee border, the elongated **Sequatchie Valley**
extends nearly one hundred miles southwest into Alabama. Structurally
associated with an anticline, where erosion of broken rock scooped out
the linear valley, it is composed mostly of Mississippian to
Ordovician-age limestones, dolomites, and shales, with some low, cherty
ridges. In the north, the open, rolling, valley floor, 600 feet in
elevation, is nearly 1000 feet below the top of the Cumberland Plateau
and Sand Mountain. South of Blountsville, the topography becomes more
hilly and irregular with higher elevations. The Tennessee River flows
through the Sequatchie Valley, until it turns west near Guntersville and
leaves the valley. Similar to parts of the Ridge and Valley, this is an
agriculturally productive region, with areas of pasture, hay, soybeans,
small grain, corn, and tobacco.

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 geologic strata include Mississippian-age
limestone, sandstone, shale, and siltstone, and Pennsylvanian-age shale,
siltstone, sandstone, and conglomerate. Streams have cut down into the
limestone, but the gorge talus slopes are composed of colluvium with
huge angular, slabby blocks of sandstone. Vegetation community types in
the ravines and gorges include mixed oak and chestnut oak on the upper
slopes, more mesic forests on the middle and lower slopes (beech-yellow
poplar, sugar maple-basswood-ash-buckeye), with some rare hemlock along
rocky streamsides and river birch along floodplain terraces.

68d. The **Southern Table Plateaus** include Sand Mountain, Lookout
Mountain, and Brindley Mountain. While it has some similarities to the
Cumberland Plateau (68a) with its Pennsylvanian-age sandstone caprock,
shale layers, and coal-bearing strata, this ecoregion is lower in
elevation, has a slightly warmer climate, and has more agriculture. It
is at higher elevations and has more gentle topography with less
dissection than the more forested ecoregions of 68e and 68f. Although
the Georgia portion is mostly forested, elevations decrease to the
southwest in Alabama and there is more cropland and pasture. It is one
of Alabama\'s major poultry production regions.

68e. The **Dissected Plateau** is so strongly dissected that it no
longer has a typical plateau appearance. The rugged, mostly forested
region contains predominantly strongly sloping land, some steep-sided
gorges and sandstone cliffs, and relief of 300-400 feet. The cool
canyons and valleys often contain plant and animal species usually found
further north. The Bankhead National Forest occupies a large portion of
68e, providing public recreation, wilderness, and forestry areas. Most
of the region is drained by the Sipsey Fork of the Black Warrior River.
The Sipsey Fork is a National Wild and Scenic River in its headwaters,
and downstream is impounded to form Lewis Smith Lake, a hydro-electric
generating reservoir, also popular for bass fishing.

68f. The **Shale Hills** ecoregion, sometimes called the Warrior Coal
Field, has more shale and less sandstone than 68e. The soils generally
have silt loam surfaces rather than sandy loams and have a silty clay or
clayey subsoil. Although it has the lowest elevations in ecoregion 68,
the surface features are characterized by extensive hills and mostly
strongly sloping topography. The shale, siltstone, and sandstone are
relatively impermeable, and streams do not have the base flow found in
more permeable adjacent areas, such as 65i or 67f. The region is mostly
forested, but coal mining is a major industry, and the extensive
open-pit mines have altered the landscape, soils, and streams.

**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 sediments of ecoregion 65, and
elevations are lower than the Appalachian ecoregions (66, 67, 68) to the
east. Mississippian to Ordovician-age limestone, chert, sandstone,
siltstone, and shale compose the landforms of open hills, irregular
plains, and tablelands. It is an important agricultural region in
Alabama. The natural vegetation is primarily oak-hickory forest, with
some mixed mesophytic forest and areas of cedar glades. The springs,
lime sinks, and caves contribute to this region's distinctive faunal
distribution.

71f. The **Western Highland Rim** is characterized by weakly to
moderately dissected rolling terrain of irregular plains and rounded
hills. In Alabama, the ecoregion tends to have less relief and
dissection than in Tennessee. The limestone, chert, siltstone, and shale
bedrock is covered by soils that are gravelly, acidic, and low to
moderate in fertility. Streams are characterized by coarse chert gravel
and sand substrates with areas of exposed bedrock, low to moderate
gradients, and relatively clear water. Although the steeper, more
dissected side slopes tend to be forested, most of the natural
vegetation has been removed from the broad, gently sloping uplands used
for pasture and cropland. Cattle production is locally significant, and
hay, cotton, and soybeans, with some wheat and corn, comprise much of
the cropland.

71g. The **Eastern Highland Rim** is flatter and has less dissection
than the Western Highland Rim (71f). Mississippian-age limestone, chert,
shale, and dolomite predominate, and springs, sinks, and caves have
formed by solution of the limestone. Cave and spring-associated fish
fauna also typify the region. In the southern part of the region,
streams flow down from the Pottsville Escarpment of ecoregion 68,
cutting north across the Moulton Valley and through narrow valleys of
Little Mountain (71j) to the impounded Tennessee River. Natural
vegetation for the region is transitional between the oak-hickory type
to the west and the mixed mesophytic forests of the Appalachian
ecoregions to the east. Much of the original bottomland hardwood forest
has been inundated by impoundments. The flatter areas in the east and on
both sides of the Tennessee River have very deep, well-drained, reddish,
soils that are intensively farmed.

71h. Mostly a dissected escarpment, the **Outer Nashville Basin** is a
heterogeneous region with rolling and hilly topography and mixed land
use. The region encompasses most of the area containing the Ordovician
non-cherty limestone and calcareous shale bedrock. These limestone rocks
and the overlying soils can be high in phosphorus. The higher hills and
knobs are sometimes capped by the more cherty Mississippian-age Fort
Payne Formation typical of the Highland Rim. Oak-hickory and
transitional mixed mesophytic deciduous forest covers most of the
steeper slopes, with cropland and pasture found in the flatter alluvial
plains along the Elk River and its tributaries. Streams are low to
moderate gradient, with productive, nutrient-rich waters, resulting in
algae, rooted vegetation, and occasionally high densities of fish. The
Nashville Basin as a whole has a distinctive fish fauna, notable for
fish that avoid the region, as well as those that are present.

71j. **Little Mountain** is a narrow, plateau-like ridge, five to ten
miles wide, that parallels the Tennessee River. It is distinguished from
the surrounding Eastern Highland Rim (71g) by its sandstone geology,
more dissected and hilly topography, and more forest cover. It therefore
has some similarities to ecoregion 68, although the elevation is lower
and the Hartselle sandstone is Mississippian, not Pennsylvanian-age. The
flatter, broad uplands of Little Mountain have mostly well-drained loamy
soils and are often in pasture or cropland. The larger streams cut
through the ecoregion, flowing from the Moulton Valley in 71g north to
the Tennessee River. Some streams are diverted for irrigation and can be
dry in their lower reaches in the summer.

**75. Southern Coastal Plain**

The Southern Coastal Plain extends from South Carolina and Georgia
through much of central Florida, and along the Gulf coast lowlands of
the Florida Panhandle, Alabama, and Mississippi. From a national
perspective, it appears to be mostly flat plains, but it is a
heterogeneous region also containing barrier islands, coastal lagoons,
marshes, and swampy lowlands along the Gulf and Atlantic coasts. In
Florida, an area of discontinuous highlands contains numerous lakes.
This ecoregion is generally lower in elevation with less relief and
wetter soils than ecoregion 65. Once covered by a variety of forest
communities that included trees of longleaf pine, slash pine, pond pine,
beech, sweetgum, southern magnolia, white oak, and laurel oak, land
cover in the region is now mostly slash and loblolly pine with
oak-gum-cypress forest in some low lying areas, citrus groves, pasture
for beef cattle, and urban.

75a. The **Gulf Coast Flatwoods** ecoregion stretches from eastern
Louisiana, across southern Mississippi and Alabama, and into west
central Florida. In Alabama, it is a narrow region of nearly level
terraces and delta deposits composed of Quaternary sands and clays. Wet,
sandy flats and broad depressions that are locally swampy are usually
forested, while some of the better-drained land has been cleared for
pasture or crops. Most of the Mobile urban area is also contained in
this region.

75i. **Floodplains and Low Terraces** are a continuation of the riverine
65p ecoregion across the Southern Coastal Plain. The broad floodplains
and terraces of the Mobile-Tensaw River system comprise the region in
Alabama. Composed of stream alluvium and terrace deposits of sand, silt,
clay, and gravel, along with some organic muck and swamp deposits, the
region includes large sluggish rivers and backwaters with ponds, swamps,
and oxbow lakes. River swamp forests of bald cypress and water tupelo
and oak-dominated bottomland hardwood forests provide important wildlife
habitat. The 75i floodplains of the Mobile Delta have important
hydrological and ecological linkages to Mobile Bay. Valuable fisheries
in Mobile Bay and the Gulf of Mexico, including shrimp, oyster, crab,
and finfish, are dependent on the energy, nutrient and filtering
processes of the bottomland hardwood ecoystems in 75i.

75k. The **Gulf Barrier Islands and Coastal Marshes** region contains
salt and brackish marshes, dunes, beaches, and barrier islands that
enclose the Mississippi Sound and Mobile Bay. Cordgrass and saltgrass
are common in the intertidal zone, while xeric coastal strand and pine
scrub vegetation occurs on parts of the dunes, spits, and barrier
islands. Dauphin Island, one of Alabama's best birding sites, is known
for the many trans-gulf migrant bird species that can be seen in spring
and fall.