From a perch on Tennessee's rooftop, Clingmans Dome, the Appalachians stretch
into the distance as what seems to be one vast, green, and uniform landscape.
But there is more to these mountains than first meets the eye. The Appalachians,
extending from Alabama to Newfoundland, contain a complex mixture of specialized
habitats. There are rich mountain coves, boulderfields, balds, and boreal forests,
all with their own unique assemblage of flora and fauna. This diverse landscape
has been created over millions of years by complex geologic events and now
harbors a diversity of plants and animals that is legendary—a diversity
perhaps unequalled outside the tropical rain forests.
Even by a geologist's standards, the Appalachians are old mountains: The bedrock was formed 1 billion years ago and the mountains are 500 million years old, 10 times older than the Rockies, Sierras, and Andes. They have been created, worn down, and created again as a result of tectonic and weathering forces. Continental drift, a phenomenon that continues on earth's surface today, has played a major role. Continental drift is explained by the plate tectonics theory, which holds that earth's continents are not part of one contiguous piece of crust, but rather are individual pieces, or tectonic plates. These plates float across earth's semifluid mantle, and when they collide, the result is an orogeny or mountain-building event.
Geologists believe three orogenies are responsible for forming the Appalachians. The first, the Taconic orogeny, occurred 440 million years ago, and the second, the Acadian orogeny, occurred during the Age of Fishes, 380 million years ago when amphibians were first exploring dry land. These first two orogenies raised the northern Appalachians, while the third, the Alleghenian orogeny, shaped the southern Appalachians, including eastern Tennessee. This tectonic event began 290 million years ago and lasted for 50 million years.
During the Alleghenian orogeny, the continents were not aligned as they are today. North America was part of Laurentia, a landmass that also included Europe. Laurentia collided with the supercontinent of Gondwana, comprised of Africa, South America, Antarctica, Australia, and parts of Asia. When Africa slammed into the eastern side of North America, rocks on the ocean floor were driven under continental crust rocks in a process called subduction. The force of the collision slid, or thrust, rocks over other rocks and raised the southern Appalachians. When the continental movement stopped, the last of the Paleozoic oceans had disappeared and one landmass, Pangea, floated on earth's surface. Pangea did not begin to break apart until early in the Age of Dinosaurs, 225 million years ago.
Geologists attempting to piece together this complex history of the Appalachians have a difficult task. As continental drift built mountains, it destroyed or distorted the original bedding planes of ancient sediments, making it tough to distinguish exactly what happened over the past 500 million years.
In the 100-million-year period between the Acadian and Alleghenian orogenies and during much of the Mesozoic Era, Laurentia existed in the tropical latitudes and was covered by lush vegetation. The land became home to primitive seed-ferns, giant horsetails, and tree clubmosses. Animal life included insects and other arthropods as well as numerous amphibians, and for a time Laurentia was covered by a shallow inland sea alive with marine creatures. By the beginning of the Age of Mammals, North America drifted north into the Temperate Zone but not before accumulating a wealth of decomposing microorganisms that created a rich layer of organic material.
Heat and pressure transformed this organic material into rich natural resources—fossil fuels—that would bring humans to the Appalachians looking for wealth. Carbon was converted to coal, and marine organisms became natural gas.
The legacy of these tectonic events in Tennessee is three mountainous physiographic provinces. From west to east they are the Cumberland Plateau, the Valley and Ridge, and the Unakas.
The Cumberland Plateau is the southern portion of the Appalachian Plateau that extends into Tennessee and south into Alabama. The eastern side is marked with a distinct escarpment 900 feet high while the western edge has been made more irregular by erosion. The plateau is essentially a wide and flat tableland trending northeast to southwest. The region is composed of hard sandstones that did not experience uplifting and fracturing and have resisted erosion, and the plateau is underlain by moderately abundant coal deposits. Where resistant sandstone strata overlie softer shales and coals, there are numerous waterfalls, including Fall Creek Falls in Van Buren County, the highest east of the Rockies.
The Valley and Ridge takes its name from its long ridges and valleys oriented in a northeast-southwest direction. This topography was shaped by folding and faulting that occurred during the Paleozoic Era. Great force from the east, possibly from northern Africa ramming into eastern North America, rippled the landscape like a rug pushed against a wall from one side. Then erosion set in, shaping more resistant rock into ridges and cutting valleys into weaker ones. The area is dominated by dolomite and highly erodible limestone, making caves numerous. The region has great habitat diversity and supports an especially diverse fish fauna, including the Upper Clinch River, which holds one of the most diverse fish faunas in North America.
The portion of the Appalachians known elsewhere as the Blue Ridge is called the Unakas in Tennessee. The Unakas characteristically display waterfalls, steep stream gradients, and forested slopes within rugged terrain. Valleys range from 1,500 feet elevation in the north to 1,000 feet in the south, and peaks rise to over 6,000 feet. This region includes such mountains as the Chilhowee, English, Bean, Holston, Roan, and Smokies. The Great Smoky Mountains are part of the Unakas restricted to the area of the Great Smoky Mountains National Park.
The southern Appalachian region is the most diverse in the Appalachian chain. In terms of flora, the southern Appalachians are home to at least 400 species of moss, 130 species of trees, and over 2,500 species of flowering plants, hundreds of which are found nowhere else in the world. When it comes to fauna, the southern Appalachians are equally rich. Field scientists have counted 175 species of terrestrial birds, 65 species of mammals, and 25,000 species of invertebrates. Here there are 39 species of Plethodontid salamanders, more than are found anywhere else in the world. These mountains are home to 167 snails—many of them endemics (found nowhere else). In the snail family Zontidae, there are 38 species native only to the southern Appalachians, and in the family Polygyridae, there are 30 endemic species in these mountains. The southern Appalachians are also the global center for millipedes: 234 species have been described, with an estimated 250 undescribed.
One major factor contributing to this diversity is water. The southern Appalachians
are second in the U.S. only to the Pacific Northwest in the amount of rainfall
they receive. Five to eight feet of water pours onto these mountains from the
skies each year. This rainfall, combined with a mild climate, grows lush mountain
forests, which manage the water and send what isn't soaked into the ground
off as rivers and streams.
Mountains also need water—the force that eventually erodes them away—for the formation of life-giving soil. The topography and the types of soils derived from rock types determine the plant and animal communities that thrive in the southern Appalachians. Soil is a combination of weathered rocks and minerals, as well as living creatures and organic detritus. The type of rock that it is eroded determines the pH or acid/base value of the soil that is formed and in turn, the plants the soil will support. As plants decompose they add their organic matter to eroded rock and concentrate nutrients in the top layer of soil, or topsoil. Topsoil helps soil retain water and nutrients instead of allowing them to wash away with rain water, and plants keep topsoil in place. An abundance of rich soil means greater plant life, so throughout the mountains, areas with rich, black topsoil, like coves, support a more diverse vegetative community than exposed ridgetops, which are covered in a thin soil layer and home to only the hardiest of plants.
Water in the form of glaciers has also affected the southern Appalachians. Over the past 2 million years, glaciers have not extended farther south than Pennsylvania, but Tennessee and the rest of the southern Appalachians have felt their effects. During the numerous cold glacial and warm interglacial times, boreal and temperate species have advanced and retreated up and down the mountain chain. Not all of the plants and animals who migrated south returned north when the glaciers receded. These northern species found niches for survival and contribute to the southern Appalachians' biological diversity. Species that remain as remnants of the ice ages are called relicts and can be found especially in north-facing coves where it is moist and cool. Examples of marooned species include yellow birch, sugar maple, and the New England cottontail.
Another remnant of the ice ages is a unique habitat called boulderfields—collections of jumbled, now moss-covered boulders usually on north-facing coves above 3,200 feet. During glacial periods, the Appalachian bedrock was subjected to freezing and thawing, and these are places were the rock eventually fractured. Today boulderfields are home to prolific displays of spring wildflowers and trees such as yellow birch and basswood.
The southern Appalachians are also diverse because not all of the mountains' plants and animals originated here. When North America was part of larger landmasses like Laurentia and Pangea, it shared species with other continents. When landmasses broke apart, species found ways to survive in new habitats on new continents. Today, red foxes and weasels are shared with Europe, while black bear, deer, and copperheads are shared with Asia. Animals that came from tropical areas include the short-tailed shrew, raccoon, and gray fox. Some of the plants found in these mountains that have their closest relatives in eastern Asia include hemlock (Tsuga), tulip poplar (Liriodendron), sweetshrub (Calycanthus), and foamflower (Tiarella).
Topography, elevation, and sunlight—along with water, soil, and history—determine what species live where. Visitors don't have to travel north to visit a variety of habitats; they can simply travel up a mountain in the Appalachians. A trip up a 6,000-foot mountain is the equivalent to driving 1,000 miles north and will lead through a variety of life zones or biomes that support unique plant and animal communities. A life zone is shaped by a variety of factors including elevation, the direction it faces and how much sunlight it receives, and rainfall. A high, north-facing valley and stream might be home to wood frogs, spring salamanders, hemlocks, and rosebay rhododendrons, while a cliff face is a more likely place for peregrine falcons, ravens, green salamanders, Carolina hemlock, and table mountain pine.
Mountains also have a way of carving up the landscape and separating species from one another, similar to the effect islands have in an ocean. On these "islands in the sky," species are genetically isolated. Mountains and valleys prevent them from mixing with other species groups, until eventually the isolated species becomes a new species. In this way, mountains contribute to their own biodiversity.
The unique conditions found in the southern Appalachians create a wide range of natural communities. Each natural community contributes to biodiversity by acting as home to a unique assortment of flora and fauna. There are dozens of distinctive habitats in the southern Appalachians, including heath balds, grassy balds, bogs, and rocky summits, but mostly there are forests. Eastern deciduous forest covers 70 percent of these southern mountains, and within the deciduous forest are several major forest types. The major forest types in Tennessee are discussed below and include the cove hardwood, oak-hickory, chestnut oak, red oak, white oak, hemlock, pine, and spruce-fir forests.
Depending on elevation and other growing conditions, every forest develops layers of plants, from the tallest trees to the fungi. Dominant trees are the tallest, with medium and smaller trees under them. Shrub layers develop under the small trees and then there are the vascular (herbaceous) and nonvascular plants growing on the forest floor.
Growing in the coves below 4,500 feet, the cove hardwood forest is the most diverse forest type in North America. These communities can support as many as 30 species of canopy trees and a great variety of shrubs and wildflowers in the understory. The reasons for this diversity are water and soil.
Coves are formed as rainfall and melted snow pour down mountain slopes carrying
soil and gravel. When this water reaches a valley, it deposits its load in
a fan delta. Vegetation takes root, stabilizing the soil and eventually decomposing
to add its own nutrients to the collection. Coves are also usually protected
from nature's elements from the rear and on each side by ridges, and they make
good homes for plants and animals, as well as humans. The fertile black soil
makes coves precious to mountain farmers, and in the 1800s and early 1900s,
many Appalachian coves were harvested for their rich timber. However, in some
remote and inaccessible areas, coves flourished untouched and now contain awesome
old-growth timber.
In the Appalachians, coves are most often found on western slopes, which face into the prevailing wind and consequently receive heavier precipitation and erosion. Nowhere is cove development more legendary than in the Great Smokies, especially on the Tennessee slopes. One of the most famous coves of its kind is Cades Cove near Gatlinburg.
Eastern hemlock (Tsuga canadensis), silver bell (Halesia carolina), buckeye (Aesculus octandra), basswood (Tilia americana), sugar maple (Acer saccharum), yellow poplar (Liriodendron tulipfera), beech (Fragus grandifolia), and yellow birch (Betula alleghaniensis) are the dominant trees in cove hardwood forests. The old-growth trees may reach 75 feet to 100 feet high with crowns sometimes reaching 200 feet. White ash (Fraxinus americana), green ash (Fraxinus pennsylvanica), northern red oak, cucumbertree (Magnolia acuminata), bitternut hickory (Carya cordiformis), red maple, and wild black cherry (Prunus serotina) are other trees that may grow among the dominant trees.
The shadowed understory consists of small and medium trees including umbrella magnolia (Magnolia tripetala), blue beech (Carpinus caroliniana), Fraser magnolia (Magnolia fraseri), yellowwood (Calrastris lutea), holly (Ilex opace), and hop hornbeam (Ostrya virginiana). The shrub layer is usually missing or sparsely developed. Strawberry bush (Euonymus americanus) and spicebush (Lindera benzoin) may grow in the cove hardwood forest at lower elevations. At higher elevations the shrubs may be alternate leaf dogwood (Cornus alternifolia), hobblebush (Viburnum alnifolium), and doghobble (Leucothoe fontanesiana). Wild hydrangea (Hydrangea arborecsens) grows at all elevations and may be a member of the shrub layer.
Throughout the southern Appalachians, but especially in cove hardwood forests, there is a large variety of wildflowers. In spring, blue cohosh (Caulophyllum thalictroides), squirrelcorn (Dicentra canadensis), Dutchman's breeches (Dicentra cucullaria), bleeding heart (Dicentra eximia), umbrella leaf (Diphylleia cymosa), trout lily (Erythronium americanium), wild geranium (Geranium maculatum), sharp-lobed hepatica (Hepatica acutiloba), dwarf crested iris (Iris cristata), bishop's cap (Mitella diphylla), showy orchis (orchis spectabilis), mayapple (Podophyllum peltatum), solomon's seal (Polygonatum biflorum), bloodroot (Sanguinaria canadensis), black snakeroot (Cimicifuga racemosa), false solomon's seal (Maiantheumum racemosum), giant chickweed (Stellaria pubera), foamflower (Tiarella cordifolia), trillium (Trillium sp.), and many violet species (Viola sp.) can be seen. In summer, white snakeroot (Ageratina altissima var. roanenis), black cohosh (Cimicifuga racemosa), blue cohosh, jewelweed (Impatiens pallida), wood fern (Dryopteris cristata), giant chickweed , foamflower, bedstraw (Galium aparine), and strawberry bush are usually found.
Oak-hickory forests thrive between 2,500 feet and 3,000 feet elevation and occupy slightly drier areas than the cove hardwoods. Northern red oak (Quercus rubra), pignut hickory (Carya glabra), white oak (Quercus alba), and mockernut hickory (Carya tomentosa) are the dominant species with black oak (Quercus velutina), sweet pignut hickory (carya ovalis), chestnut oak (Quercus prinus), black gum (Nyssa sylvatica), and tulip poplar joining in.
Understory trees are commonly red maple (Acer rubrum), flowering dogwood (Cornus florida), and sourwood (Oxydendrum arboreum). The shrub layer contains mostly huckleberry (Galussacia ursina) and mountain laurel (Kalmia latifolia), but rosebay rhododendron (Rhododendron maximum) and flame azalea (Rhododendron calendulaceum) may live among the dominant trees.
Few herbaceous plants survive on the oak-hickory forest floor. Of those that may occur are the Christmas fern (Polypodium virginianum), goldenrod (Solidago sp.), false foxglove (Aureolaria laevigata), galax (Galax aphylla), pipsissewa (Chimaphila umbellata), downy rattlesnake plantain (Goodyera pubescens), false solomon seal, and bellwort (Uvularia grandifloria).
Chestnut oak forests, once known as chestnut oak-chestnut forests, live well at 4,500 feet elevation or less. In the early 1900s, the chestnut blight removed the chestnut tree, which historically made up half of the tree count in this forest classification. Chestnut oak, northern red oak, and red maple filled about half the niche left vacant by the demise of the large chestnut trees. White oak, black oak, black gum, red maple, tulip poplar, and a small percentage of hickories enter the mix.
Above 2,500 feet in chestnut oak forests, mountain laurel, flame azalea, rosebay rhododendron, and huckleberry are the main shrubs. Also above 2,500 feet, sweetshrub (Calycanthus floridus) and highbush blueberry (Vaccinium simulatum) may be members of the shrub layer.
False foxglove, gall-of-the-earth (Prenanthus trifoliata), wood betony (Pedicularis canadensis), downy rattlesnake plantain, hellebore (Veratrum viride), and galax make up the herb layer, but at higher elevations this layer's coverage drops from 30 percent down to about 1 percent.
Red oak forests and white oak forests are not appreciably different below 4,500 feet. At higher elevations the red oak forest will have American beech and silver bell (Halesia monticola) growing in it. Red maple, basswood, black cherry, yellow birch (Betula lutea), buckeye, and white ash are found in the red oak forests and white oak forests below 4,500 feet. In white oak forests above 4,500 feet, white oak usually dominates some exposed southwestern ridges, and pignut hickory and chestnut oak will generally be present.
The shrub layers for these two forests are also similar, consisting most commonly of highbush blueberry, flame azalea, and mountain laurel.
Herbs under the red oak forests are similar to those in chestnut oak forests below 4,500 feet, whereas the white oak forests have a sparse smattering of herbs, usually ferns and grasses. In the red oaks forests and white oaks forests above 4,500 feet, the herb layers are similar, sparse with mostly sedges.
More often than not, the hemlock forests occur in dense stands between 2,500 feet and 4,500 feet elevation. They grow from mountain peaks to along streams, and they are found on north-facing slopes. The hemlock normally reaches more than 3 feet in diameter with its crown rising over 100 feet. The higher the elevation the more likely these trees will be nearly homogenous, dominating all other tree species.
If hemlock forests have a shrub layer, it will consist mostly of rhododendrons at higher elevations. Other understory shrubs include rosebay rhododendron, mountain rosebay, doghobble, wild hydrangea, and mountain laurel. The denseness of the hemlock forest and its thick understory species usually prevent a herbaceous layer. Where there are openings among the heaths, wood fern, partridgeberry (Mitchella repens), rattlesnake plantain, and foamflower may grow.
Virginia pine (Pinus virginiana) forests dominate at low elevations, 3,000 feet or less, in stands on south-facing slopes and in old fields. Mountain laurel and lowbush blueberries (Vaccinium vacillans) are usually the dominant shrubs. Herbs include little bluestem (Andropogon scoparius), broomstraw (Andropogon geradii), bracken fern (Pteridium aquilinum), goat's rue (Tephrosia virginiana), wild indigo (Baptisia tinctoria), tickseed sunflower (Coreopsis tinctoria), asters (Aster sp.), and goldenrod.
Pitch pine (Pinus rigida) forests dominate at elevations between 2,200 feet and 3,200 feet. Scarlet oak may sometimes share dominance. Mountain laurel and lowbush blueberry are the main shrubs under these pines, and the sparse herbs consist of little bluestem, bracken fern, trailing arbutus (Epigaea repens), and wintergreen (Gaultheria procumbens).
Spruce-fir forests are usually found from 4,500 feet to over 6,000 feet elevation. Red spruce (Pices rubens) and Fraser fir (Abies fraseri)—boreal species typical of more northern latitudes—dominate here. Some red spruce are known to live more than 300 years. Yellow birch, mountain maple, striped maple, serviceberry, and mountain ash (Sorbus americana) may also be found in this high forest. The shrub layer of bearberry (Arctostaphylos uva-ursi) and hobblebush hovers over herbs, including woodfern, bluebeard lily (Clintonia borealis), aster, wake-robin (Trillium erectum), twisted stalk (Streptopus roseus), Rugel's ragwort (Rugelia nudicaulis), and mosses.
The grand and generous American chestnut, Castanea dentata, once made up 40 to 50 percent of forests in the southern Appalachians, but today, for all practical purposes, it is gone. Tiny saplings still spring from old root systems, but the trees succumb to the chestnut blight before they grow large enough to reproduce. The story of this tree's disappearance is one of the most dramatic in the history of these mountains and speaks to the power of even the smallest forest invader.
These were giant canopy trees that rose to heights of more than 100 feet and had trunks 10 feet across. The chestnut's nearly rot-resistant wood was light and easily worked, and settlers used it to build everything from cabinets to barns to homes. Maybe most importantly, American chestnuts were prolific nut-producers that provided a bountiful mast crop each fall. People as well as wildlife depended on the sweet nut for food.
The American chestnut blight first appeared in the Bronx Zoo in 1904, and it is believed to have been brought to the United States around 1890 via some Oriental chestnuts. Within 10 years the blight had spread to the Shenandoah National Park. Within another 15 years it was in the Smokies, and by 1938, 85 percent of the chestnuts there were dead. Most were dead by the 1940s. It has been estimated that $400 billion worth of trees were lost in 9 billion acres of forests.
The chestnut fungus (Cryphonectria parasitica) invades the tree through any tiny opening in its bark such as a cut or bruise. The fungus spreads filaments into the cambium layer and destroys it, thereby cutting off water and nutrients to the tree. In about four years the fungus circles the tree, essentially girdling it. The roots are not infected because the fungus can't live below the soil. The wind, birds, and insects easily spread the fungus spores.
Mostly white oak and red oak have filled the niche left vacant by the dying mast-producing trees, but work continues to revive the American chestnut. The United States Department of Agriculture and other researchers have tried to hybridize the chestnut with blight-resistant Oriental species, but there is not any success to report. Work with a virus to render the fungus less virulent has been successful in Europe, and it is hoped that this hypovirulent strain can be introduced in the United States with similar results. The flaws with this less lethal strain are that is does not spread as readily as the deadly strain, and it can revert back to the potent strain.
Genetic work may yet save the majestic tree. The American Chestnut Foundation is optimistic that backcrossing techniques may make blight-resistant trees and nuts available within a few years. Mapping of the chestnut's genes has aided in telling which plants have resistance to the blight.
Balds are one of the greatest mysteries in the southern Appalachians. More than 80 of these high-altitude, treeless, open areas exist from Virginia south to Georgia, some as large as 20 acres, and no one is certain why. They defy the natural laws of succession, a process vegetative communities go through as they develop into ultimate climax communities. In the southern Appalachians, that climax community is usually one of the forest types previously discussed. However, balds have not been invaded by surrounding forests and instead have remained open grassy or heathlike areas for thousands of years. Altitude does not cause these openings because in no place do they approach treeline.
The explanations and speculations for why balds exist range from natural conditions such as fungi, parasitic insects, drought, fire, ice, and/or winds to man clearing the areas for grazing animals. It is known that some of them existed when the first white settlers arrived and that settlers used the open areas for grazing their livestock. Indians may have been the first to burn such areas to attract grazing game animals or to create places of worship.
Grassy balds are distinguished by an abrupt transition from forest to bald. Good examples of grassy balds can be seen in Tennessee in the Highlands of Roan Mountain and at Andrews Bald. Mountain oak grass is usually dominant on these balds with some introduced grasses, sedges, and various herbs. The most abundant herbs are five fingers (Potentilla canaddensis), hedge nettle (Stachys sp.), goldenrod, rattlesnake root, catbriar (Smilax rotundifolia), bluets (Houstonia caerulea), coneflower, gentian (Gentiana quinquefolia), and giant chickweed.
Rhododendrons (Rhododendron maximum or R. carolinianum) commonly dominate heath balds at lower elevations, with purple laurel (R. catawbiense) and mountain laurel (Kalmia latifolia) at higher elevations. Heath balds are also covered by blueberry and other heath shrubs, the particular species depending on the elevation. Sometimes the shrubs grow so densely (up to 10 feet high) that they become known as "hells," such as the fabled Jeffery Hell in the Tellico Ranger District of the Cherokee National Forest. Beauty Spot is an excellent example of a health bald on Unaka Mountain in the Unaka Ranger District of the Cherokee National Forest.
Herbs rarely become significant under these dense heath balds, but wintergreen, galax, cow wheat (Melampyrum lineare), Indian cucumber root (Medeola virginiana), and painted trillium (Trillium undulatum) may get a toehold.
The continuance of prehistoric balds is not understood, but it has been suggested that thick grasses and the thick root systems of the heath prevent tree seedlings from surviving and that historic grazing on the balds has limited plant succession. Now that many balds in national forests and national parks are protected from grazing and maintenance activities like fire are prohibited, some scientists are concerned trees and shrubs will invade and balds will disappear.
Bogs occur more often at lower elevations and are rare in Tennessee's Appalachian Mountains. Bogs are waterlogged areas that usually have certain plants associated with them, most frequently sphagnum moss (Sphagnum spp).
Poor drainage causes bogs to form and the stagnant environment becomes so acidic that only very specialized plants and animals can survive. Vegetative matter collects and decays, creating acidic leftovers. Swamp pink (Helonias bullata), bog laurel (Kalmia carolina), Carolina saxifrage (Saxifraga caroliniana), cinnamon fern (Osmunda cinnamonea), and an interesting group of carnivorous plants survive here.
Carnivorous plants such as sundew (Droscera rotundifolia) and pitcher plants (Sarracenia spp.) have adapted to living in nutrient-poor soil by developing ways to capture and eat animals. Their large tubular leaves attract and collect insects. Some plants have hoods with translucent spots that insects try to escape through but cannot, and they die of exhaustion. Other pitcher plants have recurved hairs in the tubular leaves to keep insects from crawling out. Insects drown in the water collected in the plant's base. The organisms decay or are digested by secreted enzymes that some of these carnivorous plants produce. The insect provides nitrogenous compounds that the plants need.
Bogs are disappearing due to eutrophication, water deprivation, and other conditions. Many of the bog plants and animals are on the endangered or threatened species list. Four such animals are the bog lemming (Synaptomys cooperi), water shrew (Sorex palustris), smokey shrew (Sorex fumes), and bog turtle (Clemmys muhlenbergii).
Along with luxuriant plant growth comes interesting and unique animals. Faunal communities, like flora, vary up and down the Appalachians according to elevation and climatic conditions. Typically, some animals are more visible than others, but with a little patience, there is lots of wildlife to see here.
Wildlife often hides in their habitats from intruders, such as hikers. Some wild animals may show themselves if visitors sit still, concealed, and remain quiet for awhile. Usually it takes about 30 minutes for an animal to feel comfortable about going about its business after being disturbed.
The wild turkey (Meleagris gallopavo) and the wild boar (Sus scrufa) are two critters that will be difficult to see. The reclusive turkey has powerful eyesight and picks out the slightest movement in the woods. It sees in color, so wear camouflage if you want to hunt or photograph the bird, and be very still, using a wide tree as your background.
The wild boar is nocturnal but evidence of its activity is easy to find along some trails through the mountains. It is better to avoid this rough character. It is a charging animal, and its sharp tusks can inflict severe wounds.
Black bears (Ursus americanus) are a signature species of the mountains, especially of the Smokies, and it has become more common to see these animals as they've learned to wander into campgrounds and picnic areas in search of human food. Campers should take precautions to avoid a bear encounter by hanging their food so the animals can't reach it. Hikers should make enough noise when walking that a bear has the opportunity to avoid them.
Hikers and those touring the mountains in automobiles may see the white-tailed deer (Odocoileus virginianus), especially at dawn and dusk. Cades Cove in the Smokies is a popular spot for viewing this animal.
Some of the animals that are more difficult to see are the elusive red fox (Vulpes fulva), gray fox (Urocyon cinereoargenteus), southern flying squirrel (Glaucomys volans), and northern flying squirrel (Glaucomys sabrinis). The flying squirrels are nocturnal, and the foxes, like the turkey, avoid humans.
The nocturnal bobcat (Lynx rufus), another rarely seen animal, usually makes a meal of rabbits and rodents but it also eats birds, mice, eggs, reptiles, and squirrels. Although bobcats are able to kill deer, they rarely feed on deer.
The gray squirrel (Sciurus carolinensis), fox squirrel (Sciurus niger), and red squirrel (Tamiasciurus hudsonicus) are usually easy to find among nut-bearing trees. Other mammals in the mountains include mink (Mustela vision), raccoons (Procyon lotor), opossums (Didelphis marsupialis), groundhogs (Marmota monax), beaver (Castor canadensis), skunks (Mephitis mephitis), cottontail rabbits (Sylvilagus floridanus), long-tailed weasels (Mustela freneta), and river otters (Lutra canadensis). Some of the smaller mammals are the pine vole (Microtus pinetorum), southern bog lemming (Synaptomys cooperi), woodland jumping mouse (Napaeozapus insignis), silver-haired bat (Lasionycteris noctivagans), Keen's myotis (Myotis keenii), and Eastern pipistrelle (Pipistrellus subflavus).
There are more than 120 species of birds that are found in the mountains. Some of the birds that are interesting to photograph are bald eagles (Haliaeetus leucocdphalus) and peregrine falcons (Falco peregrinis). Hooded warblers (Wilsonia citrina), dark-eyed juncos (Junco hyemalis), crows (Corvus brachyrhynchos), ravens (Corvus corax), yellow-throated vireos (Vireo flavifrons), black-capped chickadees (Parus atricapillus), barred owls (Strix varia), Eastern phoebes (Sayornis phoebe), and summer tanagers (Piranga rubra) are likely to be heard or seen. But, alas, the red-cockaded woodpecker (Picoides borealis) is not a bird you are likely to see. These birds require large pine trees with a sparse understory. Fire suppression practices prevented natural forest fires from clearing the understory and took away this bird's habitat.
Many birds are well adapted to second-growth forests of Tennessee, and a few that prefer them are the yellow-throated warbler (Geothlypis trichas), wood thrush (Catharus fuscescen), Louisiana water thrush (Seiurus motacilla), rufous-sided towhee (Pipilo erythrophthalmus), and indigo bunting (Passerina cyanea). Typical of the birds that inhabit hardwood forests are the whip-poor-will (Caprimulgus vociferus), screech owl (Otus asio), red-tailed hawk (Buteo jamaicensis), black vulture (Coragyps atratus), and red-bellied woodpecker (Centurus carolinus). Many of the birds that inhabit the hardwood forests will also be found in the hemlock and pine forests.
In the pines are bird species that depend on the food chain that thrives in this habitat, such as the pine warbler, red-breasted nuthatch (Sitta canadensis), evening grosbeak (Hesperiphona vespertina), and bobwhite quail (Colinus virginianus). Hairy woodpeckers (Picoides villosus), common flickers (Colaptes auratus), and pileated woodpeckers (Dryocopus pileatus) prefer the mixed pine-oak habitats.
The mixed hardwood forests are home to many amphibians, including the mountain chorus frog (Pseudacris brachyphona), Eastern spadefoot toad (Scaphiopus holbrooki), spotted salamander (Ambystoma maculatum), Eastern newt (Notophthalmus viridescens), and dusky salamander (Demognathus fuscus).
Numerous reptiles occupy niches in these mountains. The common snapping turtle (Chelydra serpentina), stinkpot (Sternotherus odoratus), green anole (Anolis carolinensis), coal skink (Eumeces anthracinus), northern water snake, Eastern ribbon snake (Thamnophis sauritus), brown snake (Storeria dekayi), and pine snake (Pituophis melanoleucus) are examples.
According to The Fishes of Tennessee, Tennessee has the richest freshwater fauna of any state in the U.S. It reports there are between 302 and 319 species of native and introduced fishes alone. This diversity can most likely be explained by the several distinct drainages within Tennessee as well as the numerous physiographic provinces. As the topography changed, certain animal populations were cut off from other members of the same species. If a mountain rises and isolates a lake or stream, fish and other aquatic and semiaquatic species are not able to leave the water and cross the mountain to breed. When these species remain separated from others of their kind long enough, they evolve into new species.
Adding to this aquatic diversity is a host of introduced species. Tennessee's numerous waterways and man-made reservoirs have attracted resource managers and others to introduce exotic fish into them, purposefully and by accident. Game fishermen benefit from some of these introductions, but other exotic fishes are nuisances and are detrimental to native fauna. Carp, rainbow and brown trout, striped bass, and yellow birch are some of the introduced species.
Just as fish isolated by mountains have evolved into new species, so have salamanders. Because 39 salamander species exist in the southern Appalachians, many scientists now believe these mountains are the center for salamander evolution. These lungless creatures spend their lives living beneath logs and loose stones among damp leaf decay. They absorb oxygen directly through their sensitive skin, which must stay moist and cool.
As temperatures rose at the end of the last ice age, salamanders probably migrated up mountainsides in search of cooler habitat. They became isolated on individual summits and evolved into the variety of species that exists today. Now some populations are in danger because of their tiny home ranges. As mountainsides are further subdivided by trails, timbering operations, and roads, individual populations become smaller and smaller and threaten to disappear completely.
The mountains have always been a desirable place to live and visit because of their natural wealth and beauty. People have shaped the landscape of the southern Appalachians for thousands of years through hunting, farming, grazing, mining, and logging.
A series of prehistoric peoples—of the Paleo-Indians, the Archaic and Woodland cultures, and the Mississippian tradition—lived by hunting on the grasslands and fishing the streams of Tennessee. Native Americans, primarily the Cherokees, valued these lands as hunting grounds, but species including mountain bison (Bison bison), gray wolves (Canis lupus), and elk (Cervus elaphus) were quickly eliminated when white settlers arrived.
The Europeans that arrived included plantation workers, immigrants of Scotch-Irish and German descent, and veterans of the French and Indian Wars and the Revolutionary War who received land grants as payment for service. All came in search of a better life. Eventually they began farming small plots and raising livestock to supplement their diet of wild game.
They learned to use the land to their advantage. Settlers soon discovered that fertile and productive soils made coves some of the best places to raise crops, but as coves became more populous with farms, graziers were left looking for grasslands to feed cattle, sheep, and horses. They turned to the grassy balds. The people of Cades Cove built a long and steep trail up to Gregory Bald, almost 3,000 feet above. Balds like these were subjected to dense clouds and fog, frequent showers, and heavy dews, making them even more succulent grasslands. Coves and balds complemented each other and settlers found ways to make the best use of the land.
Timber had also been flourishing in the southern Appalachians for thousands of years and stood as a valuable resource to be taken by white settlers. The people who lived in Tennessee from the 1830s to the 1880s had very timber-intensive lifestyles, using wood for everything from building their homes to building fires. They didn't always cut entire tracts, either. They usually went into the forests and cut the best trees they could find.
Beginning in 1890 and continuing well into the twentieth century, commercial lumbering rocked the South. New forms of transportation (steam power and an expanded railroad), new methods of felling, new mill technology, new materials (steel), and large-scale land ownership led to a new wave of exploitation of forest resources. Commercial loggers also did not usually harvest all of the trees. They took the best trees, starting at lower elevations and following major streams back and up into the forest. Usually the lands they didn't cut were the highest and roughest tracts. Such practices didn't just remove valuable timber but also left hillsides bare, without vegetation to hold valuable soil in place. Silt and sediments washed into rivers and streams, changing their character and chemistry and killing aquatic species.
Finally, mountain lovers became concerned about conserving natural resources. National forests began to be established to ensure a continuous timber supply for the country but also to preserve some areas from the logger's axe. In Tennessee, the Cherokee National Forest was created in the Unaka Mountains. The National Park Service guards the Great Smoky Mountains National Park, the largest undeveloped region in the southern Appalachians and an International Biosphere Reserve. Along with state parks and numerous other management areas in Tennessee, there are unique approaches to conservation like the Big South Fork National River and Recreation Area. This combination of national river and national recreation area preserves the river gorge as a wilderness area and offers outstanding recreational opportunities.
Eastern Tennessee offers some of the best opportunities to appreciate the lush green landscape of the southern Appalachians. While millions of people live in these hills and millions more flock here to visit, there are still plenty of places where nature's wealth and beauty can be observed. Climb to the top of a heath bald and survey the rhododendron display. Turn over a rock in a cove forest and discover a dusky or spotted salamander. Stand on the banks of the Clinch and reel in the catch of the day. The wild lands of Tennessee are waiting to be discovered.