Partager l'article ! The Appalachian Mountains: THE APPALACHIANS John Pickeri ...
THE APPALACHIANSMost people equate eastern North America with a megalopolis--Boston, New York City, Washington DC, Atlanta, and the other sprawling concrete jungles that drive the area's economy and, indeed, much of the world's. Yet nature also survives and is making a comeback in much of this region, particularly its wilderness. Here, we focus on the most extensive and pristine of its parks and protected areas; running along the 3,200 km of the Appalachian Mountains, from northern Alabama, USA, to New Brunswick, Canada, and encompassing approximately 249,000 km2 (seemap).
John Pickering, University of Georgia, Athens
Draft, March, 2002; final version published as pages 458-467 in P. R. Gil, R. A. Mittermeier, C. G. Mittermeier, J. Pilgrim, G. Fonseca, W. R. Konstant and T. Brooks (eds.), Wilderness -- Earth's Last Wild Places. Conservational International.
The Appalachians formed during the Paleozoic, with major uprisings from 650-350 million years ago. By the time humans reached their slopes, these mountains had worn down from prehistoric peaks over 5,000 m high to 2,000 m today. Their northern biota is still recovering from the last ice-age, which ended 10,000 years ago, but the Southern Appalachians were never glaciated. The chain's north-south alignment allows species to migrate easily. Had these mountains been aligned east-west, like the European Alps, they would have been a great barrier to migrations, and a trap that would have ensured mass extinctions during ice-ages. On a different scale, the elevational gradients of gorges and summits allow short-range migrations to accomplish temperature changes that could only be achieved by migrations of hundreds of miles in the plains. Perhaps this is why the Southern Appalachians are a center of endemism for terminally slow groups of organisms, including snails, vernal herbaceous plants, and salamanders. In Great Smoky Mountains National Park, for example, an area of just over 2,000 km2, there are over 30 species of salamanders and more tree species than in the whole of Europe.
Peaks and gorges also provide isolated climatic refuges for boreal and subtropical species, respectively. As a consequence of repeated glacial-interglacial cycles during the last 3 million years many of the species experienced repeated periods of isolation and connection with more extensive populations to the north or south. This appears to explain the origin of a number of species that are now isolated in the Southern Appalachians.
Assemblages of contemporary vegetation in the Appalachians are strongly influenced by elevation and moisture (Whittaker 1956), but soils and history, including disturbances and pathogens, have also shaped their composition. In southern elevations below 1,500 m, chestnut oak (Quercus montana) and white oak (Quercus alba) dominate forests that occupy the middle of the moisture gradient. These forests once had a substantial component of American chestnut (Castanea dentata) prior to an introduced blight. Short-leaf pine (Pinus echinata), pitch pine (Pinus rigida), and other fire-dependent pines frequent dry ridges. Rich hardwood forests with tulip poplar (Liriodendron tulipifera), American beech (Fagus grandifolia), red maple (Acer rubrum), black cherry (Prunus serotina) and other trees occupy the mesic valley flats and coves. These forests are famous for a luxuriant herbaceous growth. In a single square meter, some locations have a dozen species of spring wildflowers, such as mayapple (Podophyllum peltatum) and various Trillium species. Above 1,500 m, spruce-fir forest occurs, once dominated by red spruce (Picea rubens) and Fraser fir (Abies fraseri). Unfortunately, in the last few decades, an introduced pest insect, the balsam woolly adelgid (Adelges piceae), has killed most Fraser fir trees. Vegetation in this higher zone appears particularly vulnerable to acid rain, due to low buffering capacities of the thin soils, and to ozone pollution, which reaches high levels at these elevations. While the Southern Appalachians lack the tree line found in the north, they have scattered tree-less balds, which are being invaded by heaths dominated by Catawba rhododendron (Rhododendron catawbiense) and mountain laurel (Kalmia latifolia). Higher rock outcrops have alpine tundra relicts, such as three-toothed cinquefoil (Sibbaldiopsis tridentata).
In the Northern Appalachians, white spruce (Picea glauca), black spruce (Picea mariana), and balsam fir (Abies balsamea) dominate the spruce-fir forests. Red pine (Pinus resinosa) and white pine (Pinus strobus) are common in second growth stands, and jack pine (Pinus banksiana), paper birch (Betula papyrifera), and quaking aspen (Populus tremuloides) establish after severe distubances. Herbaceous understories are sparse except in openings and under deciduous trees. They often include Clinton's lily (Clintonia borealis) and nodding trillium (Trillium cernuum). The hardwood forests share many species with those of the south. American beech, sugar maple (Acer saccharum), and yellow birch (Betula alleghaniensis) dominate. Paper birch is a frequent addition. The yellow buckeye (Aesculus flava) that frequents the southern forests is absent.
Appalachian history offers a stark warning: poor management leads to species extinction. As related by Mowat (1994), intense farming and wanton extraction of natural resources following European colonization destroyed virtually all of the region's original forest. Less than 1% of eastern deciduous forest has never been cut, the most notable being 42,900 ha in the Great Smokies and 20,000 ha of virgin forest in the Adirondack's Five Ponds Wilderness Area. Unregulated hunting and habitat destruction decimated all populations of larger birds and mammals, irreversibly exterminating some forever. The well known slaughter of the thunderous American bison (Bison bison) started in the east and rolled west with such force that the species barely avoided extinction.
Likewise, it is almost unbelievable that the most common bird in North America, the passenger pigeon (Ectopistes migratorius), numbering in the billions, was hunted to extinction so it could be sold at city markets. The Carolina parakeet (Conuropsis carolinensis) was blown to world-wide extinction by farmers protecting their crops. Habitat destruction and senseless target shooting drove the ivory-billed woodpecker (Campephilus principalis) to extinction. A more purposeful onslaught of bullets, fueled by government-funded bounties, eliminated the area's top predators: gray wolf (Canis lupus), red wolf (Canis rufus), and puma or cougar (Puma concolor). Luckily, they survived elsewhere and are now candidates for reintroduction.
Not all of our charismatic flagship species were driven to extinction. Moose (Alces alces), fisher (Martes pennanti), and many raptor species survived the onslaught, finding refuge in remote mountain areas. With modern hunting and trapping regulations in place, and healthy forests reclaiming park and private land, these species are returning to their old haunts. Raptors are migrating past Hawk Mountain, Pennsylvania, in increasing numbers. Moose are spreading throughout New England and New York. Although fishers in the western USA are declining precipitously, this large relative of the weasel is now common in most northeastern wildernesses, and is even making appearances in some suburban areas.
Species reintroduction is an unpredictable task. In some cases, simple release of animals does the trick. This helped the fisher and beaver spread south down the mountain chain. Other species, such as peregrine falcons (Falco peregrinus), require much more active involvement by biologists, and often encounter surprising roadblocks. For example, a recent attempt to restore red wolves in Great Smokies failed, in part because visitors' pet dogs transmitted a fatal virus to the wolves' cubs. Reintroductions of large predators, such as gray wolf and cougar, remain controversial and hypothetical because they are not welcomed by all members of local human communities. Less dangerous species, such as the elk (Cervus elaphus), are less controversial and have been successfully reintroduced into Appalachian wilderness areas in the last few years.
Today twenty-two million people live in this mountainous wilderness, an overall density of 88 humans per km2. While human density drops to 50/km2 in the region's 296 counties that do not include major urban areas (10,104,000 people/201,000 km2) and to 21/km2 in the 65 counties centered of major protected areas (2,035,000 people/95,000 km2), over 150 million people live within 600 miles. With over half the people in North America within a day's drive of the region's 511 protected areas, millions seek outdoor recreation in the Appalachians each year. Great Smoky Mountains National Park, a jewel of southern Appalachian wilderness, has over 9 million visitors annually. The region's past and present conservation challenges portend those many wildernesses will face from the worldwide human population growth and encroachment likely this century. We should pay heed to the hard and expensive lessons that we have learned in these mountains.
Urban and suburban sprawl are fragmenting the region's natural areas. Private lands abound in the region, especially in the southern Appalachians and Maine, often with few roads scarring the land (SAMAB 1996). The largest of these areas holds the potential to form the core of new wilderness areas. Smaller natural areas between them need protection to provide corridors essential for gene exchange and recolonization. If links are severed and migration cut off, isolated populations of plants and animals will suffer. Only connected, intact ecological units can ensure long-term species survival and provide the entire region the array of ecological benefits presently enjoyed, including air and water purification, nutrient recycling, soil renewal, and climatic stability.
Existing dams and water quality issues threaten aquatic biodiversity. The region's experience suggests that some aquatic groups are over 10 times more susceptible to extinction than terrestial ones. While under 1% of the region's terrestrial plants and vertebrates went extinct in recent times, many locally-restricted aquatic species succumbed. Neves et al. (1997) list 36 of 289 bivalve mollusks and 38 of 313 aquatic snails that occurred in the southeastern United States as presumed extinct, including 4 genera and 13 species that were lost after damming on the Coosa River in eastern Alabama. Furthermore, they list 56 mussel species as endangered or threatened. Etnier (1999) attributes 40% of current fish imperilment in the southeast to siltation and other nonpoint source pollution, and 32%, to dams and other human impacts on streamflow.
The percent of the Appalachians that are covered by intact forest has recovered from historic lows of 70 to 100 years ago. Intact forest now covers at least 60% of all but a handful of eastern states. Maine's forest coverage increased from an estimated 79% in 1900 to 90% in 1990; New York's, from 39 to 62%. Unfortunately, the recovery is likely to reverse soon. Besides the predicted urbanization of millions of forested acres, many chip mills have sprung up in recent years. In 2000, 146 southern chip mills alone were being fed. Over 5 million southeastern acres were clearcut in 1998, the latest year with an available estimate. Furthermore, there is an alarming trend to switch forest production from naturally-regenerating mixed stands to planted pine monocultures. In the next 40 years, non-plantation forest acreage in the South is projected to decline at least 15% (Southern Forest Resource Assessment, 2002, <www.srs.fs.fed.us/sustain>).
Fire and recreational use are serious threats to many natural areas in the Appalachians. After 70 years of misguided fire-suppression and fuel build-up, potential wildfires threaten forests, homes, and lives. Forest managers must heed the natural cycles of burn and recovery to avoid unnatural super-fires that threaten nature and humans alike. Wilderness managers also have the power to regulate recreation, curbing trail damage from off-road vehicles, air and noise pollution from traffic jams, and poaching and over-hunting. Restricting human use of public areas is often seen as a strike against constitutional rights, and therefore, is highly political and controversial. Only balanced, objective management plans will save our public lands from the tragedy of the commons.
The greatest current threat to Appalachian wilderness is not economic development, urbanization, or the footprint of outdoor recreation - invasive species, are wreaking havoc in the region. Around 1900, horticulturalists unwittingly introduced a blight fungus that eventually killed an estimated 3 billion chestnut trees, reducing a species that was once the largest tree in eastern North America and a dominant component of the region's forest to a relatively insignificant species. Right now American elm (Ulmus americana), dogwood (Cornus florida), butternut (Juglans cinerea), and beech are all battling relatively new diseases. An introduced adelgid has destroyed many of the region's Fraser fir. Another introduced species of these insects threatens to do the same to eastern hemlock (Tsuga canadensis). In Virginia's Shenandoah National Park, most hemlocks are already dead. A tachinid fly (Compsilura concinnata) that was deliberately introduced to control introduced pests, including the gypsy moth (Lymantria dispar), is now itself out of control, attacking over 300 species of native moths. In New England it is taking a disastrous toll on many moth populations, including Cecropia and other well-known and much loved silk moths (Boettner et al. 2000). Non-native species are numerous and widespread. A quarter of 1,640 plant species inventoried in Great Smoky Mountains National Park are non-native. Additional external threats come from pollution. The region has recorded some of the highest acid rain deposition in North America.
Protecting and restoring the biological diversity and ecological health of the Appalachians will require the collaboration of many groups and individuals, including private landowners. The full recovery of the region's species and their web of ecological relationships will take decades - if not centuries - to accomplish. The success of this effort will depend on protecting large core areas of habitat, some of which are already in public ownership. The most critical of these lands are those that retain a high degree of their natural ecological function. These areas provide the healthy and stable sanctuaries from which recovery and restoration can proceed. They can also furnish the best reference data to guide the recovery of more-damaged ecosystems.
There are caveats. Appalachian species may be generally more resilient to large scale disturbance than biota elsewhere. In particular, island and tropical species that have not evolved under continental-scale disturbance regimes, such as caused by ice-age glaciation, may be more susceptible to extinction from human activity than their hardy Appalachian brethren. Furthermore, much of the Appalachian biota has, or had, wide ranging continental or sub-continental distributions. Unlike islands, such as Madagascar, where a large proportion of species are found nowhere else, only a small fraction of Appalachian species were probably endemic to these mountains. Even the extinct birds mentioned above once ranged over much of eastern North America. Another caveat is that the communities in reforested areas may differ significantly from those that were never logged. For instance, secondary forest stands, even after 80 years, have approximately half the number of wildflower species at small spatial scales as comparable areas that were never cut (Duffy & Meier 1992; Meier et al. 1995).
The Appalachians feature prominently among the conservation movements of North America. Although the land suffers many abuses, forest protection in the mountains is a tradition with more than a century of broad, bipartisan support. By 1890, forest destruction in the region was on an industrial scale, facilitated by sawmills and small-gauge railroads constructed in many watersheds, alarming visitors and residents alike. The wholesale clearing of the native forests was quickly followed by devastating wildfires and by floods, which carried away tons of the rich topsoil. In the wake of this destruction, foresters Gifford Pinchot and Charles Sargent, physician and hunter Chase Ambler, and others first agitated for national legislation to set up a federal park in the mountains. Ambler arranged a meeting of businessmen, lawyers, and others in Asheville, North Carolina, in 1899, initiating a movement to persuade Congress to create the forest reserve system.
President Theodore Roosevelt attended. In 1901 he wrote: "In this region occur that marvelous variety and richness of plant growth which have led our ablest businessmen and scientists to ask for its preservation by the Government for the advancement of science and for the instruction and pleasure of the people of our own and future generations. Federal action is obviously necessary, is fully justified by reasons of public necessity, and may be expected to have most fortunate results."
The 1899 meeting was the catalyst for a sustained campaign from Maine to Alabama that paved the way for the establishment of national forests throughout the East. Roosevelt pushed for the law that became the Weeks Act of 1911, authorizing the eastern national forest system. A year later, the first land was purchased under the Weeks Act--8000 acres around Curtis Creek, now in the Pisgah National Forest.
Administrative and legislative efforts have since buttressed the Weeks Act. Under The Wilderness Act of 1964, Congress protected places such as Linville Gorge and Shining Rock, designating them Scenic Areas and Wild Areas. The 1975 Eastern Wilderness Act created wilderness areas in Georgia, Tennessee, North and South Carolina, and Virginia, along with Wilderness Study Areas (candidates for wilderness designation) in these states. In the1980s, Congress passed Wilderness Acts for areas in North Carolina, Georgia, Tennessee, and Virginia. In 2000 and 2001, it designated national forest lands in Alabama, Virginia, and West Virginia as wilderness. Today approximately 21% (53,000 km2) of the mountainous area shown on the map is protected. Still another round of wilderness designations is needed to complete the process. Numerous deserving candidates include unroaded natural areas in the Bald Mountains on the border of North Carolina and Tennessee, Kelly Ridge in Georgia, and Bee Cove in South Carolina.
In the north, New York State is a model of big wilderness that should be followed by other states and provinces. Here, the state stepped in and filled a conservation role typically played by the federal government - and they did it better. Two enormous state parks, the Adirondacks and Catskills, are protected as "Forever Wild" by the state constitution. The constitution would have to be amended to change this protection, requiring passage by two consecutive sessions of the state legislature, and then approval by voters in a statewide referendum. Thus, legally, these are among the very best protected areas in the world (USA federal wilderness could disappear with an act of congress). Adirondack State Park, the largest park in the lower 48 states, includes over 1 million ha of public and private land. This mix of small communities, wilderness preservation, resource extraction, and recreation has taught a number of lessons about the tradeoffs and politics of conservation. Within this matrix are 16 wilderness areas totaling 434,000 ha. Throughout the state, there are over 1.25 million ha of wilderness and wild forest lands, 9.5% of the state. Conservation opportunities include the purchase of more land by the state. Challenges include fighting an unneeded interstate proposed along the northern border of the Adirondacks.
In contrast, Pennsylvania with nearly 1.8 m ha of public land, more than any state in the region, has less than 4,000 total acres protected as wilderness. Nevertheless, because of its Allegheny region, it has the potential to have large wilderness areas, and conservationists should push for the integration of these distinct parks into a cohesive regional wilderness. Maine is another state with great potential for big wilderness. Conservationists continue to justify state or federal protection of the extensive wild lands presently owned by logging companies in northern Maine.
Regional conservation groups, such as the Southern Appalachian Forest Coalition and the Northern Forest Alliance, have devoted years of research to identifying remaining natural areas and the means by which they can be consolidated, restored, and sustained. Their proposals for long-term ecological restoration center around a set of special areas (old growth forests, biological hotspots, intact watersheds, especially of drinking water supplies, roadless areas, and other elements) that form a foundation for regional conservation. Their proposals, such as the Northern Forest Alliance's 1997 Wildlands Proposal identifying 10 wild areas in NY, VT, NH, and ME, highlight priorities for public land acquisition and address how our public lands should be managed. They document the significance of private landowners for the region's conservation and ecological integrity. Klyza (2001) gives details of current and pending wilderness in the northeast: the Maine Woods National Park and Preserve Proposal would preserve 1.3 million ha around Baxter State Park and Mt. Katahdin; the Adirondacks Headwaters Wilderness Reserve Proposal would add 3.2 million ha in northern Vermont and New Hampshire, and a proposal for 77,000 ha more wilderness in New Hampshire and Maine's White Mountain National Forests.
Understanding and managing threats from invasive species and pollutants requires more scientific knowledge than we have. We know relatively little about the biology and environmental requirements of countless species. An estimated 10% of the region's species have yet even to be discovered by science and named. Research is needed to ensure the long-term survival of those facing today's threats. We must move from habitat management targeted at relatively few species, most notably endangered species, plants and vertebrates, to practices that conserve all biodiversity. Great Smoky Mountains National Park is a leader in this effort. Because it has data on only 10% of the 100,000 species, excluding bacteria, estimated to live within its boundary, it has undertaken a 15-year study to document and understand all life-forms within its borders. The magnitude of this project suggests that a worldwide network of schools, community groups, and citizen scientists, aided by scientist and technology, will be needed to assemble the knowledge society needs to protect all the planet's diversity of life. Without considerable help from the general public, professional scientists and conservationists cannot collect enough information in time to save many species from extinction (see <www.discoverlife.org>).
Ultimately, long-term wilderness protection depends on public education and support. All members of society should gain from these areas. Outdoor recreation and education hold much promise. In Georgia, the U.S. Forest Service, in response to pressure from conservation groups, has not had a commercial timber sale in 5 years. It now plans to meet the needs of its rapidly growing urban population by managing its forests for recreation and conservation education. While hikers, hunters, anglers, bird watchers, and other outdoor types may not agree on all issues, they generally prefer wilderness to urban sprawl. Witness the success of efforts such as Biodiversity Days in Massachusetts, which in 2001 organized a weekend in which an estimated 20,000 children and 10,000 adults went on nature walks around the state and reported their observations. Cititens who get outdoors and learn about nature are those most likely to appreciate and support wilderness sanctuaries.
The reasons we need wilderness abound, be they ecological, recreational, or spiritual. We must help everyone to connect with nature and understand the necessity of wilderness. "In wildness is the preservation of the world," said Henry David Thoreau. For long-term wilderness protection, we must all learn to appreciate nature as did Thoreau.