Fragmentation

These studies discuss the relative wildness of ecosystems in the southern United States, as well as remaining intact forest landscapes.

Biological Consequences of Fragmentation

A variety of human land uses, including agriculture and urbanization, fragment intact natural landscapes such as forests into smaller patches of habitat. These patches become isolated “islands,” and depending on the type and degree of fragmentation, this process can have a detrimental effect on wildlife and overall forest health. Linear land uses, including roads, power lines, and even hiking trails, bisect intact habitat and can affect wildlife distribution and ecosystem functioning. Although naturally fragmented systems are found all over the world, human habitat modification is currently the leading cause of fragmentation in the United States.

Fragmentation is problematic because it diminishes both habitat size and connectivity among individuals and populations. Many species have difficulty flourishing or surviving in these modified environments of reduced size, increased isolation, and new ecological boundaries.
Fragmentation and the Wildness Index

The Wilderness Society (TWS) has developed a national map of “wildness” showing the degree to which regions of the United States are influenced by human infrastructure and influence. In the South, growing cities are increasing the influence of humans on the landscape, but many relatively remote and unaltered areas remain, especially in the Southern Appalachians, southwestern Florida, and in the swamps and wetlands of the coastal plain.

Wildness is an attribute of the land reflecting its naturalness and its freedom from human influence. As such, wildness captures not only important elements of ecological integrity, but aspects of the land relating to the human experience of a place, such as its remoteness and its provision of solitude. This map depicts an index of wildness created by combining information representing this naturalness and freedom: population density, distance from roads, pollution, as well as ecosystem composition, structure, and function.
Great Smoky Mountains National Park

The Smoky Mountains straddle the Tennessee-North Carolina border and contain some of the highest elevation forests within the Appalachian Mountains. Today, these forests are protected by Great Smoky Mountains National Park, an International Biosphere Reserve and a UNESCO World Heritage site. The park contains the largest old-growth forests remaining in the eastern United States, as well as many rare and endangered plant and animal species. For more information, visit the National Park Service’s Great Smoky Mountains website.

Intact Forest Landscapes (IFLs) are large unfragmented forest ecosystems, at least 500 km2 in size, and without roads, logging, or other significant signs of human activity. These areas are large enough to retain all native forest biodiversity, including viable populations of wide-ranging species.
Historic Loss of Primary (Virgin) Forests

Although definitions vary, a primary (or “virgin”) forest often means a forest of native species where there are no clearly visible indications of human disturbance and where ecological processes are not significantly disturbed. Identifying primary forests with precision is difficult, since Native Americans used fire to manage forests prior to European settlement. Given this limitation, one way to approach a definition of virgin forests in the South is those that have not been cleared since European settlement.

At the time of European settlement in North America, such forests covered nearly all of the East Coast. During the next two centuries, agriculture was the most important driver of forest loss in the South. By 1850, large portions of original forest had been cleared for agriculture, although substantial areas remained.
Okefenokee Swamp

The Okefenokee Swamp is a large, peat-filled forested wetland in southeastern Georgia near the Florida border, protected by the Okefenokee National Wildlife Refuge. The Okefenokee is one of the largest swamp ecosystems in the southern United States, and provides a home and breeding grounds for many bird species such as herons, egrets, cranes, and ibises as well as large populations of American alligators and black bears. The swamp has large expanses of marshes, upland pine forests and cypress swamps. For more information, visit the the Fish and Wildlife Service’s Okefenokee National Wildlife Refuge website.
Southwestern Florida

Southwestern Florida contains extensive areas of subtropical wetland with a mosaic of sawgrass marsh, wetland prairies, cypress swamps, tropical hardwood hammocks, upland pine woodlands and coastal mangroves. While known as the “river of grass,” this region also contains large areas of intact forest in upland or drier areas. Two large protected areas conserve this ecosystem, Everglades National Park and Big Cypress National Preserve. For more information, visit the National Park Service’s Big Cypress National Preserve and Everglades National Park websites.

Intact Forest Landscapes (IFLs) are large unfragmented forest ecosystems, at least 500 km2 in size, and without roads, logging, or other significant signs of human activity. These areas are large enough to retain all native forest biodiversity, including viable populations of wide-ranging species.