Congress added many of these to the National Wilderness System, the latest being Buffalo Peaks Wilderness in 1993. However, many were subsequently logged and many new roads entered what was once relatively intact natural habitat. Old logging roads and recreational roads which fragment these large areas are the major threat to the long-term preservation or restoration of native species. Loss or serious reduction of the habitat which supports native species of plants and animals compromises the ability of the land to sustain a natural balance. The land is less able to retain water and release it slowly.
Weedy plants invade the travel corridors crowding out native plants needed for animal forage.
The proportion of bird and animal species that prefer edge habitats is increased to the detriment of interior forest dwelling species. Species that normally move seasonally across and up and down watersheds are cut off from their accustomed routes. Fires are suppressed because of adjacent development thus increasing the risk of future catastrophic fires. And perhaps most important, motorized transportation allows the human impacts to extend further, more often and faster into the interior of once undisturbed areas. Forest Service Chief Dombeck has called for protection of roadless areas in a roadless area moratorium.