Knapweed was introduced from Europe as a livestock forage plant, but it has low nutritional value. It forms monocultures along roadsides and in pastures, pushing out native plants.
NPS photo
Alien Invasion
Many non-native species have set up residence along the Blue Ridge Parkway. A non-native is any species that occurs outside its native range as a result of deliberate or accidental introduction by humans. Sometimes called "aliens" or "exotics," non-natives compete with native species for habitat and food and often take over specialized ecosystems that rare plants or animals need to survive. These non-native species are not natural components of the ecological system. As a result, they have not evolved in concert with the native species, and will not have any natural predators in their new environment, so their numbers can grow alarmingly.
Control of an non-native plant species is a long-term battle along the parkway. With thousands of "cut and fill" slopes, more than 3,000 vista openings, and more than 1,000 utility and roadway crossings, the parkway contains an unusually large number of areas that have been disturbed by construction. These are habitats where non-native plants can qucikly become established.
Non-natives plants are prolific seed producers and often become well established in a new area within one or two years. Many of these species also have long-lived seed viability, further enhancing their establishment.
Several non-native animals can also pose problems to our native species.
Eastern bluebird populations dropped significantly as the more aggressive European starlings took over available nesting cavities.
Introduced brown and rainbow trout have displaced brook trout from many aquatic systems, forcing our only native trout to move further and further upstream.
The list of nonnative species extends to invertebrates, including insects, earthworms and crayfish. Even non-native fungi can devastate our forests.
The introduced chestnut blight fungus wiped out American chestnut trees throughout the Southern Appalachian forests
Balsam woolly adelgids have destroyed spruce forests at our highest elevations
Hemlock woolly adelgids have destroyed hemlocks in our coves and along our creeks and rivers.
To help reduce the spread of non-native plants and animals
Buy firewood locally for camping.
Clean your boot treads to remove hitchiking seeds before hiking our trails.
If you live near the parkway, please help our native plants and animals by using native plants in your landscaping and controlling non-native plants on your own land.
