NNIS have significantly impacted United States ecosystems and cost millions of dollars to prevent. Whether it is an insect, plant, weed, aquatic or terrestrial - NNIS can have a huge impact on the ecosystem they invade.
What happens when a NNIS is introduced to an ecosystem?
Non-native invasive species seriously alter the landscape and disrupt critical ecosystem functions. The result can be loss and destruction of forage and/or habitat for wildlife/fish/plants, loss of available grazing land, diminished land values, lost forest productivity, reduced groundwater levels, soil degradation, increased risk of devastating wildfires, and diminished recreational enjoyment. Entire ecosystems and communities are experiencing the detrimental impact of NNIS.
Pests such as emerald ash borer, hemlock woolly adelgid and gypsy moth have long reaching consequences for plant and tree species across the country, killing off ash, hemlock and other tree species. Infestations of non-native invasive insects can cause millions of trees to die. Non-native invasive wildlife can take over or destroy habitat for native wildlife species. Impacts to native wildlife species can then impact the forest ecosystem as natural balances are destroyed. Aquatic invaders can out compete native and local fish populations or destroy their food source.
There are numerous research studies attempting to understand and control these pests. At present, though, it is a race against time. Will controls be found before the landscape is irreparably altered? We don't know. What we all can do, however, is to heed the warnings against moving wood. The natural progression of insects is relatively slow as long as we don't give them a ride. This is the reason for the ban on moving firewood.
How to Prevent Spreading Invasive Species
Stopping the spread of an invasive species depends on if it is plant, terrestrial animal, aquatic or weed.
What can you do to help? Do not bring firewood from home to the Allegheny National Forest. Do not unwittingly spread the emerald ash borer, sirex wood wasp, hemlock woolly adelgid or other firewood borne invasive species. Possession of firewood from outside the area of the Allegheny National Forest is prohibited. Firewood is available at or near camping facilities.
Aquatics
Clean your boats, waders and any other equipment before leaving an area where you've been fishing/recreating.
Eliminate any water before you transport your boat, canoe, kayak or tube.
Clean and dry anything that came in contact with the water before you leave - including equipment, pets and even yourself.
Don't put plants or wildlife into the water unless they came from that water.
Click on a heading below to find out more about Non-Native Invasive Species that impact the Allegheny:
Insects
Click on a heading below to get information on invasive insects:
Asian Long-Horned Beetle
Adult beetles are large, distinctive-looking insects measuring 1 to 1.5 inches in length with long antennae. Their bodies are black with small white spots, and their antennae are banded in black and white. Females can lay up to 90 eggs in their lifetime. Within 2 weeks, the egg hatches, and the white larva bores into the tree, feeding on the living tissue that carries nutrients and the layer responsible for new growth under the bark. After several weeks, the larva tunnels into the woody tree tissue, where it continues to feed and develop over the winter.
Hosts
In the United States the beetle prefers maple species (Acer spp.), including box elder, Norway, red, silver, and sugar maples. Other preferred hosts are birches, Ohio buckeye, elms, horse chestnut, and willows. Occasional to rare hosts include ashes, European mountain ash, London planetree, mimosa, and poplars. A complete list of host trees in the United States has not been determined.
Signs and Damage
Chewed round depressions in the bark of the tree, pencil-sized, perfectly round tree exit holes, excessive sawdust near tree bases, unseasonable yellowed or dropping leaves. Signs of ALB start to show about 3 to 4 years after infestation, with tree death occurring in 10 to 15 years depending on the tree’s overall health and site conditions. Infested trees do not recover, nor do they regenerate.
If you see signs or symptoms of infestation, report it immediately by calling 1-866-702-9938 or ( html ) report online.
Emerald Ash Borer
The Emerald Ash Borer is rapidly expanding its range and is killing ash trees by the millions. This valuable hardwood tree is prized for baseball bats and tool handles and provides critical ecosystem functions in riparian areas.
Hosts
Ash
Signs and Damage
Canopy thinning and dieback, epicormic sprouting (growing new branches and leaves wherever they can), woodpecker damage, d-shaped exit holes, s-shaped galleries and splitting bark
If you see signs or symptoms of infestation, report it immediately by calling (866) 253-7189.
Gypsy Moth
Oaks are the preferred host species for feeding caterpillars, but apple, sweetgum, basswood, gray and white birch, poplar, willow and many others serve as hosts. Gypsy moths avoid ash, yellow -poplar, sycamore, black walnut, catalpa, locust, American holly, and shrubs such as mountain laurel, rhododendron and arborvitae. Older larvae will also feed on a number of conifers such as hemlock, pines, spruces and southern white cedar.
Hosts
While they prefer oak trees, gypsy moth may feed on many species of trees and shrubs, both hardwood and conifer. In the eastern US, the gypsy moth prefers oaks, aspen, apple, sweetgum, speckled alder, basswood, gray, paper birch, poplar, willow, and hawthorns, among other species.
Symptoms and Damage
Teardrop-shaped egg masses are tan to yellowish and may possibly be hairy in appearance. Caterpillar can be up to 2 and 3/4 inches long with hairy black or brown bodies with five pairs of blue bumps toward the front and six pairs of red bumps towards the back. Adults show up in the middle of summer, the males are brown, have antennae and fly. Women are larger, cream colored and don't fly. Damage ranges from light leaf damage to branches stripped bare of leaves to a tree’s complete defoliation.
Native to Asia, the hemlock woolly adelgid (Adelges tsugae) is a small, aphid-like insect that threatens the health and sustainability of eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana) in the Eastern United States. Hemlock woolly adelgid was first reported in the Eastern United States in 1951 near Richmond, Virginia. By 2005, it was established in portions of 16 States from Maine to Georgia, where infestations covered about half of the range of hemlock. Areas of extensive tree mortality and decline are found throughout the infested region, but the impact has been most severe in some areas of Virginia, New Jersey, Pennsylvania, and Connecticut.
Hosts
eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana)
Symptoms and Damage
The appearance of cotton tuft-like masses on the underside of the foliage at the base of the hemlock needles. Needles turn grayish green. Premature needle drop. Twig dieback. Crown thinning.
The spotted lanternfly is an invasive pest. The insect will change hosts as it goes through its developmental stages. Nymphs feed on a wide range of plant species, while adults prefer to feed and lay eggs on tree of heaven (A. altissima). 1 If allowed to spread in the United States, this pest could seriously harm the country’s grape, orchard, and logging industries.
Hosts
Tree of Heaven, Fruit Trees - apples, plums, cherries, peaches, nectarines, apricots, almonds; along with pine, oak, walnut, poplar, and grapes.
Symptoms and Damage
Egg masses will have a gray putty-like covering on top of them. The eggs themselves are black/brown. Other signs are weeping wounds, dark streaks down the bark of the tree, sooty mold at the base of the tree, increased bee, ant and wasp activity around trees.
If you see signs or symptoms of infestation, report it immediately by calling 1-866-253-7189 or email badbug@pa.gov.
Sirex Woodwasp
The sirex woodwasp was introduced through imported wood products. It feeds on healthy pine trees as a vector for a fungus that kills pine trees.
Hosts
Pine species, including jack, red and white. Spruce, fir, larch, and Douglas Fir.
Symptoms and Damage
This pest is attracted to stressed trees. The problem is not the sirex woodwasp directly, but its association with the pathogenic fungus, Amylostereum areolatum, which kills the tree, making it a more suitable host for the larva. Symptoms include wilting needles, which turn downward and eventually turn red or brown. Egg laying causes the tree to produce resin flow or beading. As adults emerge, they chew round exit holes that vary from 1/8 to 3/8 inch in diameter.
For more information:
USDA Forest Service - Research and Development (html)
If you see signs or symptoms of infestation, report it immediately by calling 1-866-253-7189 or email badbug@pa.gov.
Diseases
Click on a heading below to find out more about Non-Native Invasive Diseases that impact the Allegheny:
Butternut canker
Butternut, also called white walnut, nuts are an important food source for wildlife. When butternut develops a canker, an oblong-shaped abscess that oozes, the wounds eventually cut off the trees nutrient supply and it dies.
Chestnut blight is caused by Cryphonectria parasitica. The blight fungus causes cankers, dieback and ultimately death of the above ground portions of the tree. The first sign of the disease is cankers.
If you see signs or symptoms of infestation, report it immediately by calling 1-866-253-7189 or email badbug@pa.gov.
Oak Wilt
Oak wilt is caused by Ceratocystis fagacearum. White oak is more resistant to oak wilt than red or bur oak, but can still be killed if infected. American, Chinese, and European chestnuts, tanbark oak, and bush chinquapin are also susceptible. Susceptible trees will die within a few weeks of infection, while trees with some resistance will decline slowly for two to three years.
Signs of infection include leaf tips turning brown, wilting and falling off while still green. The die-off progresses down the tree, twigs and brnaches will die off. A fungal mat develops under the bark, sap-feeding and bark beetles will feed on the fungal mat and spread spores to other trees.
For more information:
USDA Forest Service Northeastern Area State and Private Forestry (pdf)
If you see signs or symptoms of infestation, report it immediately by calling 1-866-253-7189 or email badbug@pa.gov.
Heterbasidian Root Disease
HRD is most damaging in plantation-grown conifers (especially pine and spruce) where stumps of trees that were cut down offer a place for infection to start. Once a stump is infected, HRD spreads to other living trees through root contact underground.
A phenomenon known as Sudden Oak Death was first reported in 1995 in central coastal California. Since then, tens of thousands of tanoaks (Lithocarpus densiflorus), coast live oaks (Quercus agrifolia), and California black On these hosts, the fungus causes a bleeding canker on the stem. The pathogen also infects Rhododendron spp., huckleberry (Vaccinium ovatum), bay laurel (Umbellularia californica), madrone (Arbutus menziesii), bigleaf maple (Acer macrophyllum), manzanita (Arctostaphylos manzanita), and California buckeye (Aesculus californica). On these hosts the fungus causes leaf spot and twig dieback.
Click on a heading below to find out more about Non-Native Invasive Plants that impact the Allegheny:
Garlic Mustard
Unlike most other species, though, garlic mustard moves from disturbed areas into healthy forest. There it forms dense patches which dominate and displace native wildflowers, tree seedlings, and other native plant species of intact forests. The reduced plant diversity that comes with garlic mustard monoculture means less resources for wildlife, and, ultimately, no new trees.
In addition, the roots of garlic mustard are thought to produce a toxin that kills soil fungi many plants depend on. The seeds are about the size of a grain of mustard and can move around easily. Combine that with these seeds surviving several years in the soil and you have a plant that’s difficult to manage.
Description
A biennial herb that grows 5 to 46 inches. First-year plant forms a rosette with kidney-shaped leaves which are green through winter. The second year, a flowering stem holds sharply toothed, triangular-shaped leaves. Crushed leaves emit a garlic-like odor. Flowers bloom in a cluster at stem’s end. Each flower has four white petals and blooms from May to June. Fruits are green capsules that turn brown as seeds mature.
Habitat
Most frequent in upland and floodplain forests, savannas and along roadsides. Invades shaded areas, especially disturbed sites and open woodland. Grows in dense shade and occasionally occurs in areas receiving full sun. Spreads easily through contact; brush clothes and wash vehicles to avoid accidental transference.
Native to Europe and Asia, Glossy buckthorn is an understory shrub that can grow to 15 - 20 feet tall. It was planted as an ornamental or to be a living fence, but has aggressively spread, especially in wet meadows and other moist soil areas, out competing native plants.
Description
Unlike common buckthorn, glossy buckthorn does not produce thorns. The stem/trunk can be as large as 10 inches in diameter. Leaves are oval and glossy. Since the leaves don't change color or fall off until late in fall, long after most other trees and shrubs, this helps makes the plant easier to spot in late fall. Flowers are small and greenish-white in color, which produce a dark purple berry in August and September.
Habitat
While it prefers moist, sunny areas, glossy buckthorn can be found in forest under-stories, bogs, stream and lake edges, wetland boarders, wet meadows, roadsides and other types of disturbed habitat.
For more information:
Pennsylvania Department of Conservation and Natural Resources (HTML)
Giant hogweed (Heracleum mantegazzianum) is a VERY LARGE, invasive plant that can cause painful burns and permanent scarring. Brushing against or breaking the plant releases sap that, combined with sunlight and moisture, can cause a severe burn within 24 to 48 hours.
Description
Giant hogweed is in the carrot family (Apiaceae) and can grow to 14 feet or more. Similar in appearance to native cow parsnip, only much larger, and hairs on the leaf underside are shorter (about 0.01 inch long). Easiest to identify in bloom. Many small white flowers in June or July, clustered into a flat-topped umbel up to 2 1/2 feet across. Giant Hogweed has a hollow, ridged stem, 2 to 4 inches in diameter, 8 to 14 feet tall, with purple blotches and coarse white hairs. Hairs are especially prominent at the base of the leaf stalk. Lobed leaves, deeply incised and up to 5 feet across. Dry, oval, flattened fruit, about 3/8 inch long, tan with brown lines.
Habitat
Common along railroads, roadsides, rights-of-ways, vacant lots, streams, rivers, uncultivated or waste lands and agricultural areas.
Please call the giant hogweed hotline (1-877-464-9333) to report the location.
Japanese Knotweed
A member of the buckwheat family originating in Japan that was used in the late 1800's as an ornamental.
Description
Resembles bamboo, with jointed, hollow stems, is a shrub like perennial that can grow up to 9 feet tall. Leaves are plain, oval with a pointed tip, and can be as large as six inches long. Flowers are small, and creamy white, growing in clusters during late August. The fruit is small and black-brown in color.
Habitat
Usually found in sunny areas, gardens/landscaping, along roadsides and along streambanks.
For more information:
National Invasive Species Information Center (HTML)
Kudzu is a highly aggressive invasive plant which is extremely difficult to control once established. Kudzu is so aggressive it covers and smothers all other plants in its path, resulting in solid single species stands eliminating native species.
Description
Deciduous leaves are alternate and compound, with three broad leaflets up to 4 inches across. Vines may grow as long as 98 feet. A single root crown may produce as many as 30 vines which become somewhat woody and expand out in all directions.
Habitat
Kudzu grows best in well-drained degraded or eroded land or in disturbed, sandy, deep loam soils in full sun. It will, however, invade well-drained acid-soil forests as well as the floor of a closed canopy forest.
For more information:
USDA Forest Service Northeastern Area State and Private Forestry (HTML)
Rosa multiflora is a multi-stemmed, thorny, perennial shrub that grows up to 15 ft. (4.6 m) tall. The stems are green to red arching canes which are round in cross section and have stiff, curved thorns.
Habitat
It forms impenetrable thickets in pastures, fields, and forest edges. It restricts human, livestock, and wildlife movement and displaces native vegetation. And it tolerates a wide range of conditions allowing it to invade habitats across the United States.
Purple loosestrife is an herbaceous perennial characterized by long showy spikes of magenta flowers. Usually under 4 feet in height, the plant may reach up to 10 feet tall in nutrient rich habitats. Purple loosestrife has flowers with 5 to 7 petals which occur in dense clusters on a terminal spike, and which blooms from June to September. The leaves are usually opposite or in whorls of three, lance-shaped, and without teeth.
Habitat
Purple loosestrife grows in many habitats with wet soils, including marshes, pond and lake sides, along stream and river banks, and in ditches. Purple loosestrife is also capable of establishing in drier soils, and may spread to meadows and even pastured land. It prefers full sun, but can grow in partially shaded environments.
Though purple loosestrife seeds may not be particularly long-lived in the seed bank (they can survive for at least 3 years), the sheer number of seeds produced allows them to readily capitalize on disturbance.
Spotted knapweed is a very aggressive species that can quickly infest large areas. Knapweed infestations increase production costs for farmers, degrade wildlife habitat, decrease plant diversity, increase soil erosion rate and pose wildfire hazards.
Description
It’s a biennial or perennial growing to 5 feet with a stout tap root. It is hairy and rough, with a somewhat woolly appearance. Plants start as a rosette (cluster of radiating leaves) of deeply lobed leaves the first year and then produce flowering stems.
Habitat
It can be found in meadows, pastures, rocky areas, roadsides, railroads, airports, vacant lots, hayfields, forest clearing, and near streams and rivers. It has no preference for where it takes over, and it can spread rapidly, with each plant producing up to 1,000 seeds a year, and seeds being viable for up to eight years.
A rapidly growing deciduous tree with pale gray bark, light brown twigs and large pinnately compound leaves arranged alternately on the stem (one leaf per node). Resembles sumacs (Rhus. spp.), poison-sumac (Toxicodendron vernix) and walnuts (Juglans spp.), but differs by having two teeth at the base of each leaflet, versus many teeth in sumac and walnut, and no teeth in poison sumac. Teeth are substantially thicker than the rest of the leaflet. Crushed foliage has a distinct, unpleasant odor, not easily confused with odor of walnut leaves.
Habitat
The tree of heaven is a prolific seed producer and can thrive in even the most unfavorable conditions with little management. Its rapid growth also means it can crowd out nearby native plant species, and its aggressive root system can cause damage to pavement, sewers and building foundations. It has the potential to become dominant in second growth stands in rural areas. Allelopathic compounds suppress the growth of native wildflowers and competing native trees nearby.
Click on a heading below to find out more about Non-Native Invasive Diseases that impact the Allegheny:
Mute Swan
Mute swans are large birds, intermediate in size between native trumpeter and tundra swans (57 to 62 inches long, about 26 lbs., 6 to 7 foot wingspan). The neck is often bent, not straight like native swans. The black knob at the base of the orange bill is distinguishing. Mute swans are usually silent, but make quiet hissing, puppy bark notes or whistles. Musical humming or throbbing sound of their wings in flight is very audible. They have keen vision and hearing, and communicate through visual posture displays.
Habitat
Open marsh wetlands (or open, quiet, well sheltered bays) lakes, ponds and low gradient big rivers - introduced into parks.
Wild boars look like ridge-backed, coarsely hairy dark gray-to-brown pigs. Ranging from 35 to 65 inches long and 20 to 40 inches tall, with straight 10-inch tails, and four continually growing tusks, they weigh 110 to 770 pounds. Males are larger than females. Wild boars often form herds of 20 or more animals. Wild boars are mainly active at dusk, dawn and night.
Habitat
Typically moist forest, scrubland, and especially oak forest. Wild boars are sensitive to cold (less than 50 degrees F) temperatures, and are limited in travel and foodfinding by deep snow. Home ranges vary from 250 to 1,000 acres. Male territories are twice as large as females’. Populations can exceed 80 animals per square mile.
What are the different types of problem species and how are they defined?
Weed
The USDA-APHIS defines a weed as any plant that poses a major threat to agriculture and/or natural ecosystems within the United States. Although this is more specific than a typical dictionary definition (i.e. a plant growing in an undesired location), it more accurately portrays the economic and ecological impact weeds can cause on our landscapes and on the natural ecosystems we manage.
Alien Species
A species introduced and occurring in locations beyond its known historical range. This includes introductions from other continents, bio-regions, and also those not native to the local geographic region. Executive Order (E.O.), Invasive Species, February 3, 1999 more narrowly defines an alien species and ties the definition to an occurrence outside a native ecosystem. An "alien species means, with respect to a particular ecosystem, any species, including its seeds, eggs, spores, or other biological material capable of propagating that species, that is not native to that ecosystem,"(E.O., Invasive Species). Synonyms for alien species include exotic, non-native, non-indigenous, and introduced species. Of the thousands of plants that have been introduced to the United States intentionally for cultivation or by accident, approximately 4000 of these alien plant species now occur outside of cultivation. However, only about 400 of these are considered problematic with respect to adverse effects on agricultural or our native biota.
Native Species
As defined in E.O., Invasive Species, February 3, 1999, a "native species means, with respect to a particular ecosystem, a species that, other than as a result of an introduction, historically occurred or currently occurs in that ecosystem." Accordingly, a species can not be considered native to a geographic region or habitat merely because it occurs natively somewhere within the continental United States. For example, White Pine (Pinus strobus) occurs natively in the northeastern United States, and although it is planted widely in many states, it is not a native species in several of those states.
Invasive Species
A species that demonstrates rapid growth and spread, invades habitats, and displaces other species. Species that are prolific seed producers, have high seed germination rates, easily propagated asexually by root or stem fragments, and/or rapidly mature predispose a plant to being an invasive. Alien species that are predisposed to invasiveness have the added advantage of being relatively free from predators (herbivores, parasites, and disease) and can; therefore, expend more energy for growth and reproduction. For example, Microstegium (Microstegium vimineum), introduced from Asia, displaces native vegetation in floodplains and other moist environments. Microstegium now occurs in 21 states (including Missouri) and is known to occur on the Poplar Bluff Ranger District.
Noxious Species
Any living stage (including but not limited to seeds and reproductive parts) of any parasitic or other plant of a kind, or subdivision of a kind, which is of foreign origin, is new to or not widely prevalent in the United States, and can directly or indirectly injure crops, other useful plants, livestock, or poultry or other interests of agriculture, including irrigation, or navigation or the fish and wildlife resources of the United States or the public health (1974 Federal Noxious Weed Act). For example, Spotted Knapweed (Centaurea stoebe) was accidentally introduced, through contaminated seed or ballast, into the United States in the early 1800’s and now occurs throughout the United States. It aggressively develops dense mono-cultural stands, degrades native vegetation, reduces overall vegetative biodiversity, and directly impacts wildlife by the loss of habitat and food.
