Invasive Species "Who Am I?"
For a copy in Microsoft Word or Adobe PDF, please email Beth at info@nhplt.org.
Species: Zebra Mussel
Native Region: Western Asia
When did it arrive? In the 1980’s
Why/how did it get here? Stowaways in the ballast water of large cargo ships.
Characteristics that help it thrive: As larvae, they can move to new locations by floating in the water currents. They then attach themselves to hard substances like rocks, mussels, logs, boats, pipes, etc. They have finer filters than native populations, allowing them to filter out all of the plankton from a lake or stream. One adult mussel may release up to 1,000,000 eggs each year. They can reattach themselves if they break off. They can survive out of water for days.
Effects on other species or environment: They can filter out all the plankton, leaving nothing for native species to eat. They accumulate very thickly and can clog popes of power plants, public water systems, etc.
Species: Purple Loosestrife
Native Region: Europe
When did it arrive? Early 1800’s
Why/how did it get here? Brought by people as an ornamental garden plant.
Characteristics that help it thrive: None of its insect predators occur naturally in North America. One plant can produce more than 2.5 million seeds annually. Plants grow very quickly.
Effects on other species or environment: When it invades a wetland area, it crowds out native plants, reduces the food and cover available to wildlife, and chokes waterways.
Species: Hemlock Wooly
Adelgid
Native Region: Japan and China
When did it arrive? 1924
Why/how did it get here? Accidental, on imported wood
Characteristics that help it thrive: Spread by wind or carried by migratory birds, mammals, and humans. One individual can yield up to 90,000 new adelgids in one year.
Effects on other species or environment: Feed on sap at the base of hemlock needles, causing them to fall off. Without needles, the tree starves to death. As the trees die, the plants and animals that depend on the hemlock forest are also at risk.
Species: European Starlings
Native Region: Europe
When did it arrive? 1890
Why/how did it get here? Drug manufacturer Eugene Scheiflin released 40 pairs of them in New York’s Central Park, wanting to bring to America all the birds mentioned in the writings of William Shakespeare.
Characteristics that help it thrive: Can live in a variety of habitats, from woodlands to open fields to cities.
Effects on other species or environment: Compete with woodpeckers, bluebirds, and swallows for nest cavities in trees (often destroying eggs and young birds in the process.) Form large wintering flocks, and are viewed as unwelcome pest to people.
Species: White Pine Blister Rust
Native Region: Asia
When did it arrive? 1898
Why/how did it get here? The US purchased seedlings from Germany and France to replant our forests. Some of these seedlings were infected with white pine blister rust.
Characteristics that help it thrive: White pines in the United States are not resistant to the fungus.
Effects on other species or environment: The fungus causes a canker or blister on the branches of the tree. When this goes completely around the branch, it causes the branch to die off. Trees that lose many branches weaken and eventually die.
Species: Gypsy Moths
Native Region: Europe & Asia
When did it arrive? 1869
Why/how did it get here? A scientist in MA wanted to use them to produce silk. Several of the caterpillars blew off the window sill of his home and escaped.
Characteristics that help it thrive: None of its insect predators occur naturally in North America. One plant can produce more than 2.5 million seeds annually. Plants grow very quickly.
Effects on other species or environment: Gypsy moths remove the leaves from millions of acres of trees each year. While they prefer oak, maple, and elm tree leaves, they will feed on approximately 500 different plants.
Species: Norway Maple (AKA
“Crimson King”)
Native Region: Europe
When did it arrive? 1756
Why/how did it get here? It was introduced as an ornamental plant by John Bartram of Philadelphia, in 1756. Bartram later offered it for sale in his garden catalogue in 1762.
Characteristics that help it thrive: Fast growing, buds break earlier than most native species.
Effects on other species or environment: Naturalizes in woodlands where it can outcompete native species. It able to shade out native understory vegetation. Thus, it can reduce native species diversity and change the structure of forest habitats.
Species: Japanese Barberry
Native Region: Japan
When did it arrive? 1875
Why/how did it get here? First introduced to the United States and New England as an ornamental plant.
Characteristics that help it thrive: It is readily dispersed by birds, which can bring the seeds many meters away from the parent plants.
Effects on other species or environment:
Forms dense thickets in a variety habitats ranging from closed canopy forests,
to woodlands, wetlands, pastures, meadows and wasteland. Though the exact effect
on native flora is not determined, it could prove a great threat to native
species.
Species: Oriental Bittersweet
Native Region: East Asia, Japan, Korea and China
When did it arrive? Around 1860
Why/how did it get here? Introduced as an ornamental plant.
Characteristics that help it thrive: Very aggressive, climbs up and over plants.
Effects on other species or environment: Smothers the trees that it grows on. Destroys native plants by overgrowing them. Shading (by the vigorous growth of the vine) and girdling of plants causes major damage. Mechanical damage of trees and other plants is caused by the additional weight added onto the branches - causing the branches to break.
Species: Variable Milfoil
Native Region: Eurasia, and Southern United States (Florida to Texas.)
When did it arrive? Around 1930’s.
Why/how did it get here? Not known with certainty. Perhaps traveled up waterways. May have been intentionally introduced.
Characteristics that help it thrive: Main method of dispersal is by vegetative parts breaking off and being dispersed by people, animals and water currents. Lacks natural controls that exist in its native waters.
Effects on other species or environment: Invades and congests waterways, crowding out other species of aquatic plants. The dense growths that form also provide breeding areas for mosquitoes and degrade the quality of the water for fish and other aquatic wildlife.
Species: Small mouth bass
Native Region: Central United States
When did it arrive? 1865
Why/how did it get here? Introduced as game fish.
Characteristics that help it thrive: Small mouth bass are much more aggressive than trout as both predators and competitors.
Effects on other species or environment: Prey aggressively on smaller fish, forcing trout and other species to shift to energetically-poor foods such as invertebrates. Eventually outcompete native species for food and habitat.
Species: European Green Crab
Native Region: Europe
When did it arrive? Mid 1800’s.
Why/how did it get here? Accidentally introduced, perhaps accidentally transported by large cargo ships.
Characteristics that help it thrive: Tolerance for a wide range of temperatures and salinities. Rapid rate of egg production. Much faster and more adept at opening bivalves than most other crabs. Voracious appetite, eating more than 100 different species, particularly mollusks and crustaceans.
Effects on other species or environment: These crabs are invading the habitat of native species and raising concern in the shellfish industry.
Species: Burning Bush
Native Region: Asia
When did it arrive? Around 1860.
Why/how did it get here? Introduced as an ornamental shrub. Planted in all types of landscaping - highways, malls, post offices, bridge abutments and private homes.
Characteristics that help it thrive: Seeds are usually dispersed by birds. However, they often drop just below the plant, creating a "seed shadow," where literally hundreds of seedlings can be found. This plant continues to be used as an ornamental, thus continuing its spread into the environment.
Effects on other species or environment: Have been observed in dense thickets, threatening native plants by crowding and shading. It threatens a variety of habitats such as forests, coastal scrublands, fields and prairies.
Species: Common Reed
Native Region: Europe and Asia
When did it arrive? Unknown
Why/how did it get here? Native to some parts of the United States, and probably came to New England via natural immigration. Non-native strains have also made their way here; these strains are the ones that have exhibited invasive tendencies.
Characteristics that help it thrive: Can grow in polluted and disturbed areas that other plants cannot tolerate.
Effects on other species or environment: Forms huge monocultures that spread for acres, excluding native species. Can form large, thick walls at the interface of upland and wetland habitat. In New England, this plant has gone beyond its original range, and is now encroaching into wetlands that contain rare native species.
Species: Autumn Olive
Native Region: China, Korea and Japan
When did it arrive? Initially 1830’s, widespread planting in 1940’s
Why/how did it get here? Planted for revegetation of disturbed areas.
Characteristics that help it thrive: Autumn Olive has prolific fruiting (can produce up to 80lbs. of fruit in a season.), seed dispersal by birds, rapid growth and ability to thrive in poor soils. Autumn olive resprouts vigorously after cutting or burning.
Effects on other species or environment: It creates heavy shade which suppresses plants that require direct sunlight.
Species: Asian Longhorned Beetle
Native Region: Asia
When did it arrive? First discovered in US in 1996. Not currently found in NH, but considered a potential threat.
Why/how did it get here? Arrived in North America in the wooden packing material used in cargo shipments
Characteristics that help it thrive: Currently, there is no known chemical or biological defense against the Beetle and, in North America, they have few natural predators.
Effects on other species or environment: Trees favored are predominantly maples, but infestations have also been discovered in horsechestnuts, poplars, willows, elms, mulberries and black locusts. Beetles could significantly disrupt the forest ecosystem if it became established over a large area.
Return to Facilitator Resources