Podcast: Invasive Species - Examples
Invasive species can be plants, animals, microorganisms or any other organism. Some of them live in water. Some of them live on land. Some of them live inside other organisms. There are too many invasive species in Illinois to list them here. We’ll give you a few examples, though.
house sparrow (Passer domesticus)
House sparrows from England were released in New York City in 1852. From that release and several others, the bird has been able to survive and colonize North America and South America. Native to the Middle East, it followed human agricultural development to Europe, Asia and Africa. The species often lives near humans. It can spread diseases to humans and other animals and eats agricultural products.
European starling (Sturnus vulgaris)
About 60 European starlings were released in New York City in 1890. They were so successful that the species now lives from southern Canada and Alaska to Central America. They compete with native species for nest cavities. They feed on fruit and other agricultural products. Their habitat of living and flying in large flocks can cause problems, too.
cattle egret (Bubulcus ibis)
Originally native to Asia, Africa and Europe, the cattle egret began naturally expanding its range in the 1800s. It is now present in much of the world. The species appeared in North America in 1941. Its rapid spread is due to its relationship with humans and their livestock. This bird follows large, grazing animals, feeding on the insects that are attracted to the livestock and that are stirred from the ground and vegetation by livestock as they feed and move. Although cattle egrets are considered an invasive species, they have not been shown to cause much ecological damage. They can be a safety hazard for planes at airports, though, due to their flocking behavior around runways, and they can spread some diseases.
Japanese beetle (Popillia japonica)
Native to Japan, it is believed that Japanese beetle larvae arrived in the United States in a shipment of iris bulbs. Adult beetles were first seen in New Jersey in 1916. The species has spread throughout much of the eastern half of the United States. More than 250 species of plants are eaten by Japanese beetles, and large infestations of beetles can be very destructive to plants.
emerald ash borer (Agrilus planipennis)
The emerald ash borer is a native of Asia. It was discovered in Michigan in 2002 and spread quickly to other states and Canadian provinces. By 2006, it was present in Illinois. The larva of this insect feeds only on the inner bark of ash trees causing them to die. Millions of ash trees have been killed so far. This pest has caused tremendous costs to cities, homeowners, forestry product businesses and plant nursery owners.
goldfish (Carassius auratus)
Goldfish have been released into the waters of North America since the 1600s. Among the most recent means of spreading this species are release of bait fish, release of aquarium fish and escapes from ponds. Although it can live in conditions that many other fish cannot survive, it does cause problems in aquatic habitats. As it feeds on the bottom, it stirs up soil, increasing turbidity, and it decreases the amount of aquatic vegetation.
Asian carp - Both images are bighead carp
Bighead carp (Hypophthalmichthys nobilis) and silver carp (H. molitrix) are two species of carp from Southeast Asia that are considered invasive. They are present in the Illinois, Mississippi, Ohio, Wabash and other large rivers and their tributaries in the state as well as in many lakes. Their diet is the same as that of many native species, they grow very quickly and they average about 30-40 pounds in weight, although they can weigh much more. They are taking food away from native species and can be a danger to human health. The silver carp has the habit of jumping out of the water when boat motors are near. People in the boat can be injured, and the boat itself can be damaged by these large “flying fish.”
rusty crayfish (Orconectes rusticus)
The rusty crayfish is native to the Ohio River and parts of Kentucky, Indiana and Ohio. It has spread to many other parts of the United States and Canada. It displaces and/or hybridizes with native crayfish, decreases the density and variety of invertebrates and reduces the abundance and diversity of aquatic plants that native fishes use for cover and food. This species eats plants and animals and can feed at two times the level of similarly sized native crayfish.
garlic mustard (Alliaria petiolata)
Garlic mustard is a plant that grows primarily in shaded areas, such as forests, as well as in yards and along roads. Native plants have been shown to decline in abundance when garlic mustard is present. It releases chemicals in the soil that suppress native plant growth. It was released in North America in the 1860s and has spread tremendously. It is now the dominant plant species in many woodland understories in eastern North America. This species is native to Europe, Asia and Africa.
autumn olive (Elaeagnus umbellata)
Autumn olive is native to China, Japan and Korea. It was brought to the United States in the 1830s. In the 1950s, it was promoted as a great way to control erosion while providing wildlife habitat. Many people planted it for these purposes. While it does provide some wildlife habitat, it causes more harm than good. It is a dense shrub that can grow to 20 feet tall. It grows rapidly and thickly, displacing native plants that need sunshine to grow. Each plant produces hundreds of thousands of seeds annually. It can grow in many types of habitats. Using cutting or burning to try to remove this species usually results in causing the plant to return in greater numbers than before. It can be easily spread by birds that eat the fruits and deposit the seeds in their waste materials.
West Nile virus (Flavivirus spp.)
This invasive virus is carried mainly by mosquitoes and causes illness and sometimes death in humans and wildlife, especially birds. It was first identified in Africa in 1937. By 1999, it was present in the United States, and over the next five years it spread throughout North America.