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Archive - May 2016

Invasice Species - What Are They?
Organisms tend to live in one general area on earth. They may find it hard to spread to new places because of their size or because of barriers, like mountains, oceans, deserts and rivers. Most species are very well suited for where they have developed and live.

Sometimes organisms do move to new areas. They can do so naturally. For instance, their seeds may be blown or carried by ocean currents to new areas. They may move from a central location to other areas as their population grows over time. It may take a long time for a species to expand its range, or it can happen quickly if conditions in the environment change.

Humans can be involved in moving species, too, either on purpose or by accident. Not only mature animals and plants can be transported, but their seeds, eggs, larvae, spores and other life stages can be moved. Human-influenced transport can include ships and other boats, wood products, ornamental plants and pets. Ships can pick up aquatic species in their ballast water and release them in a new location when the water is dumped. Shipping crates often contain insects or their larvae, pupae or eggs. Pets sometimes escape or are released intentionally. Other ways that species can be introduced into new habitats include: aquarium and live bait releases; horticulture and water garden aquatic plant sales and use; escape from aquaculture facilities; attachment to boats, trailers, anchors, waders, shoes, boots and other water/outdoor recreation equipment or to the feet, fur or feathers of wildlife; attachment to barges and other commercial vessels; and connections between waters and watersheds.

Organisms introduced into habitats where they are not native are called exotic or nonnative species. In Illinois an exotic species is defined as one that was not present at the time when settlers from Europe began to arrive in the land that is now our state.

Just because a species is introduced to a new habitat does not mean that it will reproduce, survive and spread into other areas. However, there are times when species adapt very well to their new surroundings. They may have no predators, parasites, diseases and/or competitors that were present in their native habitat. Often, when species move to an area where they don’t normally live, they can cause many problems.

An invasive species is one that is not native to a particular ecosystem and that does or is likely to cause harm to the environment and/or the economy. It does not have to come from another country. Invasive species can cause the elimination of native species, loss of natural biodiversity and reduction in high-quality wildlife habitats. They can prey on native species. They can take away food and other life requirements of native species. They can carry or cause diseases. They can prevent native species from reproducing or kill their young. They can change food webs by destroying or replacing native food sources. Some of them can change the conditions in an ecosystem so that native organisms can no longer survive.

Invasive species are one of the greatest threats to Illinois’ natural resources. They are especially harmful to rare species or those whose populations are declining. These species already are having trouble surviving because they are few in number and/or have difficulty adapting to change. Human health, livestock health and native wildlife and plant health can be impacted by invasive species. Businesses, agricultural activities and recreation can be harmed by invasive species, too, costing a tremendous amount of money.

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.

bighead carp and silver 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.

Invasive Species – Control

The most effective means to stop invasive species is to prevent them from being introduced and established. In Illinois, the Wildlife Action Plan sets goals and actions for conservation across the state, including an Invasive Species Campaign (ISC). The ISC identifies those actions determined to be most needed for statewide management of all groups of invasive species. Prevention includes education and outreach to raise the awareness of the invasive species problem and reduce the chance of unintentional introduction of invasive species.

When invasive species are present, a variety of actions are taken to control or eradicate them based upon the behaviors and life history of the species as well as where it lives. To be most effective, a combination of several of these techniques may be required.

Cutting, burning, digging, mowing, flooding and/or pulling are techniques used on some invasive exotic plants. Spraying chemicals on the plants to kill them or on their cut stalks to eliminate the parts underground may be necessary.

Removing an invasive plant out of its habitat is a start towards control, but what do you do with it after you remove it? Some plants can continue to develop seeds even after you remove them from the soil. Some of them can grow not only from seeds but also from plant parts. You need to dispose of invasive plants properly. Placing them in a home compost pile or bin may not work. These compost piles may not get hot enough to kill the plants and seeds. If they don’t, then you are spreading the invasives when you use the compost. Probably the best method for you to use as an individual is to bag the plants and place them with other waste for disposal in a landfill. If you are removing invasive plants from a large area of private or public property, you should check with local authorities about disposal procedures before you start removing plants.

Removing the habitat that supports a species can lead to the elimination of the species. For example, the more ash trees that the emerald ash borer kills, the fewer places it will have remaining to live. When the ash trees are gone, this pest will also be gone. Ash tree seeds have been saved in seed banks to start growing these plants again once the infestation of emerald ash borers is finished.

Invasive species often spread quickly in a new location because there are no predators that have evolved to help control them. Biological control involves releasing a natural predator from the invasive species’ native habitat into its new habitat. Animals, fungi or diseases can be used for biological control. Much study must be conducted before releasing another exotic species into the habitat.

Cultural control is managing a forest or other area to control invasive species when they are present or to limit their effects if they have not arrived but are expected. For example, trees that the invasive species will live in or use for food and/or reproduction can be eliminated or greatly reduced in number to limit the number of the invasive species that can live in that area. Trees that are resistant to the invasive species could be planted, although it will take them a long time to grow.

Asian carp are providing a challenge to control. They are aquatic, they feed by filtering food from the water and there are enormous numbers of them. Control measures have included making them into a source of income. They are in demand for use as food in Southeast Asian countries. They can also be made into fertilizer, pet food and other products. Americans tend to dislike eating them, but if they can be persuaded to do so, a cheap source of protein is available in our rivers.

It may be impossible to eliminate an invasive species once it becomes established in an area. In that case, reducing its density enough to allow native species to survive can be the goal.

When prevention doesn’t work, detecting the presence of new invasive species in an area is critical to their control. The sooner a response effort is made, the better will be the chance of eliminating their presence or slowing their spread. Early detection of new infestations requires regular monitoring of the managed and surrounding area.

Legislators have a role in control of invasive species, too. They can set policies and enact laws to stop possession and commerce of invasive species. They can provide funding for invasive species research, education and elimination, too.

Invasive Species – Joining the Fight

What can you do to help fight invasive exotic species? There are many actions that everyone can take.

Become familiar with invasive species. A good place to start is the Illinois Exotic Species List. A Web site with much information is

Learn to identify invasive species in your area. Report any sightings to your county extension agent or a local land manager. Tell landowners about invasive species that may be present on their property, what they should do and why. The New Invaders Watch Program is targeting northeastern Illinois. Find out more about this program here. The River to River Cooperative Weed Management Area Web page provides information about invasive plant-related activities in southern Illinois.

The latest information on Asian carp includes how to identify, catch, clean and cook the fish and protect yourself while boating through Asian carp-infested waters.

The Illinois Aquatic Nuisance Species Website provides information on aquatic invasive species including links to regulations. You can report sightings of invasive aquatic species on this page, too.

Look for and participate in activities in support of Illinois Invasive Species Awareness Month each May. You’ll find updates posted here.

Spread the word, not the species. Take precautions to avoid transferring invasive species from one water body to another or one area of land to another.

Fishing tournaments have the potential to spread aquatic invasive species through movement of both anglers and equipment between events. Learn how to take preventative actions at this Web site.

Many aquatic invasive species have spread to the Great Lakes through recreational water use. Once established, these invaders hinder boating and swimming, disrupt food webs and harm local economies. Learn how recreational water users can help prevent the spread of aquatic invasive species here. You will find suggestions to Be a Hero – Transport Zero™ for both aquatic and land-based activities at their Web site. Regularly clean your boots, clothes, gear, boat, tires and any other equipment you use outdoors to remove insects and plant parts that may spread invasive species to new places.

Don’t release aquatic species from aquariums, educational lessons, live food, aquaculture release or water gardens. Be a Hero-Release Zero ™ is an Illinois program that provides guidelines for disposal of unwanted aquatic organisms.
     Plants – bag and place in the trash
     Animals – find a new owner or seek advice on humane disposal
     Water – disinfect or use for a different purpose

Illinois-Indiana Sea Grant is working to reduce the introduction of invasive species in many ways. Organisms in Trade and Aquatic Plants in Trade are two routes that include the spread of invasive species through aquarium release, water garden escape, study organism release, live food and aquaculture release and live bait. Read the Illinois-Indiana Sea Grant suggestions for reducing and eliminating these problems at the links above.

Classroom specimens can end up part of the invasive species problem. With more information, schools and suppliers can be part of the solution. Learn more here.

Nab the Aquatic Invader! from Illinois-Indiana Sea Grant is an educational Web site that introduces students (grades 4-10) to marine and freshwater invasive species and their impacts through colorful cartoon characters. Many other educational resources are available online. The Illinois Department of Natural Resources (IDNR) offers an Illinois’ Invasive Species resources trunk for loan to educators statewide. You can find the list of lending locations here. The new exotic species Web page of the IDNR Division of Education contains links to lessons, podcasts and other information about invasive species.

Plant native plants in your gardens and landscaping and remove any invasive plants that are present on your land. There are many good native plant alternatives to common exotic ornamental plants. Check to see if a plant is invasive before you plant it. Do not plant or dump house plants outdoors.

When camping, buy firewood near your campsite (within 30 miles) instead of bringing your own from home, and leave any extra for the next campers. Invertebrates and plants can easily hitch a ride on firewood you haul to or from a campsite -- you could inadvertently introduce an invasive to a new area.

You can volunteer to help eradicate invasive exotic species. Federal, state and local government agencies as well as nature centers, forest preserve districts and other entities often seek assistance with the removal of invasive exotic plant species.

Working together is critical to eliminating invasive species. We can all help, and we can make a difference!