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Invasive Species

Kevin Boyle

Journalism and Mass Communications

What is an Invasive Species?
An "invasive species" is defined as a species that is 1) non-native (or alien) to the ecosystem under consideration and 2) whose introduction causes or is likely to cause economic or environmental harm or harm to human health. (Executive Order 13112).

Invasive species can be plants, animals, and other organisms (e.g., microbes). Human actions are the primary means of invasive species introductions.

Invasive and Exotic Species of North America

any species, including its seeds, eggs, spores, or other biological material capable of propagating that species, that is not native to that ecosystem; and whose introduction does or is likely to cause economic or environmental harm or harm to human health.

Recent Invasive Specie:

The Snakehead Fish

5 Types of Invasive Species

Terrestrial Plants Terrestrial Animals

Aquatic and Wetland Animals Aquatic and Wetland Plants

Microbes

Four Examples of Invasive Species

Asian Long horned Beetle

- female in sugar maple

Salt cedar - Introduced as an ornamental from Asia, invades riparian (streamside) areas throughout the American West. It accumulates salt in its tissues, which is later released into the soil, making it unsuitable for many native species.

Formosan subterranean termites are feeding on Sudan-red-stained filter paper. Tracking the termites stained with this dye allows researchers to estimate their foraging range and population numbers.

Plum Pox Virus Symptoms - The yellow spots on this leaf are evidence of infection by the Pennsylvania isolate of plum pox virus. The leaf is from Chenopodium foetidum, an important indicator species of plum pox disease

* Information obtained from: http://www.invasivespecies.gov/slideshow.shtml

Background Information on Invasive Species

Human populations have become highly mobile over the past two centuries. Innovations in transportation, such as airplanes and cargo ships, have facilitated the movement of both people and the goods they consume. Grocery store shelves are brimming with imported goods, from Chilean raspberries to bananas from Madagascar. Lush rainforest plants fill nurseries and tropical hardwoods are sold at lumberyards. Globalization has opened up a world of commerce possibilities, but the movement of foreign goods comes with an often unaccounted for risk- the introduction of invasive species.

Most of the foreign plants and animals that enter our country's borders each year are benign, temporarily filling our gardens or plates. But some, due to aggressive traits, favorable environmental conditions, and/or a lack of predators, become a serious problem. Dubbed invasive species, these non-native organisms have the ability to cause serious economic or environmental harm.

Often, they are unintentional imports; Asian long-horn beetles were living in wood used to make packing pallets, zebra mussels were accidentally transported in ship ballast water discharge. Others were intentionally introduced to provide certain functions— kudzu was used to prevent soil erosion, settlers planted garlic mustard for an early-season potherb— before realizing how aggressive these species could be once established.

Institute ecologists are at the forefront of invasive species research. From unraveling the impact that zebra mussels have in the Hudson River to predicting how forests will change as a result of beech-bark disease— by understanding how invasive species impact ecosystems, Institute research helps inform management decisions. Information gathered from http://www.ecostudies.org/IES_invasive_species.html

Possible Pathways to lakes and streams for invasive species:

Biologists seldom can prove how an invasive species got into the Great Lakes. Researchers make educated guesses, usually by eliminating other likely possibilities. Often scientists suspect multiple paths.

Ships have long delivered invading species to the Great Lakes, mainly in ballast carried for stability. Ships in the 19th century used shoreline rocks and sand for ballast. By the 20th century, ships switched to water in onboard tanks. Since 1959, when the St. Lawrence Seaway opened, two-thirds of invasive species discovered in the lakes are thought to have arrived by ships' ballast.

Release, apparently accidental

Some species, including many aquatic plants, have been released accidentally in other ways. Examples include fish dumped into lakes from bait buckets and aquarium releases.

Unknown

For about 12 percent of species, researchers have not determined a pathway into the lakes.

Stocking or other deliberate release

Some invasive species such as brown trout, chinook salmon and rainbow smelt were deliberately put in the lakes.

Canals

When canals linking inland waterways to the lakes opened in the 19th century, fish and other organisms spread.

Other

For about 5 percent of invasive species, researchers suspect multiple or conflicting pathways into the lakes. Shipping is at least suspected in each case.

Information obtained from LexisNexis(TM) Academic - Document

Can Invasive Species really cause harm to a new environment?

Natural ecosystems are under siege by many harmful species of plants, animals and diseases. The current environmental, economic, and health costs of invasive species could exceed $138 billion per year, more than all other natural disasters combined. Hundreds of new species from other countries are introduced intentionally or accidentally into the U.S. each year. This threat intensifies the need for scientists, managers, and the many stakeholders to rally together to build better systems for invasion prevention, improve early detection of invaders, track established invaders, and coordinate containment, control, and effective habitat restoration. Invasive Species Information Node (ISIN) of the NBII

Invasive Species on the Move:

Brown Tree Snake

Identification: Distinguishing characteristics for the brown tree snake include: a vertical pupil; rear fangs; a large head in relation to the body; and brownish or greenish coloring, with cross-band markings. About 18” at hatching; grows to about 3’ in first year. Adults can grow to 8’ and weigh up to 5 lbs. Mildly venomous to humans; while not fatal, its bite can nevertheless cause severe sickness in young children.

brown tree snake photo

Click here for an overview of the brown tree snake and its lifecycle

Habitat: Tropical. Lives mostly in trees and shrubs, where it forages at night. Frequently invades holes and buildings in urban habitats in search of food and hiding spots. Seeks refuge from heat and bright sunlight in daytime.

Distribution: Native to Solomon Islands; New Guinea; northern and eastern Australia; eastern Indonesia. Invasive to Guam. Sighted, but not known to be established in Hawaii; Texas; Saipan; Tinian; Rota; Wake Oahu; Kwajalein; Pohnpei; Okinawa; Diego Garcia

Dispersion Techniques: Secretive and nocturnal, the brown tree snake can coil itself in small, highly confined hiding spaces. Dispersed mainly by stowing away in cargo on planes and ships, and within plane wheel-wells.

Environmental Impacts: Has virtually wiped out the native forest birds of Guam, including the flightless rail. Twelve species of bird unique to the island have disappeared as a direct result of brown tree snake predation.

Economic Impacts: Since 1978, more than 1200 power outages on Guam have been caused by the brown tree snake, which frequently scales power lines and transformers. The outages and damage to equipment represent a significant economic burden to the island.

Brown Tree Snake information gathered from Invasive Species: Brown Tree Snake profile

Africanized Honey Bee

The Africanized honey bee, popularly known as the "killer bee," is moving into South Texas and the southern United States. Scientists are not certain how far north the bee will spread, but they do know that it will cause problems wherever it resides in large numbers.

This insect, which has been migrating from South America since the 1950's, looks just like a domestic honey bee, but it is not nearly as good natured. In fact, it has a bit of a quick temper.

The domestic bee has lived in harmony with human beings for hundreds of years. It has been bred for gentleness and good honey production.

By contrast, the Africanized bee is a "wild" bee that is not comfortable being around people or animals. Any colony of bees will defend its hive, but Africanized bees do so with gusto. These bees are more likely to sense a threat at greater distances, become more upset with less reason, and sting in much greater numbers.

Identification of Bees and Wasps
5/8 inch		1 16 inch
European honey bee	Africanized honey bee	Bumble bee
13/16 inch		7/8 inch
Carpenter bee		Mud dauber
13/16 inch		5/8 inch
Paper wasp		Yellow jacket

Africanized bees will nest almost anywhere around your home, even inside a meter box or in a rain spout. It's important to be on the lookout for bees around your home and yard, as well as in barns and pens where animals are confined.

Economic Effect of Africanized Bees $$$

The introduction of the Africanized bee could cause economic losses to the U.S. beekeeping industry ranging from $29 million to $58 million annually, according to the Economic Research Service, USDA

The Texas bee industry may lose $2 million to $4 million per year if the Africanized honey bee colonizes the state.

In some parts of Central and South America, unmanaged Africanized bees reduced honey production of domestic bees by 60 to 70 percent or more, largely due to competition for available nectar.

Domestic honey bees that interbreed with Africanized ones may become harder to manage for use as pollinators and less efficient at producing honey.

Africanized Honey Bee Quarantined Counties

As of May 28, 2004, Texas has 152 counties quarantined for Africanized honey bees. The quarantine allows beekeepers to move bee hives within but not out of the zone in an effort to prevent the assisted spread of Africanized honey bees.

Quarantined counties in Texas Many bees flying around

Information gathered from AgNews -- Africanized Honey Bees

Leafy Spurge (Euphorbia esula L.)

Native to Europe and Asia

DESCRIPTION: Leafy spurge is a member of the spurge family, or Euphorbiaceae, characterized by plants containing a white milky sap and flower parts in three's. Leafy spurge is an erect, branching, perennial herb 2 to 3½ feet tall, with smooth stems and showy yellow flower bracts. Stems frequently occur in clusters from a vertical root that can extend many feet underground. The leaves are small, oval to lance-shaped, somewhat frosted and slightly wavy along the margin. The flowers of leafy spurge are very small and are borne in greenish-yellow structures surrounded by yellow bracts. Clusters of these showy, yellow bracts open in late May or early June, while the actual flowers do not develop until mid-June.

Leafy Spurge

ECOLOGICAL THREAT: Leafy spurge displaces native vegetation in prairie habitats and fields through shading and by usurping available water and nutrients and through plant toxins that prevent the growth of other plants underneath it. Leafy spurge is an aggressive invader and, once present, can completely overtake large areas of open land.

DISTRIBUTION AND HABITAT IN THE UNITED STATES: Leafy spurge occurs across much of the northern U.S., with the most extensive infestations reported for Montana, North Dakota, Nebraska, South Dakota, and Wyoming. It has been identified as a serious pest on a number of national parks and on preserves of The Nature Conservancy in eleven northern states. Leafy spurge tolerates moist to dry soil conditions but is most aggressive under dry conditions where competition from native plants is reduced. It is capable of invading disturbed sites, including prairies, savannas, pastures, abandoned fields and roadside areas

Snakehead Fish

Introduction to the United States-- Recently, a non-native air breathing freshwater fish known as a Snakehead has generated national media attention as the latest invasive species to threaten native fish and wildlife resources and the economic sectors that depend on them. In scientific terms, snakeheads are divided into two distinct genera: Channa (snakeheads of Asia, Malaysia and Indonesia), and Parachanna (African snakeheads). Snakeheads are a diverse family of fish native to parts of China, Russia, and Korea. The Northern Snakehead, Channa Argus, is part of this family that has recently been in the news in the Eastern United States.

Snakeheads are highly predatory, some having the ability to travel overland to new water bodies, so the inevitable release of these fishes by hobbyists, , and liberation of live-food fish into U.S. waters threatens aquatic ecosystems. At all of their life stages, snakeheads will compete with native species for food. As juveniles, the food they seek includes zooplankton, insect larvae, small crustaceans and the fry of other fishes. As adults, these fish become voracious predators, feeding upon other fishes, crustaceans, frogs, small reptiles and sometimes birds and small mammals.

Possible ecosystem effects and spread of species-- If snakeheads become established in North American ecosystems, their predatory behavior could drastically modify the array of native species. As a result, they could disrupt the ecological balance and forever change native aquatic systems. In addition to the threat of their predatory behavior and its resulting impacts, there is concern about snakeheads' transference of pathogens to native fish. Snakeheads carry a disease known as Epizootic Ulcerative Syndrome. Fisheries scientists need to study this disease to determine if it can be transferred to North American species.

snakehead fish

Information obtained from Invasive Species of the Month

Bibliography

1. BugWood, Network. (8 December 2003). Invasive and Exotic Species

<http://www.invasive.org> (2004 October)

2. Environmental Law Institute (August 2002) Halting the Invasion: State Tools for Invasive Species Management. Washington D.C 2002

3. Grummey, Ray. 2004. Invaded Waters: The Great Lakes at Risk. Star Tribune, Minneapolis MN 2004.

4. Institute of Ecosystems Studies. <Http://www.ecostudies.org/> (October 2004)

5. Jackman, John. Bee Alert: What is the Africanized Honey Bee? <http://www.agnews.tamu.edu/bees> (October 2004)

6. Kellog, Sarah. (14 September 2004) Invasive species biggest threat to lakes, report finds. <http://mlive.com/news/> Washington Bureau (October 2004)

7. Thunhoust, Gwendolyn. (3 March 1999). Leafy Spurge <http://www.nps.gov/plants/alien/fact/evesl.htm> (October 2004)

8. United States Department of Agriculture. (15 April 2004) Invasive Species. <http://www.invasivespecies.gov> (October 2004)

9. Wadsworth, Bryan. (11 March 2003) Union of Concerned Scientists. <http://www.ucsusa.org/global> (October 2004)