Invasive species in the United States
Invasive species are a significant threat to many native habitats and species of the United States and a significant cost to agriculture, forestry, and recreation. The term "invasive species" can refer to introduced or naturalized species, feral species, or introduced diseases. Some species, such as the dandelion, while non-native, do not cause significant economic or ecologic damage and are not widely considered as invasive. Overall, it is estimated that 50,000 non-native species have been introduced to the United States, including livestock, crops, pets, and other non-invasive species. Economic damages associated with invasive species' effects and control costs are estimated at $120 billion per year. [1]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Kudzu_on_trees_in_Atlanta%2C_Georgia.jpg/300px-Kudzu_on_trees_in_Atlanta%2C_Georgia.jpg)
Notable Invasive Species
For a complete list of invasive species, see List of invasive species in North America
Picture | Name | Species Name | Introduced | Control Measures | Notes |
---|---|---|---|---|---|
Kudzu | Pueraria lobata | Southern U.S. | Mowing, herbicides | Known as "The vine that ate the south", forms dense monocultures that outcompete native ground cover and forest trees. Can grow by up to one foot a day | |
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Zebra Mussels | Dreissena polymorpha | Great Lakes, U.S. waterways & lakes | Ballast water transport bans, manual removal from clogged pipes | Initially spread by ballast tanks of oceangoing vessels on the Great Lakes, now spread lake-to-lake by trailer-drawn boats. May be a source of avian botulism in the Great Lakes region |
European Starlings | Sturnus vulgaris | Lower 48 states | Hunting, trapping | Introduced in 19th century as part of an effort to bring all species mentioned in Shakespeare's works to the United States | |
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Brown Tree Snake | Boiga irregularis | Guam | Dog-sniffing of incoming ships, Paracetamol as poison | Has reached densities on Guam of up to 100 snakes per hectare, caused extinction on Guam of at least 12 bird species |
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Burmese Pythons | Python molarus | Everglades | Hunting season created | Introduced by releases of pet snakes |
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Africanized bee | Apis hybrid | Southwestern U.S. | Cold weather has limited spread | Hybrid of African and European honeybees created in Brazil in the 1950's, described as "Killer bees" but no more poisonous than common honeybee |
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Asian Carp | Multiple | Mississippi River and tributaries | Rotenone poison, electric barriers | Have the habit of jumping out of the water, which can injure boaters. Introduced to eat algae in fish ponds in Southern U.S., escaped during flood events |
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Emerald Ash Borer | Agrilus planipennis | Eastern U.S. | Culling infected stands, bans on firewood transport | Threatens to severely reduce or eliminate the ash lumber industry of U.S., with an estimated value of $25.1 billion per year |
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Multiflora Rose | Rosa multiflora | Eastern U.S. | Manual removal, herbicides [2] | Introduced for erosion control and promoted as a "living fence" to attract wildlife, now competes with native understory plants |
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Spiny Water Flea | Byothrephes longimanus | Great Lakes | Ballast water transport bans | Competes with native fish for prey, spines prevent many native fish from eating it as prey |
Economic Impacts of Invasive Species
The economic impacts of invasive species can be difficult to estimate, especially when an invasive species does not effect economically important native species. This is due in part to the difficulty in determining the non-use value of native habitats damaged by invasive species, and in part to incomplete knowledge of the effects of all of the invasive species present in the U.S. Moreover, little is known about the estimated 750,000 species in the United States. [3] Estimates for the damages caused by well-known species can vary as well. The OTA has estimated zebra mussel economic effects at $300,000 a year, while an ACoE study put the number at $1 billion. Estimates of total yearly costs due to invasive species range from $1.1 billion per year to $137 billion per year [4]
According to David Pimentel's paper in 2004, some of the most costly invasive species are rats, cats, crop weeds, crop pests, crop plants, since they were estimated high on environmental losses and damages with a relative low control costs. [5] The total damage to U.S. bird population is approximately $17 billion/year. In 1993, OTA estimated that a total of $100 million is invested annually in invasive species aquatic weed control in the US. [6] The total cost of destruction by introduced rats in the United States is more than $19 billion per year according USDA's data. [7] Based on Pimentel's argument that the conservative economic losses due to exotic fish is $5.4 billion annually, and the total costs of introduced weeds to the U.S. economy is about $27 billion annually. [8] In addition, approximately $2.1 billion in forest products are lost each year to invasive plant pathogens in the United States, and a conservative estimate of the losses to U.S. livestock from exotic microbes and parasites was approximately $9 billion/year in 2001. [9]
Government polices and management efforts
The federal government has historically promoted the introduction and widespread distribution of species that would become invasive, including Multiflora rose, Kudzu, and others for numerous reasons. Before the 20th century, numerous species were imported and released without government oversight, such as the Gypsy moth and House Sparrow. Over 50% of flora recognized as invasive or noxious weeds were deliberately introduced to the United States, by either government policy or individuals. [10] Current government policy can be broadly separated into two categories: preventing entry of a potential invasive species and controlling the spread of species already present. This is carried out by different government agencies, depending on what types of damage a species can cause.
Regulations designed to prevent entry of invasive species
The Lacey Act of 1900, originally designed to protect game wildlife, its role has increased to prohibit parties from bringing non-native species that have the potential to become invasive into the United States. The Lacey Act gives the FWS the power to list a species as "injurious" and regulate or prohibit its entry into the U.S. [11] The Alien Species Prevention and Enforcement Act of 1992 makes it illegal to transport a plant or animal deemed injurious into the United States through the mail. The FWS concerns itself mostly with the invasive species likely to threaten sensitive habitats or endangered species.
The USDA is also involved in preventing the introduction of invasive species, largely through the Animal and Plant Health Inspection Service, or APHIS. APHIS was originally tasked with preventing damage to agriculture and forestry from alien species, pests, or diseases, but has had its mission expanded to include preventing invasive species spread as well. [12] This includes identifying potential pests and diseases, assisting in international and domestic eradication efforts, and the Smuggling Interdiction and Trade Compliance Program, designed initially to deal with illegally imported produce, but now tasked with preventing the entry of exotic pests, diseases, and potentially invasive species. [13] APHIS also enforces bans against interstate transport of pests, diseases, and species listed as injurious, noxious weeds, or nuisance species. An example of the USDA banning imports is the ban on fresh mangosteen fruit due to concerns about fruit flies from southeast Asia. This ban originally allowed only frozen or canned fruit, but now allows for fresh irradiated fruit to enter. [14]
Reducing the spread of invasive species
Many invasive species are spread inadvertently by human activities, such as seeds stuck to clothing or mud transporting firewood, or through ballast water. The government has instituted several different policies related to different pathways the invasive species may be spread. For example, quarantines on a federal and state level exist for firewood across the Eastern United States in an attempt to halt the spread of the Emerald ash borer, Gypsy moth, oak wilt, and others. Transporting firewood out of quarantine zones can result in a fine of up to $1,000,000 and 25 years in jail, but punishments are usually much lower. [15]
The techniques available for controlling the spread of invasive species can be broadly defined into 6 categories [16]:
- Cultural practices
- May include controlled grazing of livestock, controlled burns, timbering, and others. An example of this in action is the use of prescribed burns in the Everglades to control Melaleuca quinquenervia trees. The burns destroy Melaleuca, but not native species which have adapted to wildfires, which were common, but are now suppressed [17]
- Interference with dispersal
- May include fencing, reducing accidental seed transport, and the construction of barriers, such as the electric barrier on the Chicago Sanitary & Ship Canal, discussed below.
- Mechanical removal
- Includes mowing, harvesting, manual removal, trapping, & culling. Many invasive plants, such as garlic mustard, can regrow quickly after mowing and must be removed by the roots or chemically.
- Chemical control
- May include the use of any approved pesticide or herbicide, or vaccines to control invasive diseases. sea lampreys in the Great Lakes have had their numbers significantly reduced by a lampricide that kills larvae, which hatch in streams, before they can enter the lakes. The lampricide is responsible for reducing the sea lamprey population in the Great Lakes from over 3 million in the 1950's to around 450,000 today, and with potentially rescuing several Great Lakes fisheries. [18]
- Biological control
- Can involve the release of specific predators/herbivores, parasites, or diseases designed to control an invasive species without damaging native ones. One example of this is the city of Chattanooga's use of goats to control Kudzu growing on mountain ridges. The goats, guarded from predators by llamas, eat the vine often enough to slowly starve the roots, killing the plant. This method is much cheaper than the repeated mowing or herbicidal spraying that would otherwise be necessary [19]
- Interference with reproduction
- This can include the release of mating-disrupting pheromones or the release of sterile males. Field tests are underway to study the control of sea lampreys in the Great Lakes by the use of pheromone-baited traps in streams, in addition to current chemical controls. When female sea lampreys return to the stream to breed, they are drawn to the traps and captured, preventing reproduction from occurring. [20]
An integrated pest management (IPM) approach, as defined by the National Invasive Species Council, uses scientific data and population monitoring to help determine the most efficient control strategy, which is usually a combination of several of the methods listed above. Agencies are encouraged to use an adaptive management strategy, involving regular reviews on the efficiency of their policies and conduct research into better methods. [21]
Inter-department co-operation
Invasive species control is not overseen by one government agency. Rather, different invasive species are controlled by different agencies. For example, policies aimed at controlling the Emerald Ash Borer are undertaken by the USDA, because National Forests, the body coordinating Emerald Ash Borer control efforts, are within the USDA. [22] The National Invasive Species Council was created by executive order in 1999 and charged with promoting efficiency and coordination between the numerous federal invasive species prevention and control policies. The NISC is co-chaired by the secretaries of the three federal departments that are charged with invasive species control: Interior, Agriculture, and Commerce. [23] Many state efforts use a similar council model to coordinate agencies within a state.
Education and outreach
![](http://upload.wikimedia.org/wikipedia/commons/thumb/d/d7/Zebra_mussel_warning_sign.jpg/220px-Zebra_mussel_warning_sign.jpg)
Many of the policies used to contain invasive species, such as firewood transport bans or cleaning shoes and clothes after hiking are effective only when the general public knows of their existence and importance. Because of this numerous programs to inform the public about invasive species. This includes placing signs at boat ramps, campsites, state borders, hiking trails, and numerous other locations as reminders of policies and potential fines associated with breaking policies. There are also numerous government programs aimed at educating children [24], promoting volunteer efforts at removal, and the many ways citizens can prevent the spread of invasive species [25]
Regional/State/Local Efforts at Control/Prevention
Great Lakes
Current efforts in the Great Lakes ecoregion focus on measures that prevent the introduction of invasive species. As a major transport area, a number of invasive species have already been established within the Great Lakes. In 1998, the United States Coast Guard, in accordance with the National Invasive Species Act of 1996, established a set of voluntary ballast water management program. In 2004 this voluntary program became mandatory for every ship entering US controlled waters. [26] Current measures are among the most stringent in the world and require ships entering from outside the Exclusive Economic Zone to flush ballast water in open seas or retain their ballast water for the length of their stay in the Great Lakes. [27] [28] Failure to comply with the US Coast Guards regulations can result in a class C felony. [29]
Another preventative measure in the Great Lakes region is the presence of an electrified barrier in the Chicago Sanitary and Ship Canal. The barrier is meant to keep Asian Carp from reaching Lake Michigan and the other Great Lakes. On December 2, 2010, Michigan, Ohio, Pennsylvania and Wisconsin were denied their request to force the closing the Canal by Judge Robert Dow of the United States District Court for Northern District of Illinois. [30] [31] The closing of the Canal would have once again permanently separated Lake Michigan and the Mississippi river system. States argued that the canal, and the Asian Carp in it, posed a risk to $7 billion worth of industry. [32] Currently the electric barrier is the only preventative measure and some question its effectiveness, particularly following the discovery of Asian Carp DNA past the barrier. [33]
Hawaii
In Hawaii measures to prevent the introduction and spread of invasive species are coordinated by the Hawaii Invasive Species Council. [34] Currently the council is broken into five committees which focus on different areas of invasive species control. These focus areas are (1) prevention (2) management of established pests (3) increased public awareness (4) research and technology and (5) monetary resources.
Currently, Hawaii requires inspection of any and all plant, animal and microorganism transports. [35] This includes transports from the mainland in addition to transports occurring between islands. Travelers are required to fill out a declaration form for each journey. Failure to declare these transports can result in up to one year imprisonment or a $250,000 fine. [36] Many potential invasives or carriers for invasives require permits and quarantine periods before entry to the state is allowed. [37]
In addition, there are other preventative measures such as a hotline for reporting sitings of known potential invaders like the brown tree snake. [38]
Rocky Mountain Region
The USDA Rocky Mountain Research Station (RMRS) has a specific Invasive Species Working Group [39] to do the research about invasive species in Rocky Mountain region. The Invasive Species Working Group focuses on four key areas: (1) prediction and prevention, (2) early detection and rapid response, (3) control and management, and (4) restoration and rehabilitation. [40] Specific approaches include prioritizing of invasive species problems, increased collaboration among agencies regarding those problems, and accountability for the responsible use of the limited resources available for invasive control. [41]
Invasive species of particular concern in Rocky Mountain region include: cheatgrass; leafy spurge; tansy ragwort; spotted knapweed; bufflegrass; saltcedar; white pine blister rust; Armillaria root rot; introduced trout species; golden algae; spruce aphid; and banded elm bark beetle. [42]
California
California has created a policy system towards invasive species, including Invasive Species Council of California (ISCC), California Invasive Species Advisory Committee (CISAC) and California Invasive Plant Council (Cal-IPC), a non-profit organization. The ISCC represents the highest level of leadership and authority in state government regarding invasive species. The ISCC is an inter-agency council that helps to coordinate and ensure complementary, cost-efficient, environmentally sound and effective state activities regarding invasive species. CISAC advises the ISCC, and created the California list of invasive species California has many diverse ecoregions, and numerous endemic species that are at risk from invasive species. [43]
Florida Everglades
Invasive species in Florida currently make up more than 26% of the animal population and a full one third of the flora population [44]. In 1994, the Everglades Forever Act of 1994 was passed to help in controlling Florida's water supply, recreation areas, and diverse flora and fauna [45]. In addition to control and prevention measures the act also calls for efforts to monitor the distribution of known invasive species [46]
One invasive species occuring in the Everglades that can have serious consequences in the Burmese Python. Between 2000 and 2010, approximately 1,334 of the snakes were removed from the Everglades [47] Currently the National Park Service is researching control measures for the Burmese Python in order to limit the species effects on the delicate Everglades ecosystem [48]
See also
- Environmental issues in the United States
- List of invasive species in North America
- List of invasive species in the Mid-Atlantic region of the United States
- List of invasive plant species in New Jersey
- List of invasive species in the Everglades
- Biological pollution
References
- ^ David Pimentel, Rodolfo Zuniga, Doug Morrison. Update on the environmental and economic costs associated with alien-invasive species in the United States. Ecological Economics. 52 (2005) 273-288.
- ^ http://www.invasivespeciesinfo.gov/plants/multiflorarose.shtml
- ^ Raven, P.H., Johnson, G.B., 1992. Biology, Third Edition Mosby Year Book, St. Louis, MO
- ^ http://www.rmrs.nau.edu/invasive_species/
- ^ David Pimentel, Rodolfo Zuniga, Doug Morrison. Update on the environmental and economic costs associated with alien-invasive species in the United States. Ecological Economics. 52 (2005) 273-288
- ^ OTA, 1993. Harmful Non-Indigenous Species in the United States. Office of Technology Assessment, United States Congress, Washington, DC.
- ^ USDA, 2001. Agricultural Statistics. U.S. Department of Agriculture, Washington, DC.
- ^ Pimentel, D., Lach, L., Zuniga, R., Morrison, D., 1999. Environmental and economic costs associated with introduced nonnative species in the United States. Manuscript, pp. 1– 28.
- ^ David Pimentel, Rodolfo Zuniga, Doug Morrison. Update on the environmental and economic costs associated with alien-invasive species in the United States. Ecological Economics. 52 (2005) 273-288
- ^ The United States Naturalized Flora: Largely the Product of Deliberate Introductions Richard N. Mack and Marianne Erneberg. Annals of the Missouri Botanical Garden. Vol. 89, No. 2 (Spring, 2002), pp. 176-189
- ^ "Nation marks Lacey Act centennial, 100 years of federal wildlife law enforcement. US Fish and Wildlife Service. Retrieved on July 7, 2010.
- ^ http://www.aphis.usda.gov/about_aphis/
- ^ http://www.aphis.usda.gov/international_safeguarding/sitc/index.shtml
- ^ Karp, David (8 August, 2007). "Mangosteens Arrive, but Be Prepared to Pay". The New York Times. Retrieved 22 May, 2010.
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(help) - ^ http://dnr.wi.gov/invasives/firewood/
- ^ "Guidelines for ranking invasive species control projects. Volume I." National Invasive Species Council. May, 2005. http://www.invasivespecies.gov/global/CMR/CMR_documents/NISC%20Control%20and%20Management%20Guidelines.pdf
- ^ http://www.fws.gov/invasives/staffTrainingModule/methods/burning/practice.html
- ^ http://greatlakesecho.org/2009/05/11/pheromones-in-river-traps-attract-sea-lampreys/
- ^ http://www.nytimes.com/2007/06/05/us/05goats.html?ex=1338696000&en=cfc0f304b4a68bfc&ei=5088&partner=rssnyt&emc=rss
- ^ http://greatlakesecho.org/2009/05/11/pheromones-in-river-traps-attract-sea-lampreys/
- ^ "Guidelines for ranking invasive species control projects. Volume I." National Invasive Species Council. May, 2005. http://www.invasivespecies.gov/global/CMR/CMR_documents/NISC%20Control%20and%20Management%20Guidelines.pdf
- ^ http://www.stopthebeetle.info/
- ^ Emerton, L. and G. Howard, 2008, A Toolkit for the Economic Analysis of Invasive Species. Global Invasive Species Programme, Nairobi.
- ^ http://www.invasivespeciesinfo.gov/toolkit/outreach.shtml
- ^ http://www.fws.gov/invasives/what-you-can-do.html
- ^ http://www.uscg.mil/hq/cg5/cg522/cg5224/bwm.asp
- ^ http://www.greatlakes-seaway.com/en/environment/ballast-water/index.html
- ^ http://serc.si.edu/labs/marine_invasions/vector_ecology/bw_exchange.aspx
- ^ http://www.uscg.mil/hq/cg5/cg522/cg5224/ans.asp
- ^ http://www.greatlakeslaw.org/blog/2010/12/another-setback-in-the-legal-fight-to-keep-asian-carp-out-of-the-great-lakes.html
- ^ http://www.greatlakeslaw.org/files/dist_ct_pi_opinion_order.pdf
- ^ http://www.jsonline.com/news/wisconsin/80731962.html
- ^ http://www.twincities.com/ci_17798637?nclick_check=1
- ^ http://www.hawaiiinvasivespecies.org/hisc/
- ^ http://hawaii.gov/hdoa/pi/pq
- ^ http://hawaii.gov/hdoa/pi/pq/Exhibit_3.pdf
- ^ http://hawaiiplants.com/importfaq.htm
- ^ http://hawaii.gov/hdoa/pi/pq/bts
- ^ http://www.rmrs.nau.edu/invasive_species/iswg.php
- ^ http://www.rmrs.nau.edu/invasive_species/
- ^ http://www.na.fs.fed.us/fhp/invasive_plants/strategic/framework.pdf
- ^ http://www.fs.fed.us/rm/pubs_other/rmrs_2009_butler_j001.pdf
- ^ http://www.iscc.ca.gov/
- ^ Ferriter, et al (2001) http://mytest.sfwmd.gov/portal/page/portal/pg_grp_sfwmd_sfer/portlet_prevreport/consolidated_01/chapter%2014/ch14.pdf
- ^ Florida Statutes Chapter 373.4592, http://exchange.law.miami.edu/everglades/statutes/state/florida/E_forever.htm
- ^ Ferriter, "et al" (2001) http://mytest.sfwmd.gov/portal/page/portal/pg_grp_sfwmd_sfer/portlet_prevreport/consolidated_01/chapter%2014/ch14.pdf
- ^ http://www.nps.gov/ever/naturescience/burmesepython.htm
- ^ http://www.nps.gov/ever/naturescience/upload/PythonFactSheetLoRes.pdf
Further reading
- Coates, Peter (2007). American Perceptions of Immigrant and Invasive Species: Strangers on the Land. University of California Press. p. 266. ISBN 0-520-24930-5.
External links
- National Invasive Species Information Center, National Invasive Species Information Center, United States National Agricultural Library. Lists general information and resources for invasive species.
- Center for Invasive Species and Ecosystem Health at the University of Georgia
- Center for Invasive Species Research at the University of California, Riverside
- Invasive Species Specialist Group - global invasive species database