Invasive species pose a crucial threat to many native habitats and species in the United States and impose high costs on agriculture, forestry, and recreation. An invasive species refers to an organism that is not native to a specific region and poses significant economic and environmental threats to its new habitat. The term "invasive species" can also refer to feral species or introduced diseases. Some introduced species, such as the dandelion, do not cause significant economic or ecological damage and are not widely considered as invasive. Economic damages from invasive species and control costs are estimated at $120 billion per year.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 main geomorphological impacts of invasive plants include bioconstruction and bioprotection.
Degrees of ecological impacts by introduced faunas that can potentially compensate for extinct native animals (especially megafauna) and treatments of these animals have long been subjects to discussions most notably mustangs and burros, while contributions by other species to the native ecosystems are also debatable.Erick J. Lundgren, Daniel Ramp, John Rowan, Owen Middleton, Simon D. Schowanek, Oscar Sanisidro, Scott P. Carroll, Matt Davis, Christopher J. Sandom, Jens-Christian Svenning, Arian D. Wallach, James A. Estes, 2020, Introduced herbivores restore Late Pleistocene ecological functions, PNAS, 117 (14), pp.7871-7878, Proceedings of the National Academy of Sciences of the United States of America
Notable invasive species
Picture Common name Species name Introduced Control measures Notes Kudzu Pueraria lobata Southern U.S. Mowing, herbicides, conservation grazing Known as "the vine that ate the South", forms dense monocultures that outcompete native ground cover and forest trees. It can grow up to one foot per day. For more details, see Kudzu in the United States. Common tumbleweed Kali tragus Throughout North America Managed grazing Introduced through imported flaxseed from Russia that was contaminated with Kali seeds. Although invasive, it is used in Westerns to symbolize frontier areas of the United States. Privet Ligustrum spp. Southeastern U.S. Mechanical removal, herbicides Highly invasive in urban areas and forested areas of the southeastern U.S. Zebra mussel 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. It may be a source of avian botulism in the Great Lakes region. Common starling Sturnus vulgaris Contiguous United 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. 100 birds released in Central Park have spread across the entire mainland U.S. 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. Burmese pythons in Florida Python bivittatus Everglades Hunting season created Introduced via released or escaped pet snakes. Africanized bee Apis mellifera hybrid Southwestern U.S. Cold weather has limited spread Hybrid of African and European honeybees created in Brazil in the 1950s, described as "killer bees." While individually no more venomous than European honeybees, they attack with particular violence and usually involve large numbers of stings, which can be fatal to humans and other animals. Asian carp Multiple Cyprinidae 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 the Southern U.S., escaped during flood events. Emerald ash borer Agrilus planipennis Eastern U.S. Culling infected stands, bans on firewood transport Threatens to reduce or eliminate the ash lumber industry of U.S. severely, worth an estimated value of $25.1 billion per year. Hemlock woolly adelgid Adelges tsugae Eastern U.S. Insecticide treatment Could kill most eastern hemlocks in the U.S. within the next decade. Multiflora rose Rosa multiflora Eastern U.S. Manual removal, herbicides Introduced for erosion control and promoted as a "living fence" to attract wildlife, now competes with native understory plants. Spiny waterflea Bythotrephes longimanus Great Lakes Ballast water transport bans Competes with native fish for prey, and its spines prevent many native fish from eating it as prey. Northern Snakehead Channa argus East Coast fresh water Possession of a live specimen is illegal in many U.S. states. Invasive snakeheads can cause major ecological damage because they are apex predators. Video clip titled: "The Northern Snakehead fish wreaks havoc". Giant African land snail Lissachatina fulica Florida Pest control This invasive species was smuggled into Florida from Africa. Since they need calcium to build their shells, they attach themselves to concrete, which in many cases is house foundations, weakening house structures. Lionfish Pterois Southern U.S. Lionfish derbies Lionfish compete for food with native fish species. They have no natural predators because of their venomous spines. Cane toad Rhinella marina Florida and Hawaii Pest control They pose as threats to animals since they are toxic. Nile crocodile Crocodylus niloticus Florida Monitoring and removal Several specimens have been recently captured in South Florida, though no signs have been found that the population is reproducing in the wild. Rusty crayfish Orconectes rusticus Across the states Intensive trapping, boat and equipment cleaning, bait restrictions The larger size and aggressive nature of rusty crayfish that have been introduced to a body of water makes it harder for them to be preyed upon by native species of fish, which are not accustomed to crayfish fighting back against them. Spotted lanternfly Lycorma delicatula Northeastern and Mid-Atlantic U.S. Pest control Highly invasive, with potential to spread across much of the Midwest and Western U.S. Japanese beetle Popillia japonica Northeastern, Southern and Midwestern U.S. Poison, diseases, parasites. Pest of roughly 300 species of plants, rapid spread.Callery PearPyrus calleryanaThroughout Eastern United StatesPhysical removal and targeted herbicibe. Originally brought to the United States from Asia as an ornamental tree. They flourish in low-quality soils and also tend to be pest free. They also release chemicals that can affect the soil and make it harder for native plants to grow.
For a more in-depth example, Zebra mussels (Dreissena polymorpha), like many other invasive species, are not native to the United States and can cause significant damage to ecosystems and severely harm native aquatic wildlife, such as fish and other freshwater shellfish.
Zebra mussels (Deissena polymarpha) are a species of shell fish that originated and are native to the Caspian and Black seas of Europe and the western part of Russia. These invasive species of shellfish made their way into the United States and were discovered here in the U.S during the 1980s. Zebra mussels are known for outcompeting native fish species (mainly other shellfish) and can prevent those fish from absorbing nutrients and reproduction. Another problem humans face is (Biofouling), which occurs when mussels attach themselves to surfaces using Byssal threads, protein-based roots. This can damage property by clogging vehicles, pipes, and other systems. Given their appearance, these mussels are depicted as having light brown coloration with black stripes, hence their name, and have a very small, D-shaped shell. They are typically not that big, growing to roughly one-quarter to one and one-half inches in length, possibly two inches. Their size (like other mussel species) is usually dependent on age, and they may also possess stripes that are both yellow and brown.
Economic impact
The economic impacts of invasive species can be difficult to estimate, especially when an invasive species does not affect economically important native species. This is partly because of the difficulty in determining the non-use value of native habitats damaged by invasive species and the incomplete knowledge of the effects of all invasive species present in the U.S. Estimates of the damage caused by well-known species can also vary. The Office of Technology Assessment (OTA) has estimated the zebra mussel's economic effects at $300,000 per year, while a United States Army Corps of Engineers study put the figure at $1 billion per year. The United States government spends an estimated $1 billion annually to recover from the invasive Formosan termite, investing $1 billion of this budget in areas surrounding New Orleans, a major port city. Estimates of total yearly costs controlling invasive species range from $1.1 billion to $137 billion per year.
In 1993, the OTA estimated that a total of $100 million was invested annually in invasive-species aquatic weed control in the U.S.OTA, 1993. Harmful Non-Indigenous Species in the United States. Office of Technology Assessment, United States Congress, Washington, DC. Introduced rats cause more than $19 billion per year in damages,USDA, 2001. Agricultural Statistics. U.S. Department of Agriculture, Washington, DC exotic fish cause up to $5.4 billion annually, and the total costs of introduced weeds are estimated at around $27 billion annually.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. The total damage to the native bird population from invasive species is approximately $17 billion per year. Approximately $2.1 billion in forest products are lost each year to invasive plant pathogens, and a conservative estimate of the losses to livestock from exotic microbes and parasites was $9 billion per year in 2001.David Pimentel, Rodolfo Zuniga, Doug Morrison. Update on the environmental and economic costs associated with your face species in the United States. Ecological Economics. 52 (2005) 273-288
Government policies and management efforts The federal government has historically promoted the introduction and widespread distribution of species that have become invasive, including multiflora rose, kudzu, and others, for a variety of 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 the flora recognized as invasive or noxious weeds were deliberately introduced to the United States by either government policy or individuals.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 Current government policy can be broadly separated into two categories: preventing the 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