Exotic species are organisms that are introduced to a region or ecosystem, often unintentionally, through human migration or trade. Some exotic species are useful to man, such as horses, goats, pigs, and edible plants including wheat and oats. These are examples of species that were brought to the Americas intentionally by European colonists.
What is the introduction of exotic species?
Introduction of Exotic Species Exotic species are organisms that have been introduced into an area outside their normal distribution. Human individuals or agencies have both intentionally or accidentally introduced alien species into ecosystems, sometimes with devastating unintended consequences.
What is the contribution of exotic species to the marine environment?
The full contribution of exotic species among native assemblages remains, and probably will continue to remain unknown, but will add to the diversity of an area. There are no documented accounts of an introduced species resulting in the extinction of native species in marine habitats as has occurred in freshwater systems.
How are exotic species transported around the world?
Then, when the ballast water is discharged at the next port of call, exotic species can be introduced. Scientists estimate that as many as 3,000 alien species per day are transported around the world in the ballast water of ships. Aquaculture, the cultivation of natural products of water such as fish, also introduces invading organisms.
What are the economic costs associated with exotic species?
Economic costs associated with exotic species include agricultural losses, damage to infrastructure, as when aquatic plants clog water intakes, and the costs of attempts to restore native species whose survival is endangered by introduced species .
How does introduction of an exotic species?
Introduction of Exotic Species Exotic species are organisms that have been introduced into an area outside their normal distribution. Human individuals or agencies have both intentionally or accidentally introduced alien species into ecosystems, sometimes with devastating unintended consequences.
How are exotic species spread?
Invasive species are almost always spread by human activity. The increase of activities such as tourism and trade have meant people and goods can move all over the planet, and they often take invasive species with them, accidentally or intentionally.
What makes an exotic species invasive?
To be invasive, a species must adapt to the new area easily. It must reproduce quickly. It must harm property, the economy, or the native plants and animals of the region. Many invasive species are introduced into a new region accidentally.
What is an example of introduction of exotic species?
Exotic species are those that have been intentionally or unintentionally introduced by humans into an ecosystem in which they did not evolve. Such introductions probably occur frequently as natural phenomena. For example, Kudzu (Pueraria lobata), which is native to Japan, was introduced in the United States in 1876.
What is the cause of introduced species?
Invasive species are primarily spread by human activities, often unintentionally. People, and the goods we use, travel around the world very quickly, and they often carry uninvited species with them. Ships can carry aquatic organisms in their ballast water, while smaller boats may carry them on their propellers.
How do humans introduce invasive species?
Invasive species can harm both the natural resources in an ecosystem as well as threaten human use of these resources. An invasive species can be introduced to a new area via the ballast water of oceangoing ships, intentional and accidental releases of aquaculture species, aquarium specimens or bait, and other means.
Are all exotic species considered invasive?
Are all exotic species invasive? No, not all exotic species are considered invasive. Some exotic species are fundamental to our lifestyle, such as food crops. Only exotic species that grow and reproduce out of control and have a detrimental impact on the environment, economy, or human health can be considered invasive.
Do all introduced species become invasive?
No, actually only a small percent of introduced species ever become invasive. However, it is nearly impossible to predict which species will become invasive and new species are being introduced every day. Some species are present for many years before they exhibit invasive characteristics.
What are the effects of exotic species?
Invasive alien species have devastating impacts on native biota, causing decline or even extinctions of native species, and negatively affecting ecosystems. Invasive alien species are animals, plants, fungi and microorganisms entered and established in the environment from outside of their natural habitat.
When were certain exotic species introduced?
Assertion: When certain exotic species are introduced into a new geographical area not native to them, they start spreading fast without a check and are termed "invasive". Reason: The exotic species do not have its natural predators in that area.
Where did exotic plants come from?
Europe and Asia are the primary homelands for exotic species that have successfully colonized North American habitat. A few years ago, Peter Vitousek of Stanford University estimated that about 11% of the flora of the conterminous United States was composed of alien species.
How can we prevent the introduction of exotic species in biodiversity?
10 Ways You Can Prevent the Spread of Invasive SpeciesClean your hiking and fishing gear. ... Don't move firewood. ... Fish using native bait when possible. ... Volunteer at removal efforts. ... Talk to your local nursery when selecting plants for your garden. ... Clean your boat before transferring to a new body of water.More items...•
How does exotic species affect population?
Since invasive species are in a new environment, free from natural predators, parasites, or competitors, they often develop large population sizes very rapidly. These high populations can out-compete, displace or kill native species or can reduce wildlife food and habitat.
What are exotic species and how do they affect biodiversity?
Invasive alien species are animals, plants, fungi and microorganisms entered and established in the environment from outside of their natural habitat. They reproduce rapidly, out-compete native species for food, water and space, and are one of the main causes of global biodiversity loss.
Where did exotic plants come from?
Europe and Asia are the primary homelands for exotic species that have successfully colonized North American habitat. A few years ago, Peter Vitousek of Stanford University estimated that about 11% of the flora of the conterminous United States was composed of alien species.
What is the difference between invasive and exotic species?
Invasive: a species of plant or animal that outcompetes other species, causing damage to an ecosystem. Non-native: a species that originated somewhere other than its current location and has been introduced to the area where it now lives (also called exotic species).
When did the first exotic species come to the United States?
The introduction of exotic species into the United States probably began with the first colonists that came ashore. When the Pilgrims landed at Plymouth in 1620, various non-native rodents, such as Rattus, and the house mouse, Mus musculus, almost certainly disembarked right along with them. The problem of exotic species became even more acute in the eighteenth and nineteenth centuries, as the United States entered world trade.
What is an exotic species?
Exotic species, which are also known as alien species, invasive species, non-indigenous species, and bioinvaders, are species of plants or animals that are growing in a nonnative environment. Alien species have been moved by humans to areas outside of their native ranges. Once transported, they become removed from the predators, parasites, and diseases that kept them in balance in their native environments. As a result of the loss of these controls, they often become pests in the areas into which they are introduced.
Why is Hawaii so isolated from the rest of the world?
Because of this isolation, Hawaii originally had thousands of species that existed nowhere else on Earth. But it has suffered the highest rate of extinctions of any area of the United States and one of the highest rates anywhere in the world, with hundreds and possibly thousands of unique species already extinct. The tropical climate of Hawaii allows invasive plants and animals to thrive. Nonnative plants and animals frequently displace native species. Predation by nonnative rats, feral cats, dogs, and mongooses has led to the extinction of many species of birds. Habitat destruction by feral pigs has altered landscapes. To compound the problem, nonnative species are usually more aggressive at colonizing disturbed ground left behind by the feral pigs.
Why are invasive species so bad?
Thousands of invasive species worldwide are notorious for their distinctive habits, destructive potential, or ecological damage. Other invaders seem to be having little environmental impact. A few of the more well-known exotic species in the United States are discussed here.
What are the changes that occur when an organism reproduces with a native species?
Other ecological changes may occur when the invading organisms reproduce with native species, possibly altering the gene pool. This may lead to hybridization and homogeneity, which reduces biodiversity, the primary element associated with an ecosystem's ability to adapt to natural or human-induced changes.
How do invading species affect the ecosystem?
Invading species can cause complex changes within the structure and function of their new ecosystem. Their presence can lead to the restructuring of established food webs, the importation of new diseases to the new surroundings, and competition with indigenous organisms for space and food. Other ecological changes may occur when the invading organisms reproduce with native species, possibly altering the gene pool. This may lead to hybridization and homogeneity, which reduces biodiversity, the primary element associated with an ecosystem's ability to adapt to natural or human-induced changes.
What happens to plants once transported?
Once transported, they become removed from the predators, parasites, and diseases that kept them in balance in their native environments. As a result of the loss of these controls, they often become pests in the areas into which they are introduced. Many plants and animals can disperse naturally into new habitats.
Why are exotic species introduced?
Exotic species have been intentionally introduced worldwide for economic purposes or for biological control. However, accidental introduction has been common too. In any case, a frequent outcome of introductions is the extinction of the exotic species. If, however, exotics are able to adapt to novel conditions, a variety of outcomes is expected. In some cases, exotic and native species may reach a stable equilibrium if resources are abundant and competitive interactions between the two are sufficient to maintain them close to equilibrium. In others, interactions between exotics and natives may result in competitive exclusion and displacement of the native species.
How do exotic species reach new localities?
Exotic species of plants and animals may reach new localities through deliberate introduction by humans or accidental introduction during transport. The rate of introductions both between and within continents is rising rapidly. The most obvious introductions into freshwater systems have been plants, both aquatic (e.g., water hyacinth) and riparian (e.g., salt cedar), and fish (e.g., carp). Few invertebrates have been introduced deliberately (e.g., opossum shrimp, crayfish), but many, especially crustaceans and mollusks, have been introduced accidentally (e.g., spiny and fishhook water fleas, zebra mussels).
What is indirect feeding competition?
Indirect feeding competition is another mechanism responsible for the decrease of native populations after introductions of exotic species. In Hawaii, the introduced house gecko ( H. frenatus) feeds on the same insects as the native gecko Lepidodactylus lugubris. However, the superior ability of H. frenatus to deplete insects rapidly, especially when these occur in clumps, mean reduced acquisition rates for L. lugubris and, in turn, imply reductions in body condition, fecundity, and survivorship of the native gecko.
How do exotic species affect the ecosystem?
Often, these species do well in their introduced range because of a combination of escape from natural predators and release from natural parasites or pathogens. The loss of parasites or pathogens could simply be related to the initial introduction of few hosts, which will not harbor all possible pathogens, or the initial density of hosts is too low to sustain transmission of directly transmitted organisms. Parasites with complex life cycles may lack required intermediate hosts or vectors to complete their life cycle. These phenomena have been well-studied; examples include the release of invasive European slugs from parasitic nematodes, Wolbachia in Argentine ants (Linepithema humile), and parasitic castrators of European green crabs (Carcinus maenas). Importantly, exotic species may introduce exotic pathogens that might be important to the health of native wildlife, domestic animals, or humans. These introductions have had devastating effects on some native ecosystems, such as the introduction of avian malaria (Plasmodium relictum) to Hawaiian birds, Myxobolus cerebralis to North American salmonids, exotic parasites to native Hawaiian fishes, and Toxoplasma gondii to numerous species and locations by domestic cats. 15 Conversely, introduced species may pick up pathogens from their introduced range that may or may not cause significant disease (e.g., Mycoplasma gallisepticum) in introduced populations of eastern house finches (Carpodacus mexicanus).19 Collectively, these examples illustrate that exotic species are often successful related to their escape from natural diseases, but may represent significant risks themselves because of the introduction of novel diseases to native fauna.
How does shipping affect freshwater?
Shipping is a major cause of introductions, moving species that are attached to ship hulls or contained in ballast water. There is also a long history of introductions, many accidental, of exotic commercial and sport fish species into lakes. These exotic fish, often larger and more aggressive than the native fish fauna, may eventually drive the local fish species to extinction. Aquatic plants, invertebrates, and disease organisms can also become aggressive exotics outside their normal range.
What is the invasive species in the Mediterranean?
In the Mediterranean, the invasive green alga Caulerpa taxifolia is outcompeting native algae species and reducing fish abundance. Because Caulerpa is used as a decorative plant in marine aquariums, this is an example of one negative human impact (the trade in aquarium and ornamental species) resulting in another. One solution would be to ban harmful invasive species from the aquarium trade and provide a list of noninvasive alternatives.
What are some examples of aquatic plants that can be introduced to the waterways?
Introduced aquatic plants, such as water hyacinth and alligator weed, may blanket the surfaces of lakes and rivers. Such blanketing may reduce water quality by causing deoxygenation or by reducing photosynthesis of native plankton and aquatic plants. This, in turn, diminishes food resources for native invertebrates. Introduced riparian plants, such as tamarisk or salt cedar, may cause the loss of habitat for native invertebrates by dominating the stream banks and often by reducing water levels in the channel. Other introduced plants, such as eucalypts in Spain and Portugal, may produce dead plant material that is not readily consumed by stream invertebrates, thereby causing them to starve.
What is an exotic species?
In biology, it is called an exotic species, an introduced species, a non-native species, a foreign species or a non-native species.
Examples of exotic species
The tiger salamander was introduced to the United States as bait for fishermen.
Environmental Impact
How Do They Get Here?
- Introductions of nonnative species can be planned, incidental, accidental, or unintentional. They can also be caused by a natural disaster. Scientists have made several attempts to identify the possible pathways of introduction, with varied success. The most common method of introduction into marine environments is through the ballast water of ship...
Extent of The Problem
- Every state in the United States and nearly all communities have been affected by bioinvaders. However, two states have been especially hard hit— Hawaii and Florida—and for similar reasons. Both states are geographically isolated and both have a semitropical-to-tropical climate.
Well Known Invaders
- Thousands of invasive species worldwide are notorious for their distinctive habits, destructive potential, or ecological damage. Other invaders seem to be having little environmental impact. A few of the more well-known exotic species in the United States are discussed here.