Invasive species are non-native organisms that outcompete native species when introduced to a new environment. They can be animals, plants, or disease-causing organisms. These species often have no natural predators in their new environment and can quickly spread, causing harm to the local ecosystem.
Invasive species can cause economic damage to agriculture and forestry industries, as well as pose a threat to human health. They can also negatively impact recreation and tourism, especially in lakes, where they can impact boating, fishing, and swimming.
Native, non-native, nuisance, and invasive species
When discussing invasive species, several different terms are used, which can be confusing. You’ll often hear the terms native, nuisance, non-native, and invasive species, but what do these mean?
Native Species
Native species evolved and developed in their current environment along with other native species. They often have native predators and other environmental controls that keep their populations in check or balance. These species have been present in the environment for a long time. They may also be referred to as indigenous species.
Non-native Species
Non-native species have been introduced to a new environment from another location. Not all non-native species cause significant harm or problems in the environment. For example, tomatoes are a non-native plant species, but they are not running rampant through the environment, outcompeting native plants. Non-native species may also be referred to as introduced species.
Nuisance Species
Nuisance species can either be native or non-native, though they do cause ecological, economic, or environmental harm. In some cases, native wildlife such as the Canada goose is considered a nuisance species because they congregate on lawns, and their feces can cause water quality to degrade. Native plants such as poison ivy can also be considered nuisance species. Finally, some non-native fish species, such as smallmouth bass, may be considered a nuisance species rather than an invasive species because they are valued by anglers and cause less environmental harm.
Invasive Species
Invasive species are non-native species that outcompete native species when introduced to a new environment. They often lack natural controls on their populations, such as predators, diseases, and pathogens. Invasive species cause economic or environmental harm when established in a new environment.
How can you tell if an organism is an invasive species?
There is no single characteristic that defines an invasive species. However, they often have certain traits that make them well-suited to invade new ecosystems. These include a high reproductive rate, rapid growth, and the ability to disperse widely. Invasive species may also lack natural predators in their new environment, which can allow them to proliferate unchecked.
If you suspect that an organism may be an invasive species, the best course of action is to contact your local invasive species management authority. They will be able to confirm whether the organism is on any invasive species lists and provide advice on how to deal with it.
How invasive species are introduced to the environment
Invasive species can enter our ecosystems in several ways. They may be introduced deliberately, for example, by releasing pet fish into lakes or cultivating ornamental plants in gardens. However, accidental introductions also occur when ships discharge ballast water into port or when animals escape from captivity. Once released into the environment, it can be extremely difficult to control invasive species.
In lakes, aquatic invasive species are often introduced unintentionally by hitching a ride on boats as they are moved from one lake to another. Fragments of invasive plants can get caught on trailers, motors, or other parts of a boat. Similarly, small invasive animals can persist in water at the bottom of a boat, live wells, bait buckets, and compartments inside a motor.
Environmental impact of invasive species
Invasive species are a major global threat to biodiversity and the environment. These organisms can have a devastating impact on ecosystems, often outcompeting or displacing native species. Additionally, many native species have not evolved defenses against invasive species. They are one of the leading causes of species extinction and reducing biodiversity.
Some invasive species can permanently alter habitats in which they become established. For example, zebra mussels can smother native plants, increase water clarity, and change lake nutrient cycling.
Invasive species are also one of the leading causes of the declines in native fish populations. A textbook example is the impact of invasive lake trout on native Yellowstone cutthroat trout. Not only are the lake trout affecting aquatic organisms, but native wildlife such as osprey, bald eagles, and grizzly bears are also being impacted.
Economic impact of invasive species
The economic impacts of invasive species are also significant. In agriculture, they can damage crops and livestock, leading to losses in productivity. Within the forestry industry, invasive insects can cause tree mortality and degrade timber quality. In lakes, invasive plants and animals can impact water filtration systems, recreational use of a lake, native fish populations, and property values. And in natural ecosystems, invasive species can alter food webs and disrupt vital ecological processes.
The estimated damage of invasive species across the planet is more than $1.4 trillion US dollars. In the United States, the estimated annual economic cost of invasive species ranges from $26 to $200 billion. On a smaller scale, many lake associations spend tens to hundreds of thousands of dollars each year to manage invasive plant species and on spread prevention.
Managing invasive species
There are many challenges associated with managing invasive species. Early detection and rapid response are critical to preventing their establishment. Once established, controlling and eradicating invasive species can be very difficult and costly. Eradicating invasive species is often difficult and expensive, and sometimes impossible. Instead, management strategies typically focus on controlling invasive species populations and preventing their spread to new areas.
Several strategies can be employed to control invasive species:
Manual Removal
Some invasive species can be removed by hand, especially if the infestation is small and they have not spread to other areas. Invasive plants like purple loosestrife can easily be pulled from the ground. In aquatic environments, plants like Eurasian watermilfoil can be manually removed by divers.
Physical Alteration
Physical alteration to the local environment can be used to kill certain invasive species. Matting or mulching can be used to control invasive terrestrial plants like phragmites. If a lake or pond has a dam that fully controls the height of the water, draining can be effective at killing invasive plants or fish. Conversely, flooding can be used to control invasive terrestrial plants. Prescribed burns can also control invasive pest species like insects and plants.
Mechanical Removal
Mechanical removal is similar to manual removal but with the aid of machinery. Mowing, tilling, and girdling are all examples of mechanical control. These techniques are most often used with plants and can be applied to terrestrial and aquatic environments.
Chemical Controls
Herbicides, pesticides, and insecticides are commonly used to manage invasive species. For example, glysophate injections are commonly used on Japanese knotweed. Chemical controls often require a great deal of planning and permitting due to the potential to affect non-target species and the possibility of other environmental impacts.
Biological Controls
Many non-native species become invasive because of a lake of natural predators or controls. Introducing an additional species that selectively predate upon the invasive species being managed can be very cost-effective. Though, a great deal of study is needed before introducing a biological control to ensure the new organism doesn’t have negative affects on native species.
Cultural Controls
One of the most effective methods for controlling invasive species is to educate the public about spread prevention measures they can take. These can include limiting the transport of firewood, only planting native species in gardens, not releasing fish or other animals into the environment, and following clean, drain, dry protocols when launching their boat.
Farmers can also use cultural controls to control invasive species by modifying their farming practices. This can include planting pest-resistant crops, moving planting dates, and using cover crops.
Managing invasive species is a significant challenge for conservationists and natural resource managers. Often managers have to utilize various control and management tools to effectively control an invasive species. To prevent or control their spread, we need to take a multi-pronged approach that includes both prevention and management strategies.
Preventing the spread of invasive species
Prevention is key, and this means keeping invasive species out of our ecosystems in the first place. This can be done by increasing biosecurity at borders, better regulating the pet and plant trade, and increasing public awareness of the issue.
Public education and awareness are among the most cost-effective methods for preventing the spread of invasive species. Once people understand the impact that invasive species have on local species, they will often support efforts to prevent their introduction and spread. The Stop Aquatic Hitchhikers, Clean, Drain, Dry, and Don’tMoveFirewood.org are great examples of effective national campaigns to increase awareness of invasive species spread prevention.
State and federal governments regulate the introduction and sale of many non-native species within their borders. These regulations are meant to limit the intentional or unintentional introduction of invasive species. These regulations may include measures related to the transport of motor boats between lakes that are aimed at reducing the spread of invasive species between water bodies.
The Great Lakes region is a hotbed for invasive species because of international shipping traffic that enters the region through the St. Lawrence Seaway. Ships making trans-Atlantic crossings often pick up ballast water in their home ports before departing. This water can contain non-native species and has been a major vector for invasive species introductions into the United States. The National Invasive Species Act, passed by the United States government in 1996, requires all ships entering the Seaway to exchange their ballast water with salt water while at sea to prevent the introduction of invasive species. This is one example of biosecurity efforts that can be taken at a nation’s borders to prevent invasive species from entering a country.
Early detection and rapid response
Natural resource managers often focus on early detection and rapid response (EDRR) when planning to prevent and manage invasive species. This approach attempts to cut off an invasive species early on in the “invasion curve,” a concept that characterizes the progression of an invasive species in an environment in terms of area occupied, management costs, and realistic management outcomes.
The goal of early detection and rapid response is to detect new infestations of an invasive species early enough that eradication is possible. Once an invasive species becomes established, eradication becomes increasingly difficult, and management costs quickly rise. Furthermore, eradication’s cost savings are often seen when considering that long-term financial investment is needed for containment or long-term control.
Invasive species management authorities often employ EDDR teams focused on prevention and eradication. In addition, volunteers and community groups can get involved through invasive species monitoring efforts.
Case studies of some of the most notorious invasive species around the world
There are many invasive species that have caused significant damage to ecosystems around the world. Here are three of the most notorious:
– The Asian carp is a species of freshwater fish that was introduced to North America in the 1970s. Since then, it has spread rapidly across the continent, outcompeting native fish species and disrupting aquatic food webs.
– The brown tree snake is native to Australasia but was accidentally introduced to the island of Guam in the 1940s. It has since decimated the native bird population, causing several species to become extinct.
– The zebra mussel is a small freshwater mollusc that was introduced to North America in the 1980s. It has spread throughout the Great Lakes and other freshwater systems, clogging water intake pipes and causing economic damage.
These invasive species have caused great harm to the ecosystems they have invaded. However, with early detection and rapid response, it is possible to control their spread and minimize the damage they cause.
Conclusions
Conclusion paragraph: Invasive species are a major threat to biodiversity, and it is important to prevent their introduction and spread. By following the spread prevention measures we’ve outlined, you can help us keep our ecosystems healthy and functioning.
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Invasive Species Overviews
Learn more about individual invasive species:
