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17 Examples of Invasive Species

Invasive species vary in size and shape around the globe. Some small action like releasing a pet fish into the water or planting a foreign plant could wreak havoc on an ecosystem for centuries to come. In this article, we’ll look at some examples of invasive species along with some pictures. We’ll also find out how some of these species came to find a new habitat and how they are affecting their new home.

What is an Invasive Species?

An invasive species is a living organism that is introduced to a new ecosystem that it is not native to and causes harm. The invading species does not necessarily need to be from another country and is typically introduced, either intentionally or unintentionally, by human activity.

Now that we know what an invasive species is, let’s look at some examples of invasive species and the habitats that they have invaded upon.

17 Examples of Invasive Species

1. Burmese Pythons

Burmese Pythons are originally from Southeast Asia. They can grow up to 20 feet in length and are tan in color with Giraffe-like dark spots. These pythons are an invasive species in the Florida Everglades and arrived there as pets where they were either released or escaped.

They eat smaller animals like wood storks, Key Largo wood rats, and limpkins and larger animals like alligators and bobcats. Additionally, they are taking the food and space of other natural predators.

2. European Starlings

The European starling is native to Eurasia and North Africa, but when it comes to North America they are one of the most common examples of invasive species. They are robin-sized birds with slim beaks and plump bodies. In the winter they a brown with white spots and in the summer they get a purple-green iridescent hue. Their yellow beaks remain year-round.

The bird is invasive in all of North America, and they were brought here by Eugene Schiefflin, as Shakespeare Enthusiast, who was attempting to introduce the U.S. to all the types of birds in Shakespeare’s plays.

European Starlings are damaging in more than a few ways. They are the result of millions of dollars of lost crops such as grapes, cherries, blueberries, and even apples. In addition, they eat and defecate in cow feed, which spreads disease among cattle and humans alike.

3. Common Carp

The Common Carp, also known as the European Carp, is native to Europe and Asia. They have a long dorsal fin, large scales, and iconic whiskers on their upper jaw. Common carp are invasive across the entire World. They were introduced across the globe through various means; however, they were specifically introduced to the US as a solution for the demand for fresh fish.

This fish destroys natural habitats by reducing water clarity and destroying the habitats of native fish and amphibians. They uproot plants and release sediment drained nutrients causing algal flowers.

4. Red Lionfish

The Red Lionfish, also sometimes referred to as a Zebrafish, is a venomous, coral reef fish that has red, white, and brown stripes. The fish is native to the South Pacific Reef but has become invasive in the Caribbean, Eastern United States, and East Mediterranean.

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Scientists believe that the fish became invasive as a result of people dumping their unwanted aquarium fish into the ocean. Red lionfish are harmful to their invasive habitats because they kill key species of fish that clean algae off of coral. As a result, the reefs that they inhabit begin to decline.

5. Wild boar

A wild boar is a type of wild pig that’s native to Eurasia and North Africa. They have quickly become one of the widest spread mammals on Earth and are invasive in Oceania and North America.

Domesticated wild boars were brought from their native lands as a new type of food source. However, they either escaped or were released and quickly adapted to their new environments. Wild boar damage native plant species, take resources from competing predators, and even spread disease among humans and animals alike.

6. Northern Snakehead

image: Brian Gratwicke | CC 2.0 | Flickr

Northern snakeheads have a long single dorsal fin, are brownish in color with large splotches, and have flattened heads that are similar to a snake. They are native to China, Russia, and Korea and have become a serious problem in several US States.

Northern Snakeheads entered US waters as a method of prayer release. Some eastern cultures believe that if you purchase an animal and then release it, then you will earn merit with a deity. The concern over the invasive fish is that it spreads bacteria that may be harmful to humans and also attacks other fish that humans use as a food source.

7. Cane Toad

The Cane Toad, also known as the giant or marine toad, are typically grayish-brown in color and have a lot of large dark brown warts scattered across their body. They are Native to South and Central America.

Cane toads are an invasive species in Florida and Australia. They were intentionally introduced in both locations to control pests that damaged sugar cane crops. The toads are a large problem for pets and wild animals that try to eat them as they are poisonous.

8. Brown Rat

The brown rat, also known as the common rat, is a gray or brown rodent that is much larger than the black rat and the house mouse. The brown rat is a native of Central Asia.

Brown rats spread throughout the entire world during the 18th century via trade ships conducting international trade. They can now be found on every continent with the exception of Antarctica. While brown rats can spread disease and damage your main home systems, they have been integrated into non-native habitats for so long they don’t do much damage.

9. Kudzu

Kudzu is the first plant species on our list and has been referred to as “the vine that ate the south.” This oriental vine originated in Southeast Asia.

The plant was brought over to the US in the 1860s and was touted as a beautiful ornamental plant. Starting in the 1930s it was planted heavily as a potential tool for erosion control. The problem that remains to this day is that Kudzu grows faster than almost every other plant. Therefore it prevents biodiversity by limiting the growth of other plant species.

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10. Nile Crocodile

The Nile crocodile is a large reptile with olive-green skin and a rough, scaly hide. This crocodile is native to Africa and prefers rivers, marshes, estuaries, and swamps.

The Nile crocodile has been found in the Florida Everglades, but it is believed that the majority of the species has been captured and is not reproducing in its invasive habitat. If the Nile crocodile was to remain in Florida and intermix with the American crocodile it could threaten the American crocodile species as well as produce a larger, more dangerous crocodile.

11. Africanized bees

Africanized bees, also known as killer bees for their determination when excited or agitated, look almost identical to honey bees, except that they are slightly smaller. These bees are native to Africa and Eastern Europe and are the result of crossbreeding between the East African lowland honey bee and various European Honey Bees.

Africanized bees were brought to Brazil in 1956 to introduce a bee that could survive in the tropical climate. They have since spread all the way to North America. Despite their nickname, these bees don’t pose a real threat to humans. They threaten domestic bee populations by competing for resources that both species require.

12. Brown Tree Snake

The Brown tree snake has a long slender body with a head that is noticeably wider than its body. It is native to the Solomon Islands, Indonesia, New Guinea, and Australia.

image by U.S. Department of Agriculture via Flickr | CC BY 2.0

The snake has invaded and reproduced on the island of Guam and has been sighted in the states of Hawaii, Texas, and Oklahoma. Brown tree snakes were probably was introduced to Guma via US transports during WWII. The snake is a huge problem in Guam as it has killed almost all of the island’s native bird species.

13. Zebra Mussel

The Zebra Mussel is a small, freshwater mollusk known for its zig-zag zebra-like markings. The mussel is native to Southern Russia and the Ukraine.

source: U.S. Department of Agriculture

The mussel has been introduced around the world but is a particular problem in the Great Lakes region of the US. It is believed that the zebra mussel has been introduced to various non-native waterways via ballast water discharged by European ships. The mussels cause a whole host of issues as they eat algae that other animals need to survive, attach to other mussels, and absorb dangerous chemicals that are passed up the food chain.

14. Emerald Ash Borer

Emerald Ash Borer Adult
Emerald Ash Borer Adult | Image by City of Boulder Forest Service via Flickr

The Emerald Ash Borer is a green beetle that feeds on Ash trees. This beetle is native to Asia but found its way into North America and has been wreaking havoc. It’s not one of the first examples of invasive species you think of, but it’s made an imprint in several ways.

This species is invasive in the United States and Eastern Europe. It is believed that the beetle was spread from China on wooden packing materials. The larvae of the borer feed on the inner bark of the Ash tree and can significantly disrupt the flow of water and nutrients to the tree, ultimately killing it.

15. Giant African Snail

The Giant African Snail is about 20 centimeters in length and is identified by its conical-shaped shell that is twice as high as it is wide. This snail is native to East Africa.

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The snail has been introduced to eastern Asia, South America, the West Indies, and parts of North America. They have been introduced to new locations by accidentally being imported with agricultural products or even as pets. This mollusk is one of the most damaging snails in the world as it can eat 500 different plants and even cause meningitis in humans.

16. Rusty Crayfish

image by Cgoldsmith1 via Wikimedia Commons | BY-SA 3.0

A rusty crayfish is a reddish-brown crustacean that prefers to inhabit freshwater with rocks. Rusty crayfish are native to the waters of the southern United States.

These crustaceans are invasive to Minnesota and Wisconsin. They were introduced by fishermen trying to use them as bait. Rusty crayfish negatively impact the ecosystem in their invasive habitats by eating small fish and larger fish’s eggs.

17. Green Iguanas

Green iguanas typically have green, leathery scales and are one of the largest iguanas in the Americas. They are native to South and Central America as well as parts of the Caribbean.

Green iguanas are invasive to Florida. They were introduced to the area by illegal animal dealers in the early 1960s. The iguanas cause huge infrastructure issues as they damage the integrity of pools, housing foundations, sidewalks, and roads by digging lengthy tunnels.

Green iguanas are now one of the first examples of invasive species that I think of since a recent trip to South Florida, they were everywhere!