Invasive Species | EdZOOcating Adventures

Visit our EdZOOcating Adventures website to start your free trial to access the full "Invasive Species" lesson, including quizzes, activities, and so much more!

---

Ecosystems are filled with amazing organisms. Plants, animals, and fungi that keep the ecosystem balanced and healthy.

But what would happen if an organism got there that… wasn’t supposed to be there? We call these organisms invasive species.

An invasive species is an organism that is introduced to an area it is not native to. Invasive species can be plants, animals, or fungi and they often cause problems in the ecosystems they’ve been introduced to. Today, we are going to focus on animals.

How do invasive species get to new places?

Invasive species can reach new places both on purpose and on accident. And sometimes, we don’t know for sure how they were introduced, but we can make hypotheses.

Cane toads were introduced to Australia almost 100 years ago on purpose! Australia was having a problem with beetles eating sugar cane crops. They introduced cane toads, which are native to Central and South America, to eat the beetles to protect the crops! Cane toads are not picky eaters and are many small native animals as their population grew and grew.They outcompeted native toads and reduced the population of native species.

Burmese pythons were introduced to Florida by accident! There are many hypotheses about how Burmese pythons got from their native range of Asia to Florida. Scientists hypothesize that many pythons were released by pet owners who could no longer care for the large snakes. Large storms frequently hit Florida and have previously destroyed snake breeding centers, releasing snakes into the wild where they began to thrive.

So now we know how invasive species get to new places, let’s talk about the problems they create!

Eating native species
-Brown tree snakes are native to Australia and the surrounding islands. Scientists hypothesize they were introduced to the small island of Guam when they stowed away on a cargo ship. Prior to the arrival of brown tree snakes, native birds had very few predators and very few predator-defense adaptations. Brown tree snakes fed heavily on native birds and have even caused some endemic species to become extinct.

Out-competing native species
-American bullfrogs are native to the eastern United States but were introduced to the West in the late 1800s to control populations of insects. They are large, powerful carnivores. They have out-competed many native amphibians and have caused many to become endangered.

They can even physically change the environment
-Nutrias are native to wetlands of South America but have been introduced to several continents due to the fur market. They feed on aquatic plants. The roots of these plants keep soil in place. When nutrias feed on the plants, they loosen the soil, causing the wetland to become unstable.

For some species, their populations can grow out of control, especially if they have no predators in their introduced range. Venomous lionfish have no natural predators in the Caribbean where they are invasive. They were likely introduced by people who no longer wanted them in their home aquariums. They are powerful predators and, as their population grows larger and larger, they feed on more and more native species.

Scientists use many methods to control invasive species.

Physical: They promote hunting of invasive species to reduce their population size in introduced ecosystems. Burmese pythons and lionfish.

Chemical: Pesticides or other chemicals can be used to remove invasive species, as well. Scientists attempted to remove brown trees snakes from Guam by dropping poisoned rats for them to eat!

You can help prevent the spread of invasive species by following rules and regulations when traveling and by not releasing pets into the wild.