Invasive facts for kids

An invasive species is a type of plant, animal, or other living thing that is not native to an area and causes harm when it is introduced there. These species can spread quickly and take over new environments. They often arrive in new places because of human activities, sometimes by accident and sometimes on purpose. Once established, they can cause big problems for the native plants and animals, and even for people.

What Are Invasive Species?

An invasive species is like a visitor that overstays its welcome and causes trouble. For a species to be called "invasive," it must meet two main conditions:

• It is non-native to the ecosystem. This means it did not naturally evolve or live in that specific area.
• It causes harm to the environment, economy, or human health. This harm can be to other plants, animals, or even how people live and work.

Not all non-native species are invasive. Many non-native species live peacefully in new places without causing problems. For example, many of the fruits and vegetables we eat, like apples or tomatoes, are not native to every place they are grown, but they are not invasive.

How Do Invasive Species Arrive?

Invasive species often travel to new places because of human activities. These journeys can be accidental or on purpose.

Accidental Introductions

Many invasive species arrive by accident.

• Shipping: Ships carry water in their ballast tanks to stay stable. This water can contain tiny organisms, fish, or plant seeds. When the ship releases the water in a new port, these creatures are set free.
• Travel: People can unknowingly carry seeds or insects on their clothes, shoes, or in their luggage when they travel.
• Packaging: Pests like insects can hide in wooden crates or packing materials used to ship goods around the world.

Intentional Introductions

Sometimes, people bring species to new areas on purpose, not realizing the danger.

• Gardening: People might plant beautiful non-native flowers or trees in their gardens. Some of these can escape and spread into wild areas.
• Pets: Releasing unwanted pets, like exotic fish or reptiles, into the wild can lead to them becoming invasive if they survive and reproduce.
• Agriculture: Farmers sometimes introduce non-native plants or animals to help with farming, like certain types of grass for cattle. These can sometimes spread beyond the farm.

Why Are Invasive Species a Problem?

Invasive species can cause serious damage to the environment and economy.

Environmental Harm

• Loss of native species: Invasive species often outcompete native plants and animals for food, water, and space. They might eat native species, destroy their habitats, or introduce diseases. This can lead to a decrease in native populations or even extinction.
• Changing habitats: Some invasive plants can change the soil, water, or fire patterns in an area. For example, an invasive grass might make fires more frequent and intense, harming native plants that are not used to such conditions.
• Reduced biodiversity: When native species disappear, the variety of life in an ecosystem shrinks. This makes the ecosystem less healthy and less able to handle changes or challenges.

Economic Harm

• Damage to agriculture: Invasive insects or weeds can destroy crops, costing farmers a lot of money.
• Infrastructure damage: Some invasive plants can clog waterways, damage pipes, or weaken building foundations.
• Tourism and recreation: Invasive species can harm fishing, boating, and other outdoor activities, affecting local economies that rely on tourism.

Health Risks

• Some invasive species can carry diseases that affect humans or livestock. For example, certain invasive mosquitoes can spread viruses.
• Invasive plants can sometimes cause allergic reactions or skin irritations.

What Can We Do About Invasive Species?

Controlling invasive species is a big challenge, but there are many ways to help.

Prevention

The best way to deal with invasive species is to prevent them from arriving in the first place.

• Be careful with plants: Choose native plants for your garden. Avoid planting non-native species that are known to be invasive.
• Clean your gear: If you hike, boat, or fish, clean your shoes, boats, and equipment to avoid spreading seeds or tiny organisms to new areas.
• Don't release pets: Never release unwanted pets into the wild. If you can no longer care for a pet, find a new home for it or contact an animal shelter.
• Buy local: When possible, buy firewood or plants from local sources to avoid moving pests from one region to another.

Control and Management

Once an invasive species is established, scientists and land managers work to control its spread.

• Manual removal: For plants, this might involve pulling them out by hand.
• Biological control: Introducing a natural enemy of the invasive species (like an insect that eats only that plant) can help control its population. This must be done very carefully to ensure the control agent does not become invasive itself.
• Chemical control: Using herbicides or pesticides can help, but this is often a last resort due to potential harm to other species.
• Habitat restoration: After removing invasive species, efforts are made to restore the native plants and animals to help the ecosystem recover.

Famous Examples of Invasive Species

Many places around the world have faced challenges with invasive species.

• Kudzu (plant): Introduced to the United States from Japan in the late 1800s, kudzu was promoted for erosion control. It grows incredibly fast, covering trees, buildings, and anything in its path, earning it the nickname "the vine that ate the South."
• Zebra Mussels (mollusk): These small freshwater mussels arrived in the Great Lakes of North America from Eastern Europe in the 1980s, likely in ship ballast water. They reproduce quickly and attach to surfaces, clogging pipes, damaging boats, and outcompeting native mussels for food.
• Burmese Python (reptile): Originally from Southeast Asia, these large snakes were brought to Florida as pets. Some escaped or were released, and they have established a breeding population in the Everglades. They are top predators and are severely impacting native wildlife populations, especially mammals and birds.
• Cane Toad (amphibian): Introduced to Australia from South America in 1935 to control sugarcane pests, the cane toad quickly became a major problem. They are poisonous at all life stages, harming native predators that try to eat them, and they compete with native amphibians for food.