How Do Introduced Species Affect Ecosystems and the Economy?

Did you know that aliens are among us? Alien species, that is. Scientists use the term native species to describe plants, insects and animals that originated in an area naturally, without human action. Native species live in specific areas because they need certain environmental conditions, resources and interactions with other species.

For example, we don’t expect to see elephants in the wild in Canada. But why? For one thing, elephants do not like to live in the cold conditions that occur during winters in Canada. Elephants are also very big and eat up to 150 kilograms of food a day! While Canada has lots of tasty food for Canadian animals, it doesn’t contain the food that elephants need. Elephants also play an important role in their native ecosystems. They clear out vegetation on plains and create new land for new plants to grow. Would an elephant be happy in Canada playing in the snow, far from its favourite foods? Probably not!

But what happens when a species ends up in an ecosystem? Aliens!

Alien organisms are organisms living outside of their natural range. They can be introduced into the new area through humans (introduced species) or by a change in the environment.

Let’s look at the relationship between humans and introduced species. How can human activities result in species introductions, and how can these introduced species affect human activities?

Can humans bring in alien species?

Humans can introduce alien organisms both on purpose and by accident. For example, some people may plant decorative plants in their gardens. This is an example of alien species that humans introduce intentionally. Meanwhile, some animals catch a free ride on various forms of transportation, such as boats. These are examples of alien species that humans introduce accidentally.

Did you know? 

Scientists believe zebra mussels arrived in Canada as stowaways on commercial ships! 

Climate Change and Introduced Species 

Species are also driven to extend outside their natural range because of climate change. Human activities (such as driving cars) are contributing to climate change, and temperatures are rising at a faster rate. Changes in temperatures can push creatures out of their original habitats, and they can also allow creatures to thrive in areas where they could not before.

For example, the mountain pine beetle originally lived only in western North America. But due to climate change, winters are milder and summers are warmer. The mountain pine beetle has now extended north in British Columbia and is extending eastward through the Boreal forest in Alberta. This beetle is also able to fly, so it’s able to reach new regions very easily.

Did you know? 

Northern leopard frogs are being threatened in British Columbia by American bullfrogs, which are native to Central and Eastern Canada.  As you can see, invasive species don’t necessarily have to come from another country! 

How do invasive species affect humans? 

When alien species threaten the native species around them we call them invasive. This can  happen when they act as predators, parasites or competitors for resources. Alien species don’t always directly affect humans. However, they can disrupt and damage ecosystems. This can also cause problems for human health and the economy.

For instance, the mountain pine beetle is native to BC but is moving east. It poses a threat to forest communities. Trees are damaged when female pine beetles make holes to lay their eggs inside the tree. When the eggs hatch, the larvae spend time feeding underneath the tree bark. Eventually, this leads to the death of the tree.

During the 1990s and early 2000s, mountain pine beetles damaged over 18 million hectares of forests in roughly ten years. That’s roughly 18 million football fields!

Did you know? 

In early 2019, parts of North America experienced a polar vortex. Many humans complained about colder than usual temperatures. However, the polar vortex may have killed off many invasive insects who weren’t adapted to survive in the extreme cold!

How to stop ecosystem invaders

The Canadian government has developed ways to help protect Canadian ecosystems from current and new invasive alien species. For example, technicians and border agents now inspect containers on ships and planes to make sure no alien species are hiding.

When alien species do get in, it’s important to detect them early on and remove them before they severely damage an ecosystem. For example, to help prevent the spread of the mountain pine beetle, forest management staff are burning trees that are infested with this species.

Did you know? 

Every now and then, an invasive species can be helpful. The samurai wasp in British Columbia kills the embryos of another invasive insect, the stink bug. 

Since native species often are not equipped to survive against alien species, it’s up to us humans to help protect our ecosystems from invaders! Check your boots after going hiking. Clean your dog after a walk. Buy local plants. Don’t move small animals in the wild from place to place. These are steps you can take to make sure you prevent the spread of aliens!