Battling for biodiversity: the fight against invasive alien species

They come in all shapes and sizes, but invasive alien species (IAS) all have one thing in common: they are one of the biggest threats to biodiversity, second only to habitat loss.

IAS are also a major threat to our economy. They can cause billions of dollars of damage each year. Consequences include lost revenue to the agricultural and forest industries and trade restrictions.

May 22 marks the International Day for Biodiversity, which, among other things, focuses on the causes and impacts of IAS.  Along with Canada, other member countries of the Convention on Biological Diversity are taking action to reduce the rate of biodiversity loss resulting from IAS and other factors as part of the Convention’s target for the 2010 International Year of Biodiversity.

The price of IAS

Alien species are plants, animals or other organisms that have been moved outside their natural range by humans.

An alien species becomes invasive by successfully out-competing other organisms for food and habitat, spreading through its new environment, and increasing its population, causing harm to the ecosystem.  Alien species can have an advantage over native species if they arrive in a new environment without their natural predators and pests.

Invasive alien species cause economic, social and environmental harm, and they can also affect human health.  

The economic damage from IAS in Canada is staggering.  Between $13 billion and $35 billion has been lost annually as a result of the damage done by 16 invasive alien species, according to Canada’s Invasive Aliens Species Strategy.

The strategy indicates the impacts of IAS on the agricultural and forestry industries in Canada result in an estimated $7.5 billion loss every year. Invasive alien species can also result in trade restrictions imposed by foreign countries, which can disrupt billions of dollars in trade.

Invasive Alien Species in Canada…

Across the country, our ecosystems are feeling the effects of IAS.

On Vancouver Island, mud snails from New Zealand compete with native snails for food, and there is concern that the species has displaced local fish populations. This species, which has no natural enemies in North America, was most likely introduced by boating practices.  It has also been found in Idaho, the San Francisco Bay area and other American states.

The emerald ash borer is an invasive beetle found in Ontario that destroys ash trees. It can destroy a healthy tree within one to two years.  This species is believed to have entered the United States through infested wood packing crates or pallets from China.  It spreads slowly on its own, but is helped when people convert dead trees into firewood and move them to a new location.

Zebra mussels, native to the Caspian and Black Seas, were likely introduced to the Great Lakes through ballast water discharged by an ocean-going vessel from Europe that passed through the St. Lawrence Seaway.  Zebra mussels have significantly changed the lake bottom, food networks and fish habitat and spawning.  Any boat that takes in water from a zebra mussel-infested area becomes a carrier of their larvae, making it easy for them to move to new locations and cause more damage. And they are just one of over 180 invasive species now thriving in the Great Lakes!

These species – along with many others, from European fire ants to giant hogweed – pose a significant threat to our health and our environment.

…and the fight to keep them out!

When it comes to fighting the effects of IAS in Canada and around the world, prevention is the key.

Governments develop new control methods, study how new species interact with their new environment, conduct customs checks, inspect shipments, conduct risk assessments, regulate ballast water, develop international standards and set quarantine regulations that limit the entry of IAS.

Canada’s Invasive Aliens Species Strategy works to prevent invasions of new alien species, detect invasions that have already occurred, and to manage established IAS populations in order to protect Canada’s ecosystems and biodiversity.

Here’s how you can do your part to help prevent further invasions:

• Don’t bring fruit, vegetables, plants, or animals with you across international borders. Be cautious about what you carry across interprovincial borders.
• Before taking a recreational trip, inspect and clean fishing equipment, boats, trailers, recreational vehicles, and other items that may harbour IAS.
• Learn which plant species are invasive, and remove them from your garden.
• Keep natural habitats on your property healthy.
• Know where consumer products come from. Buy from local sources where possible.

Learn more about what you can do here.