What are invasive alien species?
Invasive species are among the biggest threats to wildlife habitat, biodiversity, and the web of life. They can be a plant, animal, fish, bird, reptile, amphibian, invertebrate, even a disease. Alien species can include species that were originally found in one part of Canada but have now moved into another area, such as moose in Newfoundland, or they can come from outside of Canada, such as the pigeon. However, regardless of the species and where they came from, one thing is certain, alien species are overrunning our lands and waters and forcing native plants and animals out of their homes.
Alien species can be introduced legally or illegally, intentionally or accidentally. For instance, purple loosestrife was intentionally introduced from Europe during the 1800s as a garden ornamental plant and zebra mussels were accidentally introduced from the ballast water of ships.
Upon arrival, some aliens flourish
With no predators, parasites, diseases or competitors in their new environment, some aliens are left to flourish as they take over their new surroundings, eliminating native species populations, resulting in a loss of biodiversity and a changed ecosystem.
Invasive species can also have negative impacts on the economy with annual cumulative costs being conservatively estimated at more than $45 billion.
Society, including human health, is also impacted by alien species. One needs to look no further than to West Nile virus. This virus was first discovered in North America in 1999 and since then has resulted in the deaths of many people and wildlife.
Education is key in preventing the unintentional introductions of alien species. As such, CWF has taken a key role in producing education and awareness materials focusing on this issue. One of our National Wildlife Week kits brought attention to this issue, with the slogan “Native Species, Nature’s Choice.”
CWF developed an Invasive Species encyclopedia to help people discover which species are considered invasive, where they came from, their invasive range, how they were introduced and their ecological impacts.
CWF also produced a Native Plant Encyclopedia. This encyclopedia allows people to choose plants that are native to their province and to choose plants that will grow in specific conditions in their own backyard.
CWF supported the development of the national strategic plan, An Invasive Alien Species Strategy for Canada that was finalized in 2004.
By learning which species are invasive along with their impacts, we can all help in preventing their introductions.