Shipping-crate wood and packing materials may also contain unwanted species, such as insects. About half of the alien shellfish species in Canada, including the highly invasive zebra mussel, probably arrived in North America in this way. For example, many unwanted aliens arrive in ballast water, the seawater or freshwater used to stabilize large ships during travel aquatic species are taken up along with ballast water at one port and released at the destination port. Accidental arrivals are rarely discovered until they have become invasive and spread some distance from their point of entry. It is more difficult to trace the pathways of species that have been introduced accidentally than it is those introduced intentionally. Unfortunately, even when programs are in place to monitor and contain imported species, the effects the species can have on the environment if they accidentally escape from their intended habitat is not always considered. A variety of legislation regulates the importation of alien species into Canada and their movement once they are in the country. Today, alien species are still being imported intentionally into Canada from around the world for use in many areas, from agriculture and horticulture to the pet trade to medical and scientific research. Without meaning to, they also introduced unwanted organisms-pests, like the Norway rat, and viruses, like deadly influenza and smallpox. They brought cattle, goats, and other domestic animals, along with familiar crops like wheat, when they came by ship to explore and settle the New World. Seafaring European explorers and settlers were the first to introduce new species to Canada. Sometimes they are brought in on purpose, but often they arrive unintentionally. Source of invasives Where do they come from and how do they get here?Īlien species come into Canada by any means of transport that moves them farther than they could move on their own. The harm they cause to the environment, the economy, or human health can be costly and sometimes irreversible. Sometimes the conditions are right for alien species to become invasive-they move into new habitats and take over, their populations sometimes expanding beyond control. Many of Canada’s alien species are beneficial, but a great number are not. And the House Finch, which originated in several western provinces, is now found in a number of provinces in the east. The bullfrog is native to some provinces, but is an alien species in British Columbia. The familiar moose, for example, is native to most parts of the country, but is an introduced species on the island of Newfoundland, as are the red squirrel and the snowshoe hare. There are also many examples of species from one part of Canada that have taken up residence in another. Potatoes came originally from the South American Andes, corn from Mexico, and wheat from Africa and the Middle East. Even many of the foods you eat originated in other countries. And the pigeon and the European Starling, birds commonly seen in Canadian cities, both came from Europe. The domestic cat is thought to have originated in Africa. For example, lawns and gardens are made up mostly of alien species, including Kentucky bluegrass, periwinkle, lily of the valley, and even the unwanted dandelion. You are already well acquainted with some alien, or non-native, species. These aliens are any species that has spread beyond its natural range into new locations as a result of human activity. They include species native to one part of Canada that move to another region of the country, as well as those that come from outside the country. They can belong to any of the categories of organisms in the world, including plants, mammals, birds, reptiles, amphibians, invertebrates, and micro-organisms. These organisms are found nearly everywhere in Canada. are one of the main threats to biodiversityĬanada is being invaded by aliens, but not by the type you see in science fiction movies.are brought into Canada accidentally and intentionally.Video & Sound Invasive Alien Species (30 seconds) Invasive Alien Species (60 seconds) Related Links Curb Aquatic Exotics Join Forces Against the Alien Invasion Species at Risk in Canada Lesson Plans