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Why would humans introduce a species? • 1. Organisms are purposely released for establishment in the wild. • 2. Species transported into a new region may escape and establish in the wild.
Introduced Species • An introduced species is an organism that is not native and has been accidentally or deliberately transported by human activity. • Introduced species can often be damaging to the ecosystem it is introduced to.
Examples of Introduced/Invasive species • Rabbits, cats, frogs and foxes in Australia • Cats on the Galapagos Islands • Red squirrels and snowshoe hares on the island of Newfoundland • Plants like Kentucky Bluegrass, periwinkle, lily of the valley and the dandelion • Many of Canada’s exotic species are beneficial, but a great number of them are not when they become Invasive species.
Rabbits introduced into Australia Look what happens when there are no natural predators
Why Introduce an Organism? • Economic gain. • Recreational activities (fish and game animals) • Aesthetic reasons (flowers)
Invasive Species • An invasive species means the species causes economic or environmental harm or harm to human health.
When species compete to survive, invasive species have traits that allow them to out-compete native species. • This could be the ability to grow and reproduce more rapidly than native species
How Introduced and Invasive Species Relate • An introduced species becomes invasive if it can out compete native species • Or some species lack the competition and natural predators freeing them to flourish quickly.
Why are we concerned with Invasive Species? • Invasive species can cause the extinction of native species • Ecosystem destruction, habitat loss • Biodiversity loss, crop loss • Threats to human health • Costs of the removal of invasive species (in the billions)
Methods of Removal • Physical control: physically removing the species from its environment (pulling out unwanted plants, burning an area, snaring and trapping, and shooting unwanted animals). • Chemical control: pesticides, herbicides, fungicides, and other chemicals used to kill the target invasive species. Ex. poison to kill rats. • Biological control: parasites and disease are used to control the growth of invasive species.
Effectiveness of Methods of Removal • It is usually difficult to trace the places that species have been introduced accidentally. Accidental arrivals are rarely discovered until they become invasive. • Controlling invasive species is very difficult, sometimes impossible • Canadian Laws are in place to prohibit some species from entering the country.
What can we do to prevent invasive species?(write 2-3) • Do not release exotic plants or animals into the wild • Do not bring fruit, vegetables, plants or animals with you across international borders • Do not transport over long distances, firewood or other wood with bark attached • Learn which plant species are invasive and remove them from your gardens • Volunteer with local environmental organizations that work to maintain healthy ecosystems • Know where consumer products come from and buy from local sources whenever possible.
Key Questions • How and why are plant and animal species introduced into new areas (give at least 3 reasons)? • What are the three of the methods for removal of introduced/invasive species? • Consider some future problems that some removal methods might cause and discuss one of them. • List three of the things we can do to prevent introducing species to Canada.