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INTRODUCED SPECIES

http://www.sprl.umich.edu/GCL/notes2/introspp.html. INTRODUCED SPECIES. DEFINITIONS. A BIOLOGICAL INVASION is when a species arrives in an area in which it was previously not found. An EXOTIC SPECIES is an organism that has invaded an ecosystem in which it did not evolve.

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INTRODUCED SPECIES

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  1. http://www.sprl.umich.edu/GCL/notes2/introspp.html INTRODUCED SPECIES

  2. DEFINITIONS A BIOLOGICAL INVASION is when a species arrives in an area in which it was previously not found. An EXOTIC SPECIES is an organism that has invaded an ecosystem in which it did not evolve.

  3. Of 100 introduced species... • @ least 10 will successfully colonize • 5 will naturalize • 2-3 will spread and become pests

  4. Of over 1000 fish in the US, CA, and MX... • 3% have gone extinct in the past 100 years while another 26% are endangered. Reasons for their decline are: • habitat destruction 73% • introduced species 68% • pollution 38% • hybridization 38% • overharvesting 15%

  5. Percentages of introduced species in... • Australia 10% • Canada 28% • Hawaii 18% • France 11% • New Zealand 47% • Spain 15%

  6. Why high numbers in these places? • geographic isolation • large amounts of human produced habitat • large amounts of tropical/sub-trop habitat • travel centers

  7. Reasons for Intentional Introduction • agriculture • ornamental • hunting and sport • biotechnology • scientific research • pet trade

  8. Causes of Accidental Introduction • ships • air travel • hitchhiking seeds • escapes from agriculture • side effects of habitat alteration

  9. Ecological Impacts • disease transmissions (smallpox, rabies) • disruption of the food web, predator-prey interactions • homogenization of the world’s biota: loss of biodiversity • extinction

  10. Ecological Impacts • hybridization • outcompetition • direct predation (domestic cat, brown tree snake) • disruption of the ecosystem (increased fire, N-fixing, change in water table) • plant pathogens (Ex. Chestnut blight)

  11. Characteristics of successful invaders • pioneer species • human commensal • prey generalist • habitat generalist • single parent reproduction

  12. What makes something invasive? • Not native • Is able to survive and reproduce • Does something destructive to the environment

  13. SOLUTIONS • PREVENTION • inspection at travel centers • regulations/policies • CONTROL • shooting and trapping • mechanical removal of plants • pesticides • biological control

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