Exotic Species

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• Exotic Species
• Species invasions may profoundly affect
  ecosystems
• Definition?
• Criteria (Woods and Moriarty, 2001)
• Human introduction
• Direct vs. Indirect
• Intention?
• Is agency important?
• Evolution
• Native
• How much does a species have to change?
• Historical range
• Exotic
• How is a historical range determined/defined?
• Degradation
• How is harm defined? Some species harm help
• Community membership

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• Exotic Species
• Species invasions may affect ecosystems
  profoundly
• Detrimental exotic species usually are
• Superior competitors
• Ex European starling
• Effective predators
• Ex Cane toad

Distribution of cane toad in Australia Wikipedia
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• Exotic Species
• Zebra mussel
• Competitor in Great Lakes and elsewhere
• Transported from Europe in ballast water
• Fouling organism
• Restricts movement of water through intake pipes
• Colonizes boat hulls, pier pilings, buoys, etc.
• Fouls other organisms (clams, mussels)
• Filter feeder removes larvae and particulate
  material
• Outcompetes native shellfish species for food and
  space
• Removes larvae from water

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• Exotic Species
• Mongoose
• Predator in Hawaii, Caribbean, etc.
• Introduced to HI in 1883 to combat rats and
  snakes in sugar cane fields
• Reproduce early and rapidly
• Females can breed at 10 weeks, 2-3x a year,
  2-3 young per litter
• Prey on native birds, amphibians, reptiles

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Nile perch Lake Victoria
Brown tree snake - Guam
Argentine ants - California
Caulerpa taxifolia - California
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• Exotic Species
• May be especially detrimental to biodiversity and
  ecosystems when populations of keystone species
  are reduced or eliminated

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• Exotic Species
• Are all exotic species bad?
• What should we do about exotic species?
• Ex Eucalyptus in California