I. I.Exotic Species Species invasions may profoundly affect ecosystems Definition? Criteria (Woods...
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Transcript of I. I.Exotic Species Species invasions may profoundly affect ecosystems Definition? Criteria (Woods...
![Page 1: I. I.Exotic Species Species invasions may profoundly affect ecosystems Definition? Criteria (Woods and Moriarty, 2001) 1. 1.Human introduction Direct vs.](https://reader038.fdocuments.in/reader038/viewer/2022110205/56649c885503460f949414eb/html5/thumbnails/1.jpg)
I. Exotic Species
• Species invasions may profoundly affect ecosystems• Definition?
• Criteria (Woods and Moriarty, 2001)1. Human introduction
• Direct vs. Indirect• Intention?• Is agency important?
2. Evolution• “Native”• How much does a species have to change?
3. Historical range• “Exotic”• How is a historical range determined/defined?
4. Degradation• How is “harm” defined? Some species harm & help
5. Community membership• What defines a “community”?
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I. 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 AustraliaWikipedia
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I. Exotic Species
A. 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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I. Exotic Species
B. 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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I. Exotic Species
• May be especially detrimental to biodiversity and ecosystems when populations of keystone species are reduced or eliminated
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I. Exotic Species
• Are all exotic species bad?
• What should we do about exotic species?
• Ex: Eucalyptus in California