Uploaded byKherlen Shinebayar
Alien species
The document outlines definitions and classifications of alien species, including non-native, domestic, and invasive species, highlighting their potential to spread disease and outcompete native species. It discusses the various vectors for species introduction and the economic costs associated with non-native species, estimated to exceed $136 billion annually. Furthermore, it explores hypotheses for the success of introduced species and the vulnerability of certain ecosystems to invasion.
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Alien species
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- 2. Definitions Introduced (non-native, exotic) -species introduced deliberately or accidentally from somewhere else Domestic/Feral (released pets, livestock and game animals) - can spread disease, compete with native species Human commensal or subsidized (out of control natives) - native species that benefit from our land use (disturbance) Invasive species - species that spread subsequent to establishment usually at some cost. 2
- 3. Nature of introductions Intentional Naturalization societies Economical gain Gameanimals Domestic animals Unintentional Ballasts of ships Unprocessed wood Fruit shipments By-pass natural barriers 3
- 4. Vectors of invasioninto ecosystems Intentional Release of Target Species into Containment Escapes from Zoos and Botanical Gardens Farmed Species Aquaculture Research Intentional Release of Target Species into the Environment Plants for Agriculture Plants for Forestry Plants for Soil Improvements (fire suppression, erosion control) Ornamental Plants Birds and Mammals for Hunting Biological Control Released Pets and Pet Trade 4
- 5. Vectors of invasioninto ecosystems Release of Non-Target Species (AKA “Accidental” Releases): Contaminants or Hitchhikers with Produce Contaminants or Hitchhikers with Ornamental Plants Contaminants or Hitchhikers with Aquaculture Timber Contaminants of Seed Stock Cars Planes Hitchhikers with Packing Material, Cargo Ballast in ships Hull Fouling Tourists, Luggage Canals 5
- 6. Why study biological invasions? Consequences Threatenbiodiversity Costly Widespread Unique opportunities for research Community ecology Animal behavior Evolution 6
- 7. Estimated annual costsassociated with non-native species Group Cost (in millions, US $) Plants 34,000 Mammals 37,000 Birds 2,000 Fishes 1,000 Anthropods 19,000 Mollusks 1,200 Microbes 41,000 All organisms over $136 billion per year 7
- 8. Hypotheses for thesuccess of introduced species • predators, parasites, disease Escape from natural enemies • outcompete native species Increased competitive ability Pre-adapted to disturbed environments 8
- 9. Characteristics of invasive species Generaldiet and habitat requirements High abundance Small body size High reproductive potential (r-strategy) Good competitors Social/gregarious 9
- 10. Stages of invasion Spread Establishment Opportunity(transport) 10
- 11. What makes certain ecosystemsmore vulnerable? Diverse, undisturbed communities have few invaders Disturbed habitat are full of invaders Human residential areas • many European species that are commensal with humans Islands • little history with competitors, predators, parasites, or diseases 11
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Editor's Notes
- #10 9