Your SlideShare is downloading. ×
  • Like
IS ecosystem effects
Upcoming SlideShare
Loading in...5

Thanks for flagging this SlideShare!

Oops! An error has occurred.


Now you can save presentations on your phone or tablet

Available for both IPhone and Android

Text the download link to your phone

Standard text messaging rates apply

IS ecosystem effects


Sample lecture presentation from HON 305, Global Environment, on ecosystem effects of invasive species.

Sample lecture presentation from HON 305, Global Environment, on ecosystem effects of invasive species.

Published in Education , Technology
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads


Total Views
On SlideShare
From Embeds
Number of Embeds



Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

    No notes for slide


  • 1. Ecosystem impacts of invasive species HON 305V Dr. Andersen
  • 2. Why do invasives become so abundant?● Competitive release: Kept in check by co- adapted competitors in native habitat● Release from natural enemies: Kept in check by “the 3 Ps” (predators, parasites, pathogens) in native habitat● Facilitation: Alter habitat to make it more favorable for themselves ● Allelopathy: Poison your neighbors ● Fire regimes: Burn your neighbors homes down
  • 3. Competitive release vs. natural enemy release● Ecologists have been debating the relative importance of competition vs. the 3 Ps since the 1950s● Still an active topic of research● Real answer seems to be “it depends”
  • 4. Allelopathy● Yellow starthistle (Centaurea solstitialis) native to Eastern Europe, highly invasive throughout the Western U.S.● Roots produce 8- hydroxyquinoline, toxic to plants that have not co- evolved with C. solstitialis
  • 5. Altered fire regimes● Cheatgrass (Bromus tectorum), native to Eurasia, now found throughout the Western U.S.● Creates dense stands of dry grass (i.e., fuel) in the hottest driest summer months● Natural grassland fire frequency in non-invaded areas about once every 60-100 years● Heavily invaded areas burn every 3-5 years● Native vegetation not adapted to this high fire frequency● Neither are native wildlife
  • 6. Effects on invaded habitats● The worst invasive plants can establish near-monocultures that displace native vegetation, and reduce habitat quality for native wildlife
  • 7. Back to the 3 Ps● Introduced predators can devastate native animal communities● Feral cats● Green tree snakes● Many of the worst offenders are fish
  • 8. Integrated strategy for combating invasive species● Prevent additional introductions through effective quarantine and regulation● Early detection and rapid response to new outbreaks● Control and management of established problem species through multiple means● Restoration and recovery of natural ecosystems
  • 9. Giant African Snail (Lissachatina fulica)● Voracious herbivore, major pest (and nuisance) in vegetable and fruit crops, and in gardens● Feeds on a broad range of host plants● Has established throughout Indo-Pacific, Caribbean, Brazil● Found in the U.S. in Florida and Hawaii
  • 10. Cane Toad (Rhinella marina)● Deliberately introduced into Australia in 1935 to control pest insects in sugarcane● Largest toad species● Eats everything● Toxic to anything that tries to eat it
  • 11. Feral pigs (Sus scrofa)● Originally native to Europe, Asia, and North Africa● Now found on all continents except Antarctica● Major problem in many areas, including (but not limited to) Australia, Hawaii, Texas● Carry many diseases of livestock and humans including ● Foot and mouth disease ● Brucellosis ● Leptospirosis ● Toxoplasmosis● Rooting and wallowing behavior damages native vegetation, may promote erosion● Opportunistic omnivores (they eat everything)● Impact water resources for wildlife
  • 12. House sparrow (Passer domesticus)● Native to Eurasia and North Africa● Now found throughout the U.S., and in many other parts of the world● Can out-compete native granivorous (seed-eating) birds● Known to evict many native birds from nests ● Swallows (here on campus) ● Woodpeckers ● Bluebirds ● Wrens ● Purple Martins
  • 13. Tree-of-heaven (Ailanthus altissima)● Native to Asia● Fast-growing, prolific seed- producer, aggressive root- sprouting; can sprout from fragments● Allelopathic● Thrives in poor soils, tolerates pollution● Can form dense stands and crowd out native vegetation● Roots can damage sidewalks and building foundations
  • 14. Giant Hogweed (Heracleum mantegazzianum)● Crowds out native species● Dies back in winter, thus can promote soil erosion● Produces toxic sap that can cause skin irritation and blindness● Established in Oregon, Washington, and Pennsylvania● British progressive-rock band Genesis (Phil Collins, Peter Gabriel) recorded a song about Giant Hogweed
  • 15. Garlic mustard (Alliaria petiolata)● Native to Europe, established in U.S. in th the 19 century● Aggressively competitive, allelopathic● Able to out-compete native forest-floor plants
  • 16. Russian olive (Eleagnus angustifolia)● Native to southern Europe and western Asia● Displaces native vegetation mainly but not exclusively in riparian (streamside) habitats● Can fix atmospheric nitrogen, shade tolerant● Forms dense stands● Provides poor habitat for native birds
  • 17. Water hyacinth (Eichhornia crassipes)● Native to tropical South America● Now found in North America, Asia, Australia, Africa, and New Zealand● In U.S. found throughout the southeast, and in California and Hawaii● Chokes waterways, leads to massive amounts of decaying vegetation and reduced flow; reduce dissolved oxygen levels, often leading to fish kills● Shade out other aquatic plants, as well as phytoplankton● Biological control promising● Can be used to make a wicker-like material that can be made into baskets or furniture● Used in World War II in Southeast Asia to fool Japanese pilots into thinking that lakes were open fields safe for landing
  • 18. ● Questions on the material?● Questions on any of the examples?● Remember competitive release, the 3 Ps, and facilitation. What are the implications of these three mechanisms for control of invasive species?● What kinds of adaptations might species have to cope with really high fire frequencies?● Invasive predators and herbivores can be especially devastating on islands. Can you think of reasons why this might be true?● What are the implications of so many widespread invasive species for our concept of “pristine nature”?● Observations on invasive species youve encountered?