1. Introduced and Invasive Species

2. Introduced species Also known as: nonnative, nonindigenous, alien, exotic Introductions can occur naturally, but now are driven primarily by human factors (esp. trade, travel)

3. From introduced to invasive Vast majority of introductions do not result in establishment of invasives However, repeated introductions can lead to invasions (European starlings were introduced 4 times) Propagule pressure

4. Ecological context Not just about species attributes Disturbance can reduce competition from native plans Nutrient availability Community diversity Enemy release hypothesis

5. Cozumel Thrasher

8. Invasives in Canada

9. Zebra mussel Originally native to Russia First detected in Great Lakes in 1988, near Detroit/Windsor Ballast water of ocean-going ships

10. 19922001 2010

12. Leafy Spurge

13. How do we reduce or manage species introductions?

14. Canada’s approach to Leafy Spurge Biological control: Sheep, Beetles Elbow Pasture, SK: 1200 sheep Reduced spurge density from 80-100 stems/m 2 to 20-50 stems/m 2 in a few years Cattle stocking 36% higher Beetles: down to 10% http://www4.agr.gc.ca/AAFC-AAC/display- afficher.do?id=1186596698988&lang=eng

15. Pragmatic approaches 1) Prevention

17. Pragmatic approaches 2) Eradication: shoot first, ask questions later video

18. Pragmatic approaches 3) Management -Chemical or biological control -Habitat modification -Manual removal -Problem: costs $$$ year after year

19. What about human values?

20. The Oatmeal’s Take Video