1. Invasive species
Coming soon to an ecosystem near you!

2. The Tens Rule
10% of introduced species escape
10% of escaped species become established
10% of established species become invasive

3. The Tens Rule
10% of introduced species escape
10% of escaped species become established
10% of established species become invasive
0.1% of species introduced become invasive

4. Exceptions
Crop plants, biocontrol agents
Ornamental trees and shrubs
Plantation species

5. Disturbance
How can disturbance
facilitate invasion?

6. Disturbance
How can disturbance
facilitate invasion?
reduce competition
increase resource
availability

8. difficulty of detection
exponential population growth
post-invasion evolution (local adaptation)
increased availability of favorable sites

10. Rare Species Narrow Geographic Range Small Population Size
Habitat Specificity

11. Invasive Species Broad Geographic Range Large Population Size
Wide Range of Habitats

12. Rapid dispersal: short generation time
long reproductive period
prolific seed production
successful dispersal
successful establishment

13. Lots of seeds!
multiflora rose
Japanese barberry
Oriental bittersweet

14. Long fruiting period
glossy buckthorn

15. Successful seedling establishment
Common buckthorn
(Rhamnus cathartica)

20. Ellsworth, Harrington & Fownes (2004)
4.5 m in 12 weeks!
2% sun
28% sun
100% sun

21. Impacts
Reduced population
size and biodiversity
of native species
Invasive species are the
second major cause of
extinctions globally
(main cause on islands)

24. Pale swallowwort
Cynanchum rossicum

28. Introduced mosquitoes spread avian malaria

29. Difficult to eradicate

36. Norway maple