invasive species coming soon to an ecosystem near you!
TRANSCRIPT
Invasive species
Coming soon to an ecosystem near you!
The Tens Rule
10% of introduced species escape
10% of escaped species become established
10% of established species become invasive
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
Exceptions
Ornamental trees and shrubs
Plantation species
Crop plants, biocontrol agents
Disturbance
How can disturbance facilitate invasion?
Disturbance
How can disturbance facilitate invasion?
reduce competition
increase resourceavailability
• difficulty of detection
• exponential population growth
• post-invasion evolution (local adaptation)
• increased availability of favorable sites
Rare Species
Narrow Geographic Range
Small Population Size Habitat Specificity
Invasive Species
Broad Geographic Range
Large Population Size Wide Range of Habitats
Rapid dispersal: short generation time
long reproductive period
prolific seed production
successful dispersal
successful establishment
Lots of seeds!
multiflora rose
Japanese barberry
Oriental bittersweet
Long fruiting period
glossy buckthorn
Successful seedling establishment
Common buckthorn(Rhamnus cathartica)
2% sun 28% sun 100% sun
Ellsworth, Harrington & Fownes (2004)
4.5 m in 12 weeks!
Impacts
Reduced populationsize and biodiversityof native species
Invasive species are the second major cause ofextinctions globally(main cause on islands)
Pale swallowwortCynanchum rossicum
Introduced mosquitoes spread avian malaria
Difficult to eradicate
Norway maple
