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 resource availability

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

Rare Species Narrow Geographic Range Small Population SizeHabitat Specificity

Invasive Species Broad Geographic Range Large Population SizeWide 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% sun28% sun100% sun Ellsworth, Harrington & Fownes (2004) 4.5 m in 12 weeks!

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

Pale swallowwort Cynanchum rossicum

Introduced mosquitoes spread avian malaria

Difficult to eradicate

Norway maple