Invasion Curve

The three typical phases of noxious weed invasion as the invasion progresses over time.

The Invasion Curve depicts the feasibility of eradicating an invasive plant, insect, or animal starting at the time the invasive species is introduced. Over time, the feasibility of eradication decreases until it is no longer possible.

Phase I (green):

The invasive species is introduced to an ecosystem.

Phase II (green-yellow):

The invasive is detected soon after its introduction making prevention and complete eradication possible if steps towards eradication are taken promptly. Public awareness usually begins later. If no action is taken before this point, eradication is unlikely and intense efforts are needed to eradicate and prevent further spreading of the invasive.

Phase III (orange-red):

The plant is detected too late or effective management plans are not implemented in time, making eradication impossible. This leaves local control and management as the only options.

Image from: Montana Science Partnership's Module on Plants and Pollinators

Last updated January 13, 2021