What are Invasive Species?

What are invasives species?
Invasive species can be plants, animals, and other organisms (e.g., microbes). To learn more, see our Species Profiles which provides general information about species considered to be invasive.

How are invasives species spread?
Invasive species can be introduced to an area by ship ballast water, firewood, accidental release, and by people. Human actions are the primary means of invasive species introductions. See our Pathways page to learn more about how invasive species are introduced to new areas.

What are the impacts of invasive species?
Invasive species can lead to the extinction of native plants and animals, destroy biodiversity, and permanently alter habitats. See our impacts section to learn more about the impacts of invasive species.

How are invasive species defined?
As per Executive Order 13112 (Section 1. Definitions) an "invasive species" is a species that is:

1) non-native (or alien) to the ecosystem under consideration and

2) whose introduction causes or is likely to cause economic or environmental harm or harm to human health.

See also: Invasive Species Definition Clarification and Guidance White Paper (2006)
Submitted by the Definitions Subcommittee of the Invasive Species Advisory Committee (ISAC), Approved by ISAC Apr 27, 2006.
Provides a non-regulatory policy interpretation of the term "invasive species"