Topics Overview

Invasive Species

Non-native species are those that do not naturally occur in an ecosystem. A non-native species is considered invasive when it is capable of aggressively establishing itself and causing environmental damage to an ecosystem. Plants, animals, and pathogens all can be invasive. Typical traits of an invasive species include: 1) generalist; being able to survive in a variety of physical and biological situations, 2) rapid reproduction, growth, and dispersal ability, and 3) lacking natural predators or pests in the invaded ecosystem. Thus, invasive non-native species are successful competitors in new ecosystems, usually displacing native species and disrupting ecosystem processes. An increase in invasive non-native species is associated with land cover change (human development and seral stage) and habitat fragmentation, human activities that transport the plants and animals or their eggs/seeds, and to changes in disturbance regimes (Hobbs 2000).

According to the Puget Sound Partnership: "After habitat loss, aquatic nuisance species pose the greatest threat to the biological diversity of Puget Sound."

A study commissioned by the Puget Sound Action Team in 2004 reported 54 exotic organisms established in Puget Sound, and 22 exotic organisms reported but not known to be established in Puget Sound.

Sources:

Puget Sound Science Review

Puget Sound Partnership

Addition resources:

Washington Invasive Species Council

USGS non-indigenous aquatic species

Noxious weeds listed by county

WDFW prohibited aquatic animals species list