BREAKING NEWS: Washington's first strategic plan is now available.  Click here to access the plan at the website of the Office of Recreation and Conservation.

Invasive Species:  The Problem

Invasive species are one of the leading threats to the world’s biodiversity. They impact nearly half of the plants and animals currently listed as Threatened or Endangered under the U.S. Federal Endangered Species Act. (National Invasive Species Council)

What is an invasive species?
A plant, animal or other organism is considered invasive when it spreads at such a rate that it causes damage or harm to other species.

Most invasive species are non-native. Also known as ‘aliens’ or ‘exotics,’ they are not native to the place they harm.

Invasive species tend to be fast growing. In the absence of predators in their new home they can spread at alarming rates.

Not all non-native species are invasive. Many are useful, such as most farm animals and crops. Just a handful of non-native species are invasive.

How do they get here?
There are many ways that non-native species can get to Washington state—these are known as ‘pathways.’

Plant seeds, insects, and small animals can hide in ships and on planes. They cling to packing containers. Marine and freshwater organisms arrive on the sides of boats and in the ballast water of ships

Invasive garden plants can escape into the wild, their seeds carried by birds, people, wind or air.

Exotic pets escape or are released into parks, lakes, or rivers.

People can carry seeds on their clothing, in suitcases, and on cars.

Why should we care?
Invasive species compete with native plants and animals for scarce resources. They can change the local ecosystem, depriving native species of habitat. They damage farm and forest lands and cause hundreds of billions of dollars worth of damage in the United States alone. (Pimentel, D. et al).

The names of some have made it into the headlines: zebra mussel, kudzu, gypsy moth, green crab. Others are less well-known or just gaining attention. By any measure, they’ve become a huge ecological threat, one demanding a thoughtful, integrated and proactive response.