Why are they so dangerous?

This frog may LOOK cute with it's googly eyes but it is actually extremely territorial and aggressive.  This anger problem allows it to out-compete native frog species and take over the potential habitats of other native species.  They ambush and eat anything that fits in their mouths, which are large!  This has greatly increased the predation on native insects, mice, fish, birds and snakes because these frogs live for 7-9 years and lay 20,000 eggs at a time.  The American bullfrog is taking over our freshwater ponds, lakes and marshes that have naturally delicate ecosystems.

The Brazilian Elodea in this lake came from South America and was originally sold as a decorative plant for aquariums.  However, they quickly became a threat to our native ecosystems because of their fast growth rate and ability to survive winters by rooting to and hibernating at the bottom of lakes, ponds, and marshes.  It's currently illegal to sell this in Washington State.

The European Green Crab has a wide range of possible habitats, they can live in mud, sand, rocks, aquatic vegetation and marshes.  Their high tolerance for a range of salinities and temperatures has made this tiny crab a big problem along the United States coasts.  They out-compete other crabs, like the delicious Dungeness crab, and are predators to delicious clams, mussels, oysters and gastropods. They were introduced by ballast water, ship's hulls, packing materials, rafting and even surface currents which makes it difficult to prevent their transportation from place to place.

Saving the most invasive for last is the Himalayan Blackberry.  This plant was consistently encountered during the field that work that the Biology 476 class did this quarter.  There is no requirement to control them because they have infested most of King County and Western Washington along rivers and wetland edges.  However, this shouldn't be ignored because they easily out-compete native understory vegetation.  They are hardier and more ferocious than the native blackberry and even prevent the establishment of native trees.  The Pacific Madrona, Douglas Fir, and Wester White Pine cannot begin to grow because this species blocks their light and uses their resources.