Alien Invasion

Can we stop nature's most harmful visitors from entering the U.S.?

The U.S. is being invaded by aliens. Strange creatures are popping up in lakes and forests. There might even be some in your own backyard!

This tale isn't as creepy as it sounds. The aliens aren't from outer space. They are plants and animals that have come to the U.S. from other countries. Some species were brought to the U.S. on purpose. Others, like the Asian long-horned beetle, arrived here by accident.

OUT WITH THE BAD
In summer 2002, northern snakehead fish were found in a lake in Maryland. This fish is from Southeast Asia, where it has predators. U.S. wildlife officials were worried because the snakehead has no enemies here. What it does have is a huge appetite!

"Predators of this kind have been among our most damaging species," says scientist Daniel Simberloff. In October, 2002, officials poisoned the lake where the snakeheads lived. Not all alien species are bad. But scientists want to keep out those that harm native species. Says researcher Faith Campbell: "We have a responsibility to take care of the environment."

SOME UNWANTED VISITORS
COQUI (ko-kee) This tiny frog from Puerto Rico has raised a racket in Hawaii. The noisy coquis compete with the islands' rare birds for food.

NUTRIA
This furry rodent from South America chews up grass in marshy areas. Nutrias have ruined 100,000 acres in Louisiana and 8,000 acres in Maryland.

ASIAN LONG-HORNED BEETLE
These wood-chomping bugs came to the U.S. from China. In six years, the beetle have killed thousands of healthy trees.

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