Invading Species Threaten America’s Biodiversity and Environment

Cruising westward at 300 feet, the helicopter is heading straight for the end of civilization. You can see it just ahead. It’s a line across the surface of the Earth—a levee, built years ago to hold back the swamp. Now it works in reverse, restraining the developers. Beyond the levee there are no shopping malls, no houses, no roads, just a wet prairie full of alligators, lily pads and saw grass.

And there’s something new, something growing, spreading—a pale-green substance that seems to be crawling all over the tree islands that speckle this portion of the Everglades. The pilot takes the chopper down for a closer look. You can see it, sure enough: lygodium. Old World climbing fern.

It has gone berserk. It’s like the Blob. The islands are caving in at the center, crushed by the dense, matted blanket of vegetation. The willows, the hollies, the cabbage palms—they’re being buried alive.

“You wouldn’t see any of this three years ago,” testifies the chopper pilot, Jim Dunn.

David Viker, deputy manager of the federally managed swamp, says, “It looks like a green bomb went off.”

What exactly is this virulent organism? It’s a houseplant. In the right context, it’s a lovely little fern.

Lygodium is the classic invasive species: an organism that’s been transported by human beings to habitats where it has no natural enemies. The counterattack against this intruder is just one isolated battle in what is becoming a major war from the Everglades to Rock Creek Park, from Hawaii to your own back yard. The scale of the conflict is planetary.

There are bombs detonating everywhere.

There have always been invasive species, but ecologists and government officials say the situation has become riotous. One study estimated that exotic species, including diseases, cost the nation more than $130 billion a year. There is an emerging sentiment that this could be the next great environmental crisis, that without serious countermeasures we will find ourselves living in what the nature writer David Quammen has called the “Planet of Weeds.”

In 1999 President Bill Clinton signed an executive order requiring all federal agencies to address the problem of invasives. The order created a new entity called the Invasive Species Council. . . . But for all the bureaucratic sparks, there are no platoons of weed-whacking commandos taking to the hills with machetes.

For the general public the issue remains relatively obscure. People grasp the dangers posed by bulldozers and acid rain. It’s not as easy to understand the menace of, say, Eurasian milfoil.

The issue also suffers from its scattered nature