Die, Weed, Die!

On a partly cloudy morning in late May, Volin and three other researchers haul two airboats an hour south of Davie to a public dock along Tamiami Trail. This is the driest month in the Everglades. The water covering the vast expanse of grass surrounding tree islands has slowly receded during the desiccated winter months, and the routine rainstorms of the tropical season have yet to begin in earnest.

The airboats are relatively small three-seaters, each driven by a cacophonous twelve-cylinder aircraft motor. The two boats weave northeasterly for about twenty minutes, sometimes crossing patches of slough that are little but mud. They pull up to a high stand of saw grass on the east side of a tree island. The real work begins on foot. Dressed in long-sleeve shirts and long pants, they begin the fern hunt by stepping off into water that's just under two feet high.

This is the first foray into the glades for Mary Ann Furedi, a new researcher who's only recently moved from West Virginia, where she walked mountainous terrain studying ginseng. A twentysomething with longish dark blond hair, Furedi will head this new project, but she and her team will go far beyond the tasks contracted for by the water district. Among other things, they'll be trying to identify "bio-indicators," which are plants or formations that act as hospitable hosts to a particular invasive species. When such a correlation is made, a bio-indicator creates a kind of shortcut for locating invasives and determining their reproductive and growing cycles. (Melaleuca, for example, is a sucker for spots that have been disturbed by fire.)

The saw grass crackles as the party of scientists wends its way through the serrated blades. A red-tinged bird chatters angrily at the intruders. The ten-foot perimeter of saw grass gives way to muckier ground with waist-high shrubs. If cave explorers go spelunking, then Everglades surveyors must go spelooshing, because that's the sound of extricating one's foot from the muddy soup.

The interior of the island is cordoned off with a thick wall of willows, vines, and holly. The plan is to use a compass and walk a straight east-west line across the island, keeping one eye out for Old World fern and the other on things like a ubiquitous prickly concertina wirelike vine that would sooner decapitate visitors than allow them passage. Furedi and her research team of three or four will spend four or five days a week trekking through tree islands like this.

One bio-indicator for Old World fern appears to be "moss collars." These grow at the base of trees and as high as four feet from the ground. So when the four researchers chance upon a decomposing log with a crewcut of green moss upon it, they crouch down under the dusky canopy. There they spy minuscule sporelings in the first stage of spore growth. Furedi takes a small plastic container from her backpack and inserts a chunk of moss-laden wood. It's the closest thing they'll see to Old World fern today.

Back in the research lab, Volin will grow the sporelings. He's conducting the same experiment in Australia, using that country's different soils. In the end, he hopes to learn if the soil has some effect on their life cycle.

So far the news is not good. This is one malleable plant. The fern is something of a sex addict, having evolved as a bisexual that can germinate its spores in any of three ways possible for ferns. The first spore to germinate in a new area is almost always female, researchers found, which then produces a pheromone that transforms surrounding spores into males.

Most ferns are very particular about moisture levels during germination; this fern has a more "whatever" attitude. It's not picky about light either; it can grow in dark shadows or in full sunlight atop trees. "This is an incredible plant," Volin enthuses. "The question is: Why is it not invasive in its own native area?" he poses. "We don't know that."

In the coming few years, the battle against Old World fern will be mostly waged with conventional weapons: herbicides, pruning shears, and elbow grease. But at the front line, soldiers know ultimate victory calls for greater weapons than those.

"The best hope we have is biocontrol," says Melvin, who stands at the edge of the moth-populated tree island. A wall of thick ferns dwarfs her. There's no sign of the fern-eating moths today, but it's a big island, and the tiny insects can't have made much headway yet. Who really knows how well these winged warriors will do in the war against Old World fern?

They're a long way from home, and their enemy is so very well entrenched. And reproducing fast.