A fern threatens to devour the Everglades
loxahatchee national wildlife refuge, fla. -- Like the insatiable plant from the musical “Little Shop of Horrors,” a verdant menace is eating the Everglades.
The Old World climbing fern, known to botanists as Lygodium microphyllum, spreads its asphyxiating fronds like fingers around the necks of native cypress and mangroves. It smothers the flora of the glades’ unique tree islands and starves out the endangered wood storks and other fauna.
“You can’t cut it because it grows right back. You can’t burn it without harming what it covers. You can’t kill it with water because it survives varying hydrologies,” said Bill Miller, a U.S. Fish and Wildlife Service biologist.
And, Miller laments, “nothing in the Everglades feeds on lygodium.”
The fern and other invasive plants now cover more than 2 million acres of the Everglades, including 70% of this national refuge and ever-expanding stretches of Everglades National Park, Big Cypress National Preserve, and the Seminole and Miccosukee reservations.
When environmentalists talk about invasive species in the Everglades, they are often referring to Nile monitor lizards, 350-pound Komodo dragons from Indonesia or the Burmese pythons abandoned there by humans. The pythons are now challenging alligators for supremacy in the swamp.
The rapacious lygodium, which originated in Australia, doesn’t grab quite the same attention.
But biologists and conservationists contend the nonnative plants pose a greater risk to the Everglades, half of which has already disappeared after a century of bulldozing and dredging.
Scientists also warn that efforts to contain and eventually eradicate alien plants will increasingly challenge federal, state and local budgets, which are already struggling to ante up their shares of the $8 billion committed through the Comprehensive Everglades Restoration Plan.
The Everglades is a natural resource that some people find hard to love. Its malodorous, sweltering bogs are a sanctuary more for creatures that bite, sting and slither than for humans. But because it is a shelter for rare flowers, birds and other animals, conservationists have fought to preserve it for a century.
The 2000 Everglades restoration project is aimed at correcting the engineering and development intrusions that have reduced wading bird populations by 95%, endangered 68 plant and animal species, and cut water flow through the glades by 70%.
It would refill canals, restore the natural flow of rivers, and cease mining and other industry encroaching on protected areas. It also would relocate some farming communities established during the early 20th century that now require water diversions and electricity supply in the government-protected refuges and that release polluted irrigation water into the Everglades’ reengineered flow.
But the restoration, the nation’s biggest environmental repair project ever, pays little heed to invasive species, which nature defenders warn could nullify the project’s results.
Left unchecked, lygodium will cover an area of southern Florida larger than the entire Everglades National Park by 2014, according to a computer-generated projection by biologist John Volin of Florida Atlantic University.
His forecast is based on aerial surveys of the Everglades made since the 1970s, when lygodium first popped up on the pest-plant radar in the glades northeast of Lake Okeechobee.
Lygodium was brought to Florida in the 1950s by gardening clubs impressed by how fast it grew on fences, posts and trellises. Winds shake loose its copious pods and carry seeds into virgin lands.
Another invasive plant, the Australian melaleuca tree, was imported a century ago: Some Floridians saw the Everglades as a useless swamp and wanted the land for crop production, so melaleuca, renowned for its water consumption, was planted among the tree islands to suck the wetlands dry.
People working to protect and restore the Everglades say they have succeeded in reducing melaleuca and other invasives, including Australian pine and Brazilian pepper. But anti-lygodium efforts could be Sisyphean.
As many as 30 contractors and wildlife experts labor daily to get rid of the invasive fern in the Loxahatchee refuge alone. But each frond is hemmed with pods, which disperse their seeds to the winds even when the fern is being burned, removed by hand or chemically treated.
The plant is spreading about 10 times faster than it is being destroyed.
Mike Page, a veteran helicopter pilot flying for the South Florida Water Management District, deploys half a dozen choppers with spraying booms over the infested tree islands to apply herbicide to lygodium and melaleuca.
The precision operation, which began this spring, costs the state up to $300 per acre. By last week, Page’s team had covered 8,000 acres -- less than 10% of the invaded areas of the 143,000-acre refuge.
Two weeks after a spray, the browned and desiccated plant scraps can be manually removed by laborers. But a drought has marooned many of the invaded tree islands -- normally reached by airboat -- preventing collection of foliage that is now dead but still smothering native vegetation.
“The goal now is control. Eradication is a long time coming,” said Miller of the Fish and Wildlife Service.
Meanwhile, dumping of other foreign species is far from uncommon in Florida (though such dumping, whether of plant or animal species, is illegal in the state).
With the Everglades’ thousands of miles of canals and millions of acres of remote territory, the risk of detection is minimal and the paths of encroachment long, vast and defenseless.
