While taxpayers are spending billions of dollars to restore the Everglades, a deadly army of foreign species is undercutting the effort by pushing out native plants and animals
- Doreen Cubie
- Feb 01, 2009
SKIP SNOW, a wildlife biologist at Florida’s Everglades National Park, is staring intently into a Martha Stewart laundry bag before quickly reaching inside and pulling out a writhing 6-foot Burmese python. It is a powerful animal and a beautiful one, with the sun glinting off its chestnut, black and gold body. But this species is a native of Southeast Asia and doesn’t belong in the Everglades. Snow believes that such pythons, popular in the pet trade, were first released into the state by their owners when the reptiles became too big to handle. One of the largest snakes in the world, it can grow to more than 20 feet long and weigh as much as 200 pounds.
Snow squeezes open the captive’s mouth, revealing the long, dagger-sharp, backward-curving teeth that, along with its massive size, make it a formidable predator. Burmese pythons are ambush hunters and constrictors, lying in wait and suffocating their prey, which so far in Florida has included alligators, limpkins, white ibises, cotton rats, round-tailed muskrats, bobcats, great egrets, endangered Key Largo wood rats and even a magnificent frigate bird.
University of Florida associate professor Frank Mazzotti believes “it is safe to say there are tens of thousands” of wild Burmese pythons in the southern part of the state, with the core of the population centered in the park. “They’re almost a textbook example of an invader species,” Mazzotti says. “They’re generalists and can live in different habitats. They have lots of young, and they grow very quickly.” He and Snow have found python eggs in the Everglades and also have seen hatchlings, which start life 20 inches long and often reach 10 feet within three years.
“They’re really a threat to this ecosystem, one that we’re spending billions to restore,” says Snow, who is based at the national park’s Daniel Beard Research Center, formerly a Nike missile facility and now the command headquarters in this new battle against pythons and other invasives. At stake is the integrity of the greater Everglades, which stretches from Lake Okeechobee 100 miles south to Florida Bay. Exotics have the potential to alter greatly this landscape by pushing out native plants and animals, making control of these invaders one of the greatest challenges in Everglades restoration.
Unfortunately, the list of species introduced into subtropical Florida is a long one. Several other large alien snakes have been found, including yellow anacondas and reticulated pythons, although they are not yet believed to be breeding. Green iguanas and Nile monitors, however, are successfully reproducing and spreading. As adults, these reptiles top out at 6 to 7 feet long, with the iguanas devouring all kinds of vegetation, and the monitors eating just about anything, including burrowing owls, gopher tortoises and domestic pets.
Nonnative birds and plants also can be harmful. Destructive plants include Brazilian pepper; Australian melaleuca, a member of the eucalyptus family; and Old World climbing fern. The latter, brought into this country as an ornamental plant sold in the nursery trade, spreads by airborne spores and is now blanketing 200,000 acres in the Everglades ecosystem. Biologists have reported more than 200 species of exotic bird in Florida. Some, like the sacred ibis, send shivers down the spines of wildlife managers. This African species preys on the young and eggs of wading birds and other creatures that gather in colonies and has begun nesting in the Everglades in small numbers.
In the struggle against the sacred ibis, which is actually a stork, scientists have only to look to France to know what could happen in this country. During the 1980s, a zoo in the south of France had a free-flying population of about 50 individuals of this species, says Garth Herring, a doctoral student at Florida Atlantic University who is studying both sacred ibises and native wading birds. The French ibises began to stray, eventually nesting outside of the facility. By 2005, their numbers had reached 3,000 birds, and today, current estimates are 5,000 individuals. “In France, sacred ibis have been documented in tern colonies, where they wreak havoc,” Herring says.
In this country it is likely the original birds escaped from the Miami MetroZoo when Hurricane Andrew demolished their enclosures in 1992. Now the problem is how to stop them before their population explodes like the one in France. “There are three approaches to invasive species,” Herring says. “You can keep them from coming into the country, remove them when they are at a very low level or manage them.” Since there are fewer than 100 sacred ibises in South Florida, scientists and government officials believe the best approach is to try to eradicate them before they begin threatening the signature birds of the Everglades—native ibises, storks, spoonbills, herons and egrets. If all goes according to plan, U.S. Department of Agriculture (USDA) sharpshooters will begin eliminating sacred ibises—which are mostly concentrated in the wetlands at a waste management facility outside of West Palm Beach—within the next year.
Another way to combat invasives is to pit species against species. One of the reasons exotics spread so rapidly in new environments is that they leave behind their natural enemies. Old World climbing ferns, for example, are well-behaved plants in their native range of Africa, Australia and Southeast Asia. But without the caterpillars, mites and other tiny creatures that munch on the plants back home and keep them under control, this vine takes off in the United States like kudzu, says Robert Pemberton, an entomologist with the USDA’s Invasive Plant Research Laboratory in Fort Lauderdale. Besides growing up and over small trees and shrubs, it also creates 3-foot-thick mats of foliage on the ground.
Until now, chemical herbicides have been the weapon of choice to combat this eco-invader, but those that worked usually killed native vegetation too. For more than a decade, Pemberton and his colleagues have been scouring the homelands of climbing fern, looking for its natural enemies. So far, they’ve found two moths, one sawfly and one mite that might do the job. But first the animals must undergo years of rigorous testing and quarantine to make certain they will not cause biological problems of their own. One of them, a dark brown, thumbnail-sized moth discovered by Pemberton on an island in Hong Kong, has been cleared for release. In February 2008, entomologists began introducing it into Jonathan Dickinson State Park, just north of West Palm Beach, with the hope that it will begin to keep Old World climbing fern in check.
Figuring out ways to keep large snakes in check is an even greater challenge. For one thing, they’re at the top of the food chain. Also, “they’re extremely cryptic,” Snow says, making them hard to locate. Researchers have turned to “snitch snakes,” captured Burmese pythons that are implanted with radio transmitters and then released back into the wild. In the spring, when the reptiles come together in breeding aggregations, one radio-tagged snake can lead scientists to many others. Snow and Mazzotti are also experimenting with traps, trying to determine whether baits or pheromones, a type of chemical signal, are more effective at enticing the animals inside.
Regulating these giant reptiles in captivity is also critical. Florida now requires anyone who keeps Burmese pythons, Nile monitors, green anacondas or three other species of python—African rock, amethystine or reticulated—to buy a $100 permit. They must also implant microchips, which identify the owner, in any pets bigger than 2 inches in diameter. It’s now a first-degree misdemeanor to release an exotic into Florida. But biologists know the genie is out of the bottle as far as Burmese pythons are concerned, and the best they can ever hope to do is manage them. “Many people thought pythons would never get established here,” Mazzotti says. “They were wrong.”
“Right now, nonnatives are innocent until proven guilty,” Snow says. “By that time it’s too late to do anything about it. We need to change our mindset and be able to respond rapidly.” The stakes are high. Eco-invaders could completely change the face of the Everglades. “Our biggest concern is the unknown,” Snow says. “We don’t know what is going to happen.”
Doreen Cubie received NWF’s 2007 magazine writing award for her article on tribal lands conservation.
NWF in Action: Affiliate Lawsuit Leads to Everglades Land Deal
In early 2008, much of the Comprehensive Everglades Restoration Plan (CERP) was moving along like an apple snail crawling up a blade of sawgrass. Eight years after its kickoff this project, designed to undo decades of human damage to the Everglades and replenish its River of Grass, was behind schedule and over budget. Funding from the federal government, which was supposed to split the costs 50-50 with the state of Florida, had dried up.
But the momentum shifted on a steamy day last June, when Governor Charlie Crist made a startling announcement. The state was going to buy 187,000 acres of the U.S. Sugar Corporation’s agricultural land—once a part of the Everglades—for $1.75 billion. Crist called it “ an opportunity to provide the missing link in our restoration activities.”
“It changes the playing field,” says Malia Hale, NWF’s director of National Restoration and Water Resources Campaigns, who points out that officials should now be able to create a much more natural flow of water from Lake Okeechobee south. The catalyst for this deal was a lawsuit won by an NWF affiliate, the Florida Wildlife Federation (FWF), and Earthjustice, another environmental group. For years, U.S. Sugar had been pumping fertilizer- and pesticide-tainted water from its farm fields into Lake Okeechobee, the “headwaters” of the Everglades. Earthjustice and FWF contended the practice violated the Clean Water Act, and U.S. District Judge Cecilia Altonaga agreed. “Once U.S. Sugar needed to meet the conditions of our successful lawsuit,” Manley Fuller, FWF president, says, “it encouraged them to sit down with Governor Crist and work out this agreement.”
As this issue went to press, many of the details were still being negotiated. In November, the buyout was scaled back to a $1.34 billion purchase of 181,000 acres. U.S. Sugar will now keep its processing mill, railroad lines and other infrastructure, and lease back most of its land for the next seven crop cycles. And in yet another development, the purchase of the lands could be complicated by an offer from The Lawrence Group, a Tennessee agricultural concern that reportedly is interested in buying U.S. Sugar. Also, according to Fuller, in order to get the best configuration for restoring the historic flow of water, some of the U.S. Sugar property will need to be swapped in the future with parcels belonging to an adjacent landowner, the Florida Crystals Corporation.
Even though there is still a long road to travel before Everglades restoration is achieved, the events of 2008 will be remembered as a giant step forward. “It’s a once-in-a-lifetime opportunity, and we can’t afford to pass it up” says Hale. “In the face of global warming, Everglades restoration is increasingly critical. It will help re-create enough of the natural water flow necessary to rebuild eroded peat lands and hold back the rising sea levels that climate scientists have been predicting.” For more information on NWF and the Everglades, go to www.nwf.org/everglades and www.fwfonline.org.
In Like a Lion
The smashing of an aquarium on Miami, Florida’s, waterfront by Hurricane Andrew in 1992 seemed a minor incident compared to the huge swath of destroyed homes and commercial buildings the storm left in its wake. Even the spilling of half a dozen red lionfish from the aquarium into Biscayne Bay would not have occasioned much anxiety. But now, 17 years later, the missing lionfish may be contributing to an ongoing and major threat to Florida’s offshore ecosystems.
Red lionfish are natives of a huge expanse of sea, ranging across Indo-Pacific waters from western Australia and Malaysia east to French Polynesia and north to Japan and southern Korea. They are propelled through the water by long, diaphanous fins that are beautiful but deadly, armed with spines that radiate like knitting needles from the 15-inch-long, 2.5-pound bodies of the adults. The spines carry venom from glands at their bases. When threatened, the fish point the spines forward and aggressively face the enemy.
A human struck by a lionfish will feel sharp, radiating, throbbing pain at the site of the sting, may break into a sweat and blister, may even go into seizures or delirium, could suffer limb paralysis or tremors, even congestive heart failure. Scorpionfish—the taxonomic group to which lionfish belong—sting about 40,000 to 50,000 people yearly worldwide, second only to the number struck by string rays.
Finding a Home in the United States
The escapees that made it into Biscayne Bay may have helped found a population there. But they were not alone in Florida seas. Other lionfish, quite likely released by aquarium owners for reasons only they can explain, also have found a home off Florida. Lionfish are big business in the aquarium trade—in 2003, 8,000 were imported to Tampa alone, according to Tom Jackson of the National Oceanic and Atmospheric Administration (NOAA).
Reports of the fish in Florida waters began cropping up in the mid 1990s. In 2000, lionfish were spotted on two wrecks off North Carolina. Today they are “more or less continuously distributed in marine waters from Florida to Cape Hatteras, North Carolina,” according to the U.S. Geological Survey. In some areas they are as abundant as native groupers. NOAA studies indicate that during the past four years the fish have increased from 22 per hectare (2.47 acres) to 200 at some sites.
So What’s the Big Deal?
Were it not for its voracious appetite, the red lionfish would just be another gracefully beautiful, potentially deadly nonnative fish in U.S. waters. But it is also a predatory reef species with no natural enemies in America’s subtropic seas, so it is posing a serious and acute threat to coral reefs and fish populations already stressed by pollution and global warming. Lionfish eat many species of native fish. A 2007 study of a patch of reefs in the Bahamas found that net recruitment (the population growth of new juvenile fishes) declined 79 percent on reefs with lionfish compared to reefs that lacked lionfish. Because some native fish help keep reefs clear of algae and seaweed, fish declines can lead to the choking out of coral reefs. Lionfish thus not only kill fish but also fish habitat.
So far, no solution to this potentially reef-devastating problem has arisen. Biologists are struggling to find a predator from Indo-Pacific waters that might help reduce lionfish in New World seas, but so far nothing has turned up. In fact, biologists are not sure that any predators prey heavily on lionfish. Stopping commercial sale of the species may help, presuming that the fish have not already established themselves so successfully in U.S. and Caribbean waters that the whole problem may be reduced to two words: Too late.
For photos and more information on lionfish off Florida, visit the website of the Florida Museum of Natural History at www.flmnh.ufl.edu. For more information on Florida invasive species, see “Everglades Invasion.”