Tuesday, 12 August 2014

A Hungry Little Squatter-A Lizard Interloper Presents Challenge in Florida - via Herp Digest

by RACHEL NUWER, 8/4/14, New York Times
FLORIDA CITY, Fla. — Deer flies swarmed around Frank Mazzotti and Joy Vinci as they stooped to get a closer look at the creature thrashing around in a metal trap they had laid off a weedy dirt road. Inside it was what some biologists consider the most troublesome invasive species in the Everglades: not a Burmese python, but a 24-inch lizard, the Argentine black and white tegu.
It thumped its long tail like a snare drum — a tactic the species uses to shift predators’ attention to that expendable appendage (it can grow a new one). Ms. Vinci, a wildlife biologist, was not fooled. Wiping her brow in the 91-degree Florida heat, she attached a cloth bag to the end of the cage and then carefully opened it, shooing the tegu inside.
As she knotted the bag, the animal went limp, playing dead. That didn’t work either: The tegu, along with three others trapped earlier, would be taking a one-way trip out of the marsh, in Miami-Dade County, and to the University of Florida’s Fort Lauderdale Research and Education Center.
Tegus (usually pronounced TAY-goos) originally came here from South America through the pet trade. Although Dr. Mazzotti prefers cats, he can understand why people like them: They are smart, attractive animals, patterned like an abstract Moroccan rug. They have a nasty bite, but with enough handling, they grow docile. “They’ll crawl on you — the reptile version of interacting,” Dr. Mazzotti said.
But like pythons and other invasive species first brought here as pets, tegus eventually found their way into the natural environment. Once they were unleashed in Florida’s wetlands, the warm weather, bountiful food and absence of natural predators allowed them to thrive.
Wild tegus were first spotted in 2008, scuttling around a trailer park in Florida City, south of Miami. But their range quickly expanded, spilling into the nearby Everglades, where they took advantage of a smorgasbord of native wildlife. The lizards have a taste for eggs — both reptile and bird — but they will also eat small mammals, insects and fruit. “Everything they get their jaws around, plant or animal, they seem to swallow,” Dr. Mazzotti said.
A wildlife biologist whose accent gives away his Long Island roots, Dr. Mazzotti, 65, has worked in Florida’s swamps for nearly 40 years. He had hoped to become a marine biologist but scrapped that plan after discovering he had crippling seasickness. On a class trip to Big Cypress National Park, he discovered a new calling: the Everglades.
For decades, he focused his research on alligators and threatened American crocodiles, earning the nickname “the croc doc.” But since the early 2000s, Dr. Mazzotti has turned his attention to the dozens of coldblooded species that have invaded the Everglades, including pythons, Nile monitor lizards, Cuban tree frogs and black spiny-tailed iguanas.
Still, he said, of all the invaders, tegus worry him the most. They are more tolerant of cold than many reptiles, meaning they have a larger potential habitat range. Rare freezes in southern Florida kill nine out of 10 pythons, but tegus have successfully overwintered as far north as Panama City, on the Florida Panhandle. (The Florida Fish and Wildlife Conservation Commission managed to wipe out that population before it could expand.) The invasion has two centers, Florida City and Riverview, southeast of Tampa. Some of the lizards escaped from captivity or were set free by owners who no longer wanted them; scientists and officials suspect many were released by reptile breeders on the theory that harvesting them in the wild is cheaper than breeding them in captivity.
Comet Siding Spring closes in on Mars; Galapagos scientists watch Darwin’s finches evolve in real time; the tegu, an invasive lizard species, has found a comfortable home in the Sunshine State. David Corcoran, Michael Mason and Joshua A. Krisch
“We know in those two areas they’re reproducing,” said Kristen Sommers, the head of exotic species at the Florida wildlife agency. “We’re trying to get a better handle on what’s going on in those areas, and we’ve really been increasing our trapping efforts.”
Dr. Mazzotti is reluctant to cite specific population figures, but he notes that the number of tegus trapped around Florida City has risen to 400 a year, from just 13 in 2009 and 21 in 2010; he thinks that represents less than 10 percent of the total population. A time-lapse map he created to track the invasion — yellow dots for traps, red for those that catch a tegu — resembles the progression of a disease outbreak.
Dr. Mazzotti and his colleagues take turns hitting the field each day, checking about 30 live traps that they bait with chicken eggs. They have also fitted several tegus with small transmitters to track their movements, and set up cameras to monitor the species’ colonization patterns. While the biologists focus on the invasion’s front lines, they have also recruited private trappers to capture the lizards in well-established core areas, nicknamed “trailer park” and “rock pit.”
Rodney Irwin, a licensed tegu trapper in nearby Homestead, has collaborated with the researchers for three years. “Everyone’s on the same page about one thing,” he said. “We’ve got to do something about these aggressive predators. Argentine tegus are taking out animals that I grew up with — that my dad and my grandfather grew up with.”
Rather than kill the invaders, Mr. Irwin chooses to sell them to pet dealers. “It would have been easy for me to put on my redneck hat, grab my rifle and just start killing them,” he said. “But I spent time with them and just fell in love.” He has more than 200 tegus and says almost all of his shipments go out of state. Prices vary from $40 to $140.
Dr. Mazzotti said he did not care whether captured tegus were euthanized or returned to the pet trade (preferably to destinations “like Montana or Mongolia,” he added dryly). His primary concern is removing tegus from the environment, and he says he thinks the invasion can still be contained or even stopped. But that will require acting quickly.
Tegu populations are creeping east toward Turkey Point Nuclear Generating Station, where threatened American crocodiles nest; west into Everglades National Park, populated by protected Liguus tree snails and endangered Cape Sable seaside sparrows; and south to Crocodile Lake National Wildlife Refuge, the home of the endangered Key Largo wood rat and cotton mouse, and more crocodiles. These rare animals or their eggs are potential prey for tegus, Dr. Mazzotti said, adding, “We cannot wait until an invasive species demonstrates negative impacts to act, because then it’s too late.”

Despite the threats to native wildlife, he said, efforts to tackle the tegu problem are lagging. Attention is still primarily focused on pythons, even though that species is already so well established that there is little hope of eliminating it. “I get weary not so much of fighting the battle to protect our resources,” he said, “but of our seeming inability to learn from past mistakes.”

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