Florida: No. 1 in world for invasive reptiles

U. FLORIDA (US) — Florida has the world’s worst invasive amphibian and reptile problem, with 137 non-native species introduced into the state between 1863 and 2010.

“Most people in Florida don’t realize when they see an animal if it’s native or non-native and, unfortunately, quite a few of them don’t belong here and can cause harm,” says Kenneth Krysko, herpetology collection manager at the Florida Museum of Natural History at the University of Florida.

“No other area in the world has a problem like we do, and today’s laws simply cannot be enforced to stop current trends.”

The Burmese python, Florida’s largest invasive species, is known to eat native birds, alligators, and mammals, including many that are protected. (Credit: Eric Zamora)


Florida law prohibits the release of non-native species without a state permit, but offenders can’t be prosecuted unless they are caught in the act. To date, no one in Florida has been prosecuted for the establishment of a non-indigenous animal.

Lawmakers need to create enforceable policies before more species reproduce and become established, urges the study that names 56 established species: 43 lizards, five snakes, four turtles, three frogs, and a caiman, a close relative of the American alligator.

“The invasion of lizards is pretty drastic considering we only have 16 native species,” Krysko says. “Lizards can cause just as much damage as a python. They are quicker than snakes, can travel far, and are always moving around looking for the next meal.”

The U.S. Department of Agriculture defines invasive species as organisms “whose introduction causes or is likely to cause economic or environmental harm or harm to human health.”

While the impact of many of the introduced species has not been determined, Floridians have experienced some of the damage these animals can cause, Krysko says, including iguanas that destroy cement walls and Burmese pythons released in the Everglades that eat protected species.

The pet trade is the No. 1 cause of invasive species proliferation, according to the study, published in the journal Zootaxa. Until about 1940, nearly all non-native species arrived through accidental means onboard cargo ships, but the boom in popularity of exotic terrarium animals in the 1970s and 1980s led to the pet trade being accountable for 84 percent of the introductions, Krysko says.

“It’s like some mad scientist has thrown these species together from all around the world and said, ‘hey let’s put them all together and see what happens,’ ” Krysko says.”It could take decades before we actually know the long-term effects these species will have.”

The study can serve as a baseline for establishing effective policies for control or eradication, says Fred Kraus, a vertebrate biologist at the Bishop Museum in Honolulu who helped establish policies for invasive amphibians and reptiles in Hawaii.

“This paper by Kenney and company I think is a good example of the approach that needs to be taken, providing the detail and being rather cautious in making immediate claims that things are established until there is evidence for it,” Kraus says.

“There is a lot more work going on now, but for years it was just ignored. For years, climate change was ignored, too. You know, humans just tend to ignore bad news until you can’t ignore it anymore.”

One of the greatest obstacles pet owners face is how to feed and house an exotic animal that has become too large or difficult to handle, Krysko says. “The biggest example is the Burmese python. It’s a large constrictor and has definitely shown impact on native species, some you just can’t even find anymore.”

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