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| Earth on Sep 19, 2011

Florida has world’s largest number of invasive amphibians, reptiles

A University of Florida study indicates that the pet trade is the number one cause of invasive species introductions in the state.

Florida has the biggest number of invasive amphibians and reptiles of any location in the world, according to a 20-year study by the University of Florida at Gainesville. The study indicates that the pet trade is the number one cause of the species introductions.

From 1863 through 2010, 137 non-native amphibian and reptile species were introduced to Florida, with about 25 percent of those traced to one animal importer. The findings appear online September 15, 2011, in Zootaxa.

Male green iguana with spines and dewlap. Non-native iguanas dig burrows that damage cement foundations and sea walls. Some green iguanas have lost their fear of humans and are often drawn to houses where pet food is left outside or where landscaping includes ornamental flowers such as hibiscus. Via Wikipedia

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.” Of the 137 introduced species, only three species have been intercepted before reaching the wild. The study shows that no established, non-native amphibian or reptile species has ever been eradicated.

Lead author Kenneth Krysko, UF Florida Museum of Natural History, said:

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

Florida law prohibits the release of non-native species without a state permit, but offenders cannot 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. Researchers urge lawmakers to create enforceable policies before more species reproduce and become established. The study names 56 established species: 43 lizards, five snakes, four turtles, three frogs and a caiman – a close relative of the American alligator.

Krysko said:

The invasion of lizards is pretty drastic considering we only have 16 native species. 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 Burmese python is Florida’s largest invasive species documented in a UF study. Released into the Everglades, the pythons consume birds, alligators and mammals, including many protected species. Via Wikipedia

Floridians have experienced some of the damage these animals can cause, from iguanas that destroy cement walls to Burmese pythons that eat protected species. While researchers have not determined the impact of many of the invasive species, the study does provide new information about how, why and when invasive species entered the state.

Pythons are cute when they are little, but one of the greatest obstacles pet owners face is how to feed and house a python (or other exotic animal) that has become too large or difficult to handle, according to one author of the study. Image Credit: Tiger Girl

The first introduction in 1863 was the greenhouse frog, native to the West Indies. One of the most easily recognized species is the brown anole – the first introduced lizard – which reached Florida from Cuba via cargo ships in 1887. Until about 1940, nearly all non-native species arrived through this accidental cargo pathway, but the boom in popularity of exotic terrarium animals in the 1970s and 1980s led to 84 percent of the introductions, according to Krysko. He explained:

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.” It could take decades before we actually know the long-term effects these species will have.

Invasive species were also accidentally introduced through the zoo or plant trade or through biological control programs, in which an animal is intentionally released to control a pest species.

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, according to Krysko. He said:

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.

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

Kraus said:

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.

Krysko said:

This is a global problem and to think Florida is an exception to the rule is silly. The Fish and Wildlife Commission can’t do it alone – they need help and we have to have partners in this with every agency and the general public. Everyone has to be on board; it’s a very serious issue.

Bottom line: Florida has the largest number of invasive amphibians and reptiles of any place in the world, according to a study by UF Gainesville researchers, who have published their findings in the September 15, 2011, online issue of Zootaxa.

Read more at University of Florida News

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