by Whit Gibbons

November 20, 2005

I went on a field trip in Miami last week, and five of us caught three snakes and about 40 lizards in a couple of hours. The operative word in the previous sentence is "Miami." Not the nearby Everglades or Big Cypress National Preserve, but the city part of the greater Miami area at Barnacle Historic State Park in Coconut Grove.

I was invited to go on a lizard collecting trip by Walt Meshaka, a Miami native and lead author of the book The Exotic Amphibians and Reptiles of Florida (2004, Krieger Publishing Co., Malabar, Fla.). Walt is with the Pennsylvania State Museum but does surveys on alien species inhabiting state parks. Who would turn down an opportunity to go looking for bizarre tropical lizards in the middle of a metropolitan area? Not I. A University of Miami graduate student, Mark Mandica, who knows a lot about the introduced lizards of Miami went with me.

Collecting animals in the field has become problematical because of increasing regulations about having proper permits and entering restricted areas. Such concerns were not an issue for us. Hank Smith, the wildlife biologist who oversees the state parks in the lower part of Florida, accompanied us. He is also a faculty affiliate with Florida Atlantic University. In addition, Tom Jackson with the National Oceanographic and Atmospheric Administration went with us. He and Hank have the permits and access to walk around the park catching reptiles. And, indeed, Tom caught two of the snakes.

As many as 40 species of introduced reptiles and amphibians are established residents in the state of Florida, with breeding populations that will continue to persist, often to the detriment of native species. Most of the exotic reptiles that now thrive in Florida are lizards, including species from Asia, Africa, India, and tropical America. Introduced species often do well in a new region because natural predators no longer control their population sizes. One way that exotic species can eliminate native species is by outcompeting them for food. Another is by eating them. For example, the Knight or Cuban anole reaches twice the size of most native lizard species, which it can easily devour. Many of Miami's exotic lizards probably arrived in Miami as stowaways on ships. Some have been accidental or intentional releases by pet owners.

We caught numerous brown anoles, a species from the West Indies. (We saw more than 200 of them.) Lizards from other regions of the world included an Indo-Pacific gecko and one tropical gecko from Africa. We stopped catching Puerto Rican crested anoles after the first half dozen, but were able to catch only one bark anole, a species from the Bahamas. The snakes were Brahminy blind snakes, a pan-tropical species introduced from who knows where, but now, like the lizards we caught, a permanent resident of Miami. These shiny black creatures are the diameter of pencil lead (not the pencil, the lead) and now qualify as the smallest snake in North America. Stretched end to end, the three totaled about nine inches in length.

All the above species are now naturalized citizens of the U.S. fauna. They are here to stay, so conducting studies on their distribution and ecology is as worthwhile as finding out about our native fauna. None was an unexpected find at the Barnacle state park, but we did find two individuals of a species that no one was sure would be there-a common green anole, the only native species we found. The question is whether they can maintain an ecological niche in a world with other lizards that climb where they climb and eat what they eat, including a few that are big enough to make a meal of a green anole.

We did not see one of the gigantic Cuban anoles at the park. But as we stood on a second-story balcony back at the University of Miami, we got a look at one. Mark pointed out the spectacular, foot-long, emerald green lizard with a huge crest lying placidly on a tree branch at eye-level with us. Clearly, exotics are all over Miami.

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