More exotic reptiles and amphibians are popping up. And Florida’s the leader in …
7:13 AM, Dec. 1, 2011 |
A red-footed tortoise, native to South America. A group of University of Florida and other researchers for the first time officially documented Florida as the worst state for invasive reptiles and amphibians. The pet trade is to blame.
Jim Waymer | | FLORIDA TODAY
NEW ARRIVALS IN BREVARD
The red-footed tortoise belongs in southern Central and South America. It turned up in July 2007 north of State Road 518 in Melbourne.
The African clawed frog, collected June 2010 in a Titusville retention pond. Indigenous to sub-Saharan Africa, the frog was released in 1964 in Miami-Dade County by an animal importer. The Titusville frog likely escaped a nearby enclosure.
The false map turtle, found May 2009 in Palm Bay, is native to the Missouri River. It likely was released or had escaped from enclosures at Florida International University and Turkey Creek Sanctuary.
Source: “Verified non-indigenous amphibians and reptiles in Florida from 1863 through 2010:Outlining the invasion process and identifying invasion pathways and stages”
Learn about Florida’s non-native species: myfwc.com/wildlifehabitats/nonnatives
Biologists refer to the tens rule: About 10 percent of non-native species transported to a new area become “introduced,” 10 percent of those species become established and 10 percent of established species become pests or have some lasting negative impact.
— “Verified non-indigenous amphibians and reptiles in Florida from 1863 through 2010: Outlining the invasion process and identifying invasion pathways and stages”
Meet the African clawed frog, the red-footed tortoise and the false map turtle, new alien arrivals to the Space Coast with unknown appetites for ecological destruction.
The clawed frog belongs in Swaziland, not in the retention pond where it floated up last year off Knox McRae Drive in Titusville. The false map turtle could use a true map: It usually bobs around the Missouri River, not Turkey Creek in Palm Bay, where a researcher happened upon it in 2009. And the red-footed tortoise is supposed to waddle in Central America, not Central Florida, as it did along Melbourne’s Jones Road in 2007.
Now the three interlopers may be in Brevard County to stay. They’re among 56 alien species scientists recently documented in the Sunshine State — many for the first time — earning Florida the dubious distinction as the worst place in the world for established alien reptiles and amphibians. Hawaii is a distant second with 31 introduced species.
Such invaders can wreak havoc with local ecosystems, sometimes wiping out entire local species of plants and animals. In areas where they have no natural predators, their populations may explode to the point they become nuisances or threats to humans.
“Most of the introductions recently are all coming from the pet industry, either careless owners releasing their pets or reptile dealers not having secure cages,” said Joe Burgess, a co-author of the study and a resource manager for the Florida Department of Environmental Protection.
Or maybe owners dump more pets during a down economy, he said. Regardless of the origin, once unleashed alien species can slither into Florida’s unique habitats, disrupting food webs and breeding hybrids with the natives.
“You pollute the gene pool,” Burgess said. “In most cases, it’s too late” to eradicate the invaders.
The researchers confirmed 137 introduced amphibians and reptiles in Florida since 1863. Of those, 56 are established and reproducing, including 43 types of lizards, three frogs, four turtles, one crocodilian and five snakes — most infamously, the Burmese python.
“There’s been so much speculation that a lot of these things that have been in manuscripts have never been proven and no one’s ever seen one,” said Kenneth Krysko, lead author and a biologist at Florida Museum of Natural History’s division of herpetology.
Their paper ends the speculation on many alien reptiles and amphibians and how they got here.
Of 149 different pathways, 125 (84 percent) were introduced by the pet trade, 18 (12 percent) via cargo shipping, two (1.3 percent) were related to biological control of other species and four (2.7 percent) escaped zoos.
Florida is losing the battle to contain all these aliens, the researchers assert. The state needs stricter laws and better enforcement on the pet trade, they say. But wildlife officials assure Florida is only just beginning to see benefits of stricter rules enacted after mass exotic wildlife escapes during the aftermath of Hurricane Andrew in 1992. Education, not eradication, is the only practical solution, they say. To significantly scale back all the the lizards, snakes, frogs and turtles that don’t belong, owners must stop dumping their pets.
“First and foremost, it’s illegal. It’s unethical and it’s generally inhumane,” said Scott Hardin, exotic species coordinator for the Florida Fish and Wildlife Conservation Commission.
Most exotic reptiles and amphibians dumped in the wild die.
“It’s a minority of them that cause you fits,” Hardin said. “What you’re seeing is accumulation of things that have gone on for a hundred years or more. We’ve tried to take a holistic approach. The law alone will never be completely effective in dealing with this.”
Invasions decades in the making
Alien species can spread disease to natives and outcompete them for food and habitat. But impacts can take decades to unfold or understand. It took four decades for biologists to figure out the brown tree snake invasion in Guam had harmed human health, the economy and eradicated 11 of 13 of the island’s land birds, the researchers noted.
Florida has its own problems lurking in the trees. Among the most notorious is the Cuban tree frog, introduced in 1931 through packing materials. It preys on native tree frogs.
Biologists describe a grand Darwinian experiment unfolding in the Everglades. Burmese pythons swallow deer and endangered wading birds. Adult birds peck up python babies, and alligators and pythons twist in alien-versus-predator death grips.
In some instances, the aliens are the unintended consequence of what were thought sound economic decisions at the time. In the 1940s, Palm Beach sugar cane farmers introduced curly-tailed lizards to control insects. The lizard now prospers in Cocoa Beach.
Reptile expert Chris Gillette of Florida International University, a co-author on the study, came across a false map turtle and a red-footed tortoise while hiking in Brevard in recent years. Biologists fear the red-foot could transmit disease to already threatened gopher tortoises, although they aren’t sure of the likelihood.
Florida already has 43 established populations of alien lizards, the researchers found.
Many sprung free of their cages during Hurricane Andrew. The 1992 storm also opened up the tree canopy in South Florida, creating more opportunity for lizards of all stripes to invade new habitat. Capturing or killing so many rapidly reproducing lizards is logistically impossible, biologists say.
Even the brown anole, by far the state’s most prolific backyard lizard, doesn’t belong here. It’s believed responsible for drastic declines in the native green anole and possibly other species. The brown anole was the first invasive anole recorded in Florida, arriving in the Keys from Cuba in 1887. Many other foreign lizards hopped on cargo ships when trade with Cuba was common.
Sometimes the impacts are in plain sight. The green iguana, a 5-foot native to Central and South America, munches native shrubs, trees and landscaping and defecates on boat docks and swimming pool decks. Two years ago, an off-duty firefighter found a 4-foot Nile monitor lizard near New Haven Avenue and Dairy Road, slithering its forked tongue at motorists.
No one prosecuted
The researchers criticize Florida’s lack of enforcement of laws that make it illegal to release non-native animals. No one’s ever been prosecuted for the establishment of a non-native animal in Florida, they note. So they want stricter, more enforceable laws that require those responsible for the introductions to pay for eradication. They also propose Florida start an early detection and rapid response program.
FWC conducts “Amnesty Days,” in which exotic pets are taken in and put up for adoption. FWC also has issued special permits to hunt Burmese pythons in the Everglades from airboats.
But such efforts barely skim the surface, Krysko said. “I think the Burmese python is just a horrible example of what the pet trade has allowed to be done. We’re going to see a lot worse things from that species.”