HERALD-TRIBUNE (Sarasota, Florida) 25 August 08 'Anoles on steroids' adapt well (Margaret Lowman is director of Environmental Initiatives at New College of Florida. On the Web: www.canopymeg.com)
Somebody put us in the really bad position of having to kill these beautiful animals.
-- Todd Campbell, University of Tampa, for National Geographic Magazine (2005)
Beginning in 2003, a series of signs posted throughout Cape Coral have depicted this headline: Have you seen one of these? An ugly, warty-skinned, long-tailed, hulking Nile Monitor lizard was draped across the notice that described one of Florida's newest invasive reptiles. Enlisting public vigilance to report invasive species is difficult, if not impossible, unless the critters are closer in size to Godzilla. But Floridians are waking up to the cost, energy, devastation and fear factor with regard to some of our recent invasions.
Monitors were introduced accidentally from Africa by frustrated pet owners, who thought they were purchasing a docile and handsome lizard, only to rear an aggressive, ornery-tempered dragonlike beast. Nile monitors were first described by the famous taxonomist, Carl Linnaeus in 1766 as Lacerta monitor. Today, one species of monitor (scientific name Varanus niloticus) is populating Southwest Florida. This species grows up to 7 feet long and can weigh over 50 pounds.
Unfortunately for Floridians, Nile monitors are extremely adaptable, and enjoy a wide range of habitats including forest, savannah, woodland, bush land, thickets, scrub, swamps, mangroves, lakes and rivers. Their only major requirement is water. Since invading Florida, they have also adapted to rooftops, swimming pools, embankments, streets, walls, yards, and roadways. In their homeland of Africa, monitor populations are kept in check by their predators: lions, mongoose, cobras, crocodiles, and large eagles. (One can only hope that, despite pressures to control monitor populations, their enemies are not introduced as an antidote; our landscape is far safer with monitors in the back yard than with lions and cobras!)
Other characteristics of monitors that give them an amazing edge on survival are their abilities to run, climb, swim, and dive. In short, they are the proverbial "anoles on steroids" and exemplify Charles Darwin's survival of the fittest. Monitors were first observed in Florida around 1990, with the first recorded sighting at Four Mile Cove Ecological Park adjacent to the Caloosahatchee River. Residents in nearby Cape Coral have reported monitors feeding on their ducks, rabbits, goldfish, and digging grubs from their lawns. Biologists have observed monitors decimating populations of gopher tortoises, burrowing owls, and larger burrowing mammals as well as bird nests.
Professors Todd Campbell and Gregg Klowden of University of Tampa are ringleaders in stalking these aggressive lizards, but their search is almost akin to finding a needle in a haystack. Since original release in the Cape Coral area, monitors have expanded their range into Miami-Dade County, Pine Island, Gasparilla Island, Naples, and Fort Myers.
Given their aggressive behavior and relatively armor-like exterior, monitors will not be easy to eradicate. Citizens are encouraged to report any sightings to county "lizard alerts" or appropriate authorities for immediate removal from public and private properties.
Like most introduced species, monitor populations underwent four classic stages in their invasion: 1. introduction; 2. establishment; 3. naturalization and dispersal; and 4. pest status. The purpose of controlling invasives immediately upon invasion is to avoid reaching stage 3 (naturalization), at which time they begin to displace native animals, eventually disrupting the equilibrium of ecosystems and costing significant expense to eradicate.
Dogs are one possible solution in the control of invasive animals. Dogs have a keen sense of smell that could be enlisted to detect monitors via odor. The U.S. Department of Agriculture has its own Beagle Brigade, which inspects baggage for agricultural contraband in many international airports. Another "dog squad" successfully sniffed skin cancer sites in human patients, and uses scent to discriminate from benign versus melanoma. Dogs have also been successfully trained to detect explosives, locate pipeline leaks, sniff drugs or firearms in airline security, and locate turtle predators and invasive brown tree snakes in Guam. Amber Roux, New College thesis student who studied the possibility of using dogs for Nile monitor detection in Florida, concluded that "Myakka River State Park could someday have its own invasive and threatened species detection dog!"
'Anoles on steroids' adapt well