One of world's only pure blue lizards at risk of extinction
By Tina Butler and Rhett Butler
March 7, 2007
Approximately 35 miles off the Pacific coast of Colombia lies Gorgona, an island with a unique past and an uncertain future. A high security prison colony was maintained on the island beginning in the 1950s until its closure in 1984. Because the island is separated from the mainland by an underwater depression 270 meters deep, Gorgona maintains some endemic biodiversity. In 1985, the island reemerged as a national park to protect the rare species that thrived in the delicate ecosystem.
The blue anole is truly stunning to behold--it is pure blue, with no color differentiation between males and females. The largest visual distinction is the male's dewlap, like other anole species, except in this case the dewlap is bright white, making the blue contrast ever more dramatic. In spite of this striking color, few humans have been lucky enough to spot the world's only pure blue lizard.
Male blue anole on Gorgona. Photo by Thomas Marent.
Thomas Marent (www.thomasmarent.com), a world renowned photographer visited Gorgona specifically to photograph the blue anole. It took him four days to find one, which was promptly eaten by a Basilisk after he had taken just two pictures. Marent was told that Basilisks are one of the reasons for the demise of the blue anole, though exhaustive conversations with herpetologists now suggest this is not the case. In any event, Marent's beautiful photo of the blue anole getting chomped by a Basilisk can be found in his wonderful book of photographs, Rainforest
Blue anole on Isla Gorgona. Photo by Maria Margarita Ramos.
Maria Margarita Ramos is a graduate student at the Ecology and Evolutionary Biology Department at Princeton University. Ramos studied Anolis gorgonae on Gorgona in 2004and notes that the lizard spends most of its time near the tops of trees where boas and other arboreal snakes are its natural predators.
In spite of troubled efforts to get a definitive population estimate for the species, local expert herpetologists agree that the blue anole is a threatened species. The primary threats appear to be habitat destruction through deforestation and over-collection by zealous admirers of the beautiful and uniquely colored lizard. Deforestation is a particular threat as the blue anole is an arboreal species, with only the females venturing to the forest floor on the occasion to deposit their eggs.
Fernando Castro, a biologist at the Universidad del Valle who has studied the reptiles of Gorgona, told mongabay.com that much of the deforestation that occurred on Gorgona took place when the island was a prison.
"The population relied heavily on the collection of fuelwood," said Castro.
Further, he says, habitat modification may disrupt the delicate ecological balance of the island, putting some species at a disadvantage to their natural predators.
"Today we really know very little about the ecological needs of this species," explained Castro. "We do not know the carrying capacity of its present area of habitat or whether biological and ecological relationships -- like predator-prey relationships -- have shifted. It is possible that A. gorgonae's natural predators, including birds, monkeys, or other reptiles, have better adapted to the changes."
An added threat, due to the isolated nature of the island and its fragile equilibrium of species, are invasive organisms. Such "alien invasives" have caused severe ecological havoc on island environments around the world.
Finally. growing interest in Gorgona as a tourist destination is a concern. Recently part of the island was privately concessioned for tourism and Castro says it is unlikely that tour operators will be overly concerned about the well-being of a small lizard [update].
A proposal for saving the blue anole
Gorgona Island off the coast of Colombia: home to the rare and spectacular blue anole. Map derived from Google Earth satellite images.
A similar project organized by the National Geographic Society (NGS) has met some success. Last year the organization announced it would offer specimen of the Wollemi Pine, one of the world's oldest and rarest trees, to consumers in the United States. NGS figured that the sales would be an opportunity to conserve and propagate the species. Some of the proceeds also went towards conservation efforts of the prehistoric species in its native habitat in Australia.
Castro says that a captive breeding program could be an effective way to prevent the extinction of the species, noting that Anolis carolinensis, a related species, is regularly bred in the United States for the pet trade.
"While it would be technically illegal to remove lizards from Gorgona under current Colombian law since A. gorgonae is a protected species, the reproductive techniques used in the U.S. could be applied here on Gorgona to help increase the population of the species," said Castro. However he warned that only a minimal number of wild anoles should be captured for any sort of captive breeding program.
He added that in situ conservation strategies, based on the island of Gorgona, are preferable to ex-situ approaches which would remove the species completely from its natural habitat.
"We need to devise in situ research -- not ex-situ -- to improve our understanding of the entire Gorgona ecosystem. If you think saving A. gorgonae is going to be difficult, wait until you try to preserve all the species on the island."
Castro has a good point. Nevertheless, using A. gorgonae as a symbolic species for the conservation of Gorgona as a whole could help the island's other species avoid singing the blues.
Note: there are other species of lizard with blue coloration -- including the Blue Iguana (Cyclura lewisi), which is also critically endangered; various chameleons, African agamids, among others -- but A. gorgonae is one of the only species with "pure" blue coloration head-to-tail. Another species is the Electric-blue day gecko (Lygodactylus williamsi)]
Update: The Aviatur Group, the tour operator that took over the Gorgona concession, has made the blue anole a symbol in its advertising campaigns for tourism in Gorgona. The lizard is featured in billboards all over Bogota.