DAILY NEWS (St Thomas, U.S. Virgin Islands) 11 January 06 Frog science - Comprehensive habitat study will be the first systematic survey of St. Thomas amphibians (Lynn Freehill)
St. Thomas: Renata Platenberg is about to begin surveying nightlife on St. Thomas, but she won't be doing it from a beach bar or dance club. Instead, she'll be trolling around woods, wetlands and residences - searching for frogs.
A wildlife biologist with the V.I. Division of Fish and Wildlife, Platenberg is beginning what she said is the first systematic survey of frogs on the island. Until at least the end of 2007, she will document the locations of the four species of the amphibians native to the territory: Antillean, whistling, white-lipped and mute frogs.
She will do the same for Cane toad, Cuban treefrog and Puerto Rican coqui, the three types of frogs that were not here originally but were introduced through shipments of plants.
Of particular interest to her are the Cuban treefrogs, which she said are "voracious predators" that have been problematic in Australia and other places, and the mute frogs, which are found only in the Virgin Islands.
In 2004, the mute frog was added to the global "red" list of threatened species by the International Union for Conservation of Nature and Natural Resources, which cited a continuing decline in the quantity and quality of the frog's habitat in the Virgin Islands as a reason for its inclusion.
The V.I. Fish and Wildlife Division considers the mute frog "locally data deficient" - a status Platenberg said she hopes her work can change.
"We know so little about these guys. We're trying to get a grip on their habitat," she said. "You put together enough of these sightings, and you can figure out who they are."
Equipped with a headlamp, a global positioning satellite unit and measuring tools, Platenberg set out in the evening on Jan. 4 to find and document any frogs she could.
Her keen sense of hearing is Platenberg's first identification tool, because she can distinguish each of the frog species' calls. But because the lungless amphibians breathe through their skin, they only call to attract mates when their environment is moist - and last Wednesday was too dry to hear anything but crickets, Platenberg said.
Tiny mute frogs, which are just an inch or two in diameter, do not emit noise, so Platenberg will search for them under rocks. She also set up PVC-pipe attraction devices to lure Cuban treefrogs.
Depending upon how prevalent she finds Cuban treefrogs to be, she may recommend species-control action to the wildlife division, she said.
In the British Virgin Islands, where the species also is not native, officials have had success since 2004 controlling Cuban treefrog breeding by distributing a pamphlet to residents that instructs them to screen their cisterns and eliminate standing water.
Frogs may receive less attention in the Virgin Islands than marine life, Platenberg said, but given that studies show they feed on cockroaches around houses, they are due for more appreciation.
"Sometimes you don't notice they're out there, but they're part of the natural ambiance," she said. "When you're having a cocktail out on your balcony, that's what you're listening to. That they can coexist with humans is a really neat thing.
And, Platenberg added, "They eat a lot of bugs."
To suggest a site for the frog survey, contact the V.I. Division of Fish and Wildlife at 775-6762.
Comprehensive habitat study will be the first systematic survey of St. Thomas amphibians