Geckos and skinks back from the brink
Researchers from The University of Western Australia are supporting a new project to trial the release of critically endangered blue-tailed skinks into a wild enclosure.
The initiative follows highly successful captive breeding programs that have brought Christmas Island's Lister's gecko and the blue-tailed skink back from the brink of extinction.
The two unique Christmas Island reptiles were widespread until the 1990s when numbers started dramatically declining, thought to be due to the introduced common wolf snake (Lycodon capucinus) from South East Asia. In the trial release of skinks to a 2500 square meter enclosure, the area was first cleared of all snakes and other introduced predators.
Researcher Jon-Paul Emery from UWA is working closely with Christmas Island National Park staff to monitor the release and fill gaps in our knowledge about the blue-tailed skink.
"We are closely monitoring the trial which began in April 2017 to assess the survival and condition of the 139 skinks which were released. So far they are doing very well," Mr Emery said.
"What we are hoping for is that the skinks will establish functioning and self-sustaining populations with minimal intervention from people, if introduced predators are controlled.
"If this release is successful, it will allow the potential for more skinks to be reintroduced into enclosures on Christmas Island, a major step in securing the future of the species.
"Not much is known about the behaviour, habitat and diet preferences of the skink in the wild so monitoring this trial is a great opportunity to advance our understanding of this species, and will be valuable for identifying potential future release sites.
"It is the success of the captive breeding program established by Parks Australia and Taronga Zoo seven years ago that has allowed us to now look at conservation strategies beyond only captive breeding, and that is terrific for the future of the species."
Christmas Island National Park Field Program Coordinator Brendan Tiernan has worked on the island for more than a decade and was involved in the captive breeding program from its inception.
"When I arrived the blue-tailed skink was roaming freely in healthy numbers across the island. But when numbers dropped dramatically national park staff intervened and in 2009 and 2010 the parks team began catching the lizards in preparation for captive breeding," Mr Tiernan said.
"It was incredible how quickly they disappeared," he said. "In 2010 we caught 20-30 blue-tailed skinks from a site the size of a tennis court. It was the last known area where we could find them."
The team overcame many unknowns as neither species had been bred in captivity before.
"It took a lot of careful management, resourcefulness and ingenuity. The project has exceeded our expectations," Mr Tiernan said.
"In 2016 the captive populations of each species doubled, starting at fewer than 500 and ending with about 1000 of each species by December 2016."