Managing wildlife populations is a tricky venture. You want to help endangered species fight for their survival in order to build up their numbers, but you don’t want to disrupt an entire ecosystem. In Australia, on the Queensland coast at Wreck Rock Beach, loggerhead sea turtles are one of those endangered species whose nests are threatened by goannas, a kind of Australian monitor lizard. These pesky lizards have devoured thousands of eggs and hatchlings, so researchers are trying everything they can to reverse this.
The World Wildlife Fund (WWF) Australia reports that there are more than 70 female loggerheads that nest at Wreck Rock Beach every year, the second largest nesting site for this turtle in the South Pacific Ocean. Predators have always been a threat to the loggerhead – before the goanna, it was the fox, a problem they solved by baiting. It isn’t as easy with goannas.
The Solution
Before arriving at the tracking device solution, researchers tried to utilize aluminum cages which were set up over loggerhead nests in order to keep the goannas from getting to the eggs and hatchlings. It was successful – the trial program started in 2014 was able to rescue roughly 1,200 hatchlings, but researchers spent about 20 minutes installing each one. Therefore, the project wasn’t feasible for a small team of researchers and a large number of nests.
Their solution not only saves the endangered loggerhead but allows researchers to take a peek into the habits of goannas in a way never before possible. They are trying out various deterrents, and adding in the use of GPS trackers. WWF-Australia, Gidarjil rangers, the Burnett Mary Regional Group, and Turtle Care are all working together on this project, with about $180,000 in funding received through the Nest to Ocean Turtle Protection Program, an initiative by both the Australian and Queensland governments. The initiative aims to cut down on incidents of predators destroying nests.
What They’re Learning
A scientist with the University of Queensland who’s working on the project, Dr. David Booth, said that it appears yellow spotted goannas – larger in size than other varieties – are typically the first to tamper with the nest. They are a lot more powerful than the smaller goannas, and thus can dig down into the sand more easily. They make these tunnels, and the smaller goannas and lace monitors (another lizard) will explore them, sometimes finding an egg left behind.
The GPS tracking unit affixed to some of the goannas seems to prove this – the yellow spotted goannas are seen wandering the beach much more often than lace monitors. So it seems that if research shows this to indeed be the problem, simply relocating the yellow spotted goannas to another area will solve the problem.
Smarter Than Your Average Lizard
The team initially tried other measures that work in other countries, such as spreading pepper over the nest and placing a flag next to the nest. Most predators get a whiff of the pepper and stay clear of the area in the future due to discomfort, and the flapping of the flag frightens others away.
This isn’t the case with the goanna – these methods were tried, and failed. However, they have discovered plastic mesh works in quite the same way as the metal cages, and they are much easier and quicker to install.
The Importance of the Loggerhead
Wreck Rock Beach is prime nesting ground for this variety of sea turtle. WWF-Australia spokespeople highlight the importance of healthy turtle populations in terms of overall health of the Great Barrier Reef. If there is anything people can do to help, it must be done for the health and well being of this amazing reef long into the future.
