October 22, 2012

The Ultimate Fraser Island Frog Blog


Ranger Nick reporting here.  Recently the resort team were lucky enough to host Dr Jean-Marc Hero  on Fraser island.  Dr Hero is an ecologist and associate professor from the Environmental Futures Centre (Gold Coast campus of Griffith University) and visited the world’s largest sand island in October to share his considerable expertise in amphibian ecology.

Dr Jean Marc Hero in action in the wallum
Dr Hero joined myself and the Ranger team at Kingfisher Bay (as part of our Special Guest line up) to share his experiences with frogs of eastern Australia and his knowledge on global amphibian declines. Having conducted fieldwork in Australia, Brazil, Fiji and Nepal, Dr Hero has been on the forefront of research into amphibian declines – including the decline of stream-dwelling frogs in relatively undisturbed habitats (due to disease and climate change) that have been observed around the world - and presented a fascinating talk aptly named ‘Global Amphibian Declines.’

It’s no secret that over the past 30 years frogs have suffered massive declines and extinctions worldwide and that these declines are linked mainly to habitat loss, fungal disease and climate change.

As soon as the Saturday night formalities were over, it was off in to the wallum at the front of the resort, with several guests and rangers in tow for a night nature walk and to see some of our amphibian friends in action.
 Dr Hero had mentioned during his presentation, that frogs have been identified as the vertebrate group at the most risk of extinction - proportionally they have more threatened species than birds, mammals or reptiles.

As we walked through the scrub – with the sound of frog-song in our ears – we reflected on the fact that more than 200 species have been reported extinct (six of these species from Australia alone) since 1979, and a further 2,000+ species have been reported as ‘in decline’… it’s pretty staggering stuff to digest!

Did you know that the way to tell the difference between male and female frogs is to look at their throats? 

A Wallum Rocket Frog on Fraser Island
Males have a dark patch and females are paler in colour. This identification technique also worked a treat on a Cane Toad that Dr Hero found down near our resort helipad. The Cane Toad (Bufo Marinus) – also known as a Marine Toad – is an introduced species that is native to Central and South America and, because of its voracious appetite, was introduced into Australia as a method of agricultural pest control.

Ironically, the Cane Toad is now considered a pest and an invasive species in many of the introduced regions in part because the Cane Toad has poison glands and the tadpoles are highly toxic to most animals – including native predators – when ingested.

Back on the frog trail, Dr Hero told us how frogs share ecosystems by utilising a range of breeding sites ranging from stream to ponds.  Some species actually avoid water altogether and lay their eggs in totally terrestrial environments.

In the coastal wallum habitats of mid-eastern Australia (and on large sandy islands like our own Fraser Island) there are a unique group of ‘acid frogs’ which only breed in the highly acidic waters of these habitats. Despite the cooler spring weather, we were lucky enough to see and / or hear three of Fraser Island’s four Acid frog species - the Cooloola Sedge Frog (Litoria cooloolensis - see below), the Wallum Sedge Frog (Litoria olongburensis) and the Wallum Rocketfrog (Litoria freycineti - pictured above).

The tiny - but loud - Cooloola Sedge Frog on Fraser
I have to say Mother Nature has a sense of humour and our visitors were amazed that such a BIG noise could come from such a tiny throat.

During Jean Marc’s Sunday night presentation, he discussed the amazing biology of amphibians and how so many species co-exist on Fraser Island. Due to a technical glitch, Dr Hero was unable to use all of his sound recordings to show the ways frogs sharing acoustic space - only male frogs call to attract female - by using different frequencies; female frogs have hearing that is finely tuned into the specific frequency of male for the same species… but with so many amphibian friends in and around the resort grounds, we were able to see them in action for ourselves.

We hope you tune in next month to find out what our feathered, furred and frog friends have been up to on Fraser Island. This is Ranger Nick signing off.

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