Do tadpoles make sounds?
Applying acoustic ecology to private land conservation
By James Hattam
While it might not be the burning ecological question of our time, it is a question few can answer. And as an ecologist I had no idea when I was asked. 'So, do tadpoles make sounds?'.
The answer is YES.
While the repetitive chorus of male frogs calling in the hope of attracting a mate is a common occurrence when we visit wetlands or other aquatic habitats, the unique vocalisations of tadpoles are something that is foreign to even the most avid nature enthusiast.
With the help of technology, we at the Protected Areas on Private Land Program, a partnership between the Tasmanian Land Conservancy and the Tasmanian State Government, are taking conservation landholders on a journey of discovery and opening their eyes and ears to the world of bioacoustics.
The field of bioacoustics or acoustic ecology is an emerging, cross-disciplinary science that brings together biology, ecology and acoustics. As conservation professionals we typically make conscious visual observations to guide and inform our understanding of ecological processes and ecosystems. We often use our ears subconsciously to listen to natural systems, yet rarely link what we learn formally.
Acoustic ecology provides that link. Bernie Krause, the famous American composer, is often referred to the god father of bioacoustics and soundscapes, and explains the emergence of the field through his life work in an inspiring TED talk.
During a recent visit to covenanted property is southern Tasmania, I along with conservation landholders Lyne and Allesandro, thought we would have a listen to one of their natural wetlands. You may ask how do you listen to a wetland? No, it doesn't involve getting wet. The answer is with the help of a hydrophone, which is a simple microphone designed to be used underwater for recording or listening to underwater sound. By setting up a hydrophone through a digital recorded we can listen live to what is going on in the aquatic environment.
It is fair to say when we put the head phones on to listen we were blown away. While it was silent above the water, it was a buzz with activity beneath the surface. Listen for yourself. And after some thorough searching we were able to decipher that the sounds we were hearing were tadpoles. This was first discovered by a team of scientists in Argentina in 2010.
This technology provides us with an incredibly powerful tool, whereby we can listen, record and share the unique sounds of ecosystems which we are naturally removed from. The soundscape can comprise a plethora of origins, from microscopic invertebrates feeding on detritus to the complexity of a dawn chorus of woodland birds. These sounds are often unique to an environment, which make them a useful means in monitoring changes in these systems through time as well as engaging the broader community through sharing these unique and often bizarre sounds to appreciate the value of protected areas on private land and the array of ecosystems and biodiversity which rely on them.
Below, Lyne and Allesandro listen to the life aquatic in a wetland on their property.
Photo: James Hattam
