The bush has a way of making you more attuned to the sounds around you, the call of the birds, the sound of the wind and rain, the rustle of leaves and the croaking of frogs.
But imagine trying to identify, in this cacophony of sound, the isolated grunt of a native mammal or the warble of a particular bird species.
“Ecologists need to measure the presence or absence of species to give them an idea of the species richness,” says Jason Wimmer, an ecology postgraduate student at Queensland University of Technology in Brisbane. To do so, they my spend hours in isolated regions, braving weather, remoteness and hard-to-discern animal noises.
“We give them acoustic sensors to record the sounds of the environment, the songs of birds, and the croaking of frogs,” he says. “We then have software that runs over the data to determine the number of animals.”
The sensors, developed at the Microsoft QUT eResearch centre, can be deployed for months recording data as memory or uploading instantly it via 3G networks.
“Because of potential loss of biodiversity and climate change we don’t know what is going on in the environment so it’s hard to get a grasp of what this change is.
“We need to get at the finer detail of what species are coming and going, monitoring the presence of invasive species and the timing of migratory birds.”
Switching onto ecology
Wimmer had an unconventional start in science, with a background in banking and IT. Wanting to switch focus, he enrolled in a PhD at QUT looking at the application of acoustic data recording and analysis to ecological surveys.
To get the record of noises, Wimmer employed experts in animal noise to create a databank for the software. Which was tough – imagine identifying dozens of bird calls without the advantage of being out in the environment.
But early results are promising. “Instead of having to be out in the field, which is expensive, [ecologists] can just throw these recorders out in the bush.
“Early trials are detecting roughly three times as many species as traditional surveys with people in the field,” he adds.
In one recent experiment, while trained observers were able to detect 12 bird species, the acoustic sensor and software employed by Wimmer picked up 58 birds in the same area.
Gauging the sounds
While acoustic sensors are used in ecological studies in the marine envoironment because of the quality of sound in water, there has been little testing of the effectiveness of the equipment on land, he points out.
“People have started grabbing hold of the idea of recording sound in the terrestrial environment. It’s cheap and accessible but to analyse the sound is really tough,” Wimmer points out.
“If we can give ecologists new tools to cover larger areas for longer periods of time, this will allow them to put in strategies to save endangered species,” he adds. And that’s got to be why we’re getting ecologists out there in the first place.