By putting microphones in the jungle, researchers are better able to perform the surprisingly tricky task of counting elephants.
Sure, pachyderm polling doesn't seem difficult. They're not exactly hard to see. But covering hundreds of square miles, day after day, requires time, money and personnel — all of which are in short supply in the developing countries where elephants live.
Enter the Elephant Listening Project at Cornell University. Using acoustic monitoring and analysis techniques originally developed for counting birds by song, it tracks elephants in the jungles of Central Africa.
In a paper published in the September* African Journal of Ecology*, project researchers describe the calibration of their model at a Central African Republic site. First they personally observed forest clearings where elephants were known to gather, counting the animals they saw and the noises they made. The researchers then turned these observations into a framework for interpreting recordings made by microphones installed throughout the forest.
The same approach "provides an opportunity to improve management and conservation of many acoustically active taxa whose populations are currently under-monitored," wrote the researchers.
In addition to being relatively inexpensive and geographically comprehensive, bioacoustic monitoring offers other advantages over traditional animal counts. It can give detailed ecological snapshots, counting anything that makes a noise.
For the elephant counts, each monitor covered a square mile of ground, "a dramatic increase in coverage over dung survey transects." In other words, it's a lot easier to listen to elephants than gather their poop.
Image: Elephant Listening Project
Via the Conservation Maven.
See Also:
- A Listening Party for Nature
- Hydrophones Help Scientists Pinpoint, Protect Right Whales
- Shhh, Listen — Rare Soundscapes of Vanishing Habitats
- Clive Thompson on How Man-Made Noise May Be Altering Earth's Ecology
Citation: "Acoustic estimation of wildlife abundance: methodology for vocal mammals in forested habitats." By Mya E. Thompson , Steven J. Schwager, Katharine B. Payne and Andrea K. Turkalo. African Journal of Ecology, *Vol. 47 No. 3, September, 2009. *
Brandon Keim's Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on a book about ecosystem and planetary tipping points.
