Heard But Not Seen - Acoustics and Rainforest Conservation

Aerial view of Congo Basin Rainforest
The dense habitat makes counting elephants from
a plane impossible. Counting elephant calls instead
is a viable alternative

Effective monitoring of forest elephant numbers is essential to the design and implementation of any plan to conserve this species. Without this, we have no way of determining the distribution and abundance of elephants, their habitat needs, and where efforts should be focused. Also, repeated monitoring is needed to assess the efficacy of conservation measures.

In the case of the savannah elephant, aerial surveys are conducted to estimate elephant numbers, but the dense canopy of the Congo Basin forest prevents use of this methodology. Instead, estimates have been based on dung-counts and intensive monitoring at forest clearings, where many elephants congregate.

The Elephant Listening Project is adding an additional and unique tool to the arsenal of methods targeted on elephant conservation. Elephants depend heavily on acoustic communication to coordinate family movements and when engaging in social interactions, and so they can be heard even where they can't be seen. We have developed tools to listen in on elephant communication, and this method causes almost no disturbance to elephants. Best of all, an elephant's infrasonic calls travel long distances, so microphones can pick up their calls from a large area (much larger than is feasible by dung-counting). Developing and refining an effective, practical acoustic system for people to use to monitor forest elephants in Africa is the Elephant Listening Project's main focus, and our results so far are extremely promising.


Animals in rainforests present a special challenge for conservationists because they are difficult to monitor. However, if the species uses sound to communicate, acoustic monitoring may be an effective tool for estimating abundance and population trends over time.

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© Andrea Turkalo

Natty2, an adult male forest elephant, enters the Dzanga forest clearing in the Central African Republic