Forest elephants shifted to nocturnal activity undetected by conventional censuses.

Evidence

The seismic prospecting in terrestrial ecosystems produces a disturbance to wild animals that is not easily evaluated by the traditional methods of line transect counts of individuals, dung, nest sites, or other biological signs. For instance, Wrege et al. (2010) have proposed an automatic acoustic survey able to collect information about movements and vocalization of populations of forest elephants (Loxodonta cyclotis) in Gabon, Central Africa in an area disturbed by oil prospection. Ten autonomous recording units (ARU) were dispersed in the area in which oil research was active. The ARU had a microphone and a geophone to collect seismic activity and sounds in atmosphere. Results indicate that elephant distribution and seasonal abundance and frequency of vocal emission apparently were not changed during blasting activity, but elephants had shifted their activity during the night, and the change toward nocturnal activity was increased with the increase of human proximity. This change in behavior would have escaped the traditional approach of censusing, demonstrating how acoustical monitoring represents an innovative and efficient system to detect changes in animal behavior that are the forerunner of long-term population dynamics. — Almo Farina, Soundscape Ecology, 1422

Categorization

• XREF: connects to: Acoustic monitoring detects behavior changes before abundance statistics do. — Almo Farina, Soundscape Ecology: Principles,…, 1416