Abstract:

Aims: Passive acoustic monitoring technology has begun to be widely used for monitoring terrestrial mammals. Such technology enables the unattended monitoring of wildlife in specific areas at a low-cost and in a non-invasive manner. The main problem, however, is the need to manually retrieve the data. Moreover, the subsequent data analysis and sorting can be complicated.
Innovation: In this study, a passive acoustic monitoring system was designed for monitoring the western black crested gibbon (Nomascus concolor). The monitoring system is powered by solar energy in the field. Sound data are collected by a directional pick-up array. The data are transmitted through a wireless network to a server in the management office building. Researchers are assisted in identifying the sound and the direction of the sound by using the sound-data management system, which simplifies data collection and processing.
Significance: This system has been continuously monitoring two groups of western black crested gibbons for at least 351 days at the monitoring site (of Pipaqing in the Ailao Mountain Nature Reserve). Monitoring results up until now demonstrate that the system has had a long continuous run-time and is not affected by the weather conditions; data transmission is convenient and efficient; the directions of sound source can be determined by the directional pick-up array well, overcoming the shortcomings of traditional monitoring equipment. This system has advantages over manual monitoring methods in terms of data continuity and integrity, intelligence in data processing, and monitoring costs. This system meets the continuous long-term monitoring needs of western black crested gibbons, and can be improved and applied in the future as an automated solution for the monitoring of this primate species.

Key words: passive acoustic monitoring, directional pick-up array, western black crested gibbon, sound source localization