The application of acoustic sensing technology to African lion (Panthera leo) ecology and conservation

Thesis

Recent technological advances are revolutionizing the field of ecology and conservation by providing tools and techniques to overcome many of the challenges that have previously limited the understanding of particular animal species and their environments. Significant improvements in acoustic sensing tools have led to an increase in their use for the research and management of vocally active species, particularly those that are difficult to monitor visually and continuously. However, the application of acoustic monitoring methods is often limited by high equipment costs and poor knowledge of many species’ vocal behaviour. This is indeed the case for African lions (Panthera leo) which are well known for their characteristic roars, but for which an in-depth understanding of vocal behaviour has been difficult to acquire due to the complexities of directly observing and manually recording vocalizations. In this work, I investigate the use of animal-borne and static acoustic recording technology for improving the understanding of lion behaviour and explore its application as a monitoring tool for the species. I begin by testing a novel acoustic biologging approach for recording animal behaviour remotely and find it to be an effective technique for acquiring rich, long-term datasets on lion activities. Coupled with machine learning methods, I then apply this approach to investigate patterns of lion vocal behaviour and show that territorial males are more likely to roar under atmospheric conditions that favour long-distance sound transmission and also adjust their vocal behaviour depending on spatial attributes. Next, I present an affordable, custom-designed passive acoustic sensing tool capable of localizing animal call signals over long ranges (> 1 km) owing to a novel multi-microphone hardware design. Finally, I demonstrate the use of this tool for localizing lion roars and, combined with on-animal audio recordings, discover an individually unique call feature that enables vocal differentiation of individual lions which could facilitate collar-free tracking. Collectively, the findings presented in this thesis highlight the value of acoustic sensing for both understanding animal behaviour and monitoring individual movements over time and space.

Authors: Wijers, MC

• DOI: 10.5287/ora-obyg0poyk
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English