And then there was one: a camera trap survey of the declining population of African elephants in Knysna, South Africa

Abstract

Conservation agencies rely on accurate wildlife population estimates to inform management practices. The importance of accuracy increases with smaller, threatened populations, but so too does the challenge in achieving it, especially for evasive species in low-visibility terrain. Non-invasive survey techniques have been successfully applied in such conditions; however, each technique bears a unique set of limitations and often deliver different results. The shy Knysna elephants (Loxodonta africana) occur at extremely low numbers in difficult terrain, and the past few decades have seen debates raging about their numbers, fuelled in part by differing survey outcomes, although a decline has been apparent over the last 150 years. We surveyed the known range of the Knysna elephant population for 15 months (July 2016 – October 2017), using camera traps, and identified one adult female elephant. The reliability of using camera trapping for surveying animal populations in conditions such as the Knysna elephant is compared with the previous faecal DNA genotyping survey. We conclude that this population has declined to a single individual and discuss the implications for local conservation authorities. Additionally, we highlight the importance of designing rigorous survey approaches where only a few individual animals are present.