Estimating Abundance of Crop-Foraging Primates in Anthropogenic Landscapes Using Camera Traps

As human populations grow, competition with wildlife increases, driving more frequent and intense negative interactions between humans and wildlife, of which crop foraging by primates like baboons (Papio spp.) is a notable example. Farmers struggle to coexist with baboons, and are particularly concerned by their abundance, with more baboons resulting in more damage. Despite extensive primate research, there are few population estimates, particularly for chacma baboons (Papio ursinus). Estimating baboon densities could inform conservation policies, including strategies to mitigate crop losses and negative human-baboon interactions. Conventional techniques for estimating density are impractical for baboons in commercial farmland or have been unsuccessful in the past, but camera trapping could provide an alternative. Through field tests of the distance sampling with camera traps (CTDS) and the random encounter model (REM) methods, we compare estimates of chacma baboon densities, assessing the potential of these methods for monitoring species that move in large and stable social groups. Chacma baboon density was 1-3 individuals/km², comparable to abundance estimates elsewhere, suggesting that these methods can provide plausible estimates for monitoring baboon populations. Baboon presence and distribution appeared to be more influenced by the availability of sleeping sites than the location of crops, with both seemingly linked to the availability of water. Between-camera heterogeneity in detections was a large source of imprecision for both methods but further investigation is required to understand how assumptions made in implementing both methods affect accuracy and precision. Future implementations must be refined to successfully identify small changes in long-term monitoring data.