Impacts of carnivores on tropical forest dynamics through trophic cascades: the study case of Central African wild cats

Carnivores, often identified as keystone species, can exert pivotal roles in ecosystems by triggering trophic cascades through density- or behaviourally-mediated pathways. Despite the documented role of carnivores in trophic cascades, the varying strength of evidence and the limited scope of studies concerning specific species and ecosystems raise questions. This study aims to fill a void in Central African tropical forests, focusing on the ecological roles of the leopard (Panthera pardus) and the golden cat (Caracal aurata) - the two largest carnivores in Central African forests. These species face imminent threats, and their direct and indirect effects on prey and vegetation remain largely unexplored. Specifically, within three study sites characterized by varied anthropogenic pressures in south-eastern Cameroon and northern Congo, our objectives are to: (i) determine wild cat densities, diet composition, and prey abundance; (ii) evaluate the impact of herbivore and granivore populations on the regeneration of some high-value timber species; (iii) explore the indirect influence of leopard and golden cat presence/absence on vegetation regeneration. Our methodology involved deploying grids of 63 camera trap sites and collecting wild cat faeces in each study site, including a protected area and two FSC-certified logging companies. Concurrently, experimental designs targeting several timber species were set up to assess predation rates on seeds and seedlings by granivore and herbivore populations. Additionally, an experiment simulating a landscape of fear using odour cues was designed to gauge potential non-consumptive effects on prey and, consequently, impacts on vegetation. Our interdisciplinary approach aims to enhance our understanding of the ecological roles played by these Central African wild cats, informing conservation strategies amidst the escalating threats of poaching and defaunation.