Danger From the Sky? The Three-Dimensional Landscape of Risk of Habituated Vervet Monkeys (Chlorocebus pygerythrus) From Aerial Predation

Predator–prey interactions are pivotal for ecosystem dynamics, with predators influencing prey not only through lethal events, but also through the establishment of a landscape of risk, that is, the spatial representation of how a prey population perceives predation risk. Habitat structure plays a crucial role in shaping this perception. A three-dimensional approach, both considering the horizontal as well as the vertical landscape dimensions has, thus far, been mostly overlooked. We hypothesize that primates in a savannah landscape perceive predation risk in a three-dimensional (3D) landscape, with both terrestrial and aerial predation risk influencing their spatial use of the environment, and that this perception is shaped by habitat structure. We employed giving-up density (GUD) as a proxy for perceived risk when foraging. A landscape of risk is observed in leafed trees, where in the central and bottom parts of the tree the lowest predation risk is perceived. When canopy cover is absent, the lowest perceived risk is on the ground instead of in the tree, indicating an impact of aerial predation risk. These findings underscore the importance of 3D landscapes and habitat structure in shaping prey spatial behaviour, demonstrating that habitat use is adjusted in response to both terrestrial and aerial threats.