Context dependence of risk effects: wolves and tree logs create patches of fear in an old-growth forest

Abstract

Large mammalian carnivores create areas perceived as having high and low risk by their ungulate prey. Human activities can indirectly shape this landscape of fear by altering behavior and spatial distribution of carnivores. We studied how red deer perceive the landscape of fear in an old-growth forest system (Bialowieza Primeval Forest, Poland) both at large and fine spatial scale. Camera traps were placed at locations with and without tree logs (fine-scale risk factor) and at different distances from the core of a Wolf territory and settlements (large-scale risk factor). Red deer avoided coming close to large tree logs and increased their vigilance levels when they were present in close vicinity. The strength of these effects depended on the distance to the Wolf core area; deer perceived tree logs as more risky when wolves were more often present. Hence, tree logs inside Wolf core areas create fine-scale patches of fear with reduced deer browsing pressure, thereby enhancing chances for successful tree recruitment. Human presence shapes this landscape of fear as Wolf core areas are located far from settlements. This human shadow on predator-prey interactions is therefore an important component that should be taken into account in human-dominated landscapes.