Do prey recognise the varying risk of lion predation?

Predators can induce behavioural changes in prey that influence vigilance, grouping patterns and space use, and these can ultimately affect prey demography and trophic interactions. Consequently, prey must respond to the risk of predation, but little is known about the features that drive the spatial responses of prey species to predators. We tested whether prey rely more heavily on olfaction or vision in determining their proximity to lions reintroduced to Addo Elephant National Park, South Africa. We also tested whether prey that are preferentially killed by lions show greater responsiveness than those that are not, and whether prey respond to predator behavioural states and hunger. Over 1588 observations of potential prey locations in relation to lions under varying wind directions, lion behaviours and hunger states throughout the day and night, we found that vision is the primary determinant of risk avoidance with no evidence of wind-driven odour responses affecting prey proximity. Prey outside the preferred prey weight range of lions occurred closer to lions than those species most at risk of lion predation. Prey were more likely to be closer to covertly behaving lions and further from stationary lions. Our evidence suggests prey responses to predators in intact, multi-species assemblages are context dependent, but driven largely by vision.

捕食者可诱导猎物发生行为改变，进而影响其警戒行为、集群模式与空间利用策略，最终还会对猎物种群统计学特征及营养级互作过程产生影响。因此，猎物必须对捕食风险做出响应，但目前学界对驱动猎物种群针对捕食者产生空间响应的具体特征仍知之甚少。本研究以重新引入至南非阿多大象国家公园（Addo Elephant National Park）的狮子为研究对象，旨在探究猎物在判断与狮子的空间距离时，更依赖嗅觉还是视觉。此外，本研究还验证了两个科学问题：一是相较于非优先被捕食的猎物，被狮子优先捕食的猎物是否会表现出更强的响应性；二是猎物是否会对捕食者的行为状态与饥饿程度做出响应。本研究在昼夜不同时段、不同风向条件下，针对狮子的不同行为状态与饥饿程度，开展了超过1588次潜在猎物与狮子相对空间位置的观测。结果发现，视觉是猎物规避捕食风险的主要决定因素，未发现任何证据表明风驱动的嗅觉响应会影响猎物与狮子的空间距离。体重处于狮子偏好捕食体重范围之外的猎物，相较于面临狮子捕食风险最高的物种，会更靠近狮子。猎物更倾向于靠近处于隐秘行为状态的狮子，而远离处于静止状态的狮子。本研究结果表明，在完整的多物种种群群落中，猎物对捕食者的响应具有情境依赖性，但主要由视觉驱动。