Herbivores balance forage acquisition with the need to avoid predation, often leading to tradeoffs between forgoing resources to avoid areas of high predation risk, or tolerating increased risk in exchange for improved forage. The outcome of these decisions is likely to change with varying resource levels, with herbivores altering their response to predation risk across heterogeneous landscapes. Such contrasting responses will alter the strength of non‐consumptive predation effects, but are poorly understood in multiple‐predator/multiple‐prey systems. We combined fine‐scaled spatial information on two predator and 11 herbivore species with remotely‐sensed measurements of forage quantity and vegetation structure to assess variation in herbivore response to predation risk with changing environmental context, herbivore body size, herbivore foraging strategy (browsers versus grazers), predator type (ambush versus coursing hunters) and group size across a South African savanna landscape. Medium‐sized herbivore species were more likely to adjust their response to risk with a changing resource landscape: warthog, nyala and wildebeest tolerated increased long‐term predator encounter risk in exchange for abundant (warthog and nyala) or preferred (wildebeest) forage, and nyala selected areas with higher visibility only in landscapes where food was abundant. Impala were more likely to be observed in areas of high visibility where wild dog risk was high. In addition, although buffalo did not avoid areas of high lion encounter risk, large buffalo groups were more frequently observed in open areas where lion encounter risk was high, whereas small groups did not alter their space use across varying levels of risk. Our findings suggest that risk effects are not uniform across landscapes for medium‐sized herbivores and large buffalo groups, instead varying with environmental context and leading to a dynamic landscape of fear. However, responses among these and other prey species were variable and not consistent, highlighting the complexities inherent to multi‐predator/multi‐prey systems.

中文翻译：

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非洲草食动物对恐惧景观的环境控制

食草动物在获取饲料与避免捕食之间取得平衡，这常常导致在现有资源之间进行权衡，以避免高捕食风险的地区，或容忍增加的风险以换取改良的牧草。这些决定的结果可能会随着资源水平的变化而改变，食草动物会改变其对异质景观中掠食风险的反应。这种不同的反应将改变非消耗性捕食效应的强度，但在多捕食者/多猎物系统中了解甚少。我们结合了两种捕食动物和11种草食动物物种的精细空间信息，以及对草料数量和植被结构的遥感测量，以评估草食动物对捕食风险的响应随环境，草食动物体型的变化而变化，草食动物的觅食策略（浏览器与放牧者），捕食者类型（伏击与追猎者）以及整个南非大草原景观的种群规模。中型草食动物物种更有可能随着资源格局的变化而调整其对风险的反应：疣猪，林羚和牛羚可以忍受增加的长期捕食者遭遇风险，以换取丰富的（疣猪和林羚）或偏爱的（野生）牧草，以及尼亚拉仅在食物丰富的风景中选择了可见度较高的区域。在野狗风险高的可见度较高的地区更容易观察到黑斑羚。此外，尽管水牛无法避免高狮子遭遇风险的地区，但在狮子高遭受风险的空旷地区，大型水牛群体更为常见，而小团体并没有在不同风险级别上改变其空间使用。我们的发现表明，对于中型草食动物和大型水牛群体而言，不同地区的风险影响并不相同，而是随环境而变化，并导致动态的恐惧环境。但是，这些和其他猎物物种之间的反应是可变的，而且不一致，这突出了多捕食者/多猎物系统固有的复杂性。