Apex predators can shape communities via cascading top–down effects, but the degree to which such effects depend on predator life history traits is largely unknown. Within carnivore guilds, complex hierarchies of dominance facilitate coexistence, whereby subordinate species avoid dominant counterparts by partitioning space, time, or both. We investigated whether a major life history trait (hibernation) in an apex carnivore (black bears Ursus americanus) mediated its top–down effects on the spatio-temporal dynamics of three sympatric mesocarnivore species (coyotes Canis latrans, bobcats Lynx rufus, and gray foxes Urocyon cinereoargenteus) across a 15,000 km² landscape in the western USA. We compared top–down, bottom–up, and environmental effects on these mesocarnivores using an integrated modeling approach. Black bears exerted top–down effects that varied as a function of hibernation and were stronger than bottom–up or environmental impacts. High black bear activity in summer and fall appeared to buffer the most subordinate mesocarnivore (gray foxes) from competition with dominant mesocarnivores (coyotes and bobcats), which were in turn released by black bear hibernation in winter and early spring. The mesocarnivore responses occurred in space (i.e., altered occupancy and site visitation intensity) rather than time (i.e., diel activity patterns unaffected). These results suggest that the spatio-temporal dynamics of mesocarnivores in this system were principally shaped by a spatial predator cascade of interference competition mediated by black bear hibernation. Thus, certain life history traits of apex predators might facilitate coexistence among competing species over broad time scales, with complex implications for lower trophic levels.

尖顶捕食者可以通过级联的自上而下的影响来塑造社区，但是这种影响取决于捕食者生活史特征的程度在很大程度上尚不清楚。在食肉动物行会中，统治的复杂等级有助于共存，而从属物种则通过划分空间，时间或同时分配两者来避免与优势物种相对应。我们调查了尖顶食肉动物（美洲黑熊熊）的主要生活史特征（冬眠）是否介导了其对三种同伴中生食肉动物物种（土狼Canis latrans，山猫山猫Lynx rufus和灰狐狸）的时空动态的自上而下的影响跨越15,000公里^2的Urocyon cinereoargenteus）美国西部的自然景观。我们使用集成的建模方法比较了自上而下，自下而上和环境对这些中生动物的影响。黑熊产生的自上而下的效果随冬眠而变化，并且比自下而上或环境的影响要强。夏季和秋季的黑熊活动频繁，似乎可以缓冲与主要食肉动物（土狼和山猫）竞争的最次要的食肉动物（灰狐狸），而食肉动物则在冬季和早春被冬眠的黑熊释放。中食肉动物的反应发生在空间中（即，占用率和站点访问强度发生了变化），而不是时间（即，迪尔活动模式未受影响）。这些结果表明，该系统中食肉动物的时空动态主要受黑熊冬眠介导的干扰竞争的空间掠食者级联的影响。因此，先头天敌的某些生活史特征可能会促进竞争物种在较宽的时间范围内共存，这对降低营养水平具有复杂的影响。