The mere threat of predation may incite behavioral changes in prey that lead to community-wide impacts on productivity, biodiversity, and nutrient cycling. The paucity of experimental manipulations, however, has contributed to controversy over the strength of this pathway in wide-ranging vertebrate systems. We investigated whether simulated gray wolf (Canis lupus) presence can induce behaviorally-mediated trophic cascades, specifically, whether the ‘fear’ of wolf olfactory cues alone can change deer foraging behavior in ways that affect plants and soils. Wolves were recently removed from the Cedar Creek Ecosystem Science Reserve (Minnesota, USA), such that consumptively mediated predator effects were negligible. At 32 experimental plots, we crossed two nested treatments: wolf urine application and herbivore exclosures. We deployed camera traps to quantify how white-tailed deer (Odocoileus virginianus) adjusted their spatiotemporal habitat use, foraging, and vigilance in response to wolf cues and how these behavioral changes affected plant productivity, plant communities, and soil nutrients. Weekly applications of wolf urine significantly altered deer behavior, but deer responses did not cascade to affect plant or soil properties. Deer substantially reduced crepuscular activity at wolf-simulated sites compared to control locations. As wolves in this area predominantly hunted during mornings and evenings, this response potentially allows deer to maximize landscape use by accessing dangerous areas when temporal threat is low. Our experiment suggests that prey may be sensitive to ‘dynamic’ predation risk that is structured across both space and time and, consequentially, prey use of risky areas during safe times may attenuate behaviorally-mediated trophic cascades at the predator–prey interface.

仅仅是捕食的威胁就可能引起猎物的行为改变，从而导致整个社区对生产力，生物多样性和养分循环产生影响。然而，由于缺乏实验手段，因此在广泛的脊椎动物系统中对该途径的强度产生了争议。我们调查了模拟灰狼（Canis lupus）的存在会诱发行为介导的营养级联反应，特别是，仅凭狼嗅觉提示的“恐惧”是否就能以影响植物和土壤的方式改变鹿的觅食行为。最近从美国明尼苏达州的锡达河生态系统科学保护区（Cedar Creek Ecosystem Science Reserve）搬走了狼，因此，消费介导的捕食者影响可忽略不计。在32个实验区，我们进行了两种嵌套处理：狼尿施用和草食动物排泄。我们部署了相机陷阱以量化白尾鹿（Odocoileus virginianus）调整其时空栖息地的使用，觅食和警惕性以响应狼的暗示以及这些行为变化如何影响植物的生产力，植物群落和土壤养分。每周施用狼尿可显着改变鹿的行为，但鹿的反应并没有影响植物或土壤特性。与对照位置相比，鹿在狼模拟的地点显着减少了夜间活动。由于该地区的狼主要在早晨和晚上被狩猎，因此这种反应可能使鹿在暂时性威胁较低的情况下进入危险区域，从而最大限度地利用景观。我们的实验表明，猎物可能对跨时空结构的“动态”捕食风险敏感，因此，