Catano Laura B, Barton Mark B, Boswell Kevin M, Burkepile Deron E
Marine Science Program, Department of Biological Sciences, Florida International University, 3000 NE 151st Street, North Miami, FL, 33181, USA.
Department of Biology, University of Missouri, St. Louis, 1 University Blvd., St. Louis, MO, 63121-4400, USA.
Oecologia. 2017 Mar;183(3):763-773. doi: 10.1007/s00442-016-3794-z. Epub 2016 Dec 22.
Non-consumptive effects (NCEs) of predators occur as prey alters their habitat use and foraging decisions to avoid predation. Although NCEs are recognized as being important across disparate ecosystems, the factors influencing their strength and importance remain poorly understood. Ecological context, such as time of day, predator identity, and prey condition, may modify how prey species perceive and respond to risk, thereby altering NCEs. To investigate how predator identity affects foraging of herbivorous coral reef fishes, we simulated predation risk using fiberglass models of two predator species (grouper Mycteroperca bonaci and barracuda Sphyraena barracuda) with different hunting modes. We quantified how predation risk alters herbivory rates across space (distance from predator) and time (dawn, mid-day, and dusk) to examine how prey reconciles the conflicting demands of avoiding predation vs. foraging. When we averaged the effect of both predators across space and time, they suppressed herbivory similarly. Yet, they altered feeding differently depending on time of day and distance from the model. Although feeding increased strongly with increasing distance from the predators particularly during dawn, we found that the barracuda model suppressed herbivory more strongly than the grouper model during mid-day. We suggest that prey hunger level and differences in predator hunting modes could influence these patterns. Understanding how context mediates NCEs provides insight into the emergent effects of predator-prey interactions on food webs. These insights have broad implications for understanding how anthropogenic alterations to predator abundances can affect the spatial and temporal dynamics of important ecosystem processes.
捕食者的非消费性影响（NCEs）表现为猎物改变其栖息地利用和觅食决策以避免被捕食。尽管NCEs在不同生态系统中都被认为很重要，但影响其强度和重要性的因素仍知之甚少。生态背景，如时间、捕食者身份和猎物状况，可能会改变猎物对风险的感知和反应方式，从而改变NCEs。为了研究捕食者身份如何影响草食性珊瑚礁鱼类的觅食行为，我们使用两种具有不同狩猎模式的捕食者物种（石斑鱼Mycteroperca bonaci和梭鱼Sphyraena barracuda）的玻璃纤维模型模拟捕食风险。我们量化了捕食风险如何在空间（与捕食者的距离）和时间（黎明、中午和黄昏）上改变食草率，以研究猎物如何协调避免被捕食与觅食这两个相互冲突的需求。当我们在空间和时间上对两种捕食者的影响进行平均时，它们对食草行为的抑制作用相似。然而，它们根据一天中的时间和与模型的距离而不同地改变摄食行为。尽管摄食行为随着与捕食者距离的增加而强烈增加，特别是在黎明时分，但我们发现梭鱼模型在中午比石斑鱼模型更强烈地抑制了食草行为。我们认为猎物的饥饿程度和捕食者狩猎模式的差异可能会影响这些模式。了解背景如何调节NCEs有助于深入了解捕食者 - 猎物相互作用对食物网的新兴影响。这些见解对于理解人为改变捕食者数量如何影响重要生态系统过程的空间和时间动态具有广泛意义。
