Predator identity and time of day interact to shape the risk–reward trade-off for herbivorous coral reef fishes

• Published in: Oecologia Vol. 183; no. 3; pp. 763 - 773
• Main Authors: Catano, Laura B., Barton, Mark B., Boswell, Kevin M., Burkepile, Deron E.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Science + Business Media 01.03.2017; Springer Berlin Heidelberg; Springer; Springer Nature B.V
• Subjects: Animals; Biomedical and Life Sciences; COMMUNITY ECOLOGY – ORIGINAL RESEARCH; Coral Reefs; Ecology; Ecosystem; Ecosystems; Fishes; Food Chain; Herbivory; Hydrology/Water Resources; Life Sciences; Mycteroperca bonaci; Pisces; Plant Sciences; Predatory Behavior; Reward; Sphyraena barracuda; Behaviorally mediated indirect interaction; Trophic cascade; Predator hunting mode; Florida Keys coral reefs; Landscape of fear; Predator–prey interactions; Predation risk
• DOI: 10.1007/s00442-016-3794-z
• ISSN: 0029-8549

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.