Fear effects associated with predator presence and habitat structure interact to alter herbivory on coral reefs

Bauman, Andrew G., Seah, Jovena C.L., Januchowski-Hartley, Fraser A., Hoey, Andrew S., Fong, Jenny, and Todd, Peter A. (2019) Fear effects associated with predator presence and habitat structure interact to alter herbivory on coral reefs. Biology Letters, 15 (10).

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Abstract

Non-consumptive fear effects are an important determinant of foraging decisions by consumers across a range of ecosystems. However, how fear effects associated with the presence of predators interact with those associated with habitat structure remain unclear. Here, we used predator fish models (Plectropomus leopardus) and experimental patches of the macroalga Sargassum ilicifolium of varying densities to investigate how predator- and habitat-associated fear effects influence herbivory on coral reefs. We found the removal of macroalgal biomass (i.e. herbivory) was shaped by the interaction between predator- and habitat-associated fear effects. Rates of macroalgal removal declined with increasing macroalgal density, likely due to increased visual occlusion by denser macroalgae patches and reduced ability of herbivorous fishes to detect the predators. The presence of the predator model reduced herbivory within low macroalgal density plots, but not within medium- and high-density macroalgal plots. Our results suggest that fear effects due to predator presence were greatest at low macroalgal density, yet these effects were lost at higher densities possibly due to greater predation risk associated with habitat structure and/or the inability of herbivorous fishes to detect the predator model.

Item ID: 61421
Item Type: Article (Research - C1)
ISSN: 1744-957X
Keywords: risk effects, coral reefs, predator-prey interactions, herbivory, Sargassum
Copyright Information: © 2019 The Author(s). Published by the Royal Society. All rights reserved.
Funders: Singapore National Research Foundation (SNRF), Prime Minister's Office, Singapore, Marine Science Research and Development Programme, AXA Research Fellowship
Date Deposited: 15 Jan 2020 07:31
FoR Codes: 31 BIOLOGICAL SCIENCES > 3103 Ecology > 310305 Marine and estuarine ecology (incl. marine ichthyology) @ 100%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960808 Marine Flora, Fauna and Biodiversity @ 100%
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