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Impact of conservation areas on trophic interactions between apex predators and herbivores on coral reefs


Rizzari, JR and Bergseth, BJ and Frisch, AJ, Impact of conservation areas on trophic interactions between apex predators and herbivores on coral reefs, Conservation Biology, 29, (2) pp. 418-429. ISSN 0888-8892 (2015) [Refereed Article]

Copyright Statement

Copyright 2014 Society for Conservation Biology

DOI: doi:10.1111/cobi.12385


Apex predators are declining at alarming rates due to exploitation by humans, but we have yet to fully discern the impacts of apex predator loss on ecosystem function. In a management context, it is critically important to clarify the role apex predators play in structuring populations of lower trophic levels. Thus, we examined the top-down influence of reef sharks (an apex predator on coral reefs) and mesopredators on large-bodied herbivores. We measured the abundance, size structure, and biomass of apex predators, mesopredators, and herbivores across fished, no-take, and no-entry management zones in the Great Barrier Reef Marine Park, Australia. Shark abundance and mesopredator size and biomass were higher in no-entry zones than in fished and no-take zones, which indicates the viability of strictly enforced human exclusion areas as tools for the conservation of predator communities. Changes in predator populations due to protection in no-entry zones did not have a discernible influence on the density, size, or biomass of different functional groups of herbivorous fishes. The lack of a relationship between predators and herbivores suggests that topdown forces may not play a strong role in regulating large-bodied herbivorous coral reef fish populations. Given this inconsistency with traditional ecological theories of trophic cascades, trophic structures on coral reefs may need to be reassessed to enable the establishment of appropriate and effective management regimes.

Item Details

Item Type:Refereed Article
Keywords:ecosystem function, Great Barrier Reef, herbivory, marine reserve, reef shark, top-down control, trophic structure
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Behavioural ecology
Objective Division:Environmental Management
Objective Group:Terrestrial systems and management
Objective Field:Terrestrial biodiversity
UTAS Author:Rizzari, JR (Dr Justin Rizzari)
ID Code:120328
Year Published:2015
Web of Science® Times Cited:44
Deposited By:Fisheries and Aquaculture
Deposited On:2017-08-22
Last Modified:2017-09-07

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