Journal Article

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

Bergseth, Brock J., Rizzari, Justin R., Frisch, Ashley J.

2015

Overview

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 top‐down 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.

• Publisher: Blackwell Scientific Publications,Blackwell Publishing Ltd,Wiley Periodicals Inc
• Subject: Animal populations / Animals / Australia / Biomass / Biota / Conservation areas / Conservation biology / Conservation of Natural Resources / Contributed Papers / control de arriba-abajo / Coral Reefs / corals / Ecological function / ecosystem function / ecosystems / estructura trófica / Fish populations / Fishes - physiology / Food Chain / funcionalidad del ecosistema / Gran Barrera de Arrecifes / Great Barrier Reef / Herbivores / Herbivorous fish / herbivory / herbivoría / humans / Marine ecology / Marine parks / marine reserve / Parks, Recreational / Population Dynamics / Predation / Predators / Queensland / reef shark / reserva marina / Sharks / tiburón de arrecife / top-down control / Trophic levels / Trophic relationships / trophic structure / viability