This repository holds code, data, and other files related to the second data chapter of Courtney Stuartโs PhD research at the University of Oxford Seascape Ecology Lab (P.I. Dr Lisa Wedding). Courtney's PhD research is part of the Seabird-Island-Reef project funded by the Bertarelli Foundation and led by P.I. Nick Graham of Lancaster University, and supports the ongoing Tetiaroa Atoll Restoration Project.
Stuart, C.E., Benkwitt, C.E., Stamoulis, K.A., Pittman, S.J., Green, S.J., Young, M.A., Purkis, S.J., Graham, N.A.J. and Wedding, L.M., 2026. Integrating spatial patterns of herbivorous fish functional diversity to inform coral reef management. Marine Ecology Progress Series. https://doi.org/10.3354/meps15071.
Herbivory is a key ecological process on coral reefs, regulating algal-coral competition, facilitating coral recruitment, and supporting reef resilience. Herbivorous fishes provide most of this function and can be categorised into five functional groups based on diet, foraging behaviour, and ecological impact. Here we assess drivers of herbivorous fish functional diversity, abundance, and richness across Tetiaroa Atoll, Te Ao Mฤ'ohi (French Polynesia) using data from 89 underwater visual transects. Spatial-environmental variables derived from in situ and remotely sensed data were incorporated alongside transect data in generalised linear mixed models. Water depth, area of grazeable coral and hardbottom habitats, seabird-driven nutrient enrichment, and proximity to spearfishing were among the strongest predictors of herbivorous fish abundance and richness, though their effects varied in magnitude and direction across functional groups. Herbivory in Tetiaroaโs lagoon appeared relatively robust, with ~75% of transects containing representatives from three of the five distinct herbivorous fish functional feeding groups. Consistent co-occurrence of functional groups suggests strong spatial complementarity in the removal of macroalgal germlings, grazing of algal turfs, and clearing of reef substrate. However, the near absence of browsers and excavators indicates a potential vulnerability in controlling mature macroalgae and sustaining the natural erosion and renewal of the reefโs calcium carbonate structure. Our spatially explicit, process-oriented generalised linear mixed modelling approach provides a scalable framework for assessing reef herbivory โ moving beyond biomass or presence-absence metrics to identify functional gaps and guide targeted, scale-sensitive strategies that maintain critical ecological processes in tropical reefs facing mounting anthropogenic and climate pressures.
Coral-algae competition, coral reef fishes, ecological processes, ecosystem function, functional groups, herbivory, seascape ecology
You are welcome to use and borrow from this repository according to the license below. However, access to the raw datasets must first be approved by the original data collectors. Please email your inquiries to Courtney Stuart (@courtney.e.stuart@gmail.com or @courtney.stuart@mansfield.ox.ac.uk) so that your requests can be forwarded to the appropriate contacts.
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This work is licensed under a Creative Commons Attribution 4.0 International License.
