Herbivory Dynamics in Coral Reef Ecosystems

Herbivory on coral reefs is a fundamental process that regulates the balance between coral and algal communities. Feeding by fishes, sea urchins and other invertebrates removes algal turfs and macroalgae, clearing space for coral recruitment and promoting reef resilience. Functional diversity among herbivores, including scrapers, grazers and browsers, underpins variation in feeding rates, selectivity and substrate modification. Environmental filters such as wave exposure, sediment load and nutrient enrichment modulate the efficacy of herbivory by altering both algal palatability and consumer performance. Overfishing, habitat degradation and declining water quality can reduce herbivore abundance or impair feeding behaviour, leading to algal overgrowth, phase shifts and diminished ecosystem services. Understanding the interplay between herbivore functional traits, algal community composition and local environmental conditions is therefore critical for predicting reef trajectories and designing effective management interventions.

Research from Nature Portfolio

High-speed videography of a surgeonfish has revealed an unexpected feeding mechanism in which ventral rotation of the head and intra-mandibular joint is employed to detach algae without lateral body bending. This adaptation minimises exposure to strong flows on reef crests and flats, suggesting an evolutionary innovation in fish trophodynamics. Experimental manipulations of overfishing and sedimentation regimes demonstrate that herbivorous sea urchins can sustain short algal turf states even when fish grazing is diminished and sediment input is increased. By clearing benthic sediments and facilitating fish feeding, urchins emerge as critical partners in maintaining reef resilience under compounded anthropogenic stress.

Herbivory Dynamics in Coral Reef Ecosystems publication trend

The graph below shows the total number of articles in herbivory dynamics in coral reef ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Herbivory: Consumption of algae and plant matter by animals, crucial for preventing algal dominance on reefs.

Macroalgae: Large, multicellular algae that can overgrow corals if unchecked by herbivores.

Epilithic algal matrix (EAM): Complex assemblage of turf algae, detritus and sediment covering reef substrates.

Resilience: Capacity of a reef to absorb disturbance and recover to a coral-dominated state.

Trophic dynamics: Interactions among organisms at different feeding levels that structure ecosystem processes.

References

1. Macroalgae exhibit diverse responses to human disturbances on coral reefs. Global Change Biology (2023).
2. Feeding kinematics of a surgeonfish reveal novel functions and relationships to reef substrata. Communications Biology (2024).
3. Epilithic algal composition and the functioning of Anthropocene coral reefs. Marine Pollution Bulletin (2024).
4. Herbivorous sea urchins (Echinometra mathaei) support resilience on overfished and sedimented tropical reefs. Scientific Reports (2024).
5. Marine protected areas enhance coral reef functioning by promoting fish biodiversity. Conservation Letters (2019).