Microtopographic refuges shape consumer-producer dynamics by mediating consumer functional diversity.

Area of Science:

• Marine ecology
• Coral reef ecosystems
• Benthic community structure

Background:

• Consumer-producer dynamics are vital for ecosystem functioning.
• Herbivorous fish grazing significantly influences coral reef benthic communities.
• Microtopography plays a role in mediating these interactions.

Purpose of the Study:

• To investigate the impact of microtopographic refuges on grazing pressure and consumer communities on coral reefs.
• To understand how refuges affect benthic community structure and diversity.
• To assess the role of small-scale refuges in mediating ecosystem processes.

Main Methods:

• Utilized experimental surfaces to simulate coral reef microhabitats.
• Quantified grazing pressure in areas with and without microtopographic refuges.
• Functionally characterized consumer fish communities associated with different microhabitats.

Main Results:

• Microtopographic refuges reduced grazing pressure by over 90%.
• Refuges excluded detritivorous fishes, favoring algal croppers.
• Two distinct benthic regimes emerged: diverse communities within refuges and low-diversity algal mats outside.

Conclusions:

• Microtopographic refuges, even at centimeter scales, mediate biotic control of coral reef communities.
• Refuges influence grazing rates and functional diversity of consumers.
• The coexistence of distinct benthic regimes due to refuges is crucial for ecosystem functioning and requires consideration in reef health assessments.