3D Habitat Complexity and Coral Morphology Modulate Reef Fish Functional Structure in a Marine National Park

Area of Science:

• Marine Ecology
• Reef Fish Assemblages
• Ecosystem Functioning

Background:

• Coral reef degradation negatively impacts reef fish populations.
• Direct effects on ecosystem functions remain unclear.

Purpose of the Study:

• Quantify mechanistic links between fish assemblages and ecological function.
• Investigate habitat structure and coral morphology influences on reef fish traits.

Main Methods:

• Quantitative analysis of fish functional traits (Gregariousness, Water Column Position, Body Shape).
• Categorization into 10 Fish Functional Groups (FFG).
• Assessing habitat complexity (Slope, Surface Complexity) and coral morphology (Branching, Mounding) impacts on FFG abundance.

Main Results:

• Fish traits significantly shape the multidimensional fish functional space into 10 FFG.
• Habitat complexity and coral morphology explain abundances of 8 out of 10 FFG.
• Branching and mounding coral morphologies, along with slope and surface complexity, are key habitat features.

Conclusions:

• Live coral morphology positively impacts reef fish functional groups more than structural complexity alone.
• Understanding drivers of FFG is crucial for predicting impacts of reef changes on fish assemblages and ecosystem function.
• Findings inform conservation and monitoring for predicting environmental change effects.