Coralline barrens and benthic mega-invertebrates: An intimate connection

Area of Science:

• Marine ecology
• Benthic ecology
• Ecosystem functioning

Background:

• Knowledge gaps exist regarding coralline barren ecosystems' community composition and functioning.
• Understanding the transition from algal forests to coralline barrens is crucial for marine conservation.
• Coralline barrens are often perceived as low-diversity habitats.

Purpose of the Study:

• To test if coralline barrens enhance benthic mega-invertebrate abundance and diversity.
• To analyze trophic functional diversity in barren and algal forest ecosystems.
• To investigate the impact of coralline barrens on overall ecosystem trophodynamics.

Main Methods:

• Utilized a patchy system comparing coralline barren and algal forest habitats.
• Quantified benthic mega-invertebrate abundance and diversity.
• Employed stable isotope analyses (δ13C and δ15N) to assess trophic structure and diversity.

Main Results:

• Benthic mega-invertebrate biomass was significantly more abundant and diverse in coralline barrens.
• Trophic structure was comparable between barren and forest states, but isotopic uniqueness was higher in barrens.
• Sea urchins (e.g., A. lixula) and starfish contributed to higher isotopic uniqueness in coralline barrens.

Conclusions:

• Coralline barrens host a more diverse benthic mega-invertebrate assemblage than previously thought.
• The presence of diverse mega-invertebrates in barrens causes limited trophodynamic changes.
• Results challenge the view of coralline barrens as depauperate ecosystems, highlighting their ecological importance.