Habitat structure shapes temperate reef assemblages across regional environmental gradients

Area of Science:

• Marine Ecology
• Coastal Engineering
• Biodiversity Studies

Background:

• Intertidal artificial habitats are increasing but often lack the biodiversity of natural rocky reefs.
• Eco-engineering seeks to improve coastal infrastructure biodiversity through structural modifications.
• Previous studies focused on small scales (up to 1m²), lacking shore-wide evidence of local structure's influence.

Purpose of the Study:

• To investigate the influence of local physical structure on sessile biotic assemblages across regional environmental gradients.
• To compare biodiversity and structure between natural and artificial intertidal reefs.
• To provide evidence for scaling up eco-engineering interventions.

Main Methods:

• Observational study at 32 natural and artificial intertidal reef sites in Wales, UK.
• Multivariate community analysis and permutation tests to assess associations.
• Canonical correspondence analysis to determine factors influencing assemblage composition.

Main Results:

• Artificial reefs exhibited lower taxonomic richness and distinct, more variable assemblage composition than natural reefs.
• Environmental variables (wave exposure, temperature, salinity) and physical structure metrics explained 40% of assemblage variation.
• Local structural metrics (roughness, verticality) independently explained 14.5% of variation, with horizontal surfaces supporting more macroalgae.

Conclusions:

• Local habitat structure significantly influences intertidal biotic assemblages across regional scales.
• Eco-engineering interventions should consider specific structural properties to maximize biodiversity enhancement.
• Findings support the scaling-up of structural modifications for improving coastal infrastructure biodiversity.