Structural complexity of hard substrates shapes shallow benthic communities Version 3

Habitats with structural complexity provide a variety of niches where the biotic and abiotic conditions differ. This generally results in higher biodiversity in complex habitats than in simple habitats. Although the importance of structural complexity is acknowledged in many ecosystems (e.g., forests, streams, mangroves, coral reefs) there is discrepancy in how complexity is measured, which leads to ambiguous results. A part of the effect of structural complexity on biodiversity can often be attributed to increasing surface area or substrate material used. In a field experiment, we use 3D-printed structures to isolate the effect of structural complexity on recruitment in a coastal reef system from surface area or substrate material in a standardised manner. We deployed reef structures with fractal-like (self-similar) pyramid shapes of three standardised complexity in sandy intertidal and subtidal coastal zones. We determined effects on taxonomic diversity, abundances and densities, and spatial patterning of five dominant reef taxa: barnacles, mussels, tunicates, anemones, and algae. This offers insight in how the niche-diversity created by structural complexity controls epibenthic communities in soft-bottom coastal ecosystems, which can be applied in ecosystem restoration. This dataset and the correspponding R-script were used for the statistics as presented in the paper. It contains a metadata file, and datafiles containing the abundances and cover fractions of different taxa on the structures in the experiment and the script to analyse them.