Macrobenthic community establishment on artificial reefs with Macrocystis pyrifera over barren-ground and soft-bottom habitats

Abstract

Kelps provide important habitat for a range of species, however they are suffering increasing levels of degradation. This has prompted efforts to restore these ecosystems, however, the trajectory of community establishment on artificial reefs has not being widely described. We examined the composition of the species and functional groups of invertebrates and fish in relation to the artificial reefs over soft-bottom and barren-ground habitats over a 10-month period. We evaluated the community structure based on species richness, biomass, species diversity, and dominance of species and functional groups. We assessed the trajectories of the ecological succession of artificial reefs planted with kelp on each bottom type and determined the changes in the dissimilarity of species and functional groups over time. We also analysed the relationship between the biogeny (of macroalgae) over time (months) and the changes in macrobenthic community structure. Successional development of reefs communities was similar across the two habitat types, macroalgae contributed most to the early stage, while invertebrates and fish were the groups that contributed the most during the middle and late successional stages. A positive relationship was found between the presence of artificial reefs with kelp seedlings and the biomass of specific species and functional groups. This study showed that new kelp habitats promote the construction of biogenic structures that increase the habitat complexity, promote biodiversity, and increase populations of commercially harvested species. In this sense, artificial reefs should be considered an important tool for restoring the function of degraded benthic ecosystems.