An ecological baseline for Laminaria hyperborea forests in western Ireland

The biodiversity associated with subtidal Irish kelp forests dominated by Laminaria hyperborea has never been described. To enumerate species assemblages in these ecosystems, surveys were done throughout the calendar year to investigate within forests, composition of benthic communities, colonizing thalli, recruitment and habitat recovery processes after canopy clearances. Surveys further undertaken maërl beds, sediment-bottom bays, Serpula vermicularis reefs, bedrock habitats for comparison. Across all four seasons, harbor richest assemblages, second only S. reefs diversity, a total 313 unique (from juvenile recruits mature macrofauna). Peak diversity occurred summer echinoderms one most abundant groups, though urchins reach densities that would threaten over-grazing. thalli L. are diverse harboring many deposit feeders, filter marine macroalgae. Epibiotic communities become more age kelp, culminating maximum 1660 individuals on stipes 949 holdfasts. Recruitment crustaceans, echinoderms, worms was high but common fish could not be monitored because life history stage. Habitat establishment took over artificial substrata which colonized macroalgae dense cover inhibited growth sporophytes. This descriptive study represents an essential baseline forest Ireland.