Can giant kelp (Macrocystis pyrifera) forests enhance invertebrate recruitment in southern Chile?

Abstract

Macrocystis pyrifera is a foundation species that modifies the environment in complex ways and provides food and refuges for a variety of coastal organisms, some of which are important for local fishery communities in the south of Chile. In this study we tested the effect of Macrocystis forests on recruitment of benthic organisms within Management and Exploitation Areas for Benthic Resources (MEABR). We placed artificial Tuffy collectors to sample recruits in three MEABRs during three different seasons. In each MEABR we installed 60 Tuffy collectors inside the kelp forest and an additional 60 outside the forest. Eight groups of invertebrate recruits were found abundantly in the study areas. The most common recruits belonged to the Mytilidae family, as well as the gastropod Tegula spp., the crabs Taliepus spp. and Pilumnoides perlatus, the keyhole limpet Fissurella spp., the sea urchin Loxechinus albus, the ascidian Ciona intestinalis and polychaetes. The kelp forest effect interacts significantly with season and locality for all eight invertebrates, the a-posteriori HSD Tukey test shows a significantly higher recruitment under the kelp forest than outside for Fissurella spp., polychaetes, Ciona, Pilumnoides and the family Mytilidae. On the other hand, only the sea urchin Loxechinus albus presented a significantly higher recruitment outside the kelp forest. As Macrocystis forests favoured the recruitment of several invertebrates, conservation of kelp forests is important for maintaining invertebrate biodiversity and science-based benthic fisheries management plans for its exploitation are required.