The potential impact of meiofauna on the recruitment of macrobenthos in a subtidal coastal benthic community of the Ligurian Sea (north-western Mediterranean): a field result

The composition and dynamics of meio- and macrofauna in a subtidal location at Zoagli (Ligurian Sea, Italy) were followed for an annual cycle (from January 1991 to January 1992). Polychaete recruitment occurred during spring and late summerautumn. The increase in density of predatory nematodes (dominated by Oncholaimellus, Viscosia, Mesacanthion and Chromaspirina) and turbellarians corresponded to the collapse of macrobenthos recruits. Such alteration was probably due to predation by turbellarians and predator-nematodes during and immediately after the macrofaunal larval settlement. Differences in predator pressure were observed between spring and autumn. Conversely, no significant impact was observed on bivalves. The selective predation operated by predator meiofauna on the dominant polychaete families of the temporary meiofauna (paraonids and spionids) modified the structure of the macrofaunal community. These results suggest that meiofauna may structure macrofaunal communities both altering density and acting selectively on a few families of macrofaunal juveniles.