Effect of epibenthic macropredators on community structure in subtidal organically enriched sediments in the inner Oslofjord

Abstract

Predator exclusion experiments were performed on an unvegetated low-energy subtidal mudflat. Exclosures were maintained for periods from 2 to 5 mo to protect infauna from epibenthic macropredators. Recruitment was studied by plac~ng trays with azoic sediment on the bottom. Predation effects were determined by comparing faunal composition and abundance on natural sediment and in recruitment trays inside and outside the cages. Community structure was not affected by the cages. There was a tendency for several specles to increase In abundance inside the cages on the natural sediment, but only a few increases were significant. Habitat modifications under the cages were small. It is concluded that in the subtidal of the Oslofjord macropredators are not important in determining community structure in sediments, and that there is only a small effect of macropredators controlling densities of infauna.