Benthic community response to experimental additions of the polychaete Nereis virens

Previous field manipulations with the predatory polychaete Nereis virens have indicated the existence of a 3-level interactive system within the infauna in Maine, USA (N. virens - Corophium volutator - other infauna). The purpose of this investigation, carried out in 1980, was to test the hypothesis that the addition of N. virens to a community where the intermediate predator/disturber C. volutator is absent should cause infaunal densities to decrease. Experimental results did not support this hypothesis. In N. virens addition treatments there was a sharp increase in the density of the infauna. Three taxa which accounted for 95% of the individuals in controls (tubificid oligochaetes, Streblospio benedicti, Capitella capitata ) were also most abundant in addition treatments. The results of this and other experiments suggest the importance of complex trophic interactions within the infauna.