Minimal predation upon meiofauna by endobenthic macrofauna in the Exe Estuary, south west England

Abstract

Field manipulation experiments were performed in the Exe Estuary, south west England, in October 1988, to investigate the importance of the meiofaunamacroinfauna trophic link in benthic trophodynamics. Four hypothetically meiofauna-predacious endobenthic macrofauna species were selected for manipulation using the criteria of high abundance and different modes of feeding: Cerastoderma edule (filter-feeder), Nereis diversicolor (omnivorous scavenger), Ophelia bicornis (sand-ingester), Scrobicularia plana (deposit-feeder). Enclosures constructed from plastic tubing, 63 μm nylon monofilament mesh and galvanized steel were deployed, containing adult members of these taxa at densities raised to approximately four times that of the surrounding sediment. The experiments ran for 12 tidal cycles. Differences in phyletic meiofaunal abundance between treatment and control enclosures at the termination of the experiment were assessed using both uni- and multivariate dataanalysis techniques. Only two univariate significant differences (p<0.05) existed for the N. diversicolor treatment and two for the S. plana treatment. Annelida, Turbellaria and copepod nauplii were the only meiofauna taxa affected. No univariate significant differences were recorded for either the C. edule or O. bicornis treatments. Multidimensional scaling ordination of the data revealed no consistent changes in community composition between treatments and controls. It is concluded that the experiments provide evidence of minimal predation by macroinfauna upon meiofauna.