THE INFLUENCE OF THE PINNID BIVALVE ATRINA-ZELANDICA (GRAY) ON BENTHIC MACROINVERTEBRATE COMMUNITIES IN SOFT-SEDIMENT HABITATS

The pinnid bivalve Atrina zelandica (Gray) is found in muddy to sandy soft-sediment habitats around the coast of New Zealand. Because of the ir size and their often dense and patchy distribution, Atrina can add complex physical structure to soft-sediment habitats. We compare diver sity and structure of benthic macroinvertebrate assemblages inside and outside of natural patches of Atrina, at two different sites in north eastern New Zealand: a muddy harbour site and a sandy open coast site . Clear differences between macrofaunal assemblages in and out of Atri na patches were noted at both sites, with stronger effects apparent at the sandy site. Further studies incorporating the effects of suspensi on feeders on both macrofaunal communities and local hydrodynamic cond itions simultaneously are needed to help our understanding of how they modify their local habitat. Our results also illustrate the importanc e of identifying differences in relationships with location so that ha bitat variation features can be encompassed in the design of experimen ts investigating the influence of key species on benthic communities. (C) 1998 Elsevier Science B.V. All rights reserved.