The strongest contributors to these relationships were spionid polychaetes, which were abundant and widespread in MH3 and not in the other habitats. Thesepolychaetes can be either suspension or surface-deposit feeders (Levin, 1984) and can live at large densities, often stabilizing the sediment with their tubes (Thrush et al., 1996). Changes in water-flow associated with pneumatophores and leaf litter may physically interfere with their feeding behaviour in some habitats. Relationships between other species and the sediment were far more patchy, with taxa characteristic of the shaded habitat (amphipods, insect larvae) important correlates with sediment in some bays and those characteristic of the open mud (such as oligochaetes) important in some bays. Thus, whilst some properties of the sediment may be important in determining the structure of the macrofauna, they are not consistently important. Similarly, different organisms may have similar effects upon sediments in different places and/or may respond to these properties in similar ways, while the same species may change response (or effect) from place to place