TEMPORAL AND SPATIAL VARIABILITY IN COMMUNITY STRUCTURE OF A SANDY INTERTIDAL BEACH, CAPE-PATERSON, VICTORIA, AUSTRALIA

The infauna of a sheltered sandy intertidal beach at Cape Paterson, Vi ctoria, was sampled on a three-monthly basis over a two-year period. I n total, 116495 individuals comprising 41 species were collected over this time. Common species collected included the dipteran Chaetocoelop a sydneyensis, the coleopteran Sphargeris physodes, the isopods Pseudo lana concinna and Actaecia thomsoni, the amphipods Talorchestia cf. no vaehollandiae and Exoediceroides maculosus, and the polychaetes Magelo na sp, and Scolelepis lamellicincta. There were significant difference s in infaunal densities and species richness between the beach heights sampled, with both factors increasing with decreasing beach height ov er the intertidal zone. In general, insects were confined to upper bea ch heights, polychaetes were confined to lower beach heights, and diff erent crustacean species spanned the entire intertidal beach. Signific ant temporal differences also existed in infaunal densities and specie s numbers at most of the beach heights sampled. These temporal differe nces were related to changes in the densities of common intertidal spe cies. Only four of these common species (S. physodes, C. sydneyensis, T. cf. novaehollandiae and E. maculosus) exhibited any seasonal patter n in this temporal variation in density. Multivariate analysis of infa unal data failed to consistently separate beach heights into the unive rsal zones previously proposed for sandy intertidal habitats. The unpr edictable nature of biotic and abiotic influences on sandy intertidal infauna makes it unrealistic to expect to be able to consistently sepa rate faunal assemblages on any given sampling occasion, with the excep tion of a characteristic fauna with terrestrial affinities that is con fined to the upper beach. Any zonation patterns identified as being pr esent on sandy beaches need to be qualified by the time of year in whi ch data were collected.