Benthos structure on tropical tidal flats of Australia

Abstract

General features of benthos communities of tropical tidal flats are defined from northeast Australia, based on surveys from 1988 to 1991 in Hinchinbrook Channel and in the Haughton River estuary. A zonation of benthic communities is described. Total abundances for macrofauna averaged 31 individuals 200 cm−2, mesofauna (defined as infauna smaller than 0.5 mm and retained on a 0.25 mm sieve) averaged 16 individuals 10 cm−2 and meiofauna averaged 231 individuals 5 cm−2. The two study sites were similar in their abundance structures, but species due to a higher diversity of polychaeta in the Channel (120 species, H′=3.80 vs. 29 species and H′=1.78 in the Haughton estuary). Species densities were comparable at both sites and rather low (6 species 177 cm−2, 2–7 species 10 cm−2 and 5 meiobenthic Plathelminth species 5 cm−2). Over 50% of the species encountered were represented by less than three individuals. Deposit feeders, dominated the assemblages both in terms of individuals as well as species numbers. Tropical tidal flats are compared with their temperate counterparts and approaches for future research in tropical benthos communities are recommended.