Structure of fish assemblages in waters of the Southern Acid Peat Flats, South-western Australia

Abstract

The structure of freshwater fish assemblages in waters of the southern acid peat flats of south-western Australia was monitored over a 3-year period. Nine locations were sampled during the course of the study; they differed in the permanence of the water supply and the degree of isolation from permanent water. The climate of the region is a Mediterranean one of high predictability (i.e. pronounced seasonality and low interannual variation). Consequently, temporary aquatic habitats were also temporally predictable in incidence and duration and were colonized by a comparatively rich fish fauna. Differences in habitat permanence and isolation were reflected in the structure of the fish assemblages, with temporary, highly isolated habitats being dominated by aestivating species. Temporary habitats not isolated from permanent water had the highest species richness and also contained one aestivating species. Permanent water habitats had the lowest species richness and diversity and were dominated by a single species (Edeba vittata). The assemblages changed little during the period of study with respect to species persistence and structure.