Diversity of wetland zooplankton in the Lachlan River catchment, New South Wales, Australia

Inland wetlands are areas of high biodiversity, providing various ecosystem services. In this study, we assessed the species diversity of wetland zooplankton in the Lachlan River catchment. Biodiversity sampling is labour-intensive and attained sample size is often not large enough to detect all species present. Therefore, we applied integrated rarefaction and extrapolation sampling curves and asymptotic analysis to estimate species richness. We observed 103 species of rotifers, 29 species of cladocerans and 13 species of copepods, with further 14 rotifers, three cladocerans and four copepods identified at higher than species level, totalling 117 taxa of rotifers, 32 taxa of cladocerans and 17 taxa of copepods from 36 wetland sites across the catchment. The observed zooplankton species included the first record of the rotifer Trochosphaera solstitialis in Australia, and the first record of the rotifers Brachionus lyratus tasmaniensis, Keratella shieli, Lepadella tyleri, Notholca salina and N. squamula and the cladoceran Alona setuloides in NSW. Based on the integrated sampling curves and asymptotic analysis of species richness in wetlands of the Lachlan River catchment, greater additions of rotifers (estimated asymptote: ≈ 145) are more likely to be realised with increasing sample size than those of cladocerans (estimated asymptote: ≈ 36) and copepods (estimated asymptote: ≈ 18).