Search

Replication is usually regarded as an integral part of biological sampling, yet the cost of extensive within-wetland replication prohibits its use in broad-scale monitoring of trends in aquatic invertebrate biodiversity. In this paper, we report results of testing an alternative protocol, whereby only two samples are collected from a wetland per monitoring event and then analysed using ordination to detect any changes in invertebrate biodiversity over time. Simulated data suggested ordination of combined data from the two samples would detect 20% species turnover and be a cost-effective method of monitoring changes in biodiversity, whereas power analyses showed about 10 samples were required to detect 20% change in species richness using ANOVA. Errors will be higher if years with extreme climatic events (e.g. drought), which often have dramatic short-term effects on invertebrate communities, are included in analyses. We also suggest that protocols for monitoring aquatic invertebrate biodiversity should include microinvertebrates. Almost half the species collected from the wetlands in this study were microinvertebrates and their biodiversity was poorly predicted by macroinvertebrate data.

Unusually large forms of Asplanchna sieboldi, Brachionus plicatilis, B. calycijlorus, Filinia pejleri, Trichocerca similis and Keratella slacki were collected from waters of south-eastern Australia. These giant forms are figured, and brief location and ecological data are given. Although the rotifer fauna of the Murray riversystem contains pan-tropical and pan-subtropical species, there exists a greater degree of endemicity than previously considered.