Inland aquatic systems and their fauna at Two Peoples Bay Nature Reserve, Western Australia, with emphasis on microinvertebrates

Context. Decisions about fauna conservation priorities in a region, and management actions required to facilitate conservation objectives, require as much information as possible about the ecology of fauna species present. Aims. This paper summarises information on the inland aquatic fauna of Two Peoples Bay Nature Reserve as part of the process of documenting the Reserve's conservation values. Key Results. Surveys in the early 1990s, and subsequently, show that rivers, creeks, and lakes of the Reserve support a rich aquatic invertebrate fauna. The microinvertebrate community is unusually rich in rotifers and cladocerans. Probably nine Indigenous fish species occur in the Reserve, including the vulnerable Nannatherina balstoni, restricted Galaxias maculatus and critically endangered Galaxias truttaceus. The installation of a vertical slot fish ladder on the Goodga River weir has likely helped these species by expanding available habitat. Although the low nutrient status and relatively deep water of the lakes limit their waterbird value, considered together the Reserve's lakes fall just outside the top 10% of nature reserves in Western Australian for number of waterbird species supported. Conclusions. The richness of aquatic invertebrate species in the Reserve's lakes contrasted with previous results from rivers in south-western Australia and has led to a changed understanding of both the diversity and conservation significance of the inland aquatic invertebrate fauna in Western Australian lakes. Implications. Invertebrate community composition and conservation values are not recognised unless surveyed by people with appropriate taxonomic expertise. Without such surveys the focus of conservation effort and management may be, at least partially, misdirected.