Granite outcrop pools in south-western Australia: foci of diversification and refugia for aquatic invertebrates

La Trobe University Faculty of Science, Technology and Engineering Murray Darling Freshwater Research Centre

MDFRC item.

Pools and streams on granite outcrops in south-western Australia are reliably filled, but highly seasonal, freshwater habitats that support a diverse array of aquatic invertebrates. A recent biological survey of the wheatbelt has more than doubled the number of invertebrates, to at least 230 species, known from these habitats. Granite outcrops contribute significantly to endemism in the aquatic fauna of the inland south-west and have particular conservation value for about 50 species, mostly rotifers, microcrustaceans, phreodrilid oligochaetes and chironomid midges, restricted to them. Outcrops may also be important for the wider aquatic invertebrate fauna as a freshwater habitat, if salinity in the Western Australian wheatbelt continues to increase.