Abstract for presentation at Biodiversity Extinction Crisis Conference - A Pacific Response

Numerous groundwater calcrete (carbonate) aquifers of central Western Australia have been shown to contain a diverse subterranean invertebrate fauna (stygofauna), including dytiscid water beetles and a variety of crustacean groups, such as Amphipoda, Isopoda, Bathynellacea and Copepoda. Morphological and mitochondrial DNA phylogeographic analyses of the water beetle, amphipod and isopod fauna provide evidence for the existence of an extraordinary diversity of subterranean species, some with considerable morphological variability (e.g. water beetles), while others are highly cryptic in morphology (e.g., amphipods). The vast majority of species are restricted in their distribution to single isolated calcrete bodies, suggesting that calcrete aquifers are equivalent to closed island habitats that have been isolated for millions of years, following the onset of aridity during the Late Miocene/ Pliocene. Similar cases of short-range-endemic (SRE) taxa have recently been reported from the Pilbara (WA), mound springs of the Great Artesian Basin (SA) and Ngalia basin (NT). The finding of a significant diversity of SRE taxa associated with groundwater-dependent ecosystems in the arid zone has important implications for their conservation management. Groundwater is used as a major source of water by mining companies, pastoralists and in towns and calcrete is used as a resource for road building and neutralising acids during mining operations. Developments involving extensive aquifer drawdown, grazing pressure and climate change having the potential to cause species extinctions. However, little is known about the natural variability in groundwater flow and hydrogeology of these systems, and the tolerance of species to environmental changes and their resilience to localised extinction events. In addition, groundwater archipelagos, with aquifer islands containing unique species, present significant challenges to the formulation of effective strategies to establish networks of conservation reserves. These and other issues relating to the conservation biology of groundwater-dependent invertebrate communities will be further discussed.