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Australia: The Land Where Time Began |
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Lake Eyre Fauna
The only life on the lake are a few small creatures, the salt lake louse (Haloniscus searlei), the brine shrimp (Artemia salina) and a camouflaged lizard, the Lake Eyre dragon (Amphibolurus maculosus). The salt lake spiders that are restricted to the salt lakes of southern Australia. These are wolf spiders, Lycosidae, Lycosa alteripa, L. eyrei and L. salifodina. The aquatic biota of the flood phases of the lake have not been studied very much. What is known suggests there is a simple food web based on species with an ability to disseminate widely and to rapidly colonise suitable habitats when they become available, as with species that can be carried from lake to lake in the form of eggs or resting stages in mud on the feet of birds. The few species of algae and bacteria, as well as the zooplankton, that have been found in the lake are also found in other salt lakes. There are some small crustaceans, water fleas and seed shrimps. There are also the larval stages of brine flies, midges and other varieties of fly. The only insects that are common in the lake are species that can disperse by flying, and can survive long periods of desiccation, usually as eggs that can blow around on the surface, which differs from the situation in other salt lakes of southern Australia. Of the freshwater fish, only 3 species do well in the lake, the carnivorous yellowbelly, and the omnivorous Lake Eyre hardyhead and bony bream. They can all tolerate a wide range of salinity, from fresh to salt concentrations higher than sea water, and can tolerate a wide range of temperatures. The 4 main species of birds that form the top of the food chain are aquatic birds, pelicans, great cormorants, whiskered terns and silver gulls. Plant fossils have been found in the oldest sedimentary unit in the basin, the Eyre Formation, from the Palaeocene to the Eocene. Large shallow lakes fed by large meandering rivers with large floodplains, covered much of the basin between the Late Oligocene and Middle Miocene. The basin gradually dried, but the desertification began 2.6 Ma in the Pleistocene Ice Age, when a series of wet and dry times, the fluctuations of the glacials and interglacials, gradually reduced the area covered by the lakes and their surrounding vegetation.
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Author: M.H.Monroe Email: admin@austhrutime.com Sources & Further reading |