Aquatic invertebrate fauna of western Tasmania

Although there are close associations with the south-western fauna , there are nevertheless some aquatic invertebrates found predominantly in western Tasmania, and some biological problems best studied by reference to such animals; examples from two families of crustacea and two insect orders are discussed in this paper .
Western Tasmania may be regarded as the freshwater crayfish ( Parastacidae) centre of the State , all four Tasmanian genera being found there . Each genus is discussed in turn ; the habitats utilised are considered and adaptation to these habitats is illustrated by particular reference to burrow systems , calcium distribution in the exoskeleton and where possible , breeding patterns . Data is also provided on distribution and associated zoogeographical questions are briefly considered .
Two genera of the fami ly Koonungidae ( Syncarida) are found in the west - Micraspides and Koonunga . Their habitats and distribution are discussed and attention is drawn to the need for more ecological data in order to formulate answers to the zoogeographical issues involved .
The Odonata exemplify an insect order with generally good dispersal power s . Al l dragonfly species found in west ern Tasmania, together with their nymphal habitats, are collated and discussed. The most interesting species are the cold- climate adapted species , especial by archaics such as Archipetalia auriculata and Synthemiopsis gomphomacromioides. Attention is drawn to the probable importance of diapaus e as an adaptation to cold montane habitats . Three component s are recognised in the odonatan fauna , - cosmopolitan groups , ancient Australasian groups , and very ancient Gondwanal and relics .
The Plecoptera is an order demonstrat ing poor vagilty and only 6 of 31 Tasmanian species are shared with mainland Australia . The major ty of Tasmanian species are cold climate adapted forms and consequently west ern waters have a particularly conspicuous s tone fly fauna . Data on the habitats and distribution of a l l species found in west ern Tasmania is collated and discussed.
The influence of man on aquatic environments in west ern Tasmania is briefly considered . Environmental modification result s from mining activities , hydro-electric development , forestry practices and from the introduction of exotic species such as trout.