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 distribut i on 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 �nd distribution are discus s ed and att ent ion is drawn to the need for more ecological data in order to formulate answers to the zoogeographical issues invo lved . The Odonata exemplify an insect order with g enerally good dispersal power s . Al l dragonfly species found in west ern Tasmania, t ogether with their nymphal habitats, are co llated and discussed. The mo st interest ing speci es are the co ld- c l imat e adapted species , especial ly archai cs such as Archipetalia auriculata and Synthemiopsis gomphomacromioides. At t ention is drawn to the probable importance of diapaus e as an adaptat ion to cold montane habitat s . Three component s are recogni sed in the odonatan fauna , - cosmopo l i tan groups , anci ent Aus tralasian groups , and very anc i ent Gondwanal and re lict s . The Plecoptera is an order demonstrat ing poor vagi l i ty and only 6 of 31 Tasmani an species are shared with mainl and Aus tral i a . The maj ori ty of Tasmanian speci es are cold c l imat e adapted forms and cons equent ly west ern wat ers have a part i cularly conspi cuous s tone fly fauna . Data on the habitats and di stribut ion of a l l speci es found in west ern Tasmania is co l l at ed and discussed. The influence of man on aquat ic environments in west ern Tasmania is bri efly cons idered . Environmental modi fication result s from mining act ivities , hydro -el ectri c deve l opmen t , fore s try practices and from the introduction of exotic speci es such a