Resolving the taxonomy, range and ecology of biogeographically isolated and critically endangered populations of an Australian freshwater galaxiid, Galaxias truttaceus

摘要: The spotted galaxias (or trout minnow), Galaxias truttaceus, is a species that restricted to south-western and south-eastern Australia, but there has long been conjecture as whether the geographically Critically Endangered Western Australian populations represent subspecies (Galaxias truttaceus hesperius). We provide evidence populations, on basis of combination genetic, geographic ecological criteria, should be considered an evolutionary significant unit, which merits management high conservation priority. Substructure at nuclear matrilineal genetic markers not suggestive species-level divergence, rather discrete western eastern subpopulations with limited contemporary gene flow. In contrast many are diadromous, all potamodromous. Adults live spawn in riverine habitats larvae drift downstream coastal lakes, where they spend several months, before undertaking distinct upstream recruitment migration juveniles colonise habitats. Instream barriers disconnect lentic restrict distributional range presumably affect reproductive success populations. Conserving remaining Australia will require ongoing efforts reduce impact emerging threats, particularly those related instream barriers, introduced reductions water quantity quality.