Habitats of the Grey Grasswren Amytornis barbatus diamantina and a review of the species’ distribution

Grey Grasswrens Amytornis barbatus were first described in swamps at the termination of the Bulloo River and that population and nominate subspecies is now considered threatened. A second subspecies is found to the north in wetlands of the Diamantina/Goyder Lagoon/Warburton system. We found the species at 54 sites within the Goyder Lagoon/Warburton floodplain and conclude that that population appears secure. Grey Grasswrens were found chiefly in Lignum (dominant at 57%, present at 88%) and Old-man Saltbush (dominant at 19%, present at 43%) with average vegetation cover of 32.5 per cent but ranging from seven per cent to 81 per cent. While the species occurs above Goyder Lagoon, in both the Georgina/Eyre and Diamantina catchments, connectivity between these localities has not been demonstrated. The Grey Grasswren occurs in a third catchment, Cooper Creek, where its relationship with other populations, including its subspecific status is unproven. The species is best known from dense shrublands of Lignum Muehlenbeckia florulenta and Swamp Canegrass Eragrostis australasica but we have shown that it occupies and may breed in more open shrublands such as Old-man Saltbush Atriplex nummularia ssp. nummularia. Our findings question the relative reliance of Grey Grasswrens on these two rather disparate habitats; whether they occupy the more open habitats when forced from deeply inundated Lignum swamps and whether the former serve to aid dispersal between what otherwise appear to be isolated populations.

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