A spear-grass - profile

Indicative distribution

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Key:

known

predicted

The areas shown in pink and/purple are the sub-regions where the species or community is known or predicted to occur. They may not occur thoughout the sub-region but may be restricted to certain areas. ( click here to see geographic restrictions). The information presented in this map is only indicative and may contain errors and omissions.

Scientific name: Austrostipa nullanulla

Conservation status in NSW: Endangered

Commonwealth status: Not listed

Profile last updated: 05 Oct 2023

Description

A small, perennial spear-grass, growing to 0.5 m tall. Plants grow as tussocks and have slender stems that bear the flower-heads. The leaves usually rolled, and rigid, 2 - 3 mm wide, and with the upper surface strongly ribbed. Leaf-margins are rough. The flower-heads are delicate and spreading, 13 - 19 cm long, and comprise spikelets that are 9 - 11 mm long (excluding the awns). The awns (bristles) are gently twice-bent and 5 - 7 cm long.

Distribution

Currently known only in NSW from Nulla Station to the north of Lake Victoria in the far south west, with the total population estimated at 200,000+ individuals. In Victoria there are an estimated 1500 plants in the Towan Plains Flora and Fauna Reserve, 300 plants in Murray-Sunset NP and 330 plants on the Raak Plain. It is more widespread in South Australia, but is still considered Vulnerable in that state and is only known from one conservation rerserve (Lake Gillies Conservation Reserve).

Habitat and ecology

Within the Murray Mallee it is restricted to gypseous lunettes and copi rises and at Nulla Station it grows on the margins of relict lakes, on the crests and sides of lunettes above old lake floors. In South Australia is thought to occupy gypseous soils on the outskirts of salt lakes across the north of the state. In all cases, gypsum is a major constituent of the soils in the habitat.
The vegetation on the lunettes at Nulla Station is an open shrubland of Pearl Bluebush (Maireana sedifolia), Bladder Saltbush (Atriplex vesicaria), Black Bluebush (Maireana pyramidata) and Spiny Saltbush (Rhagodia spinescens) with scattered Belah (Casuarina pauper), Western Rosewood (Alectryon oleifolius and Yorrell (Eucalyptus gracilis). Other species include the grass Austrostipa nitida, Cannonball Burr (Dissocarpus paradoxus), Turpentine Bush (Eremophila sturtii), Shrubby Twinleaf (Zygophyllum auranticum) and Boobialla (Myoporum) species.
Flowers from December to January, mainly in response to rain.
Seed dispersal is mainly by wind, rain and flood events; the awn and sharp point of the floret appear to be an adaptation for burying the seed into the soil; grass seed is traditionally believed to be viable for three to five years, so a long-lived seed bank is considered unlikely for this species.
Four sites are known at Nulla Station; two of these occur on the same lunette, with the total population numbering at least 60,000 tussocks; at the type location further south, only 10 plants were found; another site found on a lunette south-west of the type location comprised more than 60,000 individuals.

Regional distribution and habitat

Click on a region below to view detailed distribution, habitat and vegetation information.

Murray Darling Depression

Threats

Grazing; total grazing pressure has increased with higher numbers of rabbits, domestic stock and kangaroos.
Habitat degradation; gypseous lunette habitats damaged by rabbits, due to the softer soils in which rabbits preferentially construct their warrens.
Habitat loss from mining of gypsum deposits and possibly cultivation.
The introduction of additional watering points on Nulla Station may increase the likelihood of extinction of populations in the vicinity.
Confined to a soil type with a naturally restricted distribution.
Goats graze the plants.

Recovery strategies

Priority actions are the specific, practical things that must be done to recover a threatened species, population or ecological community. The Office of Environment and Heritage has identified 5 priority actions to help recover the A spear-grass in New South Wales.

Activities to assist this species

Eliminate or suppress the rabbit populations on lunette sites (established exclosures in Victorian populations show that this species responds quickly to the absence of rabbits).
Protect from all herbivores.
Prevent further development of watering points near populations.
Annual monitoring of fenced areas to determine the influence of different grazing animals.

Information sources

Ayers, D., Nash, S. and Baggett, K. (1996) Threatened Species of Western New South Wales. (NSW National Parks and Wildlife Service, Sydney)
Briggs, J.D. and Leigh, J.H. (1996) Rare or Threatened Australian Plants. Revised Edition. (CSIRO Publishing, Melbourne)
Everett, J. and Jacobs, S.W.L. (1983) Studies in Australian Stipa (Poaceae). Telopea 2(4): 391-400
Jacobs, S.W.L. and Everett, J. (1993) Stipa. Pp. 639-650 in Harden, G.J. (ed.) Flora of New South Wales. Volume 4. (New South Wales University Press, Sydney)
Jacobs, S.W.L. and Everett, J. (1996) Austrostipa, a new genus, and new names for Australian species formerly included in Stipa (Gramineae). Telopea 6(4): 579-595
Jessop, J.P. and Toelken, H.R. (eds.) (1986) Flora of South Australia. Part IV. (South Australian Government Printing Division, Adelaide)
NSW National Parks and Wildlife Service (1998) Austrostipa nullanulla. Draft Recovery Plan. (NSW NPWS, Sydney)
Pobke, K. (2007) Draft recovery plan for 23 threatened flora taxa on Eyre Peninsula, South Australia 2007-2012. (Department for Environment and Heritage, South Australia)
Porteners, M. and Robertson, G. (2003) Threatened Plants in Western New South Wales: Information Review. (NSW NPWS, Hurstville)
Pressey, R.L., Cohn, J.S. and Porter, J.L. (1990) Vascular plants with restricted distributions in the Western Division of New South Wales. Proceedings of the Linnean Society of New South Wales 112: 213-227
Vickery, J.W., Jacobs, S.W.L. and Everett, J. (1986) Taxonomic studies in Stipa (Poaceae) in Australia. Telopea 3(1): 1-132
Walsh, N.G. and Entwisle, T.J. (1994) Flora of Victoria. Volume 2, Ferns and Allied Plants, Conifers and Monocotyledons. (Inkata Press, Melbourne)