Nature conservation

Threatened species

A spear-grass - profile

Indicative distribution


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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: 20 Dec 2021

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

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Threats

Recovery strategies

Activities to assist this species

Information sources

IBRA Bioregion IBRA Subregion Known or predicted Geographic restrictions region
Murray Darling DepressionSouth Olary Plain Known Within 50 km of the Murray River