Territory Environments
Hummock Grasslands
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(Spinifex communities on sandplains and dunefields)
Large tracts of Central Australia are composed of spinifex sandplains and dunefields, with three species of spinifex being dominant on these landforms. Though sometimes overlapping in their distribution they are generally quite distinct in their habitat preferences.
Feathertop spinifex Triodia schinzii is primarily restricted to deep red sands and most common in the northern parts of the Centre where it is often the dominant plant on large featureless plains. Associated species include small trees of dogwood Acacia coriacea, corkwood Hakea macrocarpa, and various Acacia, Grevillea and Senna shrubs. Termite colonies never protrude above the ground surface, low clay content doesn't allow the construction of termitaria able to withstand the effect of fire and rain.
Hard spinifex Triodia basedowii is generally restricted to less deep sandy soils which often have a gravelly basement 3-5m below the surface. This species is most common in the southern areas of the Centre on sandplains and dunefields. Associated species include mulga Acacia aneura, mallees Eucalyptes spp. and various small shrubs and forbes. The Desert Oak Allocasuarina decaisnea is often associated with this spinifex. Below-ground termitaria proliferate in this habitat.
Soft spinifex Triodia pungens is common on sandplains with little moving sand and large above-ground termitaria. This species of spinifex is also found on sand-dune crests, and on calcareous and saline sands, it is less habitat specific than the other two species.
At least 16 species of birds are commonly found in spinifex grasslands. Many reptiles occur in this habitat with the Great Desert Skink Egernia kintorei listed as Vulnerable. Of the numerous mammal species the mulgara Dasycercus cristicauda and the Greater Bilby Macrotis lagotis are classified as Vulnerable. Three frog species are well adapted to this harsh area.
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Total area
The area covered by hummock grasslands in the NT is about 491 983 km2
Presence in conservation reserves
Alice Springs Desert Park, Chambers Pillar, Emily and Jessie Gap Nature Park, Finke Gorge National Park, Longreach Waterhole, Rainbow Valley, Tnorala, Uluru-Kata Tjuta National Park, Watarrka National Park, West MacDonnell National Park.
Threats
An increase in the frequency and intensity of fire, especially in areas where buffel grass Cenchrus ciliaris has intruded.
Further reading
- Latz, P. (1995). Bushfires and bushtucker. IAD Press, Alice Springs. 400pp.
- White,M., Albrecht,D., Duguid,A., Latz,P., and Hamilton,M. (2000). Plant Species and sites of botanical significance in the southern bioregions of the Northern Territory; volume 1: significant vascular plants. A report to the Australian Heritage Commission from the Arid Lands Environment Centre. Alice Springs, Northern Territory of Australia.
