large areas of desert, semi-desert grasslands with mulga bushes (Acacia aneura) predominate. Semi-desert savannas with low-growing acacia species cover large areas in the south of the arid zone, where 200 to 500 mm of precipitation falls in winter and summer. The acacia species, called mulga, grow on the plains, mountain slopes and hills of the deserts. In connection with the bushfires, which are mainly ignited by the spinifex grasses, the non-resistant mula bushes burn, which then no longer grow back. There is evidence that Aboriginal people did not start bushfires in mulga landscapes. The desert areas covered by mulga are also threatened by deforestation, extensive livestock farming and fuel wood production. At the eastern end of the arid zone is the so-called Witchetty Bush. This area is home to the endemic species of acacia, Acacia kempeana, which feeds the wood borer larva, the witchetty maggot, up to three inches in size. It is high in protein and was an important part of the Aboriginal diet. Eucalyptus woodland thrives along the dry riverbeds. Grasses grow on the soil under the eucalypts. Chenopodiaceae shrubs, which usually do not exceed 1.5 meters in height, are found in the southern desert areas. They are salt plants that grow on both dry and saline soils. In the deserts there are permanent or percolating patches of freshwater formed in rocky areas or in sandstone canyons. Bluebush and saltbush species grow in heavier soils. Between the sand ridges, the areas of wooded steppe consist of Eucalyptus gongylocarpa, Eucalyptus youngiana, and Acacia aneura (mulga) shrubs scattered over areas of resilient spinifex grasses, particularly Triodia basedowii. Most of the area is covered by hummock grasslands (Triodia spp.), with a few eucalypts, acacias, grevilleas, and bloodwoods (Corymbia chippendalei and Corymbia opaca) are found on sand hills. The vegetation of the dunefields of the Tirari Desert is dominated by either Sandhill Wattle (Acacia ligulata) or Sandhill Cane-grass (Zygochloa paradoxa) which occur on the crests and slopes of dunes. Tall, open shrubland also occurs on the slopes. In drier areas, species including Old Man Saltbush (Atriplex nummularia), Cottonbush (Maireana aphylla) and Queensland Bluebush (Chenopodium auricomum) form a sparse, open shrubland, whereas swamps and depressions are frequently associated with Swamp Cane-grass (Eragrostis australasica) and Lignum (Muehlenbeckia florulenta). The intermittent watercourses and permanent waterholes associated with tributaries of Cooper Creek support woodland dominated by River Red Gum (Eucalyptus camaldulensis) and Coolibah (Eucalyptus coolabah). Numerous