Mallee Woodlands and Shrublands: The Mallee, Muruk/Muert and Maalok Vegetation of Southern Australia

Mallee Woodlands and Shrublands are a characteristic element of southern Australian Mediterranean type climate landscapes, being most extensive in intermediate to low rainfall zones. Mallee plant communities in south-east and southern central Australia, and muruk plant communities in south-west Australia are dominated by Eucalyptus spp. with multiple stems and a large subterranean lignotuber from which plants sprout after disturbances. Maalok plant communities in southwest Australia are dominated by Eucalyptus spp. with single stems and no lignotuber, relying on seed for regeneration after disturbance. Understoreys in these communities show a continental-scale pattern of decreasing diversity and cover of sclerophyllous shrubs and increasing cover of Triodia hummock grass moving towards the arid interior. At regional scales, edaphic factors affecting soil texture and pH exert a strong influence on floristic composition and structure. The diversity and endemism of dominant eucalypts in muruk and maalok are substantially higher in south-west Australia than mallee in central southern and south-east Australia, with both historical-geological and ecological factors playing a role. Fire regimes, grazing regimes and climate variation interact to affect the dynamics of mallee, muruk and maalok plant communities, but the balance of fire versus grazing as the dominant control is dependent on land tenure and land use. In higher rainfall areas there has been widespread clearing and fragmentation of mallee, muruk and maalok plant communities, but in areas less suitable for agriculture there are still major tracts of relatively undisturbed vegetation which include some of the largest conservation reserves in southern Australia.