South-East Mallee Heathlands (Environmental Region 2.3)
This region consists of 15 environmental associations. It is made up of extensive calcreted plains overlain by a series of sand dunes and extends from the state border in the east to the foothills of the Mt. Lofty Ranges in the west. The landforms and soils in the south of the region are similar to those of region 1.4 of South East Province. The calcreted ridges which form the undulating plain have a distinct west-north-westerly trend well displayed on the LANDSAT imagery, and may be extensions of the stranded beach ridge system to the south. The soils are shallow reddish sands on the plains and deep yellowish sands on the dunes. Fans bordering the Mt. Lofty Ranges with low isolated hills rising above them have red duplex soils and calcareous earths subject to sheet erosion. A former floodplain of the Murray River is incised 30-40 m into the plains. Several terraces associated with Pleistocene seal level changes are present; most of these are above flood level and have cracking clay soils liable to salinity problems. Mallee is the dominant vegetation of the region with broombush (Melaleuca uncinata) or heath understory. Some large tracts of mallee still occur, but much of the original vegetation, including that of the Murray floodplain, has been cleared for agriculture. Annual rainfall totals range from 500 mm in the south to 300 mm in the north, with a winter maximum and a dry summer. Temperature ranges from mild to hot in summer and cool to cold in winter.
