Gulf Plains (Environmental Region 4.6)
This region consists of 16 environmental associations. It includes the northern section of Yorke Peninsula and the plains and fans between the St. Vincent and Spencer Gulfs and the Mt. Lofty Ranges. Most of the region consists of undulating plains with calcrete development and shallow reddish earths. The plain is mainly dune free but isolated areas are overlain by low indistinct sand dunes. Near the Mt. Lofty Ranges the plains have a definite westerly gradient and merge eastwards with the alluvial fans from the Mt. Lofty Ranges. Moderately deep red duplex soils occur on the fans and footslopes. Red mallee-yorrell (E. socialis - E. gracilis) association occurs throughout the region with some woodland of mallee box (E. porosa) on the plains or peppermint box (E. odorata) on the hills and footslopes. In the north, foreground and middleground panoramic views are dominated by the adjacent Southern Flinders Ranges. Elsewhere, the Mt. Lofty Ranges and the Barunga Range form the backdrops for these views. The Barunga Range itself provides panoramic views over the plains which feature rare salt lakes and small blocks of mallee. Coastal flats with mangroves and samphire provide detailed and sometimes enclosed views. There is a mild climate with a winter rainfall maximum and high summer evaporation. Mean annual rainfall shows a general increase from about 350 mm in the west to about 600 mm in the south-east of the region. Temperatures are mild to warm in summer and cool to cold in winter. Mean monthly evaporation is very high in summer and exceeds the 90th percentile of monthly rainfall for all months but July. Mean annual evaporation increases from about 1800 mm in the south to about 2200 mm in the extreme north.
