Mid-North Wheatlands (Environmental Region 3.3)

This region consists of 19 environmental associations. It is considerable drier than regions 3.1 and 3.2, and this is reflected in the land use. Geomorphologically the region is characterized by a series of wide undulating intramontane basins with red duplex soils, separated by low but distinct northerly trending strike ridges. This sequence is repeated uniformly across the entire width of the uplands. In the north the region leads into the Southern Flinders Ranges with no sharply defined landform boundary but a land use boundary marking the northern extremity of wheat cultivation. Due to widespread clearing for farming the only significant remnant of native vegetation is found in the rugged Mt. Remarkable association, where an open forest, dominated by sugar gum (E. cladocalyx) or by longleaved box (E. goniocalyx) and blue gum (E. leucoxylon) is indicative of a pocket of higher rainfall. Degraded remnants of blue gum and peppermint box (E. odorata) woodlands which originally covered most of the region can still be found on stony crests and steep slopes. The mallee vegetation associated with sandy soils, and the tussock sedgelands dominated by iron grass (Lomandra spp.) which formerly occurred in the intramontane plains and valleys in the north-east, have virtually disappeared from the region. The landscapes are dominated by the alternation of low, northerly trending ridges and long, undulating intramontane plains of variable width. Throughout the region the plains, the lower slopes and the more gentle crests are cultivated for wheat and barley in rotation with sheep and cattle grazing. Except for plantings of sugar gums and exotic conifers around homesteads, as windbreaks and along some roadsides, few trees are present on the plains. However, the ridges, when too steep or stony for cultivation, usually carry some remnants of the original woodland, except in the eastern part of the region where trees are naturally absent. In the plains the views vary from foreground to background panoramic depending on the position of the observer in this undulating to rolling country. The ridges often form backdrops to the views. Where the ridges are only separated by narrow plains, the views change to perspective, occasionally highlighted by telephone and power lines on both sides of the road. In the views on the plains these and other man-made structures such as homesteads, windmills, and ruins of abandoned buildings may form notable features. The ridges provide very different views from the plains. From suitable locations views over the plains are extensive and it is from such positions that the pattern of the fields stands out best, especially when preparations for sowing occur: yellow stubble paddocks alternate with ploughed blocks of red and brown earthy colours. On cloudy days the views can be dramatically enhanced by the play of light and shadow. In the ridge country many roads follow valleys which characteristically have foreground perspective views, widening to middleground views where the valleys transgress into plains. Rock outcrops reflecting the underlying geological structure are often a feature in views along the valleys. Because of the repetitiveness of the views no scenic assessments are given in the landscape descriptions of the environmental associations. This is a region of considerable climatic heterogeneity, reflected by the fact the four Koppen classes occur within it. In general there is a cool to mild climate with a distinct winter rainfall maximum. Mean annual rainfall ranges from 250 mm in the north-east to 700 mm in the south-west. In the uplands along the western margin annual rainfall reaches about 500 mm. Mean annual evaporation is high in summer, it falls below the median monthly rainfall during winter. Temperatures are cool to hot in summer and cool to cold in winter, and diurnal variation is higher than for regions 3.1 and 3.2.