The Australian outback landscape ranges from vast, naturally treeless blacksoil plains growing Flinders and Mitchell grasses (referred to as ‘downs’ country), to rocky hills covered in spinifex, ghostgums and coolamon trees, to dense grey mulga scrub, red sandhill country, lignum and coolabah swampy channel country, to dusty nondescript scrub of bullwaddy, lancewood, gidyea or eucalypts and wattles.
Most of these different types of Australian inland landscape can be seen in the books ‘A Million Acre Masterpiece’ and ‘Life as an Australian Horseman’.
The Tropical Savannas Co-Operative Research Centre has information on Australia’s savanna grasslands.
The less frequent and less reliable the rainfall and the older the soil, the larger the stations and the more scattered and smaller the townships are. Many stations are located hundreds of miles inland, totally dependent on artesian bore water as there is no natural surface water.
Other cattle stations have miles of ocean frontage and large, sandy, wet-season rivers lined with pandanus, paperbarks, figs and gums. The very largest cattle stations average 10,000 square kilometres in area and they run between 20,000 and 60,000 head of cattle (mostly Brahmans in a reasonable season.
The rainfall varies from a sparse and unreliable average of 150mm (6”) or less per year in semi-desert country to 500mm (20”) in the ‘dry tropics’, and 750mm (30”) or more in tropical areas closer to Australia’s northern coastline. In a good year areas below the Tropic of Capricorn (eg Queensland’s channel country) receive rain from the south in winter and from the north in summer, but in a bad year this region doesn’t get rain from either direction, or a flood down the channels.
It is often said in the ‘downs’ country between Blackall and Richmond that in any 10 year period producers can expect only three really good seasons, several rather ordinary seasons and several of severe drought.
Northern areas are completely dependent on ‘wet season’ rainfall, usually associated with a monsoon trough or cyclone that has crossed the coast. Approximately 75% of rain usually falls between the months of December and March. Most of the native grasses in the northern inland regions have evolved to the point where they only grow during the hotter months, so the occasional rain that falls in the cooler months does not promote new growth.
Unseasonable rain only rots and ruins the protein content of the dry feed that has ‘hayed off’. Some ‘herbage’ (smaller native plants) will grow after substantial winter rain but in the north there is rarely enough of it to sustain significant numbers of cattle.
Temperature-wise, the biggest difference between northern and southern Australia is that the southern winter is not just colder, it is much longer.
In Western Australia’s Kimberley region, for example, the daily temperature maximums and overnight minimums rise rapidly in August and don’t drop much until May. By November the temperature of the ground is so high it’s like sleeping on a hot brick. Wyndham (in the East Kimberley Region) has Australia’s highest year-round maximum temperatures and it’s often very humid also.
In Queensland the highest state-wide early Spring and late Autumn temperatures are invariably in the northern towns of Julia Creek and Weipa because these areas warm up a month or two before southern Queensland and stay hotter for much longer.
For up-to-the-minute weather information, including pressure charts, rainfall radar maps and satellite maps you can’t go past the Australian Bureau of Meteorology’s website. It is also an excellent source of background information on cyclones as well as providing a good warning service when cyclone watches are in place.
Tags: The Great Artesian Basin, Australian cattle stations, Conservation and the environment