The Mallee
From Wikipedia, the free encyclopedia
The Mallee is the most northwesterly district in the state of Victoria. It is usually defined as approximately extending from the southern boundary of the Big Desert to the Murray River and east to the basin of the Loddon River.
[edit] Geography and climate
The Mallee is, for all practical purposes, completely flat and very low-lying: in fact for long geological periods the whole region has been inundated by the ocean. Most of the Mallee consists of sand dunes that have been deposited as a result of movement of sand from the interior of Australia during arid glacial periods of the Quaternary. The soils are generally very infertile and sandy: the better ones on more stabilised sand dunes in the east are slightly loamy and pink to light brown and have been able to support wheat and barley growing as a result of the development of superphosphate and other fertilisers. In the west the soils are unconsolidated sands, much less alkaline than in the east, and not generally able to support any grain cropping.
The Mallee has no surface drainage: the native vegetation has so high a rooting density that the rainfall of most years is easily absorbed and the porous sandy soils mean that any excess in an exceptionally wet year will recharge groundwater supplies which tend to be highly saline. Flow from the Wimmera River to the south supplies Lake Hindmarsh and, very occasionally (in 1918, 1956 and 1975), overflows to the north. The Murray River, is, thus, the only source of fresh water for the region and is consequently overburdened by intensive irrigation.
The climate of the Mallee is the hottest and driest in Victoria owing to its inland location. Rainfall is usually only produced by the most vigorous frontal systems or by occasional penetration of tropical air in the summer. Average annual rainfall shows a well-defined north-south gradient: Mildura averages only 270 millimetres (under 11 inches) per year but Hopetoun in the south receives around 370 millimetres (just under 15 inches). Variability, however, is quite high: in 1973 the Mallee averaged as much as 650 millimetres (over 25 inches) but in 1982 only 115 millimetres (4.5 inches). Temperatures in summer are generally very hot: in January 1906 it is believed Mildura reached temperatures as high as 50.8°C (123.4°F) and the average maxima in January and February are around 32°C (90°). In the winter, maximum temperatures average a delightful 16°C (60°F), but minima average 4°C (39°F) and frosts are very common.
[edit] Population and Economy
The Mallee has a total population of around 75,000, most of which live on the Murray River. Mildura and Swan Hill are the major settlements and along with nearby towns that have merged with Mildura, contain over two-thirds of the region's population. Hopetoun, Ouyen and Birchip are the major towns in the south, but all are declining severely due to the poor incomes farming produces.
The Mallee is a primarily agricultural region: apart from possible mineral sands in the weat and salt from certain ephemeral lakes there are no mineral deposits of value and industry is generally on a small scale and confined to food processing. Wheat and barley are widely grown on the less infertile soils in the southeast of the region, but fertilizers, especially superphosphate are essential for success and yields only a quarter of those in most of Europe or North America - in drought years, they can be as little as one twentieth of European wheat yields.
Fruit growing along the Murray River has in modern times overshadowed grain crops as the Mallee's major source of revenue. Oranges and grapes are particularly important and the region produces a large part of Victoria's wine though most of it is inexpensive casque wines. Dairying on irrigated pastures is important in the south of the region, but is threatened by its high water demand and the extreme scarcity of water in the Murray-Darling Basin.
Tourism, based on the vast, remote Wyperfeld and Murray Sunset National Parks, is a specialised, if significant industry. Houseboats on the Murray are also a major attraction for visitors to the area.
[edit] Mallee Fowl
Restricted to the Mallee area of Victoria, Mallee fowl are large, ground-dwelling birds that roost in trees and need sizeable blocks of scrub to survive. If you are fortunate enough to see one of these mysterious birds in the wild, you will hear their distinctive plaintive 'hobble-bobble' call. They derive their food from scratching through the dense local bed of bark and leaf litter and are an endangered species. They are megapodes which means "big feet". They lay their eggs in large mounds of litter, the warmth of the composting plant material is how they incubate their eggs and the size of the mound and thus temperature is closely montiored by the adult pair. At birth the young chicks must struggle up through the litter and are left to fend for themselves. Recent research strongly suggests that different depths in the litter and thus different temperatures determine the sex of the chicks much like alligators or crocodiles. Exactly how this could occur is still a mystery as unlike reptiles, bird eggs already have sex predetermined when they are laid.
