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Australia's Arid Lands
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Put simply, the arid and semi-arid lands are those
remote and sparsely populated areas of inland Australia,
defined by the presence of desert vegetation and land
forms as well as by low rainfall. They are bound
by median annual rainfalls of about 250 mm in the south
but up to 800 mm in the north and about 500 mm in the
east.
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Together with sub-tropical regions and the mountain high
plains, they form the rangelands, where rainfall is too low
or unpredictable or where terrain is too inhospitable for
sustainable cropping or timber harvesting. The rangelands
amount to 70% of Australia's land surface, and by far the
largest part is arid or semi arid.
The vegetation of the arid lands has a strong influence on
land use and productivity. The saltbush, mulga and grassy
plains provide pasture for sheep and cattle as well as habitat
for unique mammals and birds. In the dry infertile interior,
the spinifex-covered sand plains and stony deserts are too
tough for livestock. Instead they are home to a multiplicity
of termite species and the world's richest lizard fauna.
 It
is an uncompromising environment at times but never monotonous.
The climate of arid Australia is more variable than in arid
lands anywhere else in the world, with highly erratic rainfall,
extremes of long dry periods and flooding deluges. As well,
soils are characteristically very infertile over vast areas
compared to other deserts of comparable aridity.
The range of flora and fauna occupying the various ecosystems
also contrasts with that from other arid regions of the world.
Major differences include the lack of many succulents, the
small number of large mammals and the high numbers and diversity
of lizards as well as social insects such as ants and termites.
These factors combined determine the arid zone's uniqueness.
 Despite
the challenges of climate and terrain, there are a diversity
of land uses, but the balance amongst them is changing with
global market forces and community values. The pastoral industry
is the major land user, producing mostly cattle in the north
and sheep in the south, but profitability is declining. Other
land uses currently include Aboriginal cultural and subsistence
activities, conservation, tourism, mining, harvesting of wild
animals and plant products, and small-area intensive industries
such as horticulture. Some of these are growing rapidly. Newer
developing industries include aquaculture, carbon sequestration
and low intensity lifestyle activities.
Whoever uses this land must come to terms with its variability
or risk destroying its rich potential.
Many Australian children have learned to recite Dorothea
MacKellar's words: "I love a sunburnt country, a land
of sweeping plains, of ragged mountain ranges, of droughts
and flooding rains." The 'outback' is regarded by most
Australians as part of the nation's heritage and, although
Australians are largely urban people, many retain a romantic
image of the outback pioneers forged in the tradition of mateship
and love of the land they wrested from the wilderness.
Realities are different today: rather than fighting nature,
we must learn how to live with it. Australia and indeed the
world is concerned about land care and the preservation of
land use options for future generations.
The obligation to maintain the arid lands is shared by many
groups of people. In collaboration with these groups CAZR's
role in the arid zone is to provide government and private
agencies, as well as individuals, with the knowledge of how
the arid lands function, principles for their management and
methods that can be applied to achieve sustainable land use.
>> Biodiversity in the
arid lands
Related sections: CAZR Research,
Education
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