Plants and Animals, Plants
mimosa plant, spinifex grass, bridal creeper, national flower of Australia, desert wildflowers
Australia’s dominant natural vegetation is essentially evergreen, ranging from the dense bushland and eucalyptus forests of the coast, to the mulga and mallee scrub and saltbush of the inland plains. The tropical northeastern belt, with its abundant seasonal rainfall and high temperatures, is heavily forested. Palms, ferns, and vines grow prolifically among the oaks, ash, cedar, brush box, and beeches. Mangroves line the mud flats and inlets of the low-lying northern coastline. The crimson waratah, golden-red banksias, and scarlet firewheel tree add color to northern forests.
Along the eastern coast and into Tasmania are pine forests. Pine ranks second to the eucalyptus in terms of economic importance. The Huon and King William pines are particularly valuable for their timber, but the Huon pine is now considered rare and is usually protected. In the forest regions of the warm, well-watered southeastern and southwestern sectors, eucalyptus predominates; more than 500 species are found, some reaching a height of 90 m (300 ft). The mountain ash, blue gums, and woolly butts of the southeast mingle with undergrowth of wattles and tree ferns.
The jarrah and karri species of eucalyptus, which yield timber valued for hardness and durability, and several species of grass tree are unique to Western Australia. The wildflowers of the region are varied and spectacular. In the less dense regions of the interior slopes grow red and green kangaroo paws, scented boronia, waxflowers, bottle brushes, and smaller eucalyptuses, such as the stringybark, red gum, and ironbark. More than 500 species of acacia are indigenous to Australia. The scented flower of one acacia, the golden wattle, is the national flower of Australia and appears on the official coat of arms. In the interior region, where rainfall is low and erratic, characteristic plants are saltbush and spinifex grass, which provide fodder for sheep, and mallee and mulga shrubs.
The most valuable native grasses for fodder, including flinders grass, are found in Queensland and northern New South Wales. During occasional seasonal floods, native grasses and desert wildflowers grow rapidly and luxuriantly, and water lilies dot the streams and lagoons.
The survival of more than 1,000 native plant species is considered threatened. Activities such as commercial agriculture, livestock grazing, and forestry have significantly altered or removed nearly all of the native vegetation in many areas of the continent. Fast-spreading introduced plants such as weeds and ornamentals pose an exceptional menace to native vegetation. The mimosa plant, capable of growing more than 6 m (20 ft) and doubling in area each year, has become a prime threat to the Kakadu World Heritage Area in the Northern Territory. Other widespread nonnative plants include blackberry and gorse from Europe; bridal creeper from South Africa; rubber vine from Madagascar; and paloverde, lantana, and mesquite from Central America. Most of these imports were associated with developments in commercial agriculture or were used as garden ornamentals; about 30 percent have been classified as “garden escapees.” The uncontrolled spread of these plants has caused financial losses in the billions of dollars.
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