A home to many animals, the Australian tropical savanna is one of the world's largest tropical savannas. The world's other savannas cover two fifths of Africa and large amounts of India and South America. The Australian tropical savanna is an area of dense grass and scattered trees that stretches across northern Australia from Broome to Townsville.
A savanna is usually very flat and with few trees and shrubs, this is because the fires destroy most of the trees and shrubs which usually aren't fire resistant. This happens frequently during the summer. This is also because savannas across the world have a limited water supply and bigger vegetation such as trees are the first to die out. Most savannas are near the equator, but the Australian savanna is south of the equator, which causes this region to have summer while we are having fall. Savannas usually occur only in a climate that has both a rainy and dry season. Each of these different seasons is very extreme.
The dry seasons, or "the dry", of the Australian savanna can last up to five months, from May to October. With each dry season come forest fires. These forest fires occur often, and geographers believe that fire keeps the savanna healthy. The tropical rain forest trees, that would have otherwise grown in that climate, don't grow because they are destroyed by the fires. Though the fires don't destroy all of the underground grasses, the fires limit the growth of any vegetation that isn't fire resistant. Usually the temperatures are cooler, with clear skies and low humidity.
During this time, water is key. The rainy season, or "the wet", can be pretty bad too. Some savannas around the world get ten inches of rain, and some ten full feet. Some pools, ponds, lakes, rivers, and streams flood. Much of the Australian savanna rain falls in heavy bursts of thunderstorms and monsoons. During the wet, which lasts from December to March, it is hot and humid. Temperatures can get as high as 50°C but usually stays around 30s (°C).
Marsupials dominate among the animals in this area of Australia. Marsupial's are mammals whose young are born undeveloped. The premature marsupial baby spends most of its growing up attached to the mother's nipple in a pouch. Marsupials are different from other mammals because they give birth to such undeveloped offspring while other mammal's young are much more mature. The animals include the Echidna, Eastern Gray Kangaroo, the Koala Agile and Whiptale Wallabies, Walaroos, Possums, Gliders, the Northern Qoull, and the Golden Bandicoot. These animals live in or near the few trees in this area for shade, food, and water. In the other parts of the tropical savanna, the reptiles dominate. The saltwater Crocodile, which is found here, is the world's largest reptile. It can grow to be from 7 to 8 meters long.
The vegetation in Australia differs from that of other Savannas. The acacia, part of the 1,200 members of the pea family, is the most common tree in other savannas. The acacia tree does grow in Australia but only in tropical and subtropical areas so, it's not the most common. Acacia's produce a gum called gum arabic, this is used in drugs, foods and others. The acacia's flowers are yellow or white and they grow in bundles.
The most common tree in Australia is the eucalyptus. They are famous for their oil, gum, and timber. The eucalyptus grows in warm climates and they are the most important tree for timber in Australia. The bark of some of these trees furnishes tannin, which is used in medicine.
There are many threats to this biome. The foreign pests and weeds that have been brought to this biome, such as the wetland weed Mimosa, threaten the survival of the region's ecosystems and native species. The Australian government has sponsored programs to clear away brush for agricultural reasons. When some of the farmers took over land, they brought with them new systems that caused some species to become endangered. The Aboriginal people have been stripped of their homes so that the government can make more room for agriculture. The World Wildlife Fund (WWF) in Australia is reacting to this destruction by working with the communities to stop the clearing programs.
This savanna is unique in many ways, including its climate, its animals, its vegetation, and its beauty. It's not quite like the other savannas of the world. It provides a home for the animals we don't have anywhere else in the world. Its vegetation is unique too. The area of the world it is in makes its climate extremely different from the others around the world. The entire planet would suffer greatly if we destroyed this biome.
Thanks to the WWF, this ecosystem may survive. Without such intervention, this world's savannas won't stand a chance.
by Alix C. 2001.
Bibliography:
Strahler, Arthur N. "Australian Savanna", Elements of Physical Geography, 3rd Edition
"Savanna" The World Book Multimedia Encyclopedia. 2000 ed.
"Tropical Savanna", http://www.wwf.org.au/tsavanna.htm (31 October, 2000)
"Reptiles give new slant on conservation", http://savanna.ntu.edu.au/publications/savanna_links5/reptile. html
"Savanna Guides - About Tropical Savannahs",