Biomes are large geographical areas with distinct fauna and flora which are
adapted to that particular environment. A region's climate and geography
determines what type of biome can exist there. Biomes are divided into aquatic
and terrestrial biomes. Aquatic biomes are those which are water based such as
the seagrass meadows in Shark Bay Western Australia, or these kelp forests
on the mid-north coast of New South Wales. Terrestrial biomes
are those based on land. Not all scientists classify biomes in the same
way. Many school textbooks use five broad terrestrial biome categories such as
forests, grasslands, tundra, deserts and marine. Others such as for World Wildlife
Fund for Nature divide the earth into 14 different biomes as can be seen here on
this map. On maps the boundaries between biomes are arbitrary and appear abrupt,
but in new reality there are transition zones between biomes where animals are plants
from neighboring biomes overlap.
Australia with an area of over seven million square kilometers and spanning 33
degrees of latitude has a large range of climate zones. Northern Australia is
characterized by a warm tropical climate with a dry season in a wet season. The
southern part of Australia has a cooler temperate climate and can even
experience snow. Of the Earth's continents Australia has the lowest average
elevation, it is the flattest and is the second driest. With such a
range of climate zones it is no surprise that there are also many types of biome
in Australia. Sclerophyll forests represent the
classic Australian vegetation type. These eucalypt dominated on native forests have
hard, short and often spiky leaves. There are two main sub-types of sclerophyll
forest . Dry sclerophyll forests are typically found in areas with low
rainfall and low nutrient soils. These forests are dominated by short to medium sized
eucalypts and have an understorey of plants such as banksias and wattles.
They have an open canopy which means more light reaches the forest floor in
some places. Dry sclerophyll forests are well adapted so they regenerate after bush
fires. Some of Australia's most well known mammal species can call these
forests home, including the Koala and the Eastern grey kangaroo, as well as
numerous species of bird and reptile.
Wet sclerophyll forests occur on moderately fertile soils in areas of
high rainfall and are characterized by tall eucalypts that grow up to sixty
meters such as these nationally significant coastal black butt trees seen
here. They have a canopy that shelters an understory of shrubs, ferns & herb's. Many
rainforest species may also be found in the understory of these wet sclerophyll
forests. In New South Wales this type of forest is located in the Great Dividing
range and on the eastern side of the escarpment. Many animals are more common
in these forests due to its diverse abundance of food resources.
Insectivorous birds will feed on the abundance of insects and spiders. Since Australia
is the driest inhabited continent on Earth, rainforests account for only
0.5 percent of Australia's land area. The wetter areas east of the Great
Dividing range is where most rainforest is found with tropical and subtropical
rainforest types in Queensland in northern New South Wales.
Temperate rainforest types can be found in southeastern Australia in and Western
Tasmania. Rainforests are characterized by dense vegetation that depends on high
rainfall and have big trees with a canopy that shuts out most sunlight and shade
tolerant plants that grow in the lower layers. Rainforests are an important
biome for biodiversity as they have almost half of Australia's plant families and
1/3 of Australia's bird and mammal species, plus an abundant diversity of
reptiles and insects.
Eucalypt Woodlands have fewer and shorter trees with an understory of
grasses and shrubs. They form a transitional zone between the forested
regions with higher rainfall near the coast and the spinifex grasslands of
the arid interior. There are significant woodlands in northern Australia. West of
the Great Dividing range in eastern Australia and the Great Western
woodlands of Western Australia. Across the continent Eucalypt Woodlands
have been heavily cleared for agriculture. Only fragments of woodland
remain, typically only by creeks, roadsides
and around rocky outcrops. The grassland biome is an ecological
community dominated by grasses with no or only sparse numbers of trees and
shrubs. Northern Australia is characterized by tropical savanna
grassland. This is because the land does not receive enough rainfall in these
regions. The tropical climate has a wet season and a dry season. Fires are common
in the dry season. Temperate grasslands are located between the woodlands and the
arid interior of Australia. In large parts of southeastern Australia as well
as the vast Nullabor Plain in the southwest.
Much of this environment has been converted to sheep and wheat agriculture.
Temperate grasslands have a greater variation and temperature than tropical
grasslands and have a wider variety of species living there. Marsupials such as
kangaroos are the dominant animals of the grasslands. 70% of mainland Australia
is arid or semi-arid desert. These regions are characterized by low
precipitation and extreme temperatures, where daytime temperatures can reach
over 45 degrees Celsius, followed by very cold nights due to the lack of cloud
cover. Due to the seasonal availability of
water, rivers in these regions are said to be ephemeral which means they are dry
for much of the year. Some deserts have stony or sandy surfaces, but other deserts have
vast grasslands containing hummocky looking spinifex grass, shrubs such as
the salt bush and trees such as the ghost gum. In the spinifex grasslands ants and
termites are the dominant insects. Despite the harsh environmental
conditions, deserts support a rich variety of plants and wildlife.
Australia's deserts contain the richest reptile communities in the world. Most of
Australia is low-lying compared to the other land masses on this planet, but
there is a region of montane grasslands and shrublands in the snowy mountains
which cover parts of New South Wales, Victoria and the Australian Capital
Territory. Due to colder temperatures at higher altitudes the higher parts of the
snowy mountains are too cold for trees to grow. Around 1,300 metres snow gums
give way to alpine plant communities consisting of heathland, alpine grasses,
herb fields and bogs.