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Bushfires in Australian Ecosystems
Transcript of Bushfires in Australian Ecosystems
Fossil evidence suggests that fire was a part of the Australian landscape long before the existence of human beings. Natural fires were caused by lightning, occassional volcanic activity or spontaneous combustion and they probably became more frequent as the Australian continent became drier.
When humans arrived the frequency of fire may have increased as Aboriginal people used fire to manage areas to sustain their own survival. They used fire as a tool for a variety of purposes such as hunting, warmth and cooking, to encourage grassland development in some areas and also to increase the abundance of plant foods and animals.
Fire and Vegetation
Many plants have interesting adaptations to fire, some of which include:
• eucalypt species produce shoots from burnt trunks and boughs. These shoots are eventually able to establish leaves, and so provide nourishment to the trees.
• Banksias and hakeas store seed in woody fruits which open as a result of fire. Consequently the seeds germinate and grow on the burnt ground with reduced competition from grasses and sedges.
• Grass trees flower prolifically after fire due to a fire-initiated release of the gas acetylene, which initiates the growth of the flower spike and the early release of seed.
Some native orchids only flower immediately after fire and sprout from bulbs which may have lain dormant in the soil for up to 20 years.
Some plants have adapted to survive in extreme conditions by having leaves that are hardened, thickened and resistant to moisture loss, such as those of a eucalypt tree or the native heath.
Advantages of Fire
Fire can also create a rejuvenated habitat for many animal species. The abundant regrowth after a fire provides plentiful food for many Australian herbivores.
Within a week, the vegetation starts to regrow succulent shoots
and attract wallabies, wombats and grasshoppers.
However, these animals require
nearby areas of unburnt habitat where they can shelter. Among bird species, the critically endangered orangebellied parrot prefers buttongrass moorland
habitat which has been burnt recently.
Fire also regenerates the soil making perfect conditions for germinating seeds.
Fire also reduces the canopy, allowing more sunlight to reach to the ground.
Removing grasses also reduces the competition for seedlings and young plants.
Disadavantages of Bushfires
Many small animals are effected by fire. Some are unable to escape and perish, or are injured and unable to recover. Others cannot survive with the removal of their food source.
Construct a PMI table for bushfires
To Burn or Not to Burn
There has been much debate as to whether the CFA (Country Fire Authority) and the DSE (Department of Sustainability and Environment) should conduct controlled burning to reduce the impact of bushfires.
What do you think?
Do you think we should regularly perform controlled burns? List some reasons for and against prescribed burning.
Black Saturday Bush Fires
Now research the topic and add to your lists. You might want to start here:
Do you still feel the same way about controlled burning? How has your opinion changed?
Discuss with a partner your view point.
ABC learn, 2010. Managing Bushfires. Retrieved August 2013. <http://abceducation.net.au/videolibrary/view/managing-bushfires-104>
CSIRO, 2012. Bushfires in Australia. Retrieved August 2013, <http://www.csiro.au/resources/BushfireInAustralia>
Department of Sustainability and Environment, 2013. Fire and other emergencies. Retrieved August 2013. <http://www.dse.vic.gov.au/fire-and-other-emergencies/planned-burning-an-introduction/dses-planned-burn-program>
News on ABC tv, 2010. Inside the Firestorm. Retrieved August 2012. <
Parks Tasmania, 2010. Fire, flora and fauna. Retrieved August 2013, <http://www.parks.tas.gov.au/file.aspx?id=6525>
SWIRK, 2013, Year 8 NSW » Science » Ecology » Australia's ecosystems » Bushfire. Retrieved August 2013, <http://www.skwirk.com.au/p-c_s-4_u-200_t-559_c-2083/nsw/science/ecology/australia-s-ecosystems/bushfire>