Unique Creatures
Because of its isolated location and size, Australia's wildlife evolved with special adaptations to its unique ecosystems. The koala is one of the outback's curious creatures. Its scientific name, Phascolarcto, Greek for "pouched bear," has led to the misleading name of "koala bear." In fact, koalas are marsupials (mammals born underdeveloped and needing to be matured in a pouch, such as kangaroos and wombats). Koalas are found in eastern Australia but have varying characteristics depending on latitudes. They have five "fingers" with sharp claws and are the only non-primates that have opposable thumbs. This is a critical characteristic, given that koalas spend 20 hours of their day clutching to trees for naps. They have the lowest brain-to-body mass ratio of the animal kingdom, which is convenient, considering their diet.
Expert Eucalyptus Eaters
When koalas are not napping, they are eating. Arguably one of koalas' most useful adaptations is a diet of eucalyptus leaves. Eucalyptus trees are widespread in Australia and are the source of habitat and food for koalas (1-2 kilograms per night--they are nocturnal animals). The trees too are adapted to the Australian climate and can tolerate droughts, nutrient-poor soils, and frequent fires. Eucalyptus trees contain harmful chemicals that are poisonous to humans and animals--except koalas! These resourceful marsupials have microbes (they are not born with them and must acquire them from the mother) in their digestive system, that are able to break down eucalyptus chemicals. The process is very energy-consuming and requires important quantities of food and sleep. In summary, koalas eat to get energy to digest their food and survive. Nonetheless, a clever adaptation since koalas have no competition for food.
Climate Change Conundrum
Koalas are threatened by poaching, and more readily by habitat loss—both natural and anthropogenic. Nowadays, the bushfire season in Southern Australia (normally December to May) lasts longer, covers more terrain, and is more intense because of climate change. According to ABC News Australia, the distribution of 90 per cent of eucalyptus species would shrink by an average 50 per cent in the next 60 years. Between 2018 and 2021, the koala population of New South Wales, the most fire-prone state of Australia, has declined by 41% (NBC News).
Indigenous knowledge can save Australia and its wildlife
The indigenous people of Southeastern Australia have been managing fires for thousands of years. In forest ecosystems, when organisms die, they form a layer of flammable biomass (twigs, dead grass and leaves...) before being decomposed and returned to the soil.
Having learned from generations of coexisting with nature, indigenous Australians conducted controlled, or "cool," fires to safely burn the biomass. This reduced the quantity of fuel for wildfires to burn during the bushfire season and stimulated plant growth by returning nutrients to the soil quickly. The colonization of Australia began in 1788 when James Cook first landed on the continent. Indigenous traditions were disrupted. Many colonists saw fires as acts of rebellion and tried to suppress the practice. The few groups who managed to continue cool fires could only delay the damage caused by the loss of the tradition. Flammable biomass became more dense, plant biodiversity was lost, less flammable species were replaced by eucalypts, and the Eastern Australian landscape was changed forever.
The consequences were severe. On February 6th 1851, less than 100 years after colonizers first reached Australia, a devastating bushfire ravaged the South. One quarter of Victoria had burned down. The catastrophe became known as the Black Thursday bushfires.
After the catastrophic 2019-2020 bushfire season, Australian fire-management officials are beginning to seek the input and expertise of indigenous people to help fight the threat most pressing to Australia, its wildlife and koalas.
Sources:
"Interesting Facts." Australian Koala Foundation. https://www.savethekoala.com/about-koalas/interesting-facts/
"Australia's koalas are in trouble. The question is how much." NBC News. https://www.nbcnews.com/news/world/australia-s-koalas-are-trouble-question-how-much-n1279807
"Australians love a home among gum trees. But can eucalyptus forests recover from the fires?" The Washington Post. https://www.washingtonpost.com/world/asia_pacific/australians-love-a-home-among-gum-trees-but-can-eucalyptus-forests-recover-from-the-fires/2020/01/17/413d25fa-36b7-11ea-a1ff-c48c1d59a4a1_story.html
"Climate change could shrink habitat of 90% of Australia's Eucalyptus species." ABC News Australia. https://www.abc.net.au/news/science/2016-09-20/climate-change-could-shrink-habitat-of-90-pc-of-eucalypt-species/7858382
"Scientist investigating Australia's past says indigenous cultural burning key to controlling bushfires." ABC News Australia. https://www.abc.net.au/news/2021-06-26/cultural-burning-to-protect-from-catastrophic-bushfires/100241046
"Black Thursday bushfires." National Museum Australia. https://www.nma.gov.au/defining-moments/resources/black-thursday-bushfires
Opmerkingen