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How have humans impacted the Australian koala population? - Coggle Diagram
How have humans impacted the Australian koala population?
What are they?
Physical description
Large furry ears
Prominent, spoon shaped, black nose
No tail
Average weight
Males. 4-14kg
Victorian koalas average weight is 12kg
The average weight of a koala in Queensland is 6.5kg
Females. 4-10kg
Victorian koalas average weight is 8.5
The average weight of a koala in Queensland is 5kg
Fur
Colour
Northern Australian koala furs are a pale grey
Southern Australian koala furs are browner
Length
Northern Australian koalas have shorter and thinner fur
Sourthern Australian koalas have longer and thicker fur
Large head
The length of a koala is 60-85cm
Hands
Long sharp claws
Two opposing thumbs
rough pads
Other name
"koala bear" is not accurate. Koala's are marsupials
Their closest relative is the wombat
Phasscolurctos Cinereus is the scientific name for the koala
classified in the Phascolarctidae family
What do they need to survive?
Diet
Koalas exclusively eat eucalyptus species
Depending on regions and seasons, koala prefer certain species of eucalyptus
They have been seen eating 120 species of eucalypt
Individuals generally gain most of their nutrition from one or a few species found at a single site
Eucalyptus species do not provide large amounts of nutrients
Koalas can sleep 18-22 hours a day to conserve energy
Koalas gain most of their moisture from the leaves they eat
Koalas eat around 1kg of eucalyptus leaves in a day
Eucalyptus species contain toxins in their leaves
Caecum
Caecum is a digestive organ found in the koala to help digest the toxins
It is 2 metres long
Location
Koalas need large spaces
Preferably 12 trees distant from another individual
Koalas live in Australia
South-eastern South Australia
Queensland
Victoria
New South Wales
Mainly live on the central and north coast
They live in a range of temperate, where eucalypt species dominate and are abundant
Sub-tropical and tropical
Forest
Woodlands
Semi-arid communities
Koalas rely on eucalyptus trees for food and shelter
Impacts on the Koala Population
Human Inflicted Threats to the Koala Population
Human induced climate changed
Increase in CO2 (carbon dioxide)
Further reducing the amount of nutrition in the eucalyptus leaves
Meaning that koalas spend more time finding food
Thus putting them at more risk of predator attacks whilst on the ground
Longer droughts
Heat stress and waves
Dehydration
Force koalas to stop sleep and come down from trees to find water
Larger risk of road accidents
Larger risk of predator attacks
Bushfires
Koalas can not move quickly, meaning they can not escape bush fires quickly
Burns trees and surrounding areas
Leaving less land for koalas
Koalas don't adapt to human induced climate change
Leaving them vulnerable for longer periods of time
Urban expansion
Deforestation
vegetation loss
Due to habitation loss, nearly 28% of the koala population decreased between 1984 and 2012
removes large areas of land for koalas to live
Increasd competition for food
Increased competition for territory
Elevate their chances of getting sick
Increased chance of vehicle strike
Increased threat of domestic dog attacks
Natural Threats to the Koala Population
Diseases
Chlamydia
Symptoms are not always clear and can not always be treated
a bacterial diseases that is highly infectious
Four main diseases are cause by Chlamydia
Conjunctivitis
causes blindness
Pneumonia
Urinary tract infections
Reproductive tract infections
cause female infertility
effect numbers of future generations
Disease weakens the koala
Making them more vulnerable to other death causes. E.g. harsh weather and predator attacks
Dieback of Eucalyptus species
Changes in the balance of the ecosystem
Leaching of soil nutrients
Rising water levels underground
salination of the soil
Exposure to weather and excessive defoliation
75% of the main koala food tree species are declining in numbers as a result of dieback
Predators
Natural predators of the koala
Goannas
Dingoes
Powerful owls
Wedge-tailed eagles
Pythons
Prey on they young
Invasive species that prey the koala
Foxes
Prey on the young once mother decent from the trees
Feral cats
Feral cat prey similarly to foxes
Human Positive Impacts
The Federal Goverment has put in place multiple projects to help the koala population grow
Habitat rehabilitation
Species monitoring
Removal of invasive species
Community awareness to stop habitat degration
Creating corridors or areas of safe passage for koalas
Lifecycle
The average lifespan of a koala is 10-20 years
In the wild the average koala lifetime is 15 years
If raised in captivity a koala can reach the age of 20 easily
Breeding
Koalas typically breed between September and February
Females can breed from around the age of 2
The gestation period is around 2 months
Producing one koala a year, rarely they produce twins
Once a newborn reaches the age of 1 th mother can breed again
Young Koala Life
For 7 months new-borns stay inside their mother pouch
They then ride on their mother back until a year of age
They are then able to live on their own