Where have all the koalas gone?
By SANDI MILLER
Feature image: Sondra Vlasic
Feature image: Sondra Vlasic
ANYONE WHO has lived in the area for any length of time will know the joys of receiving a visit from one of Warrandyte’s koalas.
Sadly, this is an increasingly rare occurrence, and as our nature columnist Glenn Jameson discusses below, the reintroduction and
subsequent drought has been responsible for the boom and bust of the local koala population over the last 20 or so years.
Koalas locally have been a large tourist drawcard, indeed the national value of the koala as a tourism icon has been estimated at over $1 billion.
In 2004, the then Department of Sustainability and Environment produced a Koala Management Strategy, which outlined the challenges faced by the koala population and the approaches to aid in their preservation.
Major conservation issues for the koala in Victoria were seen as the continuing incremental loss of mature trees through deliberate felling
associated with land development and land-use change, and the declining health of remnant trees in rural landscapes.
The potential for increased frequency of wildfire associated with climate change is also a serious concern for the Koala.
Annual koala counts in Pound Bend occurred from 1998 to 2011, with numbers declining over this period.
This local decline may be caused by dispersion along the river corridor, as individual koalas tend to require a substantial environment to accommodate their dietary needs, or other factors such as the Millennium Drought, urban encroachment or natural attrition.
In light of the Government reviewing the State’s Koala Management Strategy, which seems to have been much more successful than that of New South Wales and Queensland where koala populations are effectively extinct, the Diary sat down with Vivian Amenta, Wildlife Management Coordinator at the Department of Environment, Land, Water and Planning (DELWP).
Diary: What has led to the decline in the local koala population?
Vivian: In Victoria, the koala population was reduced to extremely low numbers by the 1920s, when the koala fur trade was finally abolished.
A re-introduction program, begun in 1923 with French Island koalas, has resulted in occupation of almost all suitable koala habitat in the State.
While we do not have statistics for koala numbers in Warrandyte, there is no doubt that numbers would have dropped over the last 20
years, and indeed would have been declining since people first moved into the area.
This is due to habitat fragmentation, removal of their preferred food trees to make way for housing, roads and other infrastructure, and significant numbers being killed directly by cars and dogs.
Though koalas are considered vulnerable in Queensland and New South Wales, in rural areas of Victoria and South Australia,
they are plentiful, and far healthier than their northern counterparts, as the diseases chlamydiosis and koala retrovirus are not nearly as
In fact, in Victoria and South Australia, fertility control and translocation are required to ensure they do not eat themselves out of house and home and end up starving.
Diary: Are there any plans to repopulate the area?
Vivian: Translocation of koalas is only undertaken in areas where their on-going welfare is well-assured.
Unfortunately, the network of roads, the ever-increasing housing density and number of predators (dogs) in Warrandyte and surrounds rules out consideration of repopulation here.
There is also a need to consider the existing population of koalas.
They are territorial, will fight to retain/establish their patch, and if the new comers are displaced, they may try to return “home”, increasing
their chances of road mortality.
This is why the Kinglake translocation undertaken in 2017 was considered ideal.
We only translocate to sites where there are very few or no existing koalas.
At Kinglake we were able to release the koalas deep within the park.
There is only one nearby road and the 400 koalas were able to move in unopposed, as sadly, the existing population had been destroyed in
the 2009 Black Saturday bushfires.
Diary: Are there tips we can give local residents to provide habitat for the animals?
Vivian: Residents can encourage koalas to remain by:
• discouraging harassment by dogs – their own animals and other residents’
• keeping dogs on-leash when in koala habitat
• not letting dogs roam
• being “wildlife aware” when driving
• requesting that speed limits be lowered on local roads, and adhering to the limits
• calling wildlife carers to assist when an animal is sick or injured
• reporting cases of wildlife cruelty (yes people are cruel to koalas) to Council and DELWP
• planting appropriate species of Eucalypts — though there are around 28 species that Victorian koalas will eat, koalas in this part of Victoria prefer manna gum (Eucalyptus viminalis), swamp gum (Eucalyptus ovata), blue gum (Eucalyptus leucoxylon) and
river red gum (Eucalyptus camaldulensis)
• leaving out shallow bowls of water for koalas in hot weather — koalas get most of their moisture from leaves, but in hot conditions will need additional water.
Diary: What are the ongoing plans for koala management?
Vivian: Victoria is currently in the process of reviewing the Victorian Koala Management Strategy (2004).
Updating the Strategy is an action under DELWP’s Living with Wildlife Action Plan, to ensure the State’s koala populations are secure and
healthy, and to guide their current and future management.
Victoria’s koala population will also benefit from the Victorian Government’s Biodiversity 2037 Plan which aims to improve the extent
and condition of native habitat and secure the greatest possible number of species in the wild.
The story of the boom and bust of the koala
By GLENN JAMESON
MY MATERNAL Grandmother was an English World War One, war bride, marrying my grandfather an Australian soldier after he was
discharged from the army suffering chronic “trench feet” from wet and muddy trenches at the Somme.
Grandmother owned a pair of gloves made from koala fur, her pride and joy, bringing them on the honeymoon voyage to Australia.
As peace spread across Europe, a war continued on koalas with an estimated eight million koalas killed between 1888 and 1927 for the fur
trade, their waterproof pelts shipped to London, the United States and Canada to line coats and make hats and gloves.
By 1924, the koala population had gone bust; they were extinct in South Australia, severely depleted in New South Wales, and estimates for
Victoria were as low as 500 animals.
The economic bust of the 1930s depression was a difficult time for Nana who had the task of bringing up a family of six by herself as
Grandfather had died, never quite recovering from the war.
By this time, the koala population on the Victorian mainland was thought to be confined to a few remnant populations in South Gippsland and the Mornington Peninsula.
Citizens concerned at the survival of the koala in Victoria during the 1930s captured individuals and placed them on Phillip Island and
French Island where they were secure and able to breed up.
Koalas had been extinct from Warrandyte for decades when in 1985, government agencies released 30 adult and eight juvenile koalas at
The following year there was another release of a similar number.
Phillip and French Islands had provided security to enable koalas to boom and breed up large numbers but now they were outstripping their habitat.
However, the koala boom was from an isolated, in-bred population, with a very low genetic diversity and this population is now the source of most of the Victorian koala populations — with the exception of unique Strzelecki Ranges wild populations, which are genetically intact and diverse.
The release was incredibly successful and by 1995 koalas were generally found everywhere in the Middle Yarra area where there was suitable habitat, especially in Warrandyte State Park, the population had even spread to private property.
In Dreaming Stories, Wurundjeri legends associate Koobor (koala) with drought.
Although they may kill koala for food, the skin may not be removed, or bones broken, until after koala is cooked.
Should anyone disobey this law, it is said that the spirit of the dead koala will cause such a severe drought that everyone except the koalas will die of thirst.
In 1997 the Millennium Drought started, the climatic version of “boom or bust”, and our local koala population went bust.
The koala diet is very restricted, there is only a few species of eucalypt leaves which they can eat.
The leaves they can eat also need to have a minimum moisture level of 45 per cent to provide them with enough water so that they do not have to drink water.
The success of the 1985 koala release allowed koala’s to fill all available niches in local habitats, but the Millennium Drought reduced the leaf moisture content below 45 per cent and koalas began falling out of trees.
In the local wildlife refuge, 52 died in care and 102 were euthanized, the population dropping dramatically.
“Boom and bust” is the breeding dynamic many Australian mammals employ to overcome one of the most erratic and variable climates
in the world; breeding prolifically during productive high levels of rainfall, which allows populations to safely diminish (bust) during
periods of drought and then expand again (boom) when the rains return, Australian mammals are genetically pre-determined to
manage their population and habitat in conjunction with this climate cycle.
B u t , as successful as the translocation program operating from the Islands has been, the lack of genetic diversity has produced
behaviour traits which do not assist in survival.
For example, not changing food trees every night, thereby killing feed trees and breeding during droughts, strategies other genetically intact and diverse koala populations avoid doing.
The good news is koalas are still in the landscape — but at highly reduced numbers and fighting for survival.
I have not seen one since 2005.
On the mainland, the amount of viable habitat available remains a limited island in a sea of urbanisation, farmland and unsuitable bushlands.
The hotter and drier our climate becomes with Global Warming the more precipitous their future becomes.
My Grandmother — a war bride and then a war widow — never needed her koala skin gloves in the hot Australian climate, but she
did need the sanctuary which her children provided for her in later years.
Something we may not be able to provide for koalas locally, as the climate warms.