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The Koala Conundrum

Credit: Philip Roetman

Credit: Philip Roetman

By Margreet Drijfhout & Dave Kendal

Wildlife managers believe that overabundant koala populations need to be culled before they strip the manna gums in which they live and begin to starve, but will the public accept culling koalas and other wildlife species, such as kangaroos and brumbies?

How do you feel about koalas? Do you think they are cute and cuddly? A good ambassador for Australia? Or just another animal in the world, no different to others? What about a pest animal?

Understanding people’s opinions is increasingly important in conservation, as public opinion shapes what managers can and cannot do. When we surveyed people across Australia we found that the public doesn’t support culling koalas (whereas many wildlife managers do), that providing information can increase public support for culling, and that people think differently about koala management compared with kangaroos and brumbies.

Koalas are very common in some parts of Victoria and South Australia. They are sometimes so common that the koalas are causing damage to their environment and themselves, as they need more food than is available. Koalas in Victoria and South Australia like eating the leaves of the manna gum (Eucalyptus viminalis). High-density koala populations can eat all the leaves of manna gum trees, and when the trees grow new leaves they will eat all those leaves too.

The trees can recover once, perhaps two or three times, but ultimately they run out of energy and die. This has happened several times in different areas around Victoria and South Australia. When this recently occurred in Cape Otway, Victoria, hundreds of koalas died of starvation after stripping the manna gums of their leaves, leaving a dead forest behind and destroying the habitat of other species. Managing the number of koalas in these areas is therefore important, not only for the koalas but for the entire forest and everything that lives in it.

There are different ways to manage koalas when there are too many of them. While you can restore an area of forest by planting new trees to replace dead ones, it takes years for trees to grow, so this will not help the koalas that are already starving.

Another option is birth control, which typically involves female koalas receiving a hormone implant that lasts for up to 10 years. This strategy has been used since the 1990s. Contraception works well in reducing the number of koalas over time but, like restoration, it does not immediately reduce the number of koalas, and therefore the pressure on remaining trees. It is also a relatively expensive approach as it requires a lot of people and equipment to catch, sedate and insert hormone implants into the koalas.

Another option is translocation, where koalas are moved from one place to another. Thousands of koalas were translocated in Victoria and South Australia last century. Moving koalas out of problem areas immediately reduces the pressure on the trees in that area, but there are not many suitable areas left in south-eastern Australia that do not already have a healthy koala population.

Moving koalas is a stressful experience. An Australian study published in the Journal of Wildlife Management in 2012 (https://goo.gl/7cMP1t) found that 37.5% of relocated koalas die within 12 months. Why not translocate koalas to New South Wales and Queensland, where they are classified as a threatened species? This is not considered a good option from an animal welfare point-of-view, as koalas from Victoria and South Australia are not adapted to the warmer climate up north: they are larger and have thicker fur. In addition, southern koalas are used to different food trees than koalas in north-eastern Australia.

What about moving them to zoos in Australia and overseas? For one, zoos might not be willing or able to accommodate even a small number of koalas, as koalas are expensive animals to keep due to the need for a continuous, large supply of Eucalyptus leaves. Hundreds of koalas would need moving to solve the problem in the short-term and may not solve this issue at all in the long term.

There is another controversial option that can be used to manage koala numbers: culling some animals in a population to reduce their numbers. In Cape Otway in 2013, hundreds of koalas were starving to death after many trees had died, and their prospect of recovering was considered close to zero. It was decided to end their suffering by euthanising them humanely.

While many wildlife managers would like to consider the option of culling koalas before too many trees die and koalas suffer, current wildlife management policies and practices do not allow preventative culling of koalas. Anecdotally, this is because there is little public support for culling, and it will lead to conflict and criticism of management. However, research is needed to understand what people really think about this issue, rather than basing decisions on what managers and policy-makers perceive people to be thinking. This is what we set out to do.

We studied how people think about overabundant koalas and their management in an Australia-wide survey. We measured how acceptable different management strategies were to people. We compared the responses of the general public and experts. We also compared responses about koalas with responses about kangaroos and brumbies to see whether koalas really are thought about differently than other animals. In addition, we looked at people’s values and beliefs about human–wildlife relationships to get a better understanding of why people are thinking the way they do.

We sent out a survey to 1150 people across Australia. Half these people received a survey about koalas, one-quarter about kangaroos and one-quarter about brumbies. Half of the people sent the koala survey were also given information about the impacts of overabundant koalas. In addition, surveys about koalas were sent to 150 experts on koala management. People were asked how acceptable they would find the use of seven possible management strategies when animals are starving to death due to a lack of food:

  1. doing nothing and letting nature run its course;
  2. restoring habitat (e.g. by planting new trees);
  3. translocating animals to another area;
  4. birth control;
  5. culling;
  6. indigenous hunting; and
  7. commercial use (e.g. of fur and meat – koala pelts were widely used to make hats early last century).

On average, 58% of the general public and 80% of the experts found it unacceptable to do nothing about overabundant koalas. Restoring habitat (public 83%, experts 74%), translocating animals (public 79%, experts 64%) and birth control (public 57%, experts 65%) were generally considered acceptable by both groups.

Acceptability of culling showed a distinctly different result. While experts found it acceptable to cull koalas (68%), the general public did not (36%), revealing a mismatch between the two and highlighting a potential area of conflict. Providing the general public with information on the impacts of overabundance made culling slightly more acceptable (43%).

The general public was more supportive of culling kangaroos (57%) and neutral about culling brumbies (53%), suggesting that people do indeed think differently about koalas. The acceptability of the commercial use of koalas was very low among the general public (31%) and the experts (37%), but positive for kangaroos (58%) and neutral for brumbies (52%).

Experts found indigenous hunting more acceptable (62%) for managing koalas than the general public (45%) found it acceptable. For kangaroos and brumbies thse figures were 65% and 56%, respectively. Indigenous hunting is not considered a control method at present.

We tested whether people’s values and beliefs about human–wildlife relationships influenced these findings. People that believe in the human mastery of wildlife (domination) tend to be much more supportive of culling all species, while people who believe that humans and wildlife are equals (mutualism) tend to be more supportive of restoring habitat.

Interestingly, a study published in 2009 by American researchers (https://goo.gl/4NHY9N) reported a shift in views towards mutualism and away from domination over time. This suggests that culling is likely to become even less acceptable in the future to the general public. So, while experts might think culling overabundant koalas is a good management option, it is likely to lead to more conflict with the community.

Future research and management should continue to explore alternatives to culling, and how to improve community support for culling.


Margreet Drijfhout is a PhD candidate at La Trobe University’s Department of Ecology, Environment & Evolution. Dave Kendal is a senior lecturer in environmental management at the University of Tasmania.