1. What is the nature of the problem at sites over-browsed by koalas?
Manna gum woodlands in a number of parks are under serious pressure from Koala over-browsing. These parks include Mount Eccles National Park, French Island (National Park), Snake Island (Nooramunga Coastal and Marine Park), Raymond Island and Tower Hill Wildlife Reserve. At these parks, high levels of defoliation have led to the death of some manna gums and there is a high risk that total defoliation of the koalas food trees will occur. This will lead to the slow, mass starvation of the koala population as has happened previously at numerous sites including French Island, Stony Point, Snake Island and most recently, Framlingham State Forest.

Mt Eccles NP is of particular importance as it occupies more than 7500 ha and is the largest remaining intact area of Stony Rises Woodland, a depleted Ecological Vegetation Class in Victoria. It is dominated by a canopy comprised almost entirely of manna gum. A recent (2004) koala population survey estimated that there were over 10,000 koalas in the park. With the existing browsing pressure, there is a high risk of a large-scale death of manna gums and resulting koala population crash within the next 3-5 years. A 2002 survey of tree condition in Mount Eccles NP indicated that more than 65% of trees were more than 50% defoliated and that tree condition was slowly declining. Large-scale death of manna gums is also likely to have an adverse impact on other dependent fauna species within the Park, such as Brush-tailed Phascogale and Powerful Owl (listed as rare in Victoria).

2. Why do we need to do anything?

Prior to European settlement, koala populations may have been kept in check through indigenous hunting practices and forest fire. The absence of these processes allows the koala population to expand very quickly. The continual over-browsing of koala food trees will result in their defoliation and death. At Mt Eccles NP, the entire 6000 hectare forest may be lost resulting in the starvation of thousands of koalas.

To prevent the landscape-scale impacts from forest loss on water quality and other flora and fauna, The National Koala Conservation Strategy (ANZECC 1998) identifies

• Translocation;
• Fertility control; and
• Habitat manipulation (protection of individual trees);

as acceptable options for management of overabundant koala populations. Culling is not an acceptable option within the parameters of the Strategy, which was agreed between Federal and State Ministers for Environment.

3. What are the views of the Traditional Owner's at Mount Eccles?
The Gunditjmara are the Traditional Owners of the area known as Budj Bim , now listed on the National Heritage List. More than 30,000 years ago the Aboriginal people witnessed Budj Bim, an important creation from Dreamtime reveal himself in the landscape. The volcano that today we call Mount Eccles, is his forehead and the scoria are his teeth. The Gunditjmara practiced the first form of aquaculture by establishing eel and fish traps and elaborate dams and channels to manage the wetlands at nearby Lake Condah.

Today the Gunditjmara still maintain a strong connection with landscape, and the protection of their heritage values includes ensuring that the forests are sustainably managed. The reduction of koala numbers to prevent the destruction of the forest is important to the Gunditjmara who witnessed the loss of their cultural values and the death of a whole forest from over-browsing by koalas at nearby Framlingham. The koala management program at Mt Eccles is being co-managed by Parks Victoria and Winda Mara Aboriginal Corporation.

4. How has the problem been managed to this point?
Relocation programs over the last century have resulted in the presence of koalas throughout all suitable habitat for them in Victoria. The koala population's growth statewide is a testament to one of the most successful wildlife conservation programs in Victoria's history.

Over the past several years, koalas at some over-browsed sites have been captured, surgically sterilised and relocated to alternative habitat with suitable food trees. Koalas have been sterilised to ensure that risk of overabundance is minimised at release sites. However, as we have monitored the outcomes of sterilisation and relocation, it has become clear that the results have been varied across the sites that Parks Victoria manages. At Snake Island, intensive radio-tracking of relocated koalas has not detected any adverse effects on the health and survivorship of koalas sterilised and relocated to similar mainland habitat. This contrasts with the unacceptable survival rate of koalas relocated from Mt Eccles, and at some release sites up to 90% have not survived beyond 30 days.

Therefore we are undertaking management programs that are tailored to individual sites, minimising the stress and mortality of the koalas.

5. What steps will Parks Victoria now take address this problem?
Koalas will still be relocated from Snake Island as they are being released to very similar habitat from where they were captured. Since 2000, only koalas that have been sterilised more than 6 months previously have been relocated from Snake Island, and only to mainland coastal manna gum woodland very close to Snake Island. At other sites, such as Raymond Island, relocation may occur after monitoring has shown that there are no adverse effects on the animals.

The relocation of koalas from Mt Eccles National Park has ceased. Without considerable research, Parks Victoria can no longer be confident in predicting the suitability of habitat for koala relocation. It is also unclear whether the condition of koalas from Mt Eccles compromises their ability to survive relocation. Therefore, we are undertaking a program to implant contraceptives in a large proportion of the fertile female koala population. Over time this will reduce the rate of population growth, resulting in a slow decline in numbers.

The contraceptive works primarily by inhibiting ovulation in females. A trial of the technique has been conducted over 6 years and no adverse side effects were apparent in any of the treated koalas. This technique will render the koalas infertile for most of their reproductive life.

The implants are a flexible, matchstick sized rod which is "injected" beneath the skin. Koalas will be anaesthetised prior to examination and insertion of implant to minimise stress to the animals during the procedure, which takes place at a mobile workstation close to the point of capture. After recovery from the anaesthesia, koalas will be released at the point of capture. The implant technique is similar to that used in humans (with only local anaesthesia) so there is only minor discomfort involved. The implants remain in the animals indefinitely.

Koala population abundance and tree condition will continue to be monitored at sites of high population density. This information continues to build knowledge for long-term, sustainable koala management in Victoria's parks.

6. How many koalas will be implanted?
To improve our understanding of the interactions between the forest and the koalas, Parks Victoria has developed a modelling approach, with the support of forestry researchers and koala biologists, through Parks Victoria's Research Partners Program. The model has used available information gathered from ongoing monitoring of koala population density & forest condition to simulate the likely forest structure/composition outcomes of different koala population densities. From this, the probabilities of forest and koala population crash have been estimated for different levels of fertility control.

As far as possible, the program at Mount Eccles NP will attempt to capture only fertile females. Inevitably, infertile females and males will be captured, and will be vet checked for their health status and released without treatment.

he aim is to treat as many fertile female koalas as possible with the hormone implants during the trial. This level of intervention is necessary to reduce likelihood of mass defoliation of the forest and a subsequent crash of the koala population crash.

7. How do you minimise stress on the koalas?
The safety and welfare of the animals involved is of primary concern and these operations are conducted within strict operational protocols. Animals are captured using experienced teams of ground staff and tree climbers using flags and ropes. To minimise stress, koalas need to be captured as quickly as possible, using techniques that minimise injury to the koalas. Qualified veterinarians determine the suitability of koalas for treatment, carry out sterilisation procedures and monitor koala recovery.

8. Is dealing exclusively with the koalas the only way you are addressing this problem?
Some of the reasons for the rapid expansion of koala populations are that they may previously have been kept in check through indigenous hunting practices and forest fire. Another possible cause is that the forests are now highly fragmented, which may not allow the koala populations at high densities to redistribute. To address this would require habitat linkages to be planted over a number of years, and it is not clear whether this would merely enlarge the area of over-browsing. In any case, at current population levels, it will only take a few years for the koala population to expand to the point where a large proportion of trees will decline and die. So we have an immediate problem which must, in the short-term, be addressed by managing the koala population.

In the long-term, managing the structure of the forest may be a sustainable way of managing the issue. Parks Victoria is engaging with stakeholders with interests in tree planting such as Greenfleet to create habitat linkages over the longer term.

Individual or small groups of manna gum trees have had their trunks banded using sheet metal to prevent koala access. This will ensure that, in the worst scenario, a viable seed source will be protected for regeneration of the forest.

On Snake Island, ground-dwelling grazers such as Hog Deer are thought to contribute to the browsing pressure on manna gum seedlings and options for their management are being investigated. This is a complicated issue as Deer are a Protected Species throughout Victoria under the Wildlife Act 1975 and Snake Island is formally classed as a State Faunal Reserve.

Parks Victoria convenes a technical advisory committee of independent experts to provide advice on the animal welfare, population and habitat management aspects of its koala operations. The program at Mount Eccles NP has been developed with input from this committee, and has been approved by Department of Sustainability and Environment's Animal Ethics Committee.

The Department of Sustainability and Environment (DSE) have overall responsibility for flora and fauna management in Victoria, and have the authority to permit intervention in wildlife populations. DSE have recently released a strategy for the management of koalas in Victoria. DSE has a key role in supporting koala management programs undertaken by Parks Victoria.