Culling koalas? Who would dare suggest such a thing?

Interestingly enough, some Queensland and New South Wales researchers have just published a paper suggesting that koalas be culled. Not just any koalas though; just those that are suffering terminal effects of Chlamydia and transmitting this disease to healthy koalas. Using computer simulations, they showed that this 'selective culling' approach would result in an increase in population size in 'The Koala Coast' population in Queensland as a result of reduced disease incidence.

Not surprisingly, their suggestion resulted in a little confusion in the media. Afterall, it wasn't that long ago that everyone was upset about 'culling' starving and extremely ill koalas at Cape Otway.

Today, I published an article about 'culling' koalas in The Conversation (http://theconversation.com/a-cull-could-help-save-koalas-from-chlamydia-if-we-allowed-it-49195). In short, I believe that culling should be available for managing koalas whether it be for disease management OR to address overabundance issues. The current 'no culling' policy has resulted in many koalas at Cape Otway suffering slow deaths due to starvation. Watching koalas die like this is horrific to witness. Although the thought of 'culling' healthy koalas doesn't entirely sit well with me (I love these animals), I would much prefer to see a few culled than to see an entire population suffer and a unique ecosystem disappear.

This is not to say that 'culling' should be used indiscriminately though. It should only be used when other approaches fail or aren't viable. Governments need to be more proactive in assessing management options in advance of problems occurring. If that had happened at Cape Otway, the population needing management would have been much smaller, fewer animals would have been affected, and a crisis situation averted.

Eavesdropping on koalas

Thanks to the generosity of Wildlife Acoustics, we will soon be eavesdropping on koala conversations. Wildlife Acoustics has provided me with some Songmeters that I will be deploying in a number of sites in the Otways. Songmeters are recorders that can be programmed to record whenever you want them to. These ones will be programmed to remotely record for 5 minutes per hour for up to a month, and capture the 'song' of any koalas vocalising at the time.

Queensland researchers already have shown that systematic recordings can be used to determine the timing of the breeding season. Our project will build on that by examining if there is a relationship between the frequency of bellows in recordings and the density of koalas (from visual surveys) in a site. If we find that there is a relationship, using Songmeter recorders may be a less time-consuming and more systematic way of monitoring koala populations throughout Victoria.

Koala 'Dave' singing

Many thanks to Wildlife Acoustics for supporting our research!

To translocate or not to translocate?

This is a question that is currently in the spotlight.

In my opinion, translocation should ONLY be undertaken as a last resort when:

• reducing the koala population in an area is critical to saving habitat, and
• it is likely that translocated koalas will have a high probability of survival.

The better option would be for governments to implement long-term management actions (fertility control and habitat management) prior to emergency situations arising. That advice was ignored for Cape Otway so unfortunately, translocation of koalas is now the only option for saving some of our manna gum woodlands and all of the wildlife it supports. It also may be the only option for avoiding more koala starvation and more koala euthanasia.

 

When a situation is allowed to get this bad, translocation may be the only answer

But do translocated koalas survive? It depends on a lot of factors. A few key things to be considered are:

• Koalas should be healthy and relatively young,
• The receiving habitat should contain koala food trees in healthy condition,
• The receiving location should have a climate similar to the original site (that's why interstate translocations should be avoided),
• Will there be any impacts of translocated koalas on the receiving habitat (including the resident koala population)? For example, koalas should not be translocated to areas like South Gippsland where koalas have more diverse genetics or to areas where there is a high incidence of disease.

Other translocations

Translocation has been a component of other long-term koala management programs. While working on the Kangaroo Island Koala Management Program, colleagues and I conducted research trials out of concern for the welfare of koalas being translocated to the south-east of mainland South Australia. We radio collared a number of koalas that were surgically-sterilised and translocated, and also radio collared some surgically-sterilised koalas remaining on the Island.

If you are interested in the full details of our study, we published the results in The Journal of Wildlife Management (Whisson et al. 2012. 'Translocation of overabundant species: Implications for translocated individuals', http://onlinelibrary.wiley.com/doi/10.1002/jwmg.401/abstract).

To summarise our main findings:

• We observed low mortality in the first three months following translocation but 37.5% translocated koalas were dead after 12 months compared to none in the control group that remained on the island.
• Translocated koalas moved greater distances than those that remained on the island. Some individuals moved up to 10km within the first three months post-translocation.

Clearly, translocated koalas were negatively impacted and this is why I believe that translocation should be a last-resort action only. An 'acceptable' level of mortality also should be decided on prior to large-scale translocations occurring.


So what about translocation of koalas in Victoria?

Obviously koalas can survive translocation (most koala populations in Victoria have resulted from koalas translocated from island populations) but under what conditions and how many koalas survive the process? Surprisingly, despite the tens of thousands of koalas that have been translocated in Victoria over the years, to my knowledge there only have been a few studies of koala survival and the results appear only in draft reports. In some cases mortality has been high (around 90% translocated koalas dying) and this is why the government has been reluctant to use the approach for management of koalas at Cape Otway.

However, the reasons for such high mortality in some translocations aren't clear. Is it that koalas can't adapt to new food sources (when moved from manna gum to other forest types), or is it that they have been stressed by their treatment (surgical or hormone implant), or are they being moved to unsuitable habitat?

Hopefully some of these questions will be answered by the current trial being conducted by the government, and that the koalas in the trial survive. I also hope that the government learns from this situation and develops long-term management strategies for koalas and their habitats to avoid having to use translocation as a last-resort management tool.

Government announces imminent management actions for Cape Otway koalas

Today, the Victorian government issued a media release about upcoming management actions for koalas at Cape Otway. The program will involve checking the health of 300 to 400 koalas, euthanasing any koalas found to be in poor condition, and initiating a study to examine the potential to translocate koalas to other forest in the Otways.

This is welcome news!

Habitats at Cape Otway are continuing to decline under the browsing pressure of so many koalas. In one of our study sites, koala densities have climbed back to 9 koalas per hectare, and the trees are showing considerable stress. Although it may be too late to save much of the manna gum woodland, it may be possible to prevent the suffering of many koalas. A lot depends on koalas surviving the translocation trial. If there is high mortality of koalas in the trial, then the only option is fertility control which is too slow acting to avoid another population crash.

Manna Gum Drive - trees continuing to decline

Without translocation, this mum and joey are unlikely to survive for long

Our research which is generously funded by Earthwatch Australia and supported by Earthwatch volunteers, continues to provide important information on koala densities and habitat condition across the Cape, and has been critical in informing the government's management actions. In fact, as I write this post, a team of Earthwatchers are surveying our long-term monitoring sites. Future teams will continue to monitor those sites and participate in studies of koala behaviour and their response to their ever-changing landscape.

Planting by Earthwatchers to rebuild koala habitat

Choosing mates.... size, age, or persistence?

Remarkably little is known about the love life of koalas. Are they fussy about who they mate with, or is it simply a case of a male being in the right place at the right time?…. and by ‘right time’ I mean when the female is receptive. This breeding season we are hoping to find the answer. We are deploying proximity collars fitted with GPS loggers to every koala we can find in a woodland patch. These collars record the time and duration of interactions between collared koalas. So far, we have 19 koalas collared but still have another 17 collars to deploy.

The study is the basis of an honours project by Deakin student ‘Darcy’. Darcy has already done an amazing job of preparing the collars, and has proven to be a capable koala catcher and handler. He will now have the task of tracking and observing these koalas, mapping resources throughout the site, and in January retrieving the collars for data download and interpretation.

Darcy bonding with the joey of one of his study animals

 

Beast

RIP Beast

I was sad to learn that 'Beast' was one of the 29 koalas euthanased during the last round of health checks of koalas at the Cape. Sad, but not really surprised.

Beast was an old fellow of around 12 years of age. He was looking a bit the worse for wear at the end of the last breeding season but I had hoped he would survive to the next. He was a legendary animal; not necessarily the prettiest koala I've encountered but he had loads of character. He showed the most aggression out of all the males in our study of responses to bellows. He survived the population crash of 2013, finding ways into banded trees and constantly wandering in search of good food (and female koalas). The vets didn't think he would survive then because he was so old. He knew the drill when it came to being caught too. He grumbled but seemed to realise that resisting would only make the process longer.

Beast always sat low in trees so he would have been a prime target for the catching crews looking to sample 10 koalas from that site. I was told that his condition was poor and that the vets did not give him more than a 10% chance of survival. I think they may have underestimated him!

I was disappointed that nobody thought to tell me at the time, or save his carcass for me. I would have loved to take some samples and save his skull.

I wonder how many of the other koalas euthanased were in poor condition due to age? When DELWP reported 29% koalas euthanased, we immediately assume that it's due to poor habitat condition but is that really the case at the moment?

Finally.... a management program for koalas at Cape Otway

This week, the Department for Environment, Land, Water and Planning (DELWP) began assessing health of koalas at Cape Otway as the first part of a long-term management program for koalas and manna gum woodlands at the Cape.

This is an extremely positive action to inform management actions that are likely to include fertility control and translocation. Such management is necessary if we are to avoid a repeat of late 2013 when thousands of koalas died of starvation.

However, the media appears to be intent on stirring up the public with headlines like 'Killing to resume at Cape Otway koala colony' (The Australian), and 'Koala cull on the cards' (Sky News Australia). I spoke with a few of the reporters and advised them on the consequences for koala welfare if health is not monitored. Obviously those stories don't sell papers and reporters/editors don't mind if their poor reporting results in animal suffering.

I respect Victoria's Minister for Environment (Hon Lisa Neville) for listening to scientific advice and requesting the development of a long-term management strategy for this issue.

If you would like to hear more about koala management at Cape Otway, you can check out DELWPs facebook post or see them on twitter;

DELWP discuss this management action (Facebook)

DELWP on twitter about Cape Otway koalas