Crises

2020

Ngarigo Country /
Peak View, NSW

A Post-Bushfire Koala Story

“The impact of bushfire events on wild koala populations is poorly understood.”

The first line in ecological consultancy Biolink's 2020 report, Quantifying the impacts of bushfire on populations of wild koalas, is clear. The report provides an analysis of the effects of the 2019/2020 Australian bushfire season to koala populations in NSW.

That koala populations are affected by bushfires is well documented. In Koala: A Historical Biography, Ann Moyal relates that in 1934 the Victorian Chief Inspector of Game, Frederick Lewis considered bushfires over previous last 20 - 30 years to have been one factor in the depopulation of koalas in Victoria to an estimated 500 to 1000.

Biolink’s report also highlights the plight of the Pilliga koalas, “once considered to be the single largest koala population remaining in NSW”. Their 600,000-hectare habitat “has experienced a series of extensive and intense fires since 1997” that make them likely to be functionally extinct.

The NSW Government’s Koala Research Plan, part of its Koala Strategy, reinforces Biolink’s observation through its identification of fire impact as a key knowledge gap in understanding of “the resilience of [koala] populations in terms of their response to hazard reduction burning and wildfire events”.

It’s the how and why of koala survival that is less understood. One Koala Research Plan contributor, Australian National University (ANU) Research Fellow, Dr Karen Ford, is running a research project that seeks to provide that much-needed insight.

The project started at the Two Thumbs Wildlife Trust (Two Thumbs) in Ngarigo Country / Peak View, NSW, in the wake of the bushfires that savaged its 3 wildlife sanctuaries during Black Summer: Hammer’s Hill, Kalandan and Irwin’s Corner. The 700 hectares of bush that covered most of its hills, gullies and flats was subjected to fire with an intensity so great it is difficult to imagine how some of the most severely burned areas will come back.

James Fitzgerald, who both operates and lives at Two Thumbs, lost his home, outbuildings, machinery and several koala enclosures and the koalas in them. 3 US air crew, Capt. Ian McBeth (Great Falls, Montana), First Officer Paul Clyde Hudson (Buckeye, Arizona) and Flight Engineer Rick DeMorgan Jr (Navarre, Florida), died when their Coulson Aviation C-130 Hercules aerial water bomber crashed while trying to protect Two Thumbs.

Fitzgerald talks about being able to take a walk through the forest before the bushfires and having no trouble spotting and hearing koalas. It is different now. There is an eeriness, a noticeable disturbance in the once tranquil bush, especially at night. Fitzgerald calls it the “ghost forest”.

Still, the bushfires left some eucalyptus canopy intact and even a few untouched pockets of bush. Maybe that was the factor in helping koalas survive long enough for a posse of volunteers, scientists, vets, friends and donors to help Fitzgerald rescue them. 12 were found alive. A further 5 were heartbreakingly found dead.

Knowing koalas can survive such a devastating fire event elicits hope for the remaining population at Two Thumbs, but that hope must be tempered. There are many questions about what happens next. Will there be enough food of enough quality to support them? Will there be enough canopy to keep them cool over the upcoming summer and help them avoid the heat-stress they are prone to, and which can kill them? How will the chances of survival differ between koalas rehabilitated through human intervention and those left in the wild? Ford’s research project - funded by Two Thumbs, the NSW Department of Planning, Industry and Environment (DPIE) and the Minderoo Foundation – hopes to provide the answers.

The project also forms the basis of ANU PhD student Murraya Lane’s thesis and lines up exactly with what she had hoped to do. Lane says, “I found out about this project and it’s really suited to what I was interested in, which is conservation, Australian mammals, seeing how animals respond post-fire and seeing how that ties in with things like nutrition.”

Lane explains how the koalas are the unwitting heroes of her project.

“We needed 3 groups of 10 koalas; two groups at this burnt site [Two Thumbs] and one group at an unburnt control site [near Two Thumbs]. At the burnt site, there is the ‘rehabilitation’ group, the koalas who were rescued and cared for before being released. There is also the ‘resident’ group with koalas that did not have human intervention.”

Each koala in all three groups is caught, tagged, given a health-check and fitted with a tracking collar. The rehabilitated koala group received additional medical and nutritional care to help them recover from injuries received during the bushfires and, in some cases, poor overall condition due to drought.

The tracking collars will record the geolocation of each koala several times a day, which will enable researchers to see how and where koalas move through the post-bushfire landscape. Researchers also hike weekly across Two Thumbs to each koala’s location to visually monitor the koala, assess the local bush and collect scat and leaf samples to analyse koala nutrition.

In late September 2020, the last of the koalas required by the study were caught and released with tracking collars.

Lane says, “We wanted 10 in each group for more statistical power, given the home range size. We only had 5 resident koalas [before this capture and release] so having a drone pilot and koala catcher come to help over the last couple of days has been huge. The more koalas we have, the easier it is to draw conclusions.”

The project is now focused on data gathering and will be run mainly by Lane for approximately 9 months, when the koalas will be recaptured, given a final health check, relieved of their tracking collars and re-released.

Then begins the data analysis that will eventually result in Lane’s peer-reviewed doctorate.

The results of the study will be important for James Fitzgerald and Two Thumbs in many ways, not least of which is simply helping to understand what happened. At the national level, the report will contribute significant and urgently needed insight into the conservation of the koalas who live in a country that has an increasing risk of bushfire in an increasingly warming climate.

Koalas have endured more challenges than just bushfires to their survival, especially since the colonisation of Australia. Once hunted for sport and their furs, their habitats continue to be threatened and lost to farming and logging.

Koalas are tough, as tough as they are cute, but that hasn’t stopped them from being pushed far enough along the path to extinction to be listed as a “vulnerable” species in 2012 by the Australian Government. Despite conservation efforts, koalas are creeping further down that path.

The Australian Department of Agriculture, Water and the Environment’s Threatened Species Scientific Committee is currently reviewing whether the koalas’ status should be increased to “threatened”. Their assessment is due on October 30 2021.

UPDATE: as of early 2021, all koalas in the study were healthy and have had their tracking collars removed.

UPDATE: as of February 12, 2022, the threatened status of koalas in Queensland, New South Wales and Victoria has been uplisted to ENDANGERED (from VULNERABLE).

This photo essay, photographed over 4 days in late-September 2020, documents the efforts of an interdisciplinary team of scientists at Two Thumbs Wildlife Trust (Two Thumbs) as they FIND, CATCH, PROCESS and RELEASE koalas included in an Australian National University (ANU) study that aims to understand how koalas survive in a post-bushfire environment and whether human intervention aids their recovery.

Photo Essay

Find

Photo Essay

Catch

Photo Essay

Process

Photo Essay

Release