Climate change was one of the main threats to the survival of the koala that were highlighted on the first day of a national koala conference that started in Port Macquarie in the eastern Australian state of New South Wales today (Friday).
Delegates also heard about the research being done on chlamydia disease, which is a main cause of koala fatalities and can cause blindness and sterility, and about dog attacks and car hits, which kill thousands of the animals.
In her presentation entitled “Up the gum tree without a paddle”, ecologist from the Port Macquarie-Hastings council Rebecca Montague-Drake said that climate change was likely to have severe impacts on koalas. The animals were particularly susceptible to extreme climate events, she said.
Montague-Drake says that changing carbon dioxide levels and drought will change the chemistry of the leaves the koalas eat, and will therefore alter the nutrient content.
“As a result, koalas may no longer be able to meet their nutritional demands, resulting in malnutrition and starvation.
“Such physiological stresses will also leave koalas more vulnerable to diseases, such as chlamydia and the koala retrovirus.”
Any changes in salinity levels in eucalyptus leaves will almost certainly affect the delicate balance of nutrients versus toxins in those leaves, Montague-Drake says. Salinity also suppresses plant height and the trees’ biomass.
An increasing number of wildfires, Montague-Drake said, would lead to direct mortality and habitat loss.
“Drought leads to reduced leaf water content, which will leave koalas vulnerable to hotter conditions. It will also reduce the canopy,” she told delegates.
Montague-Drake (pictured left) said that koala populations along the eastern seaboard, particularly in New South Wales and Queensland, were in great peril, and many of them were on “a steady downward run to extinction”.
The koala, Montague-Drake says, “is an arboreal marsupial that cannot go into torpor, fly, or shelter in hollows, leaving it vulnerable to weather extremes”.
She told delegates about modelling done in the Port Macquarie-Hastings local government area that she said revealed a new and hitherto unreported impact of climate change on koala populations.
Researchers conducted modelling of climate-induced rises in sea level, looking mainly at the spring tide scenario.
“The results revealed that, even under mild climate change scenarios, many areas of primary koala habitat will experience tidal inundation on a monthly (spring tide) basis,” Montague-Drake said.
“This tidal inundation will increase soil salinity levels and increase shallow ground water tables.”
This, Montague-Drake says, will be likely to reduce the survival of koala food trees such as Swamp Mahogany, Tallowwood, and Forest Red Gum.
“Even presuming that trees are able to survive such incursions, even small rises in salinity will likely impact nutrient uptake by eucalyptus species.”
The researchers found that a third of all koala habitat on the coastal flood plain would be inundated within 100 years. Across all koala habitat, 14 percent would be lost within 50 years, and 22 percent would be lost within 100 years.
In coastal swamp forests in the Port Macquarie-Hastings area, 100 percent of the canopy often comprises koala food trees, Montague-Drake says. These forests, she says, are the environment that support the highest level of koala activity.
The Port Macquarie analysis is applicable to all coastal swamp forests, Montague-Drake says, “and probably lots of other koala communities along that stretch of the eastern seaboard as well”.
Montague-Drake is concerned that the 2013 modelling may already be out of date and the loss of koala habitat could reach 40 percent in 100 years. She wonders whether more regular King Tides (the very highest tides) would be enough to start triggering damaging chain reactions.
“A study that has come out of the US this week shows that we’re outstripping the rates of sea level rise that were expected.”
A few coastal swamp forests are protected as threatened ecological communities under New South Wales legislation, but some are not, the ecologist says. “Our coastal swamp mahogany forests on sand are prime development areas and are not currently listed as a threatened ecological community.”
There are more immediate threats to koalas, Montague-Drake says, but unless there are major turnarounds within the next five years, “we are really heading on that track to functional extinction within 50 years, and that’s a very sobering thought”.
Speaker Ruth Lewis, who is the president of the Ipswich Koala Protection Society, told delegates that there were areas of Ipswich where koalas were already functionally extinct.
Reducing fatalities, and using dogs for detection
Thor Aaso, also from the Port Macquarie-Hastings council, spoke about the dog- and owner-training that is being done in an effort to reduce canine attacks on the urban koala population in Port Macquarie.
He also told delegates about a mobile GIS-enabled¹ data recording system that assists the staff of the Port Macquarie hospital, the local council, and researchers. It enables the capture and collation of location, clinical, and other information about koalas.
The app has helped researchers to do heat map analysis to work out where there is a high incidence of car hits.
Aaso cited the case of one elderly koala that was hit by vehicles four times on the busy Ocean Drive, which cuts through a koala hub. The last hit was fatal.
The founder of Queensland Koala Crusaders (QKC), Meghan Halverson, and Josey Sharad from The International Fund for Animal Welfare (IFAW) told delegates about the work being done with koala detection dogs. All the dogs trained for detection are rescue animals.
QKC and the IFAW are working in collaboration with the University of the Sunshine Coast and there are now four trained dogs detecting koalas in the “Detection Dog for Conservation” initiative.
Thanks to the dog detection, Halverson says, strides can be made to analyse larger samples of data and give a better picture of koala health and genetic distribution throughout the landscape.
“In training koala detection dogs, we will be able to assist in recovery and management strategies for koalas and their habitat in years to come by providing a new approach model in koala conservation.”
Halverson says that combining efforts and resources is the only way to win the war to save the koala, “and a war it is”.
Felled pine forest near Bathurst, Queensland. Photo by Louise O’Brien.
At the last koala conference in 2013, Halverson’s message was “while we are talking they are dying”.
Four years later, everyone is working harder and more collaboratively, Halverson says, “but we are still talking and they are still dying”.
Halverson cites the fact that, in Queensland, one million hectares of land have been cleared of native vegetation. “Out of this, the WWF estimates that at least 84,000 hectares are in critical koala habitat.”
Now, more than ever, we need to develop better ways to find koalas, Halverson says.
“Current methods can be slow, erroneous, and expensive. Vegetation maps not only become rapidly outdated due to development and climate change, but they also don’t always reflect where the koalas are, and where they’re thriving.”
The detection initiative has discovered that dogs are 20 times quicker at finding koala scats (faecal pellets) than people are, and 150 percent more accurate.
Adam Polkinghorne from the University of the Sunshine Coast talked about the chlamydia pecorum infections that are widespread in koala populations and also highly prevalent in Australian livestock.
Koalas are affected by two different strains of chlamydia: chlamydia pneumoniae and chlamydia pecorum. Chlamydia pecorum is the most prevalent and the highest rates of infection are in Queensland and northern New South Wales. Many animals are infected with chlamydia, and are passing it on, but don’t show actual signs of the disease.
Polkinghorne said that comparison of koala chlamydia pecorum strains with those from livestock strains provided strong evidence that supported the hypothesis, supported by some molecular evidence, that all infections in koalas might have ultimately resulted from the introduction of chlamydia pecorum infected livestock to Australia.
“A continued expansion of our analysis to include historical koala chlamydia pecorum samples and a more diverse range of overseas livestock strains is anticipated to provide more evidence to test the latter hypothesis.”
Nearly two hundred people are attending the three-day Port Macquarie conference, which is entitled “Their Future is in our Hands”.
The conference is being organised by the town’s koala hospital, with the backing of the local council. It brings together a wide range of delegates, including carers, campaigners, scientists, and veterinarians.
There is also a Hello Koalas Festival running in Port Macquarie until June 11. The event includes a Koala Sculpture Trail, which features 56 one-metre-high koala sculptures, individually designed and hand-painted by local artists.
Three people demonstrated outside the conference this morning.
Susie Russell from the North Coast Environment Council, which has a delegate at the event, said: “The New South Wales government, while pretending to be concerned about koalas – and it’s the same with the federal government – are actually introducing policies that will see the best remaining koala habitat cleared as part of their forestry proposals.”
The government’s strategy would see koalas driven towards extinction by their own policies, “which is that they are favouring the logging industry over the protection of Australia’s unique and extremely biodiverse forests,” Russell said.
Left to right: Drusi Megget, Greg Hall, and Susie Russell.
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