Koalas in cri­sis:

why the Aussie mar­su­pial is un­der threat

Australian Women’s Weekly NZ - - NEWS - PHO­TOG­RA­PHY ● NICK CUBBIN

Dr Valentina Mella is scan­ning through video footage show­ing fluff yeared koalas crouch­ing over wa­ter bowls, lap­ping greed­ily. In one clip, a furry mar­su­pial is cau­tiously shar­ing a drink with an echidna.

That might not seem re­mark­able, ex­cept for the fact that koalas aren’t sup­posed to drink. Tra­di­tion­ally, they take their wa­ter from the gum leaves they eat. Yet a com­bi­na­tion of drought, cli­mate change and fiercer El Niño weather pat­terns has put koalas in the Aus­tralian states of Queens­land and NSW un­der in­tense stress – so much so that they are be­gin­ning to change be­hav­iours es­tab­lished over mil­len­nia.

In to­tal, Dr Mella and her fel­low re­searchers have col­lected hun­dreds of clips of koalas drink­ing from spe­cially de­signed wa­ter sta­tions. That’s an enor­mous amount of wa­ter for an an­i­mal whose name lit­er­ally means “no drink”.

“We didn’t find any ba­bies this time,” says Ital­ian-born Dr Mella, who is delv­ing into the habits of the iconic tree dweller in an at­tempt to un­lock the se­crets of the koala’s long-term sur­vival in a chang­ing cli­mate. “We had the hard­est catch I’ve ever seen.”

Dr Mella has just re­turned from her lat­est re­search trip to Gunnedah, Aus­tralia’s self-pro­claimed koala cap­i­tal. De­spite the north­ern NSW town’s rep­u­ta­tion, lo­cals have been re­port­ing fewer sight­ings of the pop­u­lar mar­su­pial. “People who had koalas in their back­yards for years told us, ‘I had five and now I have zero,’” Dr Mella says. “We can see ev­ery year that we go how the num­bers are go­ing down.”

Koalas have al­ways been shy crea­tures, but in this part of Aus­tralia there has been a no­table de­cline in num­bers. The na­tive an­i­mals that are most of­ten seen cling­ing to tree trunks with their fear­some claws may look hardy, but they are a del­i­cate species. They’re re­liant on the eu­ca­lyp­tus trees that pro­vide them with food, hy­dra­tion and shelter. As Aus­tralian sum­mer heat in­creases in in­ten­sity, de­hy­dra­tion and heat stress are tak­ing their toll.

A heat­wave that hit north­ern NSW eight years ago was par­tic­u­larly dev­as­tat­ing for the koala pop­u­la­tion. “They were thriv­ing un­til 2009 and then the de­cline started,” Dr Mella says.

Koalas were found dead or dy­ing at the base of trees. Vets who tried to treat the dy­ing an­i­mals found their kid­neys were fail­ing. Among the sur­vivors, chlamy­dia rates in­creased. Re­searchers es­ti­mate up to one-quar­ter of the Gunnedah koala pop­u­la­tion was wiped out. In NSW, Queens­land and the ACT, the koala is now listed as a threat­ened species.

When Dr Mella signed on as the be­havioural sci­en­tist as part of a large Univer­sity of Syd­ney koala study in Gunnedah, she met lo­cal farmer Robert Frend, who told her some­thing was chang­ing. “They’re not do­ing well,” he said. “I think it has some­thing to do with wa­ter.”

Sci­en­tific lit­er­a­ture is full of state­ments that koalas do not need wa­ter to sur­vive be­cause they are able to get their flu­ids from eu­ca­lyp­tus leaves. Yet the lo­cals in Gunnedah told Dr Mella they thought koalas needed to drink.

We know they seek out wa­ter when they need it. Ev­ery sum­mer, pho­tos emerge of koalas drink­ing from bird baths, swim­ming pools or the fam­ily dog’s bowl. Aus­tralian Koala Foun­da­tion CEO, Deb­o­rah Tabart, says the foun­da­tion has been telling people to put wa­ter out for koalas for 20 years.

Dr Mella says, “I ap­proached Rob and I said to him, ‘Shall we try to give them some wa­ter?’”

She is hope­ful her find­ings could help save the lives of Aus­tralia’s most beloved na­tive an­i­mal.

Ground­break­ing re­search

Dr Mella’s study is a world first, but when it started it wasn’t the most sci­en­tific of ex­per­i­ments. Rob cre­ated a rudi­men­tary drink­ing sta­tion out of half a car tyre. They placed it in a tree, then sat back to wait and see if the koalas would be tempted. It was April and Dr Mella wasn’t sure the koalas would drink.

“I will never for­get this – we were in the field and I saw a koala climb­ing up the tree to drink,” Dr Mella says.

She whipped out her phone to cap­ture some pho­tos. They turned out hor­ri­bly, Dr Mella says, laugh­ing, as she couldn’t keep her hand still – she was shak­ing from hap­pi­ness.

“We thought, right, this is a goer.”

All of the fund­ing avail­able to the Univer­sity of Syd­ney koala project had been al­lo­cated, so Rob made drink­ing sta­tions for the koalas us­ing scrap metal and other items he had on hand. He came up with a de­sign to de­liver wa­ter to koalas in a safe en­vi­ron­ment and rigged them up with mo­tion-sen­sor cam­eras that are ac­ti­vated if an an­i­mal stops for a drink.

They set up 20 wa­ter sta­tions, dubbed Blinky Drinkers, to mon­i­tor the drink­ing habits of koalas. Very quickly, they found the an­i­mals were stop­ping to drink for an av­er­age of 10 min­utes at a time. The poor lit­tle crea­tures were parched.

“This tells us they do need wa­ter and it’s some­thing that they’re not find­ing any­where else,” Dr Mella says.

Through­out the au­tumn and win­ter months, koalas drank from the sta­tions 124 times. In sum­mer, this more than dou­bled to 262. “My thought was there must be such bad mois­ture in

those leaves that they need to drink from some­where be­cause oth­er­wise I can­not ex­plain why we would have so many koalas come to drink from our sta­tions in cool months,” Dr Mella says.

“If the wa­ter level in the leaves they eat has de­creased and it’s get­ting worse and worse with cli­mate change and hot­ter and drier con­di­tions, then these an­i­mals are ob­vi­ously go­ing to show be­hav­iours that ear­lier were only rare.”

Univer­sity of Queens­land eco­log­i­cal re­searcher Dr Bill El­lis, who has been study­ing koalas for decades, says he has ob­served the mar­su­pi­als die in greater num­bers dur­ing sum­mer.

“Fe­males seemed to lose ba­bies more of­ten when it was re­ally hot and dry than at other times,” he says.

“You would no­tice in the good years there seemed to be more joeys float­ing around.”

Thirsty work

Dr El­lis has wit­nessed first-hand the ter­ri­ble ef­fects of heat on koalas. “When­ever we get those re­ally hot, dry sum­mers, we find the koalas sit­ting on the ground just try­ing to keep cool,” he says. “Poor lit­tle char­ac­ters, they strug­gle.”

He says the in­creas­ingly long hot sum­mers pose a dou­ble threat. When con­fronted with a heat­wave, koalas will sim­ply stop eat­ing. “We find koalas that have empty tum­mies. They just haven’t been eat­ing for days. And that’s their re­sponse to those 40-de­gree days. Their body tem­per­a­ture will get up to 38 de­grees,” he says.

They need wa­ter to keep cool, but if there’s not enough mois­ture in the leaves, just the act of eat­ing raises their body tem­per­a­ture. Be­cause koalas get their wa­ter from the leaves, if they don’t eat, they don’t get enough wa­ter from their food to stay cool. “If they don’t eat, they die and if they do eat, they over­heat,” Dr El­lis says.

What makes things even harder for koalas is that as the mois­ture con­tent in the leaves de­creases, they be­come more dif­fi­cult to digest.

“Stud­ies have shown that with cli­mate change, the ra­tio be­tween nu­tri­tional com­po­nents in the leaves and toxic com­po­nents change,” Dr Mella says. “Not only do they be­come more toxic, which means koalas take longer to digest them, they also be­come less nu­tri­tious.

“This is why cli­mate change is so scary when you think about koalas be­cause if it af­fects the tree, it af­fects their whole life.”

The next step for Dr Mella is to an­a­lyse the im­pact the ad­di­tional wa­ter is hav­ing on the health of the an­i­mal. The fact that koalas drink wa­ter doesn’t tell us if it’s ac­tu­ally help­ing them through the sum­mer.

Dr Mella has started look­ing at the health of the an­i­mals and hopes to get fund­ing to mi­crochip them so she can mon­i­tor who is drink­ing and if those who do are bet­ter off.

“We don’t re­ally know whether those an­i­mals even­tu­ally sur­vived,” she says, “but cer­tainly, if you run out of wa­ter, you die pretty quickly.”

Sci­en­tist Dr Valentina Mella with one of her koala charges. There are be­lieved to be fewer than 80,000 koalas left in the wild.

The re­search team hard at work. BELOW: Dr Mella and farmer Robert Frend with two of the wa­ter sta­tions known as Blinky Drinkers.

ABOVE AND BELOW: The re­searchers com­pile data on Robert Frend’s prop­erty. LEFT: A koala’s paws are adapted for grip­ping and climb­ing.

Dr Mella and her team have made world-first dis­cov­er­ies about the koalas and wa­ter.

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