Gum Tree

Up a gum tree, out on a limb

19 December 2009

published by www.canberratimes.com.au

Outside a hardware store in Rockhampton, a small group of volunteers brandishing barbecue tongs are working the weekend house-and-garden crowd. They’re on a mission to raise money to help scientists keep studying the impact of climate change on central Queensland’s koalas, and they’re doing it the hard way one sausage sandwich at a time. But if the city’s home renovators have an appetite for a worthy cause, these car-park sales can steadily add up for the 30-odd members of the Central Queensland Koala Volunteers.

Last year, these sausage sizzles and sales of toy koalas, baseball caps and tins of chocolate-coated macadamia nuts raised $8000 for koala research, including studies assessing how rising summer temperatures affect the koala’s ”water turnover”. University of Central Queensland ecologist Dr Alistair Melzer explains that during hot, dry weather conditions, koalas use evaporative water loss mostly through their lungs to cool down, and need to eat eucalypt leaves with a high moisture content. It’s one of the many reasons they’re ill-equipped to cope with climate change.

In a paper published two years ago in the journal Australian Mammalogy, Melzer and a research team that included Dr Bill Ellis from the San Diego Zoological Society suggested climate change could adversely affect the ability of koalas to ”thermoregulate in conditions of extreme heat”. Other scientists warned that climate change was altering the leaf chemistry of eucalypts, reducing protein and moisture content, but increasing toxic, indigestible tannins. Poor nutrition, as a result of continuing loss of habitat and diminishing leaf nutrients, has also been linked to the spread of a deadly nasal fungal infection among koala populations.

Earlier this week at the United Nations climate summit in Copenhagen, the International Union for the Conservation of Nature issued a report ranking koalas with polar bears, Arctic foxes and emperor penguins as one of 10 species most at risk from climate change. The report said koalas faced multiple threats, including more frequent bushfires, heat stress, starvation and malnutrition. Bushfires had ”already wiped out considerable populations of koalas” and scientists were ”not optimistic of the ability of this highly specialised species to adapt to climate change”.