Tasmanian Devil population decline mapped by UTAS

In a paper published in peer review journal Ecology Letters, wildlife ecologist Calum Cunningham estimated that the wild Tasmanian Devil population had declined significantly from 53,000 in 1996.

Dr Cunningham said the spread of the tumour disease now occupies 90 per cent of Tasmania, which is almost all of the devils' geographic range.

"Devil facial tumour disease has caused severe population decline in Tasmanian devils, but previously we didn't have a good grasp on what factors influenced the spread of the disease or how many devils remained in the wild," Dr Cunningham said.

"In this paper, we traced the spread of DFTD across Tasmania and put numbers on the total size of the devil population, which was a deceptively difficult task."

Researchers spent almost 2000 nights trapping devils to collect the data in a massive team effort.

The group also analysed multiple streams of data, including spotlight counts and trapping records from the last 35 years, to reveal the population decline.

"The spread of DFTD slowed significantly from the mid-2000s when the disease-front reached areas of western Tasmania with lower devil densities."

However, it's not all bad news; Dr Cunningham said while the disease had caused devil populations to fall by 82 per cent, this sharp decline is predicted to level off in the next decade.

Professor Menna Jones says levelling off is encouraging. However, it was essential to note devils are still much rarer than they once were and no longer play critical ecological roles like consuming carrion and suppressing cat numbers.

"We caution that the species is not out of the woods yet, and we need to do all we can to reduce other sources of mortality like vehicle collisions."

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