Canberra - Four hundred and eighty million animals could have died in the Australian state of New South Wales (NSW) since the bushfires started in September, according to one ecologist's estimate.
The "figure is based on a 2007 report for the World Wild Fund for Nature (WWF) on the impacts of land clearing on Australian wildlife" in NSW, the University of Sydney said on Friday in a statement.
More than 150 bushfires were burning on Friday across NSW, the country's most populous state, of which Sydney is the capital.
The bushfire season started early this year in September. So far, more than 3.6 million hectares of land - an area larger than Belgium - have already burned, while more than 1,800 homes have been destroyed or damaged. Also, 16 people have died, eight of them this week.
To calculate the impacts of land clearing on NSW wildlife, the authors of the previous study had obtained estimates of the population density of mammals in NSW and then multiplied it by the areas of vegetation approved to be cleared.
Professor Chris Dickman, co-author of the original study, used the same formula and came to the estimation that 480 million animals have died in the NSW bushfires since September.
All six Australian states and one territory have been hit by the bushfires, but the study on animal fatalities relates only to NSW.
"The authors deliberately employed highly conservative estimates in making their calculations. The true mortality is likely to be substantially higher than those estimated," the university said.
"Many of the affected animals are likely to have been killed directly by the fires, with others succumbing later due to the depletion of food and shelter resources and predation from introduced feral cats and red foxes."
The university said the figure includes mammals, birds and reptiles, but does not include insects, bats or frogs.
"The true loss of animal life is likely to be much higher than 480 million," it added.
Wildlife experts told the NSW state parliament in November that at least 2,000 koalas had died in bushfires, although that estimate was said to be extremely conservative.
The experts told the inquiry that the bushfire crisis had increased the risk of koala extinction, only adding to the destruction of their habitat by extensive land clearing for agriculture and urban development.
Australian farmers have also lost tens of thousands of livestock in the bushfires, with many having to euthanize animals suffering from heat stress and burns.
"While we don't know exact numbers yet, there has been a significant loss of livestock in parts of the country, most recently in areas such as northern Victoria and the south coast of NSW," Fiona Simson, president of the National Farmers' Federation, said.
She said the dairy sector was among the worst affected sectors.