Two-thirds of that area was koala habitat, Ashton said. "If we look at a 50% survival rate, that's around about 350 koalas and that's absolutely devastating," Ashton said of the death toll. "We're hoping it's not as bad as that, but because of the intensity of the fire and the way koalas behave during fire, we're not holding out too much hope," she added.
Koalas climb high into trees during wildfires and survive if the fire front passes quickly below them. The koala colony was particularly heathy and genetically diverse, Ashton said. Koalas prefer coastal forests, which are being cleared for suburban expansion. Increasingly isolated koala colonies have become inbred and diseased.
Australia's wildfire season has made a particularly early and devastating start in the southern hemisphere spring due to above-average temperatures and below-average rainfall that has left much of the east coast in drought.