It’s estimated 480 million animals have been affected since bushfires in NSW started in September 2019—a figure that beggars belief. Professor Chris Dickman, an expert in the ecology of Australian mammals from The University of Sydney, has explained how that figure was calculated.
This figure is based on a 2007 report for the World Wild Fund for Nature on the impacts of land clearing on Australian wildlife in New South Wales.
To calculate the impacts of land clearing on the state’s wildlife, the authors obtained estimates of mammal population density in NSW and then multiplied the density estimates by the areas of vegetation approved to be cleared.
Estimates of density were obtained from published studies of mammals in NSW and from studies carried out in other parts of Australia in similar habitats to those present in NSW.
The authors deliberately employed highly conservative estimates in making their calculations. The true mortality is likely to be substantially higher than those estimated.
Using that formula, co-author of the original report Professor Dickman estimated that 480 million animals have been affected since the bushfires in NSW started in September 2019. This figure only relates to the state of NSW. 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 figure includes mammals, birds and reptiles and does not include insects, bats or frogs. The true loss of animal life is likely to be much higher than 480 million.