The world's most comprehensive model for understanding bird extinction has been created by a University of Queensland researcher.
The significance of habitat loss, human persecution and predation on extinction of bird species has been investigated. It is the first study that explicitly takes into account the different routes to extinction.
The study will be published in the prestigious North American journal, Proceedings of the National Academy of Sciences.
The rethink of how animals become extinct has revealed some simple underlying principles that will change development of conservation priorities, according to Dr Ian Owens of UQ Department of Zoology and Entomology, and Imperial College Department of Biology. He has developed new extinction models in collaboration with Dr Peter Bennett from the Zoological Society of London.
"In the past, studies of extinction have focused on what species have become extinct, where they were and which species are most likely to become extinct in the future. However, there haven't been detailed studies asking why particular species become extinct while others remain abundant," Dr Owens said.
"Despite the wealth of data that has been collected, the best models were only able to account for about 10 percent of the variation between species in extinction risk."
They examined a database of 95 bird families covering over 1000 threatened species. Dr Owens said that he chose birds to examine first because of the size of the database compiled over the past ten years. The first implementation of their model already can account for 50 percent of variation in avian extinction patterns.
"Previous models had a built-in assumption that all extinctions could be modelled by a single cause. What we have done is allow for different causes," Dr Owens said.
"Two main causes appeared as particularly significant in our model: habitat loss due to human development, and human persecution or predation by introduced species.
"Over 70 percent of threatened species are at risk from habitat loss and 35 percent at risk from persecution or predation. Interestingly, only a fraction of species is at risk from both. This indicates that understanding the reason for extinction in particular cases is critical for developing appropriate conservation strategies."
Some of the ideas behind Dr Owens' work were proposed over 20 years ago but researchers at that time did not have sufficient data to do a proper analysis. He said that, due to that lack of data, conservationists had to rely on anecdotal evidence to develop appropriate protection strategies.
"In a sense, the huge push for general conservation strategies ambushed research into the ecological processes that lead to extinction. While the overall goals were important, we lost the focus on scientific approaches to conservation.
"With a clearer understanding of what factors are important in extinction risk, we can create targeted plans for saving species at risk," Dr Owens said.
Dr Owens is also applying his model to species other than birds. His preliminary work on marsupials is showing similar explanatory success. As there are only about 150 Australian marsupials, the data set available is much smaller but it includes data for all marsupial species in Australia. As predicted by field conservationists, predation by foxes seems to be the critical factor.
For more information, contact Dr Ian Owens (telephone 07 3365 4823) or Jan King at UQ Communications (telephone 07 3365 1120) or email: communications@mailbox.uq.edu.au.
