News in Science

Cute animals 'skewing' extinction debate

News analysis Global extinctions are rarer than commonly believed and the extinction debate is too narrowly focused on pin-up images of charismatic birds and mammals, an Australian zoologist says.

Instead Professor Nigel Stork, of the University of Melbourne, urges greater focus on threats facing invertebrates and local extinctions.

Stork says statements about "100 extinctions a day" have become accepted, cited by organisations such as the United Nations and repeated in the popular media.

But Stork believes the science does not back this.

"The truth at the moment is we don't have enough information to talk about hundreds of species dying out," says Stork, the head of the university's School of Resource Management and Geography.

Stork says the number of known extinctions since 1600 is several thousand with only 60-70 species of insects included in the list.

Most of the extinctions occurred on islands, he says, and coincided with the arrival of humans.

"When you compare birds and mammals to snails, molluscs and insects, there is a seven times greater chance of a species becoming rare and endangered for birds and mammals than for these invertebrates," he says.

Stork says this reflects a lack of information about insect and other invertebrate numbers.

"It's bad science, when you've got millions of species, to extrapolate in the same way," he says.

"The threats are different. For birds and mammals the threats are hunting and loss of habitat, for invertebrates and other insects it may be another suite of threats."

Stork says he accepts many larger animals are as threatened as various reports outline.

"[But] we need to take a broader range of approaches to looking at extinction and extinction rates and look more carefully at other groups before we can extrapolate the rates of extinction from birds and mammals to the rest of biodiversity."

Certainly skewed

Environmental scientist Professor Mark Burgman agrees and says extinction data is "certainly skewed".

The director of the Australian Centre of Excellence for Risk Analysis at the University of Melbourne says we don't know the degree to which the "biased data" affects our potential to manage the changing environmental landscape.

He says the problem of bias is caused by scientists' lack of interest in studying the invertebrates that make up most of biodiversity.

"We know 90% of the vascular plants in Australia, but we only know 5% of the fungi," he says.

"We know a great deal about birds and mammals ... but the majority of living things aren't these things."

Instead he says there should be a focus on dealing with the processes and things that threaten invertebrates.

Burgman says the consequences of our inattention could be catastrophic and that increased interest and funding of taxonomy is required.

He says the classification of species is "not a groovy topic for government expenditure".

But he says that knowledge of new species could be vital for future biosecurity.

Stork says local extinctions of "keystone" vertebrate species are also a concern because they cause major changes to ecosystems by altering key processes such as the dispersal and pollination of flora.

Climate change effects widespread

Climate change may be the next driver of widespread extinctions and that this will be "less discriminating" in its impact, says Stork.

His comments follow recent reports by environmental group WWF-Australia and CSIRO that show climate change will severely affect the survival and habitats of Australian native animals.

Professor Peter Steinberg, of the School of Biological, Earth and Environmental Sciences, at the University of New South Wales, says Stork's view on the extinction debate has some merit.

But Steinberg says it has been "reasonably documented" that the world is now experiencing extinction rates comparable to some of the major extinction events in history.

He says if "we have a feel for this with high-profile animals" then it is possible to postulate this might be reflected among other living organisms.

Steinberg also believes more focus needs to be directed at the smaller organisms that make up biodiversity.

"Biodiversity develops on an evolutionary scale," he says.

"The rate of extinction is so rapid the evolutionary process is not going to be able to replace the loss of biodiversity."