Your number is up: Species doomed by mathematics

Kathy Marks The Independent 8 Apr 11;

It seems rather grim: a mathematical formula to calculate the probability of animals becoming extinct.

But its Australian creators say that it will aid any decisions on where to target resources – as well as helping to recognise species so close to the brink that they are beyond help.

The Red List of Threatened Species, produced by the International Union for Conservation of Nature (IUCN), already ranks plants and animals in categories ranging from safe to critically endangered.

But it does not distinguish between species at the top and bottom of a category, which is where the new index – called Safe (Species Ability to Forestall Extinction) – comes in.

Devised by researchers from the University of Adelaide and James Cook University, in northern Queensland, Safe can determine how close a population is to its minimum viable size. Professor Cory Bradshaw, director of ecological modelling at Adelaide's Environment Institute, called it "the best predictor yet of the vulnerability of mammal species to extinction".

The issue is particularly sensitive in Australia, which has the world's worst record for mammal conservation. Of all the mammals that have disappeared in the past 200 years, nearly half were Australian.

The Safe index, detailed in a paper published in the journal Frontiers in Ecology and Environment, builds on previous studies into minimum population sizes required to survive in the wild. According to Professor Bradshaw, the tipping-point is 5,000; below that, the risk of extinction from extreme events such as bushfires or cyclones is much higher. Among the animals close to the tipping-point are the tiger and the African wild dog.

Professor Bradshaw acknowledged that, based on the index, some species – such as the Javan rhinoceros and the New Zealand kakapo, the world's largest parrot – might not be worth trying to save. There are just 40 to 60 rhinos left, and 120 or so kakapos.

"If an animal is so rare, and it's going to take a lot of money and resources and could be impossible to restore because the habitat is not there... it might not be worth saving," Professor Bradshaw told The Australian newspaper.

"It's controversial, but when you have a finite amount of resources, one species might be more likely to be brought back from the brink."

The index would assist "practitioners of conservation triage", he said, explaining that: "During wartime, medicos have to go out and say: 'Well, this guy's too far gone, we're not going to waste our time because there's too few of us.' So we have to say: 'These ones are probably too far gone.'"

The Safe index exposes subtleties within the Red List. Both the Javan rhino and Sumatran rhino are critically endangered, but while it may be too late to save the former, the latter – with a population of 220 to 275 – may still be capable of being rescued.

So it therefore makes no sense, argues Professor Bradshaw, to spend more on the Javan species, as is currently the case. "Not all critically endangered species are equal," he said.

To test their formula, designed to be used in conjunction with the Red List, researchers applied it to 95 mammal species. They found that nearly one-fifth were close to extinction, and more than half of those had populations that had already fallen to unsustainable levels.

The Australian animal species that may have to be "cut loose", based on the Safe index, include the hairy-nosed wombat, which is now a critically endangered mammal. The high extinction rate in Australia is believed to be mainly due to the introduction of feral cats and foxes.

Conservationists fear species index may lead to extinctions
ABC Net 8 Apr 11;

MARK COLVIN: Conservationists have criticised suggestions that some rescue programs for endangered species could and should be cut. Australian scientists have created a new tool which they say will help approach the conservation of threatened species in order of priority.

The index is a mathematical analysis that can be used to weigh up which creatures to bring back from the brink.

But it's worried Australian and foreign agencies which have been working to rescue vulnerable animals including the hairy nosed wombat. Adrienne Francis reports.

ADRIENNE FRANCIS: A new tool designed to improve conservation of vulnerable species has ignited concerns among some conservationists. Patrick Medway is the secretary of the Wildlife Preservation Society of Australia.

PATRICK MEDWAY: We could not accept that even any or some of these species should be allowed to become extinct. It would be against the grain of our members and our organisation who have worked so hard to save and conserve Australia's wildlife for the next generation.

ADRIENNE FRANCIS: The charitable organisation, staffed by volunteers has been working to rescue threatened species since 1909.

PATRICK MEDWAY: They used to shoot koalas, platypus, wombats and turn them into skins. Now we have gone past that, we've been able to get legislation through federal and state Parliament to protect Australia's wildlife.

To think that you might be allowed to, for some to become extinct, is contrary to what we would believe and what we would oppose.

ADRIENNE FRANCIS: The tool that has ignited this discontent was designed by a team of researchers from James Cook University and the University of Adelaide. They've created a 'SAFE index', which is a probability tool for conservation triage.

Co-author Corey Bradshaw says they based the index on existing research which suggests populations of less than 5,000 individuals are hard to rescue.

What are the Australian species that your index suggests we shouldn't save?

COREY BRADSHAW: Well you know I wouldn't go so far as to say we shouldn't save them but I mean if you take a strictly empirical view, you know things that are well below in sort of numbering in the hundreds; white footed rock rats, we've got certain types of hare wallabies, a lot of the smaller mammals that have been really nailed by feral predators like cats and foxes.

And in some cases it's probably not worthwhile putting a lot of effort because there's just no chance.

ADRIENNE FRANCIS: He says the WA dibbler and the hairy nosed wombat are among the Australian species where conservation is clearly not cost effective.

COREY BRADSHAW: Certain species like that, if they are truly numbering in the hundreds if not even lower than that, without a huge investment and a lot of time and effort they are pretty really probably not worth trying to throw too much at them.

ADRIENNE FRANCIS: The Wildlife Preservation Society of Australia strongly disagree. The society has been a long time advocate for efforts to increase the estimated 140 surviving northern hairy nosed wombats in central Queensland.

PATRICK MEDWAY: Now it's not a case of assessing it on a dollar basis. It's a commitment as a civil high group of people who do not want to have species go extinct on their watch.

ADRIENNE FRANCIS: That commitment is echoed among other conservation organisations. Dr Barry Trail is the director of the Australian arm of the US based philanthropic conservation organisation, the Pew Environment Group.

BARRY TRAIL: Unfortunately I do find is that there is a thread that has been coming up over the last few years of academics doing what I find is frankly a bit academic exercises, almost like a household budget showing oh this year we can't afford both a swimming pool and an overseas holiday, so we'll just go for the pool.

ADRIENNE FRANCIS: A spokeswomen for the Federal Environment Minister, Tony Burke says the Government welcomes the new tool which could assist the identification and support the recovery of threatened species.

The Wildlife Preservation Society of Australia fears the index could be used by the Government to knife some project funding. But the Pew Environment Group remain optimistic that the public and other organisations will continue to give generously.

MARK COLVIN: Adrienne Francis.