Extinction of species ‘not as bad as feared’

By JOHN VAN RADOWITZ
Published on 25/01/2013 02:07

Reports of the death of numerous species on Earth have been greatly exaggerated, according to a team of scientists.

Extinction rates have been wildly overestimated, partly because of misconceptions about how many plants and animals exist on Earth, they said.

They claimed that, globally, about 1 per cent of species were likely to be vanishing per decade rather than the 5 per cent figure some experts have proposed.

“Our findings are potentially good news for the conservation of global biodiversity,” said Professor Mark Costello, from the University of Auckland in New Zealand.

Writing in the journal Science, the researchers said there were about five million species of plants and animals on Earth, of which 1.5 million had been named.

This is far fewer than some estimates, which have put the figure as high as 100 million.

If a habitat is thought to contain more animals than it does, this can easily lead to a mistaken idea of how quickly they are disappearing.

Finding 500 members of a species in a population estimated to top 1,000 would indicate a more than 50 per cent decline. But if the population was actually 500 in the first place, the loss rate falls to zero.

“Overestimates of the number of species on Earth are self-defeating because they can make attempts to discover and conserve biodiversity appear to be hopeless,” Prof Costello said.

“Our work suggests that this is far from the case. We believe that with just a modest increase in effort in taxonomy and conservation, most species could be discovered and protected from extinction.”

Co-author Professor Nigel Stork, from Griffith University in Brisbane, Australia, said: “Surprisingly, few species have gone extinct, to our knowledge.”