Database aids research on extinction

By SIMON COLLINS science reporter

A unique record of New Zealand fossils started almost 60 years ago is helping to solve a global puzzle over factors driving the birth and death of species.

The record, started by geologist Harold Wellman in 1946, is the only one in the world to record locality and surrounding rock type for every fossil found in a country. It has been backdated to the 19th century and details more than 700,000 fossils.

Now six New Zealand scientists have published the first results of a three-year, $420,000 study using the database to analyse factors affecting mass extinctions, such as that which wiped out the dinosaurs 65 million years ago.

One of the authors, Dr James Crampton of the Institute of Geological and Nuclear Sciences, said the flourishing and extinction of species was one of the biggest puzzles.

"It's tied up with periods when 90 per cent or more of the world's species became extinct, and how the planet recovers from those extinctions," he said.

"A classic case was the extinction of the dinosaurs, which were replaced by the mammals.

"Traditionally all these things have been based on North American and Western European data.

"We are finding out from studies of climate and other things that perhaps North America and Western Europe don't lay down all the knowledge for the rest of the world."

Although the biggest mass extinctions appear to have been global, the New Zealand study suggests that some "extinction events" in the Northern Hemisphere data may be biased by the fact that rocks of some ages are more common.

The first report on the study, in this week's international journal Science, says the number of fossil records from each geological period is related to the area of surface outcrops of rocks from that age.

Dr Crampton said this was a kind of "housekeeping" that was needed so that the resulting bias could be taken into account in interpreting the fossil record.

"The fact that this bit of housekeeping has gone into Science is telling you that there is huge interest in what New Zealand has, because it is well documented and because we sit geographically in such an important part of the world," he said.

Geographically, New Zealand has been isolated for 80 million years, forcing local plants and animals to adapt or die. Unlike those on larger continents, they could not migrate when the climate changed or the rising sea level submerged much of the country.

But Dr Crampton said the comprehensive fossil database was a result of a more transient phenomenon - the co-operative, "can-do" approach that prevailed in New Zealand half a century ago.

"I don't think you'd ever get it off the ground today.

"Today the drivers have changed. There is a lot more competition.

"Everyone is competing for the same funds. We don't get that level of co-operation."

Harold Wellman, who helped discover the Alpine Fault that created the Southern Alps, started the database through the Geological Society of New Zealand in 1946.

All geologists since then, including those in the oil industry and private amateurs, have continued to contribute.

Dr Wellman's work was recognised by a Doctorate of Science from the University of New Zealand in 1956, and he later became a professor at Victoria University.

He died in 1999, aged 90.