Mammals Not So Extinct After All

A story out of Wired reports that many mammals that have been traditionally thought to be extinct may not be. Brian Switek writes:

In order to determine how often extinct species had been rediscovered, University of Queensland scientists Diana Fisher and Simon Blomberg created a dataset of 187 mammal species that have been reported extinct, extinct in the wild, or probably extinct since 1500, as well as those which have been rediscovered. They also looked at historical data on the threats that caused species to become extinct — or brought them close to it — including habitat loss, introduced species and overkill by humans.

It turns out that rumors of the extinction of more than a third of these species have turned out to be premature, the scientists report in Proceedings of the Royal Society B Sept. 29. At least 67 species — a little more than a third of those presumed to be extinct — were later found again. And in most cases, these were animals that had been hardest hit by habitat loss.

This is encouraging, but that doesn't mean you should pull out your elephant gun:

Humans and invasive species have been significantly more efficient killers. It’s rare that a species reported extinct due to one of these causes has been seen again.

“If you think that a missing species is extinct and the main cause of decline was introduced predators such as feral foxes, cats or rats, then you are very likely to be right,” Fisher said. But, she added, “If the main cause of decline was habitat loss, you are quite likely to be wrong if you say that it’s extinct, unless it was restricted to a very small area.”

Now the catch is if we can stop habitat loss in countries that need to survive and yet need to preserve their biodiversity. Not an easy thing to do in this day and age.

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New Global Model for Speciation

ScienceDaily has a report on work done that is adding support to the idea that geographical isolation need not be present for speciation to occur. The article notes:

In a new study just published in Nature, Les Kaufman, Boston University professor of biology and associate director of the BU Marine Program along with a team of researchers from The New England Complex Systems Institute, have collaborated and found a way to settle the debate which deals with the origin of species independent of geographic isolation.

They demonstrated, using a computer model, how diverse species can arise from the arrangement of organisms across an area, without any influence from geographical barriers or even natural selection. Over generations, the genetic distance between organisms in different regions increases, the study noted. Organisms spontaneously form groups that can no longer mate resulting in a patchwork of species across the area. Thus the number of species increases rapidly until it reaches a relatively steady state.

"Our biodiversity results provide additional evidence that species diversity arises without specific physical barriers," the study states.

The computer simulations, the authors, note showed the distribution of species formed patterns similar to those that have occurred with real organisms all around the world.

This is a boost for the sympatric speciation model, although it is likely that both take place all over the world in different populations.



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