THE birth of the US Appalachian mountain chain caused mass extinction

THE birth of the US Appalachian mountain chain may have been behind a major ice age and a mass extinction.

The extinction event at the end of the Ordovician 450 million years ago was the second largest Earth has ever seen. It has long been believed that an ice age caused it, but no one knew what triggered the freeze.

Seth Young of Indiana University in Bloomington, and colleagues, believe two factors conspired to create the deep freeze. First, layers of lava show that climate-warming volcanic activity slowed down at this time. The second factor was an increase in the weathering of the Appalachian rocks between 462 and 454 million years ago, which is indicated by changes in strontium isotope ratios in Ordovician oceanic rocks (Geology, DOI: 10.1130/g30152a.1).

YouTheria: Predictive Animal Database for Endangered species

A new animalia database that allows users to explore the factors that predispose different mammalian species to extinction – from human encroachment to slow reproductive rate – could be useful in planning conservation schemes, its developers say. Anyone can access the online system, YouTHERIA, which allows users to manipulate parameters including habitat ecology, litter size and diet, and test their own hypotheses.

It relies on a vast database of all known and recently extinct mammals, called PanTHERIA, which lists details of the species' ecology, behaviour, diet, geographical range and habitat, based on more than two decades of published research. The database also records the extent to which each of the 5000-odd species is being impacted by humans and habitat degradation.

Warning signs

Analysis of the database has already highlighted a set of key characteristics – slow reproductive rate being one – which predispose mammals to extinction.

"For example, the Seychelles flying fox isn't declining in abundance now because its habitat is intact," says Andy Purvis, a biodiversity researcher at Imperial College London, who helped produce the tools. "But our database suggests that its slow reproductive rate will predispose it to extinction if and when its habitat is disturbed."

Purvis also recommends that conservationists focus on protecting the tundras of Siberia and Canada, where mammals predisposed to extinction because of slow reproduction, are currently thriving in healthy habitat.

Until now, the database has been restricted to the team of biologists who developed it, but Kate Jones at the Zoological Society of London and colleagues have made it freely available to other researchers, hoping that they will contribute to the data.

Encyclopedia of Life, another collaborative database of species, launched two years ago, has already seen contributions from 2 million people from 200 countries. This week it reached its 150,000th entry.

Journal reference: Ecology, DOI: 10.1890/08-1494.1

Life Kills life