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Sunday, June 10, 2012

How Populations Collapse: MIT Study

MIT researchers are studying how populations collapse at tipping points. This should be extremely relevant to our future:

In the early 1990s, overfishing led to the collapse of one of the most bountiful cod fisheries in the world, off the coast of Newfoundland. Twenty years later, the cod population still has not recovered, dramatically affecting the economic life of the region.

To explain this kind of collapse, ecologists have long theorized that populations suffering a decline in environmental conditions (such as overfishing) appear stable until they reach a tipping point where the population plummets. Recovery from such collapses is nearly impossible. "This is thought to underlie lots of sudden transitions — in populations, ecosystems or climate regime shifts," says Jeff Gore, an assistant professor of physics at MIT.

Gore and his students have now offered the first experimental validation of this theory. They showed that in populations of yeast subject to increasingly stressful conditions, populations became less and less resilient to new disturbances until they reached a tipping point at which any small disruption could wipe out a population.