Wednesday, January 26, 2011

Extinction cascades can be prevented, scientists find

Rescuing ecosystems. Diagram by Zina Deretsky courtesy National Science Foundation via

EVANSTON, Illinois, January 25, 2011 (ENS) - Extinction cascades are often observed following the loss of a key species within an ecosystem. As the system changes to compensate for the loss, availability of food, territory and other resources to each of the remaining species can fluctuate wildly, creating a boom-or-bust environment that can lead to even more extinctions.

New research at Northwestern University has found that more than 70 percent of these extinctions are preventable, assuming that the ecosystem can be brought into balance and no new factors are introduced.

Northwestern University physics professor Adilson Motter and his student, Sagar Sahasrabudhe, have developed a mathematical model to describe interactions within ecological food webs that could rescue fragile ecosystems and halt complex cascade events.

Published in the January 25 issue of the journal Nature Communications, their study illustrates how human intervention may be effective in species conservation.

"Our study provides a theoretical basis for management efforts that would aim to mitigate extinction cascades in food web networks," Motter said.

The scientists found evidence that some extinctions are caused not by a primary disturbance but as the result of a cascade.

"We find that extinction cascades can often be mitigated by suppressing, rather than enhancing, the populations of specific species," he said.

Motter and his team conclude that large-scale failures can be avoided by focusing on preventing the waves of failure that follow the initial event. …

Extinction Cascades Can Be Prevented, Scientists Find

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