Top Predators Key to Extinctions as Planet Warms

ScienceDaily (June 21, 2012) — Global warming may cause more extinctions than predicted if scientists fail to account for interactions among species in their models, Yale and UConn researchers argue in Science.

"Currently, most models predicting the effects of climate change treat species separately and focus only on climatic and environmental drivers," said Phoebe Zarnetske, the study's primary author and a postdoctoral fellow at the Yale School of Forestry & Environmental Studies. "But we know that species don't exist in a vacuum. They interact with each other in ways that deeply affect their viability."

Zarnetske said the complexity of "species interaction networks" discourages their inclusion in models predicting the effects of climate change. Using the single-species, or "climate envelope," approach, researchers have predicted that 15 percent to 37 percent of species will be faced with extinction by 2050.

But research has shown that top consumers -- predators and herbivores -- have an especially strong effect on many other species. In a warming world, these species are "biotic multipliers," increasing the extinction risk and altering the ranges of many other species in the food web.

Continued:  http://www.sciencedaily.com/releases/2012/06/120621151520.htm