'The stage was set:' Arrival of first North American bison changed ecosystem

EDMONTON — Scientists finally have been able to pin down when bison first arrived in North America and helped set the stage for the Great Plains that eventually supported the continent's first humans.

"(Bison) showed up and they interrupted an ecosystem that had existed, more or less, for a million years," said Duane Froese, a University of Alberta earth scientist and lead author of a paper published Monday. "The stage was set for North America."

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