Elk Herds Upsetting Ecosystems In Parks

"We have to plan for some of those things not happening," Patterson said. "If they do, we would cull fewer animals."

A conservation group called WildEarth Guardians opposes shooting elk, preferring the introduction of wolves, which helped control the elk population in Yellowstone National Park -- more than eight times larger than Rocky Mountain -- beginning in the mid-1990s. The organization has threatened to file a lawsuit.

Bryan Richards, who studies elk for the U.S. Geological Survey, said the combination of healthy habitat and few predators is likely to create a continuing elk problem for Rocky Mountain, Theodore Roosevelt and South Dakota's Wind Cave National Park. Human intervention is a necessity, he said.

"Unfortunately, with the hand of cards that has been dealt to the Park Service, there aren't any clear-cut great answers," he said. "If there are not tools implemented to keep those populations in check, the populations will spiral out of control."

Steve Torbit, Colorado-based regional director for the National Wildlife Federation, sees lessons for the future in the elk conundrum. He said the nation is "paying the price for these smaller parks that do not allow for the animal herds to have seasonal movement."

When parks expand, or new parks are created, Torbit says, they should include buffer zones where hunting and wildlife management are permitted "and you don't build the subdivisions or the ranches right up against the park boundary."

Staff writer Kari Lydersen contributed to this report.