The Grand Canyon’s North Rim is overrun with bison. They trample wetlands and lake shores and devour the grass. That’s changing the ecosystem, a situation that’s been building for more than a decade… Now the National Park Service intends to do something about it. KNAU's Melissa Sevigny reports.

A single bison can drink up to ten gallons of water and chew through 30 pounds of grass in one day. That’s significant in a desert region like Arizona, says ecologist Tom Sisk.

“Problems we don’t deal with tend to become bigger problems,” Sisk says.

And this problem is tangled up in a complicated question: Do bison belong in Arizona? Sisk says there’s no clear answer. Historically Arizona was the edge of their range. “Were they a presence to be reckoned with? Did they have an ecological role that affected the fate of the Colorado Plateau ecosystems? Almost certainly not,” he explains.

This herd has a strange history. A man named Charles “Buffalo” Jones brought bison to Arizona in the early 1900s. He bred them with cattle to make “cattalo” in an experiment meant to create a hardy and tasty cross-species. It was a financial disaster. Jones abandoned a handful of the animals near the North Rim—ancestors of today’s herd.

Sisk says, “They’re amazing animals, and even if they’re perhaps descended from this hybrid and have some cattle genes in them, you see them and you have to smile.”

But their effect on the ecosystem isn’t pretty. Just a few miles past the North Rim entrance of the park, dozens of bison graze along the road. Meadows are mowed to stubble. Ponds are muddied from trampling and dung is everywhere.

Greg Holm, wildlife manager at Grand Canyon National Park, says, “If you drive through here with your windows down, you can actually smell the bison …. In a nutshell, we want to reduce the number of bison in the population as quickly as possible in the next 3 to 5 years to a level under 200 animals.”

To do that, the Park Service plans to relocate or kill hundreds of bison. Volunteers will be allowed to do supervised shooting, and the meat will be donated to tribes or food banks.

Craig McMullen, Flagstaff district regional supervisor for the Arizona Game and Fish Department, says “Clearly the bison are having ecological impacts on the park. That’s not something we’re happy about at all.”

Grand Canyon National Park prohibits hunting of all kinds. But McMullen says his agency wants to change that for bison. “We think the least expensive and most efficient and most expedient way to get that population down in a hurry is through the use of licensed hunters.”

It’s a solution that appeals to Flagstaff resident Danny Hogg. He and his family have tried to hunt bison on the North Rim, just outside the park boundary. “It was the most beautiful country you’d ever see, the most rugged country you could ever be in,” he remembers.

They never found any bison. But inside the park, Hogg says they were everywhere.

He thinks there should be some kind of hunt to control the numbers. “We would like to be part of the solution, is what it’s all about,” he says.

Others believe the priority should be relocating the bison to ranches or tribal land. Alicyn Gitlin of the Sierra Club worries unsupervised hunters would drive the animals deeper into the canyon. “That would just be a mess, because they would be that much harder to round up and control,” she says.

Gitlin thinks the bison are basically stray livestock. Others, including hunters like Hogg, say they’re part of Arizona’s rich wildlife heritage. But they both agree on one thing. As Gitlin says, “It’s really heartbreaking to see what’s happening, and so we really need to manage these animals soon.”

The Park Service could begin culling the herd as early as this fall.