The National Park Service will begin reducing the number of bison at the Grand Canyon National Park.

Other agencies, tribes and volunteer shooters will participate in lethal culling and non-lethal capture in order to bring the herd size down to 200 bison or less.

“They don’t have any natural predators, so the herd size is growing quickly. They’re starting to really impact the resources out there, and we want to control the size of that herd,” said Jeffrey Olson, Grand Canyon spokesman.

Olson said it could take three to five years to reduce the herd size. There are currently 400 to 600 bison in the area.