The National Park Service announced it’s developing a plan to manage the wolf and moose populations in Michigan’s Isle Royale National Park, National Parks Traveler reported Wednesday.

The planned environmental impact statement is a response to the drop-off in gray wolf numbers. Since wolves first crossed the ice bridge from Lake Superior to the Isle Royale archipelago more than 65 years ago, the park has been home to about 20 of the animals, according to Minnesota Public Radio.

This year, only three have been documented. With fewer wolves, the park’s moose population has soared, which threatens to affect park resources, including vegetation, according to the NPS.

The NPS is considering a number of management possibilities, including introducing new wolves to Isle Royale now or waiting until the current pack dies off.

The public has until August 29 to comment on the plan on the NPS website.