Kinka warns that if a creek channel has degraded too far it might need assistance getting to the point where it can spill water onto the floodplain again. Near where I camp at Telegraph Creek, I see workers from the Montana Conservation Corps, an organisation putting Montana youth to work rehabilitating public and private lands, pounding barriers made of wooden posts, brush and mud in the creek to partially block water during spring runoff. The structures, known as Beaver Dam Analogues (or BDAs), slow the water, trapping sediment and raising the creek bed. It’s a technique known as low-tech process-based restoration.
“We don’t do it with backhoes [diggers],” Kinka says. “We do it with people in waders.” Sometimes a few BDAs can raise the water table enough to get a real beaver to move in and take over.
Here on Beaver Creek, this hard work wasn’t necessary. What excites Kinka about the recovery here is its simplicity. “We didn’t go down there, we didn’t reintroduce beavers, we didn’t build BDAs. We didn’t do anything,” he tells me. “We just put bison here. This is resilience that is inherent in the system. It just needed a little bit of a break from grazing to be able to do this all on its own.”
What’s more, the creek is still improving, he says. “Every year the creek gets a little wider, a little more meandery, a little more like a pool and less like a trench.”
While the evidence for the benefits of bison is compelling, many cattle-owners think the story needs more nuance. Malou Anderson-Ramirez and her husband run cattle on a ranch bordering Yellowstone National Park, 300 miles (480km) to the south-west of American Prairie. When we talk about grazing and stream health, she inserts an important qualifier.
“It’s not the cow, it’s the how,” she says.