A $35M wolfpack that moved rivers
Twenty five years ago, there were < 5 beavers in Yellowstone National Park. Today, there are > 500. The beaver population exploded after 14 gray wolves were relocated to the 3,500 square mile park in 1995.
Yellowstone National Park is big.
3,500 square miles of wilderness. Rugged mountains, deep glacier-carved valleys, forests, lakes, rivers, and streams.
And all of that wilderness is home to lots of really cool animals, including massive herds of elk.
There have always been elk in Yellowstone. At times, too many.
Park rangers say Yellowstone elk can sometimes “exceed the carrying capacity of their habitat.” When that happens, the rangers cull herds by strategically killing animals and even controlling fertility using contraceptives, with funding from Yellowstone’s $34M annual operating budget.
But before Yellowstone was called Yellowstone, elk herds didn’t need to be managed by park rangers with a $34M operating budget. Gray wolves elegantly culled the herds for free.
Until we pushed them out. Throughout the 1900s, wolves were hunted and poisoned by fearful farmers and landowners across the US.
By 1995, there were 20,000 elk in Yellowstone.
But just 20 wolves.
A group of wildlife biologists didn’t think 20 was enough. They pitched the rangers.
“Yellowstone doesn’t need more sophisticated elk management. Yellowstone needs more wolves.”
The rangers got on board.
“Sure, let’s try it.”
In 1995, biologists captured fourteen wolves in Canada and released them in Yellowstone, triggering a still-unfolding cascade effect on animals and plants.
It started with the elk.
The fourteen wolves thinned out weak and sick elk, creating more resilient herds. The remaining elk radically changed their grazing behavior, avoiding spots in open fields and rivers that made them easy prey.
In areas where the elk had previously grazed all vegetation away, grass and shrubs returned. Bare hillsides became forests, and the height of some trees quintupled in six years.
And beavers like tall trees.
They eat them and use them to build dams - niche habitats for dozens of other species. Otters, muskrats, ducks, fish, reptiles, and amphibians.
The wolves ate coyotes too. And that led to more rabbits and mice. Which led to more foxes and badgers.
The wolves even changed the behavior of the rivers. Newly stabilized forests and vegetation prevented erosion on river banks. Channels narrowed, creating more pools and riffles. More habitats.
And on top of all that, the wolves were profitable. More wildlife led to more tourists. One 2005 study estimated wolves added $35M in visitor spending to local economies.
The fourteen wolves didn’t just boost wildlife in Yellowstone. They moved rivers and stimulated surrounding economies.
When we’re confronted with a problem, for example… herds of elk that exceed the carrying capacity of their habitat. We can consider complicated solutions that involve spreadsheets and fertility models and hiking through rugged terrain with rifles and syringes.
Or we can consider more elegant solutions.
We can introduce fourteen wolves to 3,500 square miles of wilderness.
And then sit back to watch what happens.
