This video mentions something really important.
It’s called the ecology of fear hypothesis.
In this hypothesis, fear plays the vital role. If a prey animal has to be afraid of a predator in a certain area, its behavior will change.
This is perhaps best described in study that examined the role coyotes play in keeping domestic cats out of areas where birds nest. Coyotes do kill cats, and when cats figure out that coyotes might be stalking in the brush, they avoid the brush. Because they avoid the brush, the birds can nest in the brush and not be eaten by cats. The birds are able to nest and produce offspring– only because they are afraid coyotes might be stalking in the exact same area where birds like to nest.
In Yellowstone, elk browse on aspen, willows, and cottonwood less when they have to worry about wolves. The aspen forests have started to regenerate, which is great news for riparian areas. These improved riparian areas are good for a wide range of wildlife. Beavers return to eat the willows. They make ponds, which are good for lots of other wildlife, and the trees are great for songbirds.
So ecosystems benefit because wolves scare the hell out of elk.
Of course, they also protect the trees through taking a certain number of elk every year, but it is through this ecology of fear that the really protect the trees from the browsing elk.
The ecology of fear hypothesis is an important part of William Stoltenburg’s Where the Wild Things Were, which is one of the best accounts of what scientists currently know about the role of predators in the ecosystem.
Predators do play a role in ecosystems.
And they don’t just do it through killing prey species.
They also do it by making the prey species fear predation.
And that fear has real ecological ramifications.