Tropical Cascade or How Wolves Change Rivers

When 14 wolves were released in Yellowstone National Park in 1995, scientists did not suspect that this would radically change the entire ecosystem of the park.
Wolves have not been in the park for 70 years and all this time there reigned deer, which over the years of uncontrolled breeding (all efforts of people to control their population were unsuccessful) caused the strongest damage to the local flora. The fourteen wolves, of course, were unable to slay all the deer, but they forced them to choose places for pastures more carefully and avoid some parts of the park. In these places vegetation has begun to revive. In six years, the number of trees has increased five times. There have been bobras who love to eat trees and love to build dams. In the factories there were owls, ducks and fish. Wolves decreased the population of chakals, which led to an increase in the number of rabbits and mice, and those in their direction attracted the park of frogs, chickens and foxes. Bears came to the park, as they could feed on wolf undernourishments, plus the number of berries in the park increased.
But most surprisingly, the wolves forced the rivers to change their behavior. Their streams were straightened and stabilized, and the erosion of the shores decreased. This happened because the influence of wolves on deer led to the explosive growth of trees and grass on the banks of the rivers, which led to their strengthening. The geography of the park itself has changed, and all thanks to the fourteen wolves released there less than thirty years ago.