When wolves were reintroduced to Yellowstone National Park in the United States after being absent nearly 70 years, the most remarkable “trophic cascade” occurred. Learn what is a trophic cascade and how exactly do wolves change rivers in this fascinating video.
Wolves were once native to the US’ Yellowstone National Park — until hunting wiped them out. But when, in 1995, the wolves began to come back (thanks to an aggressive management program), something interesting happened: the rest of the park began to find a new, more healthful balance.
Not only they affected the entire live of the park—increasing the number of species in it!—but actually changed the geography of the park itself, affecting the rivers in a way that positively affected everything.