Food web stability depends on competition and predation in the higher trophic levels. Reintroducing predators can help to rebalance ecosystems.
Aldo Leopold is generally credited with first describing the mechanism of a trophic cascade, based on his observations of overgrazing of mountain slopes by deer after human extermination of wolves.
A classic example of a terrestrial trophic cascade is the reintroduction of gray wolves (Canis lupus) to Yellowstone National Park. This example of a trophic cascade is vividly shown and explained in the viral video “How Wolves Change Rivers”.
REINTRODUCING PREDATORS
