Shocking facts: What happens if a top predator species vanishes from our ecosystem?

trophic cascade

What happens when a top predator breed is removed from our ecosystem? Can you imagine, the whole ecosystem can break, geography of a place can change, course of rivers can alter because of the absence of only one species? Ecologists describe the phenomenon as trophic cascade. A top-down cascade is a trophic cascade where the food chain is disrupted by the removal of a top predator.

A top-down cascade was observed in several areas in the northern Rocky Mountains of the United States and one of those areas was Yellowstone National Park, when wolves, the top predators were exterminated from most of its natural habitats. In the absence of wolves, herbivores’ population had exploded. Researchers observed changes in the physical aspects of the park, including plant life. The whole ecosystem balance started to fall apart, the erosion level of the rivers made the rivers change the course and the whole geography of the place started changing.

This video describes what has happened when wolves were re-introduced, after a gap of 70 years to these areas. Wolves act as ecosystem engineers by maintaining a healthy ecosystem. The profound benefits from the re-introduced wolves almost immediately became apparent.

After re-introduction, wolves halted the herbivores’ population by hunting the ailing and aging ungulates like wapiti. For the presence of wolves, wapitis even stopped munching in the valleys where wolves can easily attack them. As a result native flora began to re-grow, thereby increasing biodiversity by providing food and shelter to a growing variety of plants and animals.

The most notable change was the decrease in the erosion level of the riverbanks. How? Well, the re-established vegetation stabilized the riverbanks, which in turn altered the geography of the park itself.

This wonderful documentary video shows how one species can have a huge cascading effects on the entire ecosystem; particularly showing the changes that Yellowstone National Park had after re-introduction of wolves.


Image courtesy: stemjobs