How did the removal of wolves from Yellowstone National Park impact the flow of matter and energy in the park

The removal of just a single species from a food web can have devastating effects on the entire food web. In a food web, predators are organisms that feed on other organism. A prey is an organism that is used by the predator as a source of food.

In the Yellowstone National Park, the wolves were the top predators. The wolves mainly fed on elk. After the removal of wolves from the park, there were no predators to feed on elk. Hence, the population of elk increases to such a level which couldn't be supported by the habitat. Or in other words, the population of elks increased more than its carrying capacity.

Elks fed on trees like aspen. As the population of elk increased, the number of predators for aspen increased. Hence, the population of aspen trees declined. As aspen tree was also the source of food and shelter for other organisms, hence they were affected too.