So do Wolves hunt their prey to extinction?
Since reintroducing wolves into Yellowstone National Park, our understanding of how ecosystems function has radically developed. An ecological effect known as a ‘trophic cascade’ has being identified, showing us that wolves are initiating a more natural ecosystem balance. But what is a ‘trophic cascade’ and how are wolves achieving this balance? The term trophic simply refers to the different levels in a food chain, whereas the term cascade forces us to look at a traditional food chain from a different perspective. As a carnivore, the wolf has an effect on all trophic levels. As wolves returned to an ecosystem, they began to hunt and chase prey, competing with other species and therefore changing the ecosystem.
Since being reintroduced to Yellowstone in 1995, wolves have had a significant impact on Elk and Aspen. With this top predator now back in the ecosystem, elk are forced to run faster and further, allowing them to become stronger. As these elk run, their hooves aerate the soil, allowing more grasses to grow. Aspens and willows become healthier and taller as they are no longer heavily grazed because elk can no longer remain stationary for too long due to predation risk. Wolves have also had an impact on coyotes through competition. Numbers have reduced, enabling other species such as eagles and raptors to make a comeback due to increased prey availability. Bears have even benefited, not only by stealing wolf kills but also from the increase in berry producing shrubs due to reduced elk numbers.
So there is a great deal of evidence demonstrating that by starting ecosystem recovery at the top with predators like wolves, the whole systems benefits. Previous conservation and restoration efforts were predominately based on a bottom up approach. The plants form the basis of life from which everything grew. Once healthy plants established then everything else, the herbivores and carnivores etc. fall into place. This idea meant that biologists would try rebuild the plant life before anything else. But this classic example has demonstrated that a wild wolf population actually makes for a stronger, healthier and more balanced ecosystem.