In the late 1990’s, scientists William J. Ripple and Robert L. Beschta were documenting browse levels in Yellowstone National Park after wolves had been returned. Upon doing so, they noticed that wolves, as a keystone predator had a direct influence on these levels. Because wolves had been removed from this area for seven decades and then returned, they had documented evidence of the eco-system prior to wolf predation in the area and after. Due to this unprecedented study, a Trophic Cascade was unfolding which suggested that wolves effected everything from cold water to beaver dens along with healthier bears, elk, birds, frogs, etc.
So how does a Trophic Cascade work? In a simple example, it can be defined as this: When wolves hunt, they make the elk run. When the elk move, they are not eating as many leaves from trees and brush. Willow trees that grow by the banks of rivers and would have otherwise been eaten down by elk, provide shade for colder water. When water temperatures drop, this allows fish to spawn, birds to make more nests and fallen branches are used by beavers to make dens. When elk move, they get more exercise and wolves prey on the sick, young and old of which keeps the herds healthy. Bears profit from wolf kills and become healthier as a result. This goes on and on so that the end result is that a predator has a top- down effect on everything in that eco-system. Bottom- up effects are also being studied. Without the wolf, or as other examples- the shark, lion, bear, etc., we can see that these key species in their environments are essential to the health of eco-systems including our oceans and tropical forests. It is important to understand why these animals play such an important role on our planet and must be protected.
Ecology of Fear:
Upon their studies, William (Bill) Ripple and Robert Beschta also noticed another key benefit to the return of wolves to Yellowstone. Prior to wolves being re-introduced, elk and deer became very used to not having to worry about something such as the wolf chasing them so over grazing occurred. This had direct effects on vegetation, tree survival and plummeting effects on other plant and animal species. The theory in simple terms, as an example, would mean that when wolves are present, deer and elk raise their heads in caution causing less grazing in certain areas. They move more frequently and even run so that the graze is more spread out and less frequent. This simple change in behavior is now responsible for the recovery of more vegetation and increase in plant and animal species once on the decline.
There are new developments and studies constantly occurring in the world of animals and what roles they play on our planet. The latest, most interesting study is being conducted on sea otters and kelp forests and how these simple creatures as well as other animals influence Co2 levels in the atmosphere. This very study can lead to direct evidence that predators having an influence on prey that eats vegetation, can actually make a case for saving our planet.