How Wolves Change Rivers
"How Wolves Change Rivers" is a fantastic video that depicts the impact wolves have on the Yellowstone National Park ecosystem.
It discusses the devastation that can occur from trophic cascades, especially when a keystone species is taken out of an ecosystem. Specifically it focuses on wolves and how they had been missing from the Yellowstone National Park Ecosystem for almost 70 years and how their reintroduction to this ecosystem changed everything, including the rivers! When wolves left the ecosystem the population of deer increased and because of this sharp increase in number the deer decimated all the vegetation from grazing. When the wolves came back they preyed on the deer and decreased their population but also kept the deer out of certain parts of the park. These parts then began to flourish, with the vegetation rebounding in just 6 short years to be better then ever before. Once the vegetation increased, the number of birds and beavers increased. The beavers created dams in the rivers that helped reestablish ducks, otters, muskrats, fish and amphibians. The wolves also killed coyotes which then caused the rabbit and mice population to increase. As a result, more hawks, badgers, weasels, foxes. The leftover carrion that wolves left behind attracted more ravens, bald eagles, and bears to appear. More bears also appeared because of the increased vegetation increasing the number of berry bushes for them to eat. All of these plants and animals were affected by the reintroduction of wolves back into the ecosystem. The video concludes with how these wolves not only affected all these organisms but how they also changed the behavior and structure of the rivers. It is mind boggling to think that one species of animal could actually change the physical geography... but they did! The rivers meandered less, there was more pools and there was less erosion in response to the wolves. This occurred because the wolves controlled the deer population which helped allow more vegetation to grow. This increase in vegetation ended up stabilizing the banks of the rivers, prevented the banks from eroding and allowed them to become more fixed in place.
It is amazing to think that just one species can be so impactful, but this video very clearly displays how vital one species could be to an entire ecosystem. This speaks to the current problem of climate change and other anthropogenic factors that are devastating entire ecosystems. We as citizens, and stewards of the environment must all work together to do our part to prevent humans from destroying our ecosystems. The threat of changing the trophic webs on our planet could be devastating not only to the animals and plants that live in these ecosystem but also to the people around it.
