How Wolves Change Rivers

Wolves have always been a symbol of the wild, free in spirit and roamers of the land. These animals are considered majestic and protectors of the wilderness. They have always roamed the western United States, although their population has fluctuated over time. Over the past 10 years wolf reintroduction into Yellowstone National Park has been a controversial topic to those of the United States. As of 1995, wolves have been reintroduced into the park. This has come with some strong opposition and yet has prevailed. The future of the wolf in Yellowstone park is now looking bright, although not certain since there still are those who want them banished again.

While highly controversial, the reintroduction of wolves in Yellowstone Park has provided many beneficial ecological changes to the entire parks ecosystem. After a nearly 70 year absence, in January of 1995, 14 wolves from separate packs were captured in the Canadian Rockies and transported to Yellowstone National Park in the states of Wyoming, Montana and Idaho (Sanders par. 2).

Since the reintroduction of wolves into Yellowstone they have created an astounding and advantageous trophic cascade. A trophic cascade is an ecological phenomenon triggered by the addition or removal of top predators and involving reciprocal changes in the relative populations of predator and prey through a food chain. These often result in dramatic changes in ecosystem structure and nutrient cycling. In a three-level food chain, an increase (or decrease) in carnivores causes a decrease (or increase) in herbivores and an increase (or decrease) in primary producers such as plants and phytoplankton according to briticanna (how to make better). The entire ecosystem was able to become whole again because the wolves, a key species, were reintroduced. Now this may seem weird, a predator comes into the area a begins to kill animals, how can this be beneficial in any way? Well the fact of the matter is that it is extremely beneficial. The reason being the problem in Yellowstone was the overpopulation of the elk. These elk had no predators, they were free to roam and reproduce, and they did this very well. Now elk are also a

“Restoring an ecologically complete ecosystem in Yellowstone requires the return of willows--and with them, beavers. There's a clear threshold for ecosystem recovery. Willow stands must be more than 6 feet tall, the scientists found. That height is important, says Marshall. Then willows are beyond the reach of browsing elk, and can serve as seed sources for new young willows. Once willows have returned, beavers will gnaw down a certain number of them to build dams. The dams will further slow stream flow, allowing yet more willows to grow. The results offer new insights on the role of wolf-driven trophic cascades in the Yellowstone ecosystem, says Hobbs. Trophic cascades like that in Yellowstone occur when predators--or the lack thereof--in an ecosystem change the abundance or alter traits of their prey, in turn affecting the next lower trophic level.” ("National Science Foundation", 2013)

Ed Yong makes very valid points on how the wolves of Yellowstone have impacted the overly populated elk herds. He has this to say about the herds; “Today the population stands at just over 6,000 down from 19,000 in the elk’s wolf-free heyday,” (ll57). This might seem like a terrible drop in the elk’s numbers, but it is actually a good thing. Yong tells us, “The large deer had run amok in the wolf-free decades, causing serious damage to the park’s trees,” (ll5-6). So in reality, while there are far less elk now, the trees can start to build back up again.

Wolf recovery would be a big step in maintaining wildlife. For instance, in Yellowstone a

I am taking a class called global environmental issues and heard about how reintroduction of wolves has had very positive impact in Yellowstone, but we did not go much deeper than just stating so.

George, J. C., & Minor, W. (2008). The wolves are back. New York, NY: Dutton Children's Books. The Wolves are Back is a wonderful children’s picture book.

The area of Yellowstone National Park has a long history of inhabitants, even before it became the nation’s first national park. In the area now known as Yellowstone National Park, wolves were once very prominent. However due to westward expansion in the 1800s, agriculture began to increase. This led to the wolves that once thrived in this area to being practically completely removed. The increase in agriculture in this region led to a lot of the wolves’ prey becoming reduced or eliminated. Since the wolves had a decrease in prey, the wolves began to prey on domestic animals, which then resulted in humans eliminating the wolves almost completely. By the 1930s the wolf was eliminated from the area. This was before people had an understanding of how ecosystems work and the interrelation of species. Now that the wolves were gone, elk then became overpopulated. A lot of the vegetation began to disappear as well due to the overgrazing of the elk. However after about a 70-year absence, in 1995 the wolves were carefully brought back to Yellowstone. When they brought the wolves back to the park, there was not just an effect on one species or one area but rather they affected the entire ecosystem of the area. I will discuss their effects on areas such elk, beaver colonies, scavengers, aspen trees, willow trees and cottonwood trees.

According to the documentary, “How Wolves Change Rivers”, wolves were eliminated from Yellowstone National Park for about 70 years until being reintroduced in 1995. They were killed by hunters and tourists at first because it was legal, to the point where there was none left, even though they were so beneficial to the environment that they changed rivers from the effect that they changed populations of some animal species by hunting them. However, humans hunting would be able to do the same job as wolves, which is too hunt for a specific species to balance the ecosystem and, like the wolves, change rivers in the aspect that the forests which were regenerated would stabilize the banks of rivers. To add, some people would agree that removing wolves from Yellowstone National Park was a good idea to balance animal populations and keep animals away from specific areas of the park, but I disagree because I believe humans would be able to control these populations by hunting for the proper species according to the food chain. To paraphrase, in the documentary wolves killed deer because they overpopulated the ecosystem, leaving almost no vegetation. This hunting by the wolves had later affected the environment as the population of birds

In Yellowstone National Park, scientists have been carefully documenting the impacts of wolves on the ecosystem, noting many changes for the better since reintroduction, (Berger et al. 2008; Beschta and Ripple 2010). As the ecosystem depends on the Gray Wolf to properly function predation, the wolves also regulate distribution and group size of each species, which impacts overall native biodiversity. Wolves primarily prey on large hoofed mammals such as deers, elk and moose. By preying on the most vulnerable (diseased, young, old, weak or injured) individuals, wolves can help keep prey populations more healthy and strong, (Carbyn

In contrast, the lecturer dismisses this point due to the fact that the animals population such as deers were recovered since there exiset new opputunities for them in the park. He says that the smal plant which grew after the Yellowstone park were good habitats for the smal animals like rabits. With the growth of the rabit population, the population of their predators also will increase. Accordingly, yhe food chains will be

Many people tend to be afraid of wolves because of how big they are and their strength. However, we don’t see how important they are until there are drastic changes. For almost 70 years Yellowstone did not have a night where a wolves howl could be heard. In that time the deer population grew fast; because of the increase in their

It's a cold December night on the ranch, and you are slowly drifting off to sleep, when a sudden howl brings a shiver up your spine. You look out your window and see a Gray Wolf, the snow caresing its soft, eligant face, beautiful. When morning comes you go out to your livestock pen, one dead, that could cost you up to $20,000, that beautiful creature no longer seems so beautiful. In 1995, on accord of the Endangered Species Act, the Gray Wolf was introduced to Yellowstone National Park, Since then the ecosystem has flourished and more animals have come, rivers are not caving, trees are blooming and more plants are growing and tourism has exploded. So was wolf reintroduction really a good thing.

A keystone species is an organism that helps define an entire ecosystem. Without a keystone species, the ecosystem will either cease to exist or dramatically change. If a keystone species were to disappear from the ecosystem, no other species would be able to fill its ecological niche. This means that keystone species have low functional redundancy. This forces an ecosystem to radically change. This may allow new invasive species to populate the habitat. Keystone species can range from plants to fungi. They are usually not the most abundant species in the ecosystem. The way these animals impact the food web varies from habitat to habitat. Keystone species are usually a predator. An example of a keystone species is the gray wolves in the Greater Yellowstone Ecosystem (GYE). Elk, bison, rabbit, and bird population at GYE are