Wolves can change the flow of rivers

In the 1920s, wolves disappeared from Yellowstone National Park. Nearly a hundred years later, the rivers have changed their course. What happened?

We have learned in school about food chain phenomena and nutrient cascades. While you might memorize their definitions, there's really no way to know the real-time consequences for a real-life food web.

A waterfall with a change in flow was observed in Yellowstone National Park, USA. In the mid-1920s, an attempt to exterminate wolves in the park (and across the United States) caused the river in the park to change course. The connection is intriguing because wolves, which are terrestrial carnivores, are not directly related to rivers. So what happened here?

Food chains and orders are living organisms that depend on each other for food and energy. Disrupting the food chain could therefore lead to a hypothetical nutrient cascade change. It takes a while for a new nutrient layer to form, but a clear case is what happened in Yellowstone National Park. Due to the extermination of the gray wolf, which occupies the top position in the food chain, the species present in the lower levels became out of control and led to population explosion and overuse of resources. nature. The disaster from this unplanned relocation took about seven decades to define.

Ecological food chain.

The wolf eradication program began in the mid-1920s in response to ranchers' concerns about the safety of their pets. Wolves are one of the park's top carnivores, primarily preying on elk.

Due to the extinction of wolves, the hunting pressure of elk was reduced, and their population began to thrive and peak within a few decades. The increased numbers of herbivores put more stress on the vegetation, and as a result the park's grass and young trees were stripped. The loss of riparian vegetation and young trees is more obvious, as moose have both food and water sources near the riverbanks. Populations of other species are also declining due to a lack of food availability.

The park also has a thriving beaver population. The beaver will eat the rich nutrients found in the new shoots of the plant. But due to overgrazing of elk, and the thinning of foliage around the rivers, the beavers began to migrate from the riverbanks to other areas. With them comes one of nature's greatest engineering wonders - the beaver dam. The water holding capacity of these beaver dams saturates the nearby soil, ensuring a steady supply of moisture to the plants, even without rain…

Vegetation and beaver dams near the riverbank disappear, which inevitably leads to soil erosion in the area. Seasonal flooding begins, causing rivers to meander differently from their original flow. Changes in the river will disturb the groundwater level and affect the growth of vegetation in the neighboring areas. It also affects the movement patterns of species from one side of the river to the other.

Thus, a long story that begins with just one species disappearing from the top of the food chain has affected each link in a variety of ways, including population growth of elk, biodiversity loss, destruction of beaver habitat, and ultimately alteration of river flows.

Direct and indirect effects of wolf eradication

Soon after scientists discovered this tropical waterfall in the natural system, 41 wolves were brought back to Yellowstone National Park after an absence of nearly 70 years. Wolves began to hunt with large populations of elk, and elk gradually avoided open areas, such as riverbanks, for fear of being hunted. As a result, overgrazing near riverbanks has stopped, allowing new saplings to grow.

The beavers also returned, building elaborate dams and providing adequate cover for the smaller rodents. The rate of soil erosion slows down and rivers begin to return to their original paths. As a result of the reintroduction to the top predator in the food chain, the entire ecosystem was restored.

Does all this imply that if we treat wolves as species to be eradicated and replace them with moose, will it be better for the reproductive system? Obviously not. Here, it should be emphasized, we still need to protect species, but impacting a stable ecosystem can be a mistake.

Wolves can also be an important part of the story. They are active predators, wolves preying on beavers and other animals that live and thrive on riverine vegetation. However, too many predators, such as wolves, can also change the flow of rivers.

Natural processes are inherently complex and the result of many interactions between different biotic and abiotic factors. Scientists are still looking for other variables that could help restore the Yellowstone National Park ecosystem to its original form. They also admit that they do not fully understand the factors that cause the park's surroundings to change and that there is still a lot of research to be done.