February 5, 2017 Biodiversity No Comments
Why are wolves good for the ecosystem
Although man domesticated his best friend from the

wolf species at least 15,000 years ago, humans have long regarded the wolf as their worst enemy. This is evidence in many facets of our civilisation, for example the wolf prowls through stories such as Red Riding Hood, Peter and the Wolf or the Norse myth of the beast that will swallow the sun at Ragnarok¹. But thankfully conservationists and scientists have influenced our thinking about wolves and shed light on the important role they play in sustaining ecosystems.

Before being hunted down by humans, the wolf was the most widely distributed land mammal in the world except man². For example, the gray wolf’s range has been reduced by one-third³. Their decreased population has had serious implications for their local environment. Indeed, it is for this reason that in areas where wolves became extinct, authorities have taken steps to reintroduce them, as was the case in Yellowstone National Park in the US.

As a large predator, wolves play a key role in regulating populations of other animals. Without them the balance in those ecosystems is upset. A 2001 study, for example, found that when wolves went extinct in Yellowstone, the moose population increased by five times and ravaged the woody vegetation which birds need to nest. As a result, several bird species were eliminated in the park. What is more, wolves benefit other animals, like scavengers. Because they hunt down their prey, wolves leave leftovers behind that are the key source of food for a number of other species such as ravens, magpies, bald eagles, golden eagles, weasels, mink, lynx, cougar, grizzly bear, chickadees, masked shrew, great gray owl, and more than 445 species of beetle. This is a most impressive list of species that depend on wolves! But wolves’ leftovers also benefit the soil. For example, studies have found that wolf-killed elk carcasses dramatically enhance the levels soil nutrients and nitrogen.

Wolves can also play an important role in limiting the negative effects of disease. For examples, deer and elk congregate in smaller groups when wolves are present which helps reduce the risk of transmission of illnesses like Chronic Wasting Disease. This disease is a major threat to elk and deer; wolves also help by reducing sick animals’ lifespans and in turn limiting the amount of time they have to spread infections. Similarly, tick-borne Encephalitis (TBE) is a serious life-long disease with no known cure. A Swedish study found that an increase in the numbers of red fox was correlated with an increase in the number of human cases of TBE. But with wolves able to regulate the number of foxes, researchers wonder whether the frequency of human TBE could be reduced by restoring wolf populations².

What is more, the positive effects of wolf population can also be seen once the species is reintroduced. A very illustrative case is that of Yellowstone National Park where the last wolf was killed in 1926. A wolf reintroduction program was launched in 1995 and today there are currently around 100 wolves in the park³.

Since the reintroduction of wolves to the National Park, they have created a chain of positive changes in the local ecosystem; this is often referred to as a “trophic cascade” effect. With wild wolves roaming the grounds, the elk and deer have become stronger, the aspens and willows are growing healthier and the grasses taller. This happens as a result of a series of chain reactions started off by the presence of wolves. For example, when wolves hunt elk, the elk are forced to run faster and farther. As the elk run, their hooves aerate the soil, allowing more grasses to grow. Since wolves are hunting them, the elk cannot remain stationary for too long, and as a result aspens and willows in one area are not heavily grazed, and therefore can fully recover between migrations.

Few of us would think that the presence of wolves could trigger this set of positive reactions. But the improving situation in Yellowstone is testament to the importance of wolves. Many other examples of ways in which the presence of wolves has vastly improved the ecosystem also exist, such as the regulation of coyote populations whose populations was previously nearly out of control in Yellowstone. The reduction of coyotes meant that more food was available for other species such as raptors like the eagle and osprey, which are now also making a comeback.

With our increasing knowledge of wolves, maybe there is a case for starting to tell a different story to our children about this majestic species – one that moves away from depicting them as the “big bad wolf”.

 


References

¹ https://goo.gl/xbble
² http://www.ecology.info/wolf.htm
³ https://goo.gl/dsXiLd
http://www.motherjones.com/environment/2011/04/10-reasons-protect-wolves-climate-change
http://www.missionwolf.org/page/trophic-cascade/

Written by Greentumble Editorial Team