Grey Wolf Population in Yellowstone

When Yellowstone was first appointed as a national park in 1872, there was no legal protection for any of the wildlife (Dockrill, 2018). Over time government predator control programs majorly contributed to the mass culling and subsequent extirpation of the grey wolves in Yellowstone by 1926 (Wikipedia, 2019). The eradication of this apex predator had unintended consequences on the ecosystem causing trophic cascade (Dockrill, 2018). The grey wolf’s absence caused a large relief of predatory pressure for the Elk population causing them to thrive (Farquhar, 2019). This surge in numbers resulted in significant overgrazing of aspen cottonwood and willows, trees which are vital shelter, food and dam building resource for Beavers who migrated to the northern range of park. Consequently, these dams collapsed turning swamps into flowing streams. There was major stream erosion and loss of mature aspen, cottonwood and willow, affecting an array of animal and plant species. In the wolfs absence, the coyote became an apex predator, diminishing populations of red fox, rodents, pronghorn antelope and birds. Local scavenger species, including grizzly bears eagles and ravens also suffered greatly with no wolf kills to rely and feed on. After the wolf was reintroduced into the ecosystem in the northern range, coyote numbers drastically declined by 50%, allowing fox, rodent and antelope populations to flourish again. The Elk population began to decline, and the single beaver colony increased to 12. Insects, birds, amphibian and fish began to thrive again as did the vegetation. Scavenger populations befitted too, feeding off of the wolves’ leftovers. The wolves caused the rivers to mender, erode and collapse less due to the regenerating stability of the vegetation. Many more pools were formed. Elk also changed their behaviours, avoiding valley and gorges, places where they could be trapped by predators allowing these areas to regenerate significantly (Earthjustice, 2019).

When first established, there were no protective laws for animals in the park, people were essentially free to hunt all wildlife. The Secretary of the Interior declared a policy forbidding hunting of majority of the park’s wildlife in 1883, however, the policy did not apply to wolves, bears, coyotes and other predators. Poisoning was a form of predator control used in the park during the late 1800s and early 1900s (Wikipedia, 2019). Poisoning is a highly unethical form and inhumane method of predator control, involving unnecessary pain and cruelty. The Yellowstone National Park Act of 1872 newly stated that the Secretary of the Interior will protect against the vicious destruction of all wildlife within the park, however, the wolves’ habitual killings of prey was considered “vicious destruction”, causing at least 136 wolves to be killed in the park from 1914 and 1926. By the mid-1900s, wolves had been almost entirely eliminated across North America (National Park Service, n.d.). The governments’ public vocalisation and actions against wolves influenced and the public’s view on the wolves leading them to believe that their presents is a nuisance and support the idea that park will thrive without them (Wikipedia, 2019).

Predators maintain balanced in an ecosystem through populations and food webs therefore the extirpation of grey wolves in Yellowstone sent the ecosystem into a trophic cascade. The removal of wolves had indirect influences throughout the ecosystem altering the densities of lower trophic herbivores and thereby affecting the growth of primary producers (Living with Wolves, 2019). The populations of herbivores exploded consequently causing severe overgrazing and suffering waterways having radically reducing many species key food source and habitat. Many species which relied on microhabitats including songbirds, amphibians, reptiles, and insects, effectively vanished. Unforeseen by biologists the structure of the ecosystem changed drastically. This extirpation allowed for biologists to witness one of the few and most recognised examples of top-down trophic cascade. Only then did biologists fully comprehend the complexity of the ecosystem initiating widespread effort and research into reintroduced of the wolves (Duffey, 2019).

As a result of federal and state predator controls, Grey wolves were listed under the Endangered Species Act (ESA) in 1973. Collaboratively the National Park Service, Fish and Wildlife Service, state wildlife agencies and environmental groups developed a restoration plan for the wolf (Wikipedia, 2019).

In January 1995, 14 wolves from, Alberta, Canada were captured and brought to Yellowstone to be let lose in March after a trial period. 17 additional wolves were also released in April 1996. As of December 2014 the wolf population stands at 104 in 11 packs (Dockrill, 2018).

While the reinstated wolves of Yellowstone were protected within the park’s boundaries a wolf a hunting and trapping season was used to take place in areas adjacent to the park to maintain numbers. However, after only one season, in 2014 a US Federal Court ordered a stop to wolf hunting of wolves in parks surrounding states after the tagging limit of 400 was exceeded (Wikipedia, 2019).

All of the reintroduced wolves were also radio-collared before their release allowing them to be monitored. The collected information has allowed the Wolf Project to study survival, reproduction, dispersal and distribution, sociality and genetics, disease, and predation on ungulates (Yellowstone Wolf, n.d.).

The reintroduction of wolves had both economical and societal benefits on the park. A survey conducted after reinstatement showed a 3.5-4% increase in tourism, equating to approximately 120,000 visitors and a subsequent increase in income and popularity. The strict hunting ban also ensures that these continue to incline (My Yellowstone Park, 2011). Organisations such as Yellowstone Forever monitors the wolves through their collars ensuring they remain healthy and observing their interactions throughout the ecosystem (Yellowstone, 2019). All these implications helped with grey wolf population security allowing each the trophic level to remain stable resulting in removal of the endangered status in 2008 to Experimental Population-Non-Essential.