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    The Ecological Impacts of Removing the Gray Wolf (Canis Lupus) from the Endangered Species List in the Yellowstone/ Idaho Area.

    Adam Meyer

    ENVS 190

    13 May 2014

    Canis lupus Credit: Gary Kramer / USFWS

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    Table of Contents:

    Acronym list:2







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    Acronym list:

    ESA: Endangered Species Act

    NPS: National Park Service

    USFWS: United States Fish & Wildlife

    YNP: Yellowstone National Park

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    The goal of this project is to evaluate the ecological impacts of removing the gray

    wolf (Canis lupus) from the endangered species list in the Yellowstone/ Idaho area.

    Removing a keystone species has proven detrimental to ecosystems. In June 2013, the

    United States Fish & Wildlife [USFWS] has proposed to remove the gray wolf off the

    endangered species list. This decision is backed with scientific research that has proven

    that the gray wolf has grown outside their historic range and the reintroduction has proven

    successful. As of now, the gray wolf is preying on a lot of livestock which is causing issues

    with many livestock ranchers. Because of these reasons, the ranchers also want the gray

    wolves delisted.


    Gray wolves were eradicated from the Yellowstone/ Idaho area in the 1940-1970s

    ( After the recognition of the wolf

    as a keystone species in the 1970s, the United States added the gray wolf to the federal

    endangered species list. Following the listing of the gray wolf, Yellowstone National Park

    was in desperate need of a top predator to restore its ecosystem, and in the spring of 1995

    the gray wolf was reintroduced to the park

    ( After close to 20 years of careful

    conservation practices, the gray wolf is now flourishing in the Yellowstone/ Idaho area.

    Currently, the gray wolf is still protected under the federal Endangered Species Act. This

    act protects the wolf from hunting and trapping; however, there are people that want the

    gray wolf delisted in North America. After several comprehensive studies, it has been

    determined that the gray wolf has outgrown its historic range and has proven the recovery

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    methods effective. The USFWS has proposed to have the gray wolf delisted from the

    endangered species list because of these reasons.

    The gray wolf is a member of the dog family. Gray wolves are the ancient ancestors

    to our domesticated dogs and are related to the coyote (Canis latrans) and several other

    wild dog species. Like many other dog species the gray wolf is a pack hunter; however, it is

    not uncommon for an individual wolf to break from a pack and form its own pack

    ( These individual wolves may

    remain alone from days to years before they can find a mate. Although wolves are pack

    hunters, an individual is still a highly efficient hunter. The gray wolf in most ecosystems is

    the top predator. There are several populations of gray wolf; however this study focuses on

    the Idaho/ Yellowstone population. The Yellowstone/ Idaho population of wolves is a

    larger than average wolf; males weigh between 100-130 pounds and females weigh

    between 80-110 pounds ( The

    average life span of these wolves is 5 years; however, they can live up to 12 years in the

    wild ( The average pack size in this

    area is 2-11 individuals. The pack size varies under a number of conditions including food

    availability, disease, wolf mortality from other packs, and poaching

    ( They mate in February and give

    birth to average of five pups in April. Each pack has its own unique structure, with some

    individuals being an alpha male or female and some members being subordinate

    ( Each member has its role in the

    pack. Packs mark their territory by urinating around the boundary and howling. A wolf

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    caught crossing another wolfs territory is most likely to be greeted with a fight


    The reason why the gray wolf is considered a keystone species is because of its role

    as a top predator. In most ecosystems, a top predator is needed for the ecosystem to

    function properly. Although the Yellowstone/ Idaho area does contain grizzly and black

    bears, these bears cannot kill large prey such as elk or deer on a regular basis. The gray

    wolf primarily feeds on ungulates where as a bears diet might contain berries and other

    plants. By feeding on these ungulates, the gray wolf effectively controls these species from

    over grazing an area. After making a kill, the wolves also contribute to several other species

    that prey on the carcass ( Unlike

    mountain lions and grizzly bears, wolves abandon their prey after feeding on the carcass.

    Abandoning the carcass leaves much needed meat for scavengers, which include the

    coyote, bald eagle, golden eagle, grizzly bear, black bear, raven, magpie, and red fox

    ( This extra food source for

    scavengers is essential in hard winters when other food sources are unavailable.

    During the early 1800s, the native people worshipped and idolized the wolf; man

    and wolf lived harmoniously. That story would change however, westward expansion

    brought settlers from the east. Many settlers staked out a claim in what is now Idaho,

    Montana, and Wyoming ( These

    settlers made a living however they could, and many of them chose livestock ranching as a

    means to get ahead. Their livestock overgrazed many areas causing local wildlife to have a

    shortage on food. This shortage would cause a ripple effect, local wildlife would soon starve

  • Meyer | 6 Figure 1: (Zmyj 1996)

    and populations would drop. The wolves that would prey on the local wildlife would also

    need to find a way to eat. It is believed that because the wolf is such an efficient hunter that

    it invokes fear in us. This meant preying on the livestock that replaced the local wildlife.

    Losing livestock to a predator was not

    something taken lightly, and men would poison,

    trap, and shoot any wolf that was viewed as a

    threat (Zmyj 1996). Between 1914 and 1926,

    at least 136 wolves were killed in the park; by

    the 1940s, wolf packs were rarely reported. By the mid-1900s, wolves had been almost

    entirely eliminated from the 48 states

    ( It was not only the wolf being

    poisoned and trapped, any predator viewed as a threat to livestock or more desirable

    wildlife like elk or deer were also hunted. This meant the death of many bears, coyotes,

    foxes, and cougars (Wilmers 2003).

    The 1950s & 1960s marked a harsh time for the wolves; more accurate rifles,

    "In those days we had never heard of passing up a chance to kill a wolf. In a second we were pumping lead into the pack, but with more excitement than accuracy" ~Aldo Leopold

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    stronger poisons, and more lethal traps were available to hunters and ranchers9 (Zmyj

    1996). [Figure 1, shows some of inhumane methods some of the ranchers used to capture/

    eradicate the wolves]. During this time, white men set out on a mission to eradicate the

    wolf and create a predator free ecosystem. The U.S. government even implemented a

    nationwide wolf control policy. This wolf control policy was highly effective; an intensive

    survey conducted in the 1970s found no evidence of a wolf population in Yellowstone


    This hunting free- for- all would soon come to a halt in 1973 when the Endangered

    Species Act [ESA] was passed (Perry 2012). The ESA would protect any plant or animal

    facing extinction. Under the Act a threated or endangered species will have a significant

    amount of its habitat protected in order for the species to fully recover. Because of the gray

    wolves low numbers, they were listed as an endangered species, and any person caught

    poisoning, trapping, or shooting the wolves for no reason would have been penalized

    heavily. Two decades after the passing of the ESA marked a controversial time in U.S.

    history, and on March 21, 1995, gray wolves were reintroduced back into Yellowstone

    National Park ( This decision

    would prove to be a heavily debated one through the years. Today, many farmers and

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    ranchers still do not agree with the reintroduction of the wolves.

    Figure 2:

    [Figure 2, shows the population trend of the gray wolf from 1982-2013. This graph

    emphasizes the dramatic population growth following the reintroduction of the wolves.]


    National Park [YNP]

    was created as the

    first national park in

    1872. YNP expands

    over 3,472 square

    miles. The park

    resides 96% in

    Figure 3: Map of Yellowstone. Lonely Planet. (2009)

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    Wyoming, 3% in Montana, and 1% in Idaho

    ( Yellowstone is home to many

    species including threatened Canada lynx and grizzly bear, and the endangered gray wolf

    ( The history of the park states that

    the gray wolves were in the park when it was created

    ( United States created a

    Yellowstone National Park Act of 1872. It states the Secretary of the Interior "shall provide

    against the wanton destruction of the fish and game found within said Park

    (" Although the wolves resided in

    the park, people viewed them as a wanton destruction of the fish and game, and the

    eradication methods followed. These eradication methods would continue for nearly 200

    years until the passing of ESA in 1973. During 1995 to 1997, Yellowstone was designated

    as one of three recovery sites for the gray wolves and 41 wild wolves from Canada and

    northwest Montana were released in YNP



    The gray wolf is one of the most researched species in the world. I focused on the

    research pertaining to the gray wolf as an important species to ecosystems. Many of these

    studies compare what the Yellowstone/ Idaho area was like before the reintroduction of

    the wolf to what the ecosystem is now, and how the gray wolf has enhanced the area. I will

    be utilizing a meta-approach style to conduct this study. I will review the current studies

    and literature on this topic.

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    There have been several studies pertaining to the listing of the gray wolf as an

    endangered species, one of which is an analysis conducted by Chris Woolston (2013). He

    reviewed the decision of USFWS to delist the gray wolf from the endangered species list.

    The USFWS argues that the gray wolf has outgrown its historic range and that the agency

    needs to focus on the recovery of the Mexican gray wolf now (Woolston 2013). However,

    many scientists and organizations believe that USFWS did not use proper researching

    methods for their studies. Without proper research methods, these studies would be

    incorrect. This was of particular interest because it shows the misconnection between

    scientists and general public. The general public believes that all studies conducted by a

    federal branch i.e. USFWS should be truthful and correct. Still many scientists speculate on

    the correct population of Canis lupus. Another study conducted by Creel and Rotella (2010)

    reviews the scientific justification of the 2009 delisting of the Rocky mountain population

    of the gray wolf. The researchers believe that USFWS based their justification on many

    social attitudes toward the wolves (Bruskotter et. al 2010). In general, stakeholders calling

    for reductions in wolf numbers are concerned about three issues: livestock losses, effects

    on ungulates (particularly elk) and human safety. In 2008 and 2009, Northern Rocky

    Mountain wolves were responsible for an average of 203 confirmed kills of cattle (from a

    population of approximately 5.9 million cattle) and 538 confirmed kills of sheep (Creel and

    Rotella 2010). These stakeholders have a huge influence in the law making in the

    endangered species list. Creel and Rotella (2010) conclude that the USFWS should

    reevaluate their decision and use accurate population surveys to determine if the gray wolf

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    is in need of delisting. This study is of particular interest because it solidifies the

    importance of good science when determining the need for a delisting of a species. Not

    only is good science a necessity when it comes to delisting an endangered species, it is

    severely important to be accurate in population estimates when the species that is in

    consideration for delisting is also one of the keystone species of the ecosystem. Another

    study conducted in 2009-2010 researchers (Ausband, Rich, and Glenn) used surveys from

    hunters, howling and sign surveys to help predict wolf population in Idaho. The authors

    emphasize the importance of using more than one survey method to improve the accuracy

    of the study. The difficulties in

    estimating a wolf population is

    highlighted in this study, Methods for

    estimating the size of large carnivore

    populations are financially and

    logistically challenging (Ausband etal.

    2014). These difficulties could lead to

    inaccuracy which could misconstrue

    population estimates (Ausband et al.

    2014). Since the gray wolf population

    is being evaluated for delisting, it is

    essential that population estimate surveys are accurate. [Figure 4, shows a team of

    researchers taking measurements and fitting a wolf for a radio collar. A lot of data

    regarding the species is gathered this way (Smith et. al 2010)] .

    Figure 4: Radio-collaring a wolf.

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    Many other studies have been conducted regarding the wolfs impacts on other

    species. Researches Ripple, Beschta, and Fortin (2014) analyzed the secondary effects of

    reintroducing wolves back into YNP. The researchers theorized that the threatened grizzly

    bear would benefit from a lower elk population. Lower elk populations would decrease

    forging from these ungulates and in turn have more berry-producing shrubs for the grizzly

    bear to eat (Ripple et. al 2014). Their study on the impacts of ungulates on the threated

    grizzly bear population was the first of its kind. Their research and finding were significant



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