Reintroduction of Wolves to Yellowstone

Nicole Zuidema – Animal Science
Emma Reichard – NRC
Nicole Sheridan – Animal Science
Will Holder (2005) told his story through the perspective of the ranching family he was born into. His grandfathers and great-grandfathers grew up shooting predators such as coyotes and lions in the area, so it was natural that Will follow in their footsteps and continue with that culture. He grew up with the mentality that the more coyotes you kill, the better. One day, however, he realized that after generations of killing these beasts of prey, their populations were not decreasing. After some of his own research, he found studies revealing that killing these animals just forces them to have bigger litters or a new predator moves in and kills to establish territory. This made him think differently about killing predators for reasons he didn’t even know himself.
In the following months, Will made every effort to not kill the predators he once did, but killings of his calves soon followed and his resolve weakened. Will jumped into action and attempted to save his herd. He moved them to where he knew fewer predators resided naturally and trained his cattle to stay in one big herd. Surprisingly enough to him, the predators did not follow the cattle. For the ones that did show up, they were greeted with a tight herd and got scared away. The cattle learned that this was the best way to scare off such predators. He said that because of his precautions, he cut his losses and made about $5,000 more a year (Holder,2005).
At about the same time, talk of wolf reintroduction in the Yellowstone area was beginning. He and his family were terrified. They all heard horror stories of wolves confronting humans, dogs being attacked, and wolves killing calves. They worried about wolves attacking their livestock or even coming after them. The even bigger problem in their mind was the fear that the federal government would run the reintroduction. They had done a terrible job managing prey populations in the past and it would be harder to handle a predator. No one could even tell them for certain what would happen if wolves were released. However, Will thought back to what he had done to save his herd from the predation of coyotes and lions. His trial and error experiments were not perfect, but they definitely made a difference when it came to his ranch. He and his family decided then to support the impending wolf introduction. They figured that they already account for loss of cattle from things like disease and predation. It was just a part of being a rancher. As long as he continued to stay vigilant and find new ways to protect his herd, one more predator would make little difference (Holder, 2005).
This is the problem that wolves face when they are being reintroduced back into the Yellowstone National Park. Untrusting ranchers shoot them without hesitation. The killing of these animals could threaten the success of reintroduction, which as a result, would have negative effects on the ecosystem of both the park and surrounding areas (Holder, 2005).
When ranchers see wolves they see predators and a loss of profit. To them, the reintroduction of the grey wolf to Yellowstone created a new threat to their business and their income. With the wolves known as a natural predator to livestock and many other species, it is understandable that ranchers were opposed to the idea of reintroduction when it was first proposed. They knew that the presence of wolves near their livestock would lead to stress and possible livestock predation. This predation would in turn cause them to lose money due to product damage or complete loss (Dobson, 2014). Once the reintroduction was set into motion and several wolves were present, ranchers began complaining that not only were they experiencing wolf attacks, but their livestock were also losing weight, especially the calves. They explained that the weight loss was due to stress from the wolves getting too close to their herds (Ramler et al. 2014).
Nonetheless, a survey from 1994, around the time reintroduction peaked, found that out of the overall percent of deaths per year of livestock in Yellowstone (39%), only .36% of those deaths are due to wolves. Also, out of the 412,000 livestock animals that graze in the area of the Yellowstone National Park, the coyotes killed approximately 41,000 while the grey wolves only killed about 1,500. This shows that the wolves killed a very low percentage of livestock and that the coyote was more of a threat to them(USFWS, 1994). Research also determined there to be a weight loss problem in livestock. The results showed that an average weight loss of 3.5% was expressed in calves (Ramler et al. 2014). Ramler et al. (2014) concluded that there was no direct evidence that this weight loss was due to the presence of wolves. Based off of these percentages and the researchers’ conclusions, one can see that the impact the wolves have on livestock is rather low. The misconceptions of the ranchers is what blinded them, causing an overlook of all the benefits that the reintroduction of wolves brings to their environment.
The eradication of wolves from Yellowstone National Park in the mid-1920’s left a hole in its ecosystem. Without these predators, the herds of elk in the park grew in number and pushed it to carrying capacity. The elk became relatively stationary in the winter because there was a lack of pressure from wolves. This pressure in the past caused them to migrate. After eradication instead of moving around the park, they would stay in one area browsing and essentially decimating the vegetation in those areas. This included not only grasses, but young willow, aspen, and cottonwood saplings as well (Nelson, 2012) Without the wolves, other plant and wildlife populations in the park began to decline.
Reintroduction of wolves back into Yellowstone in the 1990’s led to a cascade event that is still unfolding to this day. When the wolves returned, elk were forced to begin moving around the park again. They now avoided areas such as valleys and gorges where they could easily be trapped. These areas began to regenerate immediately. With the pressure off of the plants, the young willow, aspen, and cottonwood began to flourish again. They were more numerous and grew in size, which attracted many migratory birds back to the area (Monbiot, G, 1:20). Even though the population of elk in the park is now three times more than in 1968, the pressure from wolves keeps them from intensely browsing on the trees. This allows plants to thrive and become more robust (Farquhar, B, 2011).
Furthermore, with more trees, the quality of water in the park gets better. Tree roots remove nutrients that can be harmful to the water ecology and quality. The leaves that fall off of trees also decay and form an organic layer that allows water to percolate into the soil (Shanstrom, N, 2014). There is also less erosion, channels narrow, pools and riffle sections form and because the regenerated forests stabilize the banks of rivers they collapse less often (Monbiot, G, 3:32). Overall, when the quality of water increases, this creates a healthier ecosystem for the fish and other organisms in the park.
Additionally, before reintroduction of wolves, there was only one beaver colony in the park. Today there are nine with the promise of more (Farquhar, B, 2011). This is because beavers need willows to eat and the other trees to build their dams. The dams that beavers make create niche habitats for other species, including otters, muskrats, ducks, fish, reptiles, and amphibians (Monbiot, G, 2:20).
As far as organisms that live mainly on land, wolves in the park kill coyotes, which allows the number of rabbits to increase, causing hawks to come back to the park. Wolves also create carrion that attract weasels, foxes, badgers, ravens, and bald eagles, who all come to feed on it. The bears eat the carrion that the wolves left and their population numbers have also increased as a result of this and the regenerated shrubs that they eat as well. Killing off some of the ungulate calves in turn reinforced the effect of wolves (Monbiot, G, 2:50).
The above explanation makes apparent that the wolf reintroduction into the park created a trophic cascade, which is “an ecological phenomenon triggered by the addition or removal of top predators and involving reciprocal change in the relative populations of predator and prey through a food chain, which often results in dramatics changes in ecosystem structure and nutrient cycling” (Carpenter, 2010, para 1). It started at the top of the food chain and worked its way down to the smallest organisms in the park. Yellowstone is a healthier, more vibrant place now as a result of reintroduction.
On another note, wolves are decreasing the presence of diseased wildlife that could infect livestock. Chronic wasting disease, or CWD, is an emerging prion pathogen that is fatal to all species it infects. If spread from its natural hosts, elk and deer, to grazing cattle, it would prove deadly. The new disease is said to be similar to mad cow disease, a prion pathogen that was originally thought to only infect cows but now can infect humans. If it continues on this path, it could arguably be the biggest biological threat to ranching in the region. Decreasing the number of affected animals means decreasing the chances of this pathogen to spread to livestock and humans.
Also, the bacterial disease, brucellosis, is presently spreading from bison to cattle and humans. It causes abortions and lesions and is highly infectious. As many as 40-60% of bison in Yellowstone are exposed making it hard to avoid. A vaccine exists, but no treatment is available, the wolves that prey on bison aid in the prevention of this disease. It cost the cattle industry in the U.S. to lose $400 million in 1952. Therefore, we know it is a serious hazard to livestock both in Yellowstone and the U.S. if not controlled (Miller and Williams, 2000). Ranchers need to recognize the threat of disease and consider it seriously when opposing reintroduction.
In brief, in order to ensure we reap the ecological benefits of the reintroduction of wolves, we need to ease the mind of locals. There are a multitude of solutions that can greatly decrease predation of livestock and satisfy ranchers that the wolves affect.
One way to gain support from ranchers is to offer financial compensation for those who lost livestock due to wolf predation. Although livestock loss has been shown to be at a low percentage, it is still recognized that ranchers are losing money due to the presence of the wolves (Cohn, J. P., 1990). To make up for the profit loss that the ranchers experienced due to the reintroduction process, a private fund will be established to compensate each rancher who lost any of their livestock and shows proof of the loss. This is similar to the fund that the Defenders of Wildlife set up in Montana, that payed ranchers $43,000 in damages (Cohn, J. P., 1990). Hopefully, when the compensation program is in place and ranchers are able to receive their lost earnings back the benefits of the reintroduction will be clearly seen and more support will be given to ensure its success.
Another way to ease the minds of locals is to help them understand and use what is known as integrated damage management, which is a method that combines many different techniques to reduce predation of livestock. To learn these techniques, ranchers can turn to Wildlife Services (WS), the Animal and Plant Health Inspection Service’s (APHIS) program. Education can be brought to Yellowstone and multiple meetings can be set up so every producer can be taught how to utilize integrated damage management. Lawson and Duncan (2002) point out that benefit-cost analyses of predator management shows that for every dollar spent on livestock protection, WS saves ranchers anywhere from $2 to $7 in losses.
For one, this program will explain that keeping livestock confined in lit corrals or pens would protect livestock from predators. If this is not a feasible option, ranchers should at least corral their animals at night, since that is the prime time for wolves to hunt. The best pastures for livestock would be away from areas well known for predation and close to a building with plenty of human activity. Producers should be especially careful when they have young livestock. Moving both the mother and the young indoors for several weeks after birth gives the young time to strengthen and have a fighting chance when let back outside.
Another tool that can help with predation is purchasing guard animals like dogs, donkeys, llamas, and mules. These animals can help prevent isolated attacks because they passively or actively intimidate onlooking predators. Guard dogs can bond with the herd and become full-time members. The most effective are Eurasian breeds that are instinctual and will aggressively repel wolves. Because they are also vulnerable to attacks, it is suggested that the number of guard animals is based on factors like flock size and terrain. Guard animals become even more effective when a fence is also put up. Although this can be expensive, it is more cost effective when used to protect large, flat pastures. These should be at least 5.5 feet high with a buried wire underneath to prevent wolves from jumping over or digging under.
Other useful tools are frightening devices, like sirens and flashing lights that easily scare predators like wolves. WS researchers have radio-collared wolves in the Western U.S. so they can use radio technology to detect when wolves come into livestock areas. The detected signals can be used to trigger frightening devices and scare predators away (Lawson and Duncan, 2002). This is an effective and non-lethal way to reduce livestock predation.
In conclusion, the reintroduction of wolves to Yellowstone National Park proved to have many ecological benefits. Although there are concerns from ranchers about product and profit loss of their livestock, the benefits significantly outweigh the costs. The plant population of the area is thriving again just as it was before the grey wolves were removed from the area. This allowed the water quality to improve and the disease rate in animals to go down. Having the wolves back in their natural environment allowed the ecosystem to thrive better than it has in years and hopefully the success of this project will lead to many more species being introduced back into their environments so the same can be done to improve those ecosystems as it is being done in Yellowstone.

References

Carpenter, S. (2010). Trophic cascade, In Encyclopaedia Britannica Online. Retrieved from
http://www.britannica.com/science/trophic-cascade

Cohn, J. P. (1990). Endangered wolf population increases. Bioscience, 40(9), 628-632. Retrieved
from EBSCOhost Environment Index.

Dobson, A. P. (2014). Yellowstone wolves and the forces that structure natural systems.
PLoS Biology, 12(12), 1-4. Retrieved from Agricola.

Farquhar, B. (2011, June 21). Wolf reintroduction changes ecosystem. Retrieved from http://www.yellowstonepark.com/2011/06/wolf-reintroduction-changes-ecosystem/

Holder, W. (2005, November 4). Learning to Live with Predators: A Rancher’s Story. Retrieved
November 10, 2015.

Lawson, E., & Duncan, D. (2002, October 1). Wildlife Services: Helping Producers Manage
Predation. Retrieved November 10, 2015.

Miller, M. & Williams, E. (2000) Chronic wasting disease in cervids. Brain Pathol, 10: 608-608.
Retrieved from PubMed.

Monbiot, G. [Sustainable Human]. (2014, February 13). How wolves change rivers. [Video file]. Retrieved from https://www.youtube.com/watch?v=ysa5OBhXz-Q

Nelson, A. A., Kauffman, M.J., Middleton, A.D., Jimenez, M.D., McWhirter, D. E., Barber, J., &
Gerow, K. (2012). Elk migration patterns and human activity influence wolf habitat use in the Greater Yellowstone Ecosystem. Ecological Applications, 22(8), 2293–2307. doi:
http://dx.doi.org/10.1890/11-1829.1

Ramler, J.P., Hebblewhite, M., Kellenberg, D., & Sime, C. (2014). Crying wolf? A spatial analysis
of wolf location and depredations on calf weight, American Journal of Agricultural Economics. 96(3), 631-656. doi: 10.1093/ajae/aat100

Shanstrom, N. (2014, June 25). How trees and soil improve water quality. Retrieved from http://www.deeproot.com/blog/blog-entries/how-trees-and-soil-improve-water-quality

U.S. Department of the Interior Fish and Wildlife Service. (USFWS) (1994). The reintroduction of
gray wolves to the Yellowstone National Park and central Idaho Washington, D.C.:Retrieved from http://www.fws.gov/mountain-prairie/species/mammals/wolf/eis_1994.pdf

Evan

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