Reintroduction is defined as the act or attempt to bring back a species to its known niche after being threatened to near extinction (Howard and Somers 2009). This was the case for the gray wolf population in Yellowstone National Park, as well as throughout most of the U. S. The gray wolves at one point occupied the U. S. in large numbers, but when settlers came to America, a conflict between the wolves and the settlers became apparent. The conflict was that farmers and settlers needed the land in which the wolves inhabited.
Farmers were also afraid of wolves attacking their livestock. At a time when humans did not understand the importance of ecology, and minimal value was placed on nature and the environment, the only reasonable solution was to kill the wolves to the point of near extinction. Although this was the way farmers and settlers chose to deal with the problems they had with the wolves, it was not the best method. Eventually, reintroduction was the only way to save the gray wolf population from extinction.
When it comes to the reintroduction of the wolves to Yellowstone, there are three main aspects to consider: how the wolves were reintroduced to the park, the influence of the wolves on ecology, and the wolves as a keystone species. All of these aspects played a crucial role in bringing back [a top predator] from the verge of extinction. How The Wolves were Brought Back In 1926, the last known wolf pack was eliminated in Yellowstone National Park (Howard and Somers 2009). With the wolves gone, there was a massive rise in the elk population. This contributed to the loss of vegetation such as aspen from long term elk browsing.
With the loss of vegetation, the land became barren and aesthetically less pleasing. As the years went by and the public perception of the environment and the ecosystem began to change, scientists wanted to figure out a way to control the growing elk population. Thus, a study was done to determine if there were any wolves within the park. According the Yellowstone Wolf Project 1995 and 1996, after completing the study, biologist John Weaver wrote in his 1978 report to the U. S. Department of the Interior, the Wolves of Yellowstone: “The wolf niche appear[ed] essentially vacant” (Phillips and Smith 1997).
This brought to the mind of many scientists, the idea of bring back the wolves. In 1973, the wolves were placed on the endangered species list. Under the Endangered Species Act, any species of plant and animal listed as either threatened or endangered should be restored (Howard and Somers 2009). The issue to reintroduce the wolves to Yellowstone was very controversial since many farmers believed that the elimination of the wolves was the best way to keep their livestock from being seen as prey. Nonetheless, after decades of controversy, a plan was put into effect that would reintroduce the wolves to the park.
The restoration program began in 1995 in which 14 wolves were translocated from Canada to the U. S. in January 1995 and 17 in January of 1996 (Phillips and Smith 1997). When the wolves arrived at the park, they were fed elk, bison, roadkill and other livestock. Scientists later created three wolf packs that consisted of a male dominant and female dominant wolf along with other non-dominant wolves. Eventually, in two of the three packs, pups were born. To allow time for the wolves to adjust to their new environment, they were released into the wild within three months after being captured; this was known as soft release.
An alternate method of released known as hard release was done in Idaho in which the wolves were not placed in family groups and taken care of, but rather released into the wild a few days after being captured. Wolves as a Keystone Species With the wolves back, a study was done on the effect of the wolves on both elks and aspen. The purpose of the first experiment conducted by Oregon State University was aimed at figuring out whether or not there was any link between aspen growth and risk sensitive foraging of elk – meaning carefully choosing where to feed to avoid predation.
The study done by Ripple and Beschata was conducted at Lamar Valley. The researchers compared aspen heights in riparian areas and upland areas. Ripple and Beschata also measured the location of each aspen forest to the nearest conifer forest and road. This was done to determine possible escape paths of elks. The result of the was that ‘[much] of the aspen growth observed in riparian areas after the reintroduction of wolves appears to have been due to reduced browsing by elk at sites with poor escape and terrain reduced visibility…” (Ripple and Beschata 2007).
Also, many of the aspen in the upland areas were unable to grow because of extensive browsing. This shows that the wolves had a strong influence in the growth of aspen throughout the ecosystem. Since many of the elks were fearful of the wolves, elks avoided feeding in areas that provided less protection and few escape paths. Thus, the aspen in those areas had a chance to grow. The second study was aimed at the tradeoff between increased predation risk and an animal’s foraging needs. The researches made observation of elk and bison feeding in areas known to have a wolf population and in wolf-free areas as well.
According to the research done, both bison and elk were more vigilant in the areas of the park that contained wolves. From the results of the experiment, “fear of predation not only control the foraging patterns of individuals but can have significant consequences for the population level” ( Laundre et al 2001). The increase in fear of predation caused the biodiversity of Yellowstone to increase as well, mainly because the presence of a predator just as the wolves kept the elk population in control; thus leading to the growth of vegetation as plants are grazed upon less often.
Influence of Wolves on the ecology The reintroduction of the wolves is considered to be a success. The wolf population has increased significantly since the first being translocated from Canada. In 2003, 174 wolves were known to be residing at Yellowstone (Howard and Somers 2009). Although things are not as they were in the years before the settlers and farmers arrived, today the wolves are roaming around the park at will without any interference. Also, the number of livestock killed by wolves is lower than expected.
The wolves are an important part of the ecosystem because of the role they play in regulating the population. In doing so, they increase the biodiversity of the landscape. With the return of the wolves, Yellowstone is more complete (Howard and Somers 2009). Today, many states are considering removing the gray wolf from the Endangered Species Act. Although this may mean that the killing of wolves will be permitted in certain areas of the U. S. , the wolf population should still be fairly stable as long as they are ensured some sort of protection.
It is important to remember what caused the wolves to be put on the list of endangered species. When the wolves were nearly extinct, reintroduction was the only plausible method to bringing them back. Now that the wolves have been successfully brought back, it is necessary to keep them from going extinct. This can be done even with the wolves removed from the list of endangered species. As long as farmers, hunters, and others are prevented from excessively killing wolves for their fur, and other personal benefits, the wolf population can continue to grow on its own without any assistance.
