By the mid-1930’s the gray wolf (Canis lupis) had been extirpated from its natural habitat in Yellowstone National Park through hunting, trapping, and poisoning in attempt to control predator populations (Phillips 1997). Their extirpation allowed elk (Cervus elaphus) populations to reach high numbers because they were no longer mediated by a predator and could not be controlled by human hunting (Kauffman 2010). The park attempted to cull elk numbers after becoming concerned about their impact on vegetation and soils caused by over-browsing. The program ended in 1968, and the elk population increased dramatically from 3,000 in 1968 to 19,000 in 1994 (Ripple 2014). A plan was developed in 1980 to recover gray wolf populations in Yellowstone
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In previous translocations, it was found that wolves tended to travel more towards their original home when they were not held in captivity for an acclimation period than when they were. Wolves were held in one-acre acclimation pens for around ten weeks in hope that it would increase the likelihood that the translocated wolves would stay within the park when released. 17 wolves were translocated in 1996 and were also held in the acclimation pens for ten weeks. Both shipments of wolves included both adults and pups, with a total of 16 females and 15 males. All wolves were fitted with radio collars to monitor their movement (Phillips …show more content…
Growth ring analyses have shown that trophic cascades allowing greater plant growth commonly occurred in Yellowstone National Park when gray wolves were present but eventually diminished after the extirpation of the wolves. With the wolves gone, ungulate populations were allowed to grow to problematic levels and affect plant growth (Ripple 2014).
When the wolves were reintroduced, elk browsing decreased, either due to the predation of elk or the behavioral responses of elk avoiding areas where wolves were present (Ripple 2014). Fortin et al. conducted a study to explain the mechanics of how wolves affect net primary production not only by preying upon the elk, but also altering the elks’ foraging behavior and distribution in the park. They found that in general, elk avoided areas where wolves were present but that there was a trade off between the need to occupy certain types of cover and the need to avoid certain landscape characteristics that could limit escape for the elk. Elk were found to avoid areas with steep slopes and valleys where they could be trapped by the wolves. In low wolf-use areas, elk showed a preference for aspen stands and open areas, whereas in high wolf-use areas, elk preferred the cover of conifer forests (2005). Elk behavior shifts in winter when the risk of starvation outweighs
In previous translocations, it was found that wolves tended to travel more towards their original home when they were not held in captivity for an acclimation period than when they were. Wolves were held in one-acre acclimation pens for around ten weeks in hope that it would increase the likelihood that the translocated wolves would stay within the park when released. 17 wolves were translocated in 1996 and were also held in the acclimation pens for ten weeks. Both shipments of wolves included both adults and pups, with a total of 16 females and 15 males. All wolves were fitted with radio collars to monitor their movement (Phillips …show more content…
Growth ring analyses have shown that trophic cascades allowing greater plant growth commonly occurred in Yellowstone National Park when gray wolves were present but eventually diminished after the extirpation of the wolves. With the wolves gone, ungulate populations were allowed to grow to problematic levels and affect plant growth (Ripple 2014).
When the wolves were reintroduced, elk browsing decreased, either due to the predation of elk or the behavioral responses of elk avoiding areas where wolves were present (Ripple 2014). Fortin et al. conducted a study to explain the mechanics of how wolves affect net primary production not only by preying upon the elk, but also altering the elks’ foraging behavior and distribution in the park. They found that in general, elk avoided areas where wolves were present but that there was a trade off between the need to occupy certain types of cover and the need to avoid certain landscape characteristics that could limit escape for the elk. Elk were found to avoid areas with steep slopes and valleys where they could be trapped by the wolves. In low wolf-use areas, elk showed a preference for aspen stands and open areas, whereas in high wolf-use areas, elk preferred the cover of conifer forests (2005). Elk behavior shifts in winter when the risk of starvation outweighs