The goal that the authors, Taal Levi and Christopher C. Wilmers, are trying to accomplish is to show their audience how the abundance of three species, wolves, coyotes, and foxes, can impact each other and the ecosystem in Minnesota, USA in three different habitats, forest, transition fields, and farmland. The question that I believe that this journal is asking whether or not predation or the lack of it can act as a domino effect if wolves suppress coyotes in an environment, then that could possibly save the fox population and maybe other species along the way.
Both authors are trying to test the hypothesis that wolves suppress coyote populations, resulting in a cascading release of fox populations. They are trying to test this hypothesis
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by making use of an over 30- year time series of wolf, coyote, and fox relative abundance. They analyzed the qualitatively distinct canid time series in three habitat zones to test their hypothesis. They had two approaches. In one they examined the long- term population trends of each species with respect to one another in each habitat zone while in their second approach they analyzed fox, coyote, and wolf population time series to test how the population growth rate of foxes and coyotes depend on intraspecific density dependence and interspecific competition. The independent variables were both scent stations and current patterns among fox, coyote, and wolf population in either species throughout the years. The dependent variables were the history of either species throughout the years. In figure one they show a map of carnivore scent station survey routes organized by habitat zones in Minnesota, USA.
They show the three different habitat zones, forest, transition, and farmland. The graphs are done over a 30 year time period that shows the abundance of wolf, coyote, and foxes in the three habitats. The year to year change was observed between coyotes and foxes while being influenced by the presence of wolves. The time frame was the independent variable while the population of the three populations was the dependent variable. In figure 1B they show that for a while the fox and coyote population was all over the place because wolves were being hunted and then in 1996 wolf hunting started to slow down and the population of foxes and coyotes started to stabilize. In figure 1C they show that in the transition habitat the populations are all increasing over time until about 2004 when the fox population fell below the coyote population. In figure 1D they show what happens in farmlands where wolves are not present. Coyote populations are pretty low compared to the fox population until sometime between 1996 and 2001 where things dramatically changed and the coyote population was way higher than the fox population. In figure three they made a food web that shows that wolves negatively affecting coyotes. Then coyotes negatively affect foxes. This could be due to niche overlap and competition, by the wolves negatively affecting coyotes they are positively affecting
foxes. The authors, Taal Levi and Christopher C. Wilmers, concluded that their hypothesis was correct, so the restoration of wolves across the northern hemisphere lengthens interaction chains which could result in an increase of small predators,like foxes, in wolf occupied habitats where coyotes are suppressed.
Now, just a couple of years later, the Colorado Division of Wildlife is planning to release over 180 more lynx into the Colorado wilderness within the next five years. However, out of nearly 100 Canadian Lynx that have already been released so far, about half of them have died and none of them have reproduced. With the type of results that the process has received so far, the agencies involved in the reintroduction process should stop reintroducing the lynx into Colorado. Instead, they should try to find a way different way that will get results that save the species. The government agencies that are involved in reintroducing the lynx argue that it should be done in order to save an endangered species. In this argument they bring out three strong points for trying to save the lynx: every animal should have the opportunity to exist, many people feel happy when they see the animals they share the land with and all living things are part of a complex ecosystem ("Wildlife Commission . . ."). However, they aren't sure how to reintroduce the lynx so that they don't all die.
A species in particular that I have researched is the red fox or Vulpes vulpes as it is known in the scientific community. The animal is native to North America, Asia and Europe where they thrive in habitats ranging from temperate deserts to boreal forests, but its range spans the entire globe (Tesky 1995). The red fox is omnivorous which means that it feeds on animals and plants equally, which, creates impacts on both types of populations within its habitat. What makes the red fox invasive is its introduction to Australia and Eastern parts of the United States, as a result of migration of Europeans t...
The wolves’ were hunted in late 1800 s’ and early 1900‘s in the United States because farmers wanted more land for their cattle’s to graze upon. As farmers were moving out west they felt threaten that the wolves would hunt their cattles so the farmers thought that the best solution would be to take them out of the picture. This was possible because at the time there were no government regulations on hunting....
Over the past several years, the gray wolf, native to the Wisconsin area, has been listed federally as an endangered species due to the graphic and horrific treatment they had received during the industrialization periods of America, when they were frowned upon and hated because they are predatory creatures and did, on occasion, attack livestock and pets. Because the government was encouraging the hunting, including bounties for the animals, the wolves were hunted to near extinction. However, now Wisconsin faces a new problem. With the reintroduction of the wolves to the state, and their continued endangered status federally, the population has increased well beyond expectations, reaching what could be considered a problematic state. A regulated hunt and a population control procedure has become necessary in Wisconsin to protect state's economic endeavors of game, wildlife, and agriculture, and also the wolves themselves, to keep them from overpopulating and facing starvation and lack of land.
The history behind the extirpation of the grey wolf in the United States dates back to the very first European settlers that colonized eastern North America in the late 16th century. The killing of gray wolves was done primarily out of fear in an attempt to protect livestock, and, in some cases, to protect human life within the colonies. As more settlers expanded West, the practice of killing wolves was considerably increased to protect livestock that included cows, pigs, and chickens. As waves of European settlers expanded westward, they began to deplete the deer, moose, and elk populations. The gray wolves food source continual depletion gave rise to wolf populations actively targeting the settler’s livestock, causing great financial loss. The fiscal loss of livestock became such an issue to wealthy ranchers and settlers that they began to offer cash rewards for wolf pelts. This practice gave birth to a lucrative cottage industry of professional hunters and trappers. As the wolves began to move further West, and into Wyoming, they began to diminish the elk and moose population. To respond to this threat, Congress approved funding in 1914, to eliminate the native gray wolves from
Wolves used to thrive in the western United States. There was ample game to hunt and plenty of places to live and wander. Until people moved in, wolves were settled. As European settlement expanded to the west, it began to take its toll on the wolves and their habitat. Clearing of the forests came first, which was then accompanied by significant over-hunting in this area (Noceker). Slowly wolves became concentrated into smaller and smaller areas in the west. Finally, they were assumed to be bothers to the ranchers and farmers and maybe a threat to those people who lived in the area.
Hypotheses of the Effects of Wolf Predation Abstract: This paper discusses four hypotheses to explain the effects of wolf predation on prey populations of large ungulates. The four proposed hypotheses examined are the predation limiting hypothesis, the predation regulating hypothesis, the predator pit hypothesis, and the stable limit cycle hypothesis. There is much research literature that discusses how these hypotheses can be used to interpret various data sets obtained from field studies. It was concluded that the predation limiting hypothesis fit most study cases, but that more research is necessary to account for multiple predator - multiple prey relationships. The effects of predation can have an enormous impact on the ecological organization and structure of communities.
Mader,T.R. Wolf reintroduction in the Yellowstone National Park: a historical perspective. Common Man Institute. 1998. 26 pgs.
Gibson, J. William. "The New War on Wolves." Los Angeles Times. 08 Dec. 2011: A.25. SIRS Issues Researcher. Web. 21 Feb. 2014.
One example that shows that the wolf and moose population on Isle Royale are not stable are the constant temporary disturbances that cause the populations to fluctuate. The graph in Case Study Update #2 shows the wolf population at its peak in 1980 with 50 wolves on the island. However, in the same year a wolf disease was introduced to the island accidentally by humans, canine parvovirus, causing the population to drop and reach 14 wolves in 1982. Then in Case Study #3 another disturbance took an effect on the wolf population. In 1998, a new wolf that wandered from an ice bridge to Isle Royale was introduced to the local wolves. The new wolf, no.93, made itself at home and started breeding with other wolves resulting in many births and increased the population to 29 wolves. Unfortunately, the lack of food caused the population to drop down again to 17 in 2003. With these constant disturbances a few years after another, the wolf population does not look stab...
The controversy surrounding the reintroduction of the wolves are many from both sides. Some local farmers are against it because some wolves hunt their animals. However, if the farmers can prove their animal was attacked by a wolf, then the government would reimburse them for the animals value. Another problem is that some taxpayers are against the reintroduction because it cost them money to get the wolves back into the park. Another issue for taxpayers is that they have to pay for the damage the wolves do to the farmer’s animals.
The wolf reintroduction to Yellowstone National Park improved the park’s ecosystem greatly! An example of this can be found in the article “In the Valley of the Wolves,” which states “Now, nearly a dozen years since the wolves returned, the recovery of that same system to its natural balance is well underway, says ecologists William Ripple and Robert Bescheta of Oregon State University” (“In the Valley”). The article explains that the ecosystem has started to recover and is continuing to recover because of the wolf reintroduction. Another example is from “In the Valley of the Wolves,” “… wolves affect elk; elk affect aspen; and therefore wolves affect aspen” (In the Valley”). In other words, if there were no wolves to eat the elk, there would be more elk eating the aspen, and aspen is a huge factor in Yellowstone’s ecosystem. Without the gray wolf, Yellowstone’s ecosystem might function, but not to the best of its abilities.
The current ban on fox hunting has been very controversial, and there have been many arguments, both for and against hunting. Fox hunting is typically viewed as a traditional British activity, but actual fox hunting that uses hounds takes place all over the world. Historically wherever the British have gone building their empires, they have taken the sport of fox hunting43 with them. In addition, plenty of other countries have their own fox hunting traditions. In France, Italy and Ireland they are thriving fox hunts.
Studies show that wolves play a significant role in maintaining healthy ecosystems, and could even help stave off some of the effects of climate change. They help keep large animal herd populations in check, which can benefit numerous other plan...
One huge impact of global warming is the change in animals’ habitats. When the earth’s temperature is increasing, it creates the change of weather conditions in a certain area, which causes some kinds of animals in this area to live with many difficulties, or sometimes those kinds of animals are forced to move to new region when they cannot handle the difficulties. The arctic fox is an example for this situation. According to the article “How Does Global Warming Affect Wildlife,” arctic foxes prefer to live in the cooler environment while their habitat is getting warmer and warmer due to global warming, so arctic foxes have to leave their own home to seek a more suitable area (National W...