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The Return of Canis Lupus
Transcript of The Return of Canis Lupus
- The maximum population size that can be supported by the available resources.
Wolf populations affect others populations, as well.
As the wolf population decreases, elk populations increase. This causes
among the elks (for a limited amount of time). Likewise, if there is an increase in the wolf population, the elk population would decrease.
According to the graph below, the
from the years 1995-2011 is approximately 174 individuals. Many factors determine this.
The Reintroduction of Wolves
Westward expansion inhibited a stable survivalship rate of wolves, resulting in them becoming an endangered species.
In order to antagonize human impacts, wolves were reintroduced to Yellowstone National Park (YNP) in 1995.
Close observation of how the reintroduction of wolves affected the YNP ecosystem has been collected over the years.
There are pros and cons to having wolves in this area, and many factors cause a fluctuation in population.
Cons: Disadvantages of Having Wolves in an Ecosystem
Pros: Advantages of Having Wolves in an Ecosystem
is a form of
competition in which members of the
same species compete for the same
resources in an ecosystem.
• Intraspecific competition occurs
when a population reaches carrying capacity.
• Wolves compete with each other,
, for a limited
amount of resources (territories, food,
The Elk and Bison population would stay among carrying capacity. Predation, competition, and natural selection would keep the ecosystem stable.
Without wolf competition, coyotes' population would increase. This increase would cause a decrease in small game and rodents. This leads to a decrease in foxes, hawks, and eagles population. (All reactions in an ecosystem are interrelated.)
Wolves are endangered and reintroduction would help them survive. This would cause a balance in the ecosystem, otherwise known as
The first 14 wolves introduced to Yellowstone Park would create a
gene pool diversity
Other animals consume the unfinished carcasses that were left behind by the wolves.
Causing resources to be used completely and wasting less resources
The wolves would prey on livestock, thus affecting business of farming and/or ranching.
Wolves can overhunt animals such as deers and caribou, depleting food sources for other organisms.
The presence of wolves endangers nearby families living close to such areas. This would cause a safety issue among humans.
Wolves would try to move into private lands.
Wolf reintroduction is costly. The government can use the money on more precautionary issues.
Reintroduction of wolves reduces the availability of game animals for hunters.
Why does Yellowstone need wolves?
Top down model- predation controls community organiation
Predators limit herbivores, herbivores limit plants, and plants limit nutrient levels.
N V H P
trophic cascade model
Effects of manipulation move down the trophic structure as alternating +/- effects
Top Down Model
The prescense of wolves determines the size of the elk population
Less wolves/no wolves= higher elk population
More wolves= smaller elk population
In turn, the elk population determines the status of primary producers in Yellowstone Park.
Top Down Model (Herivore)
If wolves are not present in the park, then the elk population rises. This leads to overgrazing, as elks are herbivores that consume grass.
If wolves are present, the elk population will stabalize and overgrazing will not occur.
Wolvs indirectly determine the amount of vegetation in Yellowstone.
Top Down Model (Vegetation)
Wolves are at the top of this model as predators.
Wolves determine herbivore population, which determine the status of primary producers in Yellowstone, which in turn affects the nutrients.
The presence of wolves affects every level of the ecosystem's food chain
Top Down Model (Predators)
Any characteristics varying with an increase in population are considered to be
Limiting resources are affected by the increase in population.
If wolf population reaches carrying capacity, limited resources become scarce.
Factors that do no vary with an increase in population density are
Climate is an example.
Climate change can cause severe weathers and natural disasters to occur, causing a decrease in the wolf population.
Density-Dependent and -Indepdendent Factors
In order to raise awareness about the importance of wolves as a keystone species in an ecosystem, we can promote the cause with wolf campaigns and educational activities.
Offer tour guides to lead kids and adults of all ages through the area and teach them along the way
Have children make posters of all the things that they have learned so that they can spread the word
To ensure safety for ranchers, farmers, and common people, we can take several steps:
Implement thorny bushes around the perimeter of YNP to keep wolves away from private property
Or chemical plants that give off a smell that is unfavorable to the wolves
We can also inform ranchers of ways to keep their properties safer:
Remove attractants - Wolves are attracted to dead carcasses as a food source. We can advise farmers and ranchers to burn or bury (at leasat 8 feet underground) a dead animal as soon as it dies.
Hazing/scaring devices - As a harmless form of preventing wolves from trespassing, we can encourage farmers and ranchers to invest in hazing/scaring devices, which range from emitting sound and/or lights.
Wolves are a keystone species of Yellowstone
Wolves play a critical role in maintaining the structure of Yellowstone
Have control over community structure through their ecological niche
When an elk is killed by wolves, its carcass is scavenged by other carnivore species (coyote, bald eagle, bears, ravens, and fox) and less intensely by up to 20 other species.
Wolves create a food source for other carnivores
The presence of wolves caues the abundance of plants to use more nutirents during their growth.
Nutrient levels decrease
Wolves affect every trophic level in Yellowstone Park
Wolves stabalize the ecosystem and allow
Top Down Model (Nutrients)