Essay Keystone Species

An Australian study shows that cats help some endangered animals survive. On Australian islands where cats were eliminated, rat populations rose exponentially. Rats are notorious for eating bird eggs, and a result bird populations on those islands were becoming extinct. They also increase biodiversity, because predators are more likely to kill animals that have a higher population. For example, Shrews and birds both

“Restoring an ecologically complete ecosystem in Yellowstone requires the return of willows--and with them, beavers. There's a clear threshold for ecosystem recovery. Willow stands must be more than 6 feet tall, the scientists found. That height is important, says Marshall. Then willows are beyond the reach of browsing elk, and can serve as seed sources for new young willows. Once willows have returned, beavers will gnaw down a certain number of them to build dams. The dams will further slow stream flow, allowing yet more willows to grow. The results offer new insights on the role of wolf-driven trophic cascades in the Yellowstone ecosystem, says Hobbs. Trophic cascades like that in Yellowstone occur when predators--or the lack thereof--in an ecosystem change the abundance or alter traits of their prey, in turn affecting the next lower trophic level.” ("National Science Foundation", 2013)

The removal of predators such as excessive fishing and shell collecting, allowing populations of the Crown of Thorns Starfish to increase beyond natural levels. Predators such as the giant triton snail, sweetlips emperor feed to some extent feed on crown-of-thorns starfish. Juvenile starfish are likely to be eaten by their predator fish about six months after they begin feeding on corals. If numbers of

When herbivorous species such as white-tailed deer and elks are the main predators in a habitat, they create an imbalance in the habitat, and force other species in the habitat to go extinct. Natural predation also has a stronger impact in stabilizing or reducing the population of white-tailed deer than human hunting alone. One of the main reasons for the overpopulation of the deer was the extinction of their predators. Every animal in the food web is highly important in keeping the balance in the ecosystem. Yellowstone National Park was a great example of how every species support the

Sea otters consume benthic invertebrates, such as sea urchins, abalones, clams, mussels, crabs and snails. In some areas bands of sea otters additionally consume fish. A sea otter must consume approximately 25% of its body weight each day to maintain its high metabolism (Anonymous 2015). When eating, sea otters often utilize stones to act as a sort of hammer or anvil to dislodge prey and smash open the hard shells of certain prey items, such as

According to Van Driesche, nonnative species are more likely to establish if they invade habitats with lowered biotic resistance, encounter prey with poorly developed mechanisms of self-defense, or invade habitats unaccompanied by their specialized natural enemies or when their invasion is facilitated by earlier invaders (2000).  Damage to these communities, then, can be seen both in cumulative effects and in a cycle of self-reinforcement.  Although pristine environments are still at risk from invasion, this positive feedback loop makes habitats already with a disturbance by exotics even more vulnerable to other invasions.

A keystone species is a species that has a disproportionately large effect on its ecosystem relative to its population’s size. There are three main types of keystone species, the predator species who feed on other animals which helps balance out the ecosystem The Mutualists who have mutually beneficial interactions with other organisms and lastly the engineer species that will burrow into ground which can be used as shelter for another animal. Without these important species several ecosystems would collapse. While all species are important to an ecosystem, the keystone species are a lot more important due to their crucial roles, such as being top predators, controllers of prey, or conduits for spreading seeds.

There are many threats to Sea Otters. The death of these mammals are mainly caused by food shortages, but oil spills are the larger threat. If their fur is soiled by oil, the fur can no longer be used as an insulator. This results in the mammal not being able to sustain body heat. Predators such as Killer Whales, Bald Eagles, Sharks, and humans are also threats. Bald Eagles are the main cause of the death of pups and Humans are harmful because of how we contaminate the water.

Above the sea, migrating and native sea birds thrive, diving from the sky into shallow waters for fish. Sea lions, marine iguanas, and turtles also make an appearance, thriving with the abundance of food.

The Krill prey on plankton near the top of the water, but as a result for leaving the security of the deep sea they themselves become prey to other animals like fish. El Diablo Rojo Squid, also swimming near the shore use the fish, lured in by the Krill, consume the fish as their main source of food. In addition to Krill, Jellyfish also consume plankton. Larger Jellyfish, like the egg yolk Jellyfish (Phacellophora camtschatica), eat larger prey by stinging them to immobilize

In conclusion, many things are impacting the populations and changes in the ecosystem. Lions impact their ecosystem and control the populations through predation. Keystone species like bees are highly depended in their ecosystems and have many symbiotic relationships. Finally there are nonliving changes like global warming changing the environments all over the world. I believe that we have changed the Earth so much and that it has changed so much itself that there is nothing we can really do, but just let them happen.

That is the role of prey. So they have a huge impact on predators’ diets like eagles, hawks, owls, weasels, wolves, coyotes, foxes, and cats including wildcats, and raccoons. For some of these animals their population’s species would decline due to not having enough of the main food that they eat. Paul Ehrlich made an analogy about the food chain comparing it to the rivets on an airplane. In this analogy, if the rats were rivets of a plane and the rivets were taken out one by one, the plane is endangered and could be destroyed along with everyone onboard.

Keystone species maintain ecological communities by providing structure and balance for their habitat. The concept behind a keystone species is that they support species diversity through their presence, activities and abundance within the community (Mills et.al. 1993). If a disturbance happens within the community and the keystone species disappears, the organization and diversity drastically shifts. To be defined as a keystone species, there are a few characteristics a species must demonstrate. The first is that their presence within the community must help structure and assist the diversity of their community (Mills et.al. 1993). The second is that they must have some importance to their community in relation to the other species who

Sea Otters contribute towards the overall health and well-being of the ecosystem they inhabit. The sea otter is an important predator in the nearshore marine ecosystem of the North Pacific Ocean. It is considered a “keystone” species in the ecosystem. They limit the prey populations of a variety of marine invertebrates that reside near the shore. Sea otters “have large-scale community effects disproportionate to their abundance.” (Carswell and Long, 2). Their main prey consists of sea urchins and abalone. Sea urchins and abalone devour the kelp forests that run along the coasts of California. Sea otters contribute to kelp production by eating these invertebrates, thus where there are sea otters, kelp forests spread along the continental shelf. The California kelp forests have the greatest biodiversity of the temperate latitudes (Recarte) “Kelp forests are the Ocean’s rainforest” (Recarte). Sea Otters are considered a sentinel species, which means their fitness reveals the health of the ecosystem. Contaminants in the ocean have a large effect on Sea Otters. These contaminants cause biomagnification because of the lack of enzymes to break down and expel the toxins. Examples of contaminants that affect Sea

Many animals influence their local habitat by energy and material uptake and waste production while many other organisms changes the chemical balance and alter the local infrastructure. Through a variety of mechanisms, animals are equipped to modify their local community but animals that change a habitat’s structure through the physical process of engineering and consumption of plant material indirectly regulates an ecosystem’s infrastructure and dynamics. (Wright and Jones, 2006; Davidson and Lightfoot, 2008). These engineers increase and shape landscape heterogeneity and biodiversity by creating unique patches of habitat that differ from the surrounding landscape (Wright and Jones, 2006; Davidson and Lightfoot, 2008). While