Keystone Species

Humans have heavily affected sea turtle mortality rates, but one may ask what the benefit of having a stable and healthy population of sea turtles is. Sea turtles hold many important roles in both terrestrial and marine ecosystems where they are found. Along coasts where sea turtles are found nesting, beaches have been seen to have an increase in organic matter, phosphorus, nitrogen, and lipids (Bouchard 2000). This matter left by the sea turtle is in the forms of unhatched eggs and eggshells, which are then brought into the food chain through decomposers, such as beetles, or sea turtle predators, such as crabs (Bouchard 2000).

The study conducted by Weisle, Nagaswami, and Peterson is displayed about river otters and how they are different in structure from other marine mammals. River otters must depend on their thick layer of hair for survival. River otters are semi-aquatic mammals, which are considered to have denser fur than any other mammals. It’s thick, sleek coat, which keeps it dry and warm, is made up of two types of hair. The longer outer hairs are water repellent as known as guard hairs, and the other is underhair. The guard hairs could provide some protection for the more delicate underhairs. The three authors of this article, “River otter hair structure facilitates interlocking to impede penetration of water and allow,” addresses a question upon why the

The sandy shores of beaches can be considered as a very harsh environment to live in (Ted Klenk, 1999). Survival in such a habitat requires an organism to withstand strong wave and current action, tidal rise and fall, unstable substrate, heavy predation and wide variations in salinity and temperature (The Otter Island Project). Any organism found in this type of harsh environment is specialized and highly adapted (The Otter Island Project).

Many species vital to ensuring that today’s environment will thrive are becoming extinct. If a species is slowly dwindling, and in imminent danger of becoming nonexistent, this species is considered to be endangered. “One in four mammals, one in eight birds, one third of all amphibians and 70% of the world’s assessed plants on the… IUCN Red List are in jeopardy” (IUCN, 2016). According to the International Union for Conservation of Nature, or IUCN, upwards of 16,000 species are threatened with extinction, including both plants and animals (IUCN, 2016). Before becoming endangered, a species will show warning signs, either by starting to lose biological diversity or by losing the habitats for that species to flourish in, or in the worst case, both. The word endangered can sometimes be confused with threatened, extirpated, or extinct. Extirpated refers to the state of a species where its population has died out in a certain area or range, but other populations of said species still exist elsewhere (Olden, Julian D., 2008). When a species is considered threatened, or vulnerable, this refers to the state of the species being susceptible to endangerment and extinction (“Extinction crisis escalates”). So if a species is threatened, the first signs of endangerment come along, which are similar signs to that of a species in danger of becoming threatened, including lack of genetic diversity, or overhunting may be evident. (“Extinction crisis escalates”). When a species is labelled

Bull kelps have strands about 30 meters long with floats to help keep the algae close to the surface within reach of the sunlight. Because California has a consideration amount of sunlight, the giant kelp can be found along the coastal regions. Because of this, California sea otters gather in the kelp forest and snooze during spring. To prevent themselves from being drift away by tides and currents, they anchor themselves by scraps of kelp around their body. In some aspects, sea otters are guardians of the region. Several creatures that shelter in the kelp have to venture in the opening to feed, like the bat ray. They feed in the sandy floor of the open sea, they use jet of water to blown the sand away and expose invertebrates. They will either eat or be

A keystone species has a high impact on a community by keeping an ecosystem together. Most often Beavers, Bears, and Bees are just a couple of keystone species.

The lecture explained how the population of sea otters declined, due to the environmental pollution. First, the oil rigs along the Alaskan coat serve as an indication to pollution. This directly refutes the reading passage which states that predation was most likely the reason, since the bodies of the dead sea otters didn't wash on the shores.Secondly, the passage mention that the water samples that were extracted from the sea revealed the presence of chemicals. Again, this contradicts with the lecture which claims that the whales which the otters consume were not available anymore. Which had forced the sea otters to change their diet to include small sea animals. Thirdly, the lecture mentions that the decrease in sea otters population was

The area of research that I have selected is the effects of overfishing in the Sea Otter ecosystem off the coast of California. The effects caused by the fishing pressure on the ecosystem will have different outcomes, depending on the strength and the types of relationships of the organisms present. (4) Red Abalone populations have declined drastically, to the point of the abalone fishery collapse. Several factors have led up to the collapse including Withering Syndrome, where the organism loses the ability to attach itself to rocks, making it more susceptible to predation, or the organism can eventually wither and starve to death. Sea Urchins and Red Abalone are a part of the same ecosystem, and are competitors of each other.(5) Both organisms graze on macroalgae and are a primary food source for Sea Otters. Sea Otters occurred from the North Pacific Rim down to Baja California, Mexico, but now only occur in small isolated patches (9) It is understood that Sea Otter presence can characterize community structure, where they can control and determine the size of Sea Urchin and Red Abalone populations. In the absence of Sea Otters, “Urchin Barrens” are created from the overgrazing of macroalgae by Sea Urchin. In these areas the ecosystem have changed dramatically, due to the overfishing, or in this case the over hunting, of Sea Otters causing a trophic cascade.(7)In some areas, Sea Otters have been reintroduced, in other areas they were never removed, and in others they

In a documentary film directed by Bill Wisenski, “Threatened: The Controversial Struggle of the Southern Sea Otter,” it reveals some of the reasons why the California sea otter population is declining. In addition, it shows the controversy surrounding the “No Otter Zone”. Furthermore, it ensures why the California sea otter population is important to the marine ecosystem. In the film, sea otter populations are endangered because of the significant impact by some human factors. In the 1700’s and 1800’s, fur traders hunted sea otter population to near extinction. Besides this, threatened events such as shipping and drilling oil across the Pacific and along coastal areas; the California sea otters is vulnerable to oil contamination. As a result,

Bradshaw, C.J.A., Hindell, M.A, Best, N.J., Phillips, K.L., Wilson, G. and Nichols, PD. (2003). You are what you eat: describing the foraging ecology of southern elephant seals (Mirounga leonina) using blubber fatty acids. Proc. Roy. Soc. Lond. B. Biol. Sci. DOI 10.1098/rspb.2003.2371.

Firstly, the author states that pollution sources such as oil rigs near Alaskan beaches is killing the sea otters. Also, a research held on water samples in the area showed that it contains high levels of chemicals that may indirectly kill the otters. This view is objected by the lecturer. He proposes that Orcas use the animals as source of food, that is why there are no signs of dead otters on shores of Alaska, which would however be

Sea otters, (Enhydra lutris), are considered a keystone species, and for this reason, can be useful indicators of nearshore ecosystem health (Kreuder et al. 2003). With the implementation of the Marine Mammal Protection Act, southern sea otter (Enhydra lutris nereis) populations within their California range rebounded from post fur trade levels of approximately 50-60 in 1938, to more than 3000 today. However, growth rates have been slower than expected for this population (Riedman and Estes 1990). Definitive explanation for this is unclear, but contributing factors may be that sea otters face a range of physiological and environmental challenges to reproduce.

Ecosystems can be impacted by many factors such as climate, natural disasters, human pollution, water shortage etc. All of these are the factors that controls an ecosystem’s stability, productivity, and sustainability because these factors can kill, drive out, intoxicate, and destroy species’ natural habitats. These factors are spontaneous and temporarily and these can impact a very specific species which in turn can cause the collapse of an entire species. These species are call the Keystone species and they are organisms that are basically the arch or the support of the food chain in an ecosystem. They are special because without them, the population will be impacted negatively, such as too much overgrazing, overpopulation, and lack of food or predators for some animals. Keystone species are important

Sea otters (Enhydra lutris) are marine mammals capable of spending their entire lives in water. Being carnivorous in nature, they feed on sea urchins, crabs, fishes, mussels and clams. They are referred to as keystone species due to their profound impact on marine ecology. The interaction between sea otters, sea urchins and kelp forests has been studied as a model of the impact of predator-prey interaction on community ecology. Sea otters are keystone predators, whose presence has a far-reaching influence on the marine food web by affecting the population of sea urchins in particular, and kelp forests & other marine organisms in general. There has been a steep decline in sea otter populations due to water pollution and exploitation for

A keystone species is a species that has a disproportionate effect on its environment relative to its abundance. Such an organism plays a role in its ecosystem that is analogous to the role of a keystone in an arch. While the keystone feels the least pressure of any of the stones in an arch, the arch still collapses without it. Similarly, an ecosystem may experience a dramatic shift if a keystone species is removed, even though that species was a small part of the ecosystem by measures of biomass or productivity. It has become a very popular concept in conservation biology.