Sea Otters A Keystone Species

By Brendan Delia

Basic Info about Sea Otters

• SCIENTIFIC CLASSIFICATION:

• Kingdom: Animalia

• Phylum: Chordata

• Subphylum: Vertebrata

• Class: Mammalia

• Order: Carnivora

• Family: Mustelidae

• Subfamily: Lutrinae

• Genus: Enhydra

• Species: E. lutris

Basic Info about Sea Otters (2)

•Biological Name: Enhydra Lutis [Linnaeus, 1758]

What are Keystone Species?

• A keystone species is a species that is crucially depended on by other species in the same ecosystem.

• If the said keystone species was removed from the ecosystem it would cause drastic changes due to the keystone species’ abundance and total biomass.

• A keystone species has the important role of maintaining the crucial structure in the ecological community.

The History of Keystone Species

• The theory of a keystone species was first proposed by Zoology Professor, Robert T. Paine of the University of Washington in 1969.

• Paine studied a community of organisms that inhabited the intertidal zone along Washington's Pacific coast.

• He found that one species, the carnivorous starfish Pisaster ochracceus, played a key role in maintaining the balance of all other species in the community.

• Paine observed that if Pisaster ochracceus was removed from the community, the populations of two mussel species within the community grew unchecked. Without a predator to control their numbers, the mussels soon took over the community and crowded out other species, greatly reduced the community's diversity.

(Robert T. Paine)[In the picture above]

(Pisaster orchracceus)[In the picture above]

Keystone Species Conservation Efforts

• Because of the commensurately large influence Keystone Species have on ecological community structure and specie diversity in ecosystems, have caused Keystone species to be a top target for conservation efforts.

• The logic being, protect the keystone species and by doing so the entire ecological community will remain stable. In theory the plan looks great, but in reality it hasn’t worked out as expected.

• The plan remains young in the theory stage due to lack of proof.

Important Question

• What did all of that have to do with Sea Otters?

Sea Otter’s Ecologically Effected

Chain

Sea Otters

SeaKelp

SeaUrchins

Fish

1st Historic Example of How Sea Otters are Keystone

Species

• In the 1700-1800s, on the coast of California, the sea otter was hunted for its sleek, beautiful fur. It was also killed by fishermen who thought they were eating too many of the fish they wanted to catch. The sea otters were hunted to almost extinction.

• Without the sea otter, fishermen began to see changes in the ecosystem. Sea otters are one of the few animals that can eat sea urchins. When the otters disappeared, the sea urchin’s population grew very quickly. Soon there were more sea urchins on the California coast than ever before. Sea urchins eat kelp. With so many more sea urchins, they ate up all the kelp beds. The kelp beds are very important to many fish as a place to have their young. This set off a chain reaction. With the otters gone and the sea urchins numbers growing quickly, the kelp beds began to disappear. Then the fish, with no safe place to spawn, began to disappear. In just a few years, the fishermen noticed that the fish were suddenly gone.

Sea Otter’s Ecologically Effected

Chain

Sea Otters

SeaKelp

SeaUrchins

Fish

Fishermen

How the Sea otter is a Keystone Species

• Sea Otters eat seas urchins. Sea urchins graze on the lower stem of sea kelp and this causes the kelp to drift away and die. Loss of habitat as well as nutrients that were provided by the kelp beds leads to intense cascade effects on the marine ecosystem.

• Cascade effects: An ecological cascade effect is a series of secondary extinctions that is triggered by the primary extinction of a key species in an ecosystem. Secondary extinctions are likely to occur when the threatened species are: dependent on a few specific food sources, mutualistic(dependent on the key species in some way), or forced to coexist with an invasive species that is introduced to the ecosystem.

The Effects of Species Migrating From their Environment and Becoming Invasive Species

• Species introductions to a foreign ecosystem can often devastate entire communities, and even entire ecosystems. These exotic species monopolize the ecosystem’s resources, and since they have no natural predators to decrease their growth, they are able to increase indefinitely.

Problems in Areas Without Sea Otters

• North Pacific areas that do not have sea otters often turn into urchin barrens, with abundant sea urchins and no kelp forest.

• urchin barrens: is an area where the population growth of sea urchins has gone unchecked, causing devastating destructive grazing of kelp beds.

• Urchin barrens are caused by lack of predators such as sea otters in the area. This makes it extremely crucial to protect the ecological balance in kelp beds.

What We Can Do To Help

• Keep in mind that one species can drastically affect an entire ecosystem and support the efforts to protect endangered species.

What Has Been Done to Help The Sea Otters

• The International Fur Seal Treaty passed in 1911, it helps protect sea otters from being hunted. This treaty has caused the sea otters to come back and control the sea urchin population. That caused the kelp beds to recover, which eventually caused the fish population to return.

• This is just proves how keystone species are interconnected with the responsibility of maintaining the crucial structure of the ecosystem as a whole.

Work Cited In MLA Format

• "-- Exploring Nature Educational Resource." -- Exploring Nature Educational Resource. N.p., n.d. Web. 20 May 2013.

• "Keystone Species." - National Geographic Education. N.p., n.d. Web. 20 May 2013.

• N.d. Photograph. Commons.wikimedia.org. Web. 20 May 2013.

• N.d. Photograph. En.wikipedia.org. Wikimedia Foundation. Web. 20 May 2013.

• N.d. Photograph. Lawyersusaonline.com. Web. 20 May 2013.

• N.d. Photograph. Www.greendiary.com. Web. 20 May 2013.

• N.d. Photograph. Www.scuba-equipment-usa.com. Web. 20 May 2013.

• N.d. Photograph. Www.tumblr.com. Web. 20 May 2013.

• "Sea Otter." Wikipedia. Wikimedia Foundation, 18 May 2013. Web. 20 May 2013.

• "Urchin Barren." Wikipedia. Wikimedia Foundation, 19 Apr. 2013. Web. 20 May 2013.

• "What Is a Keystone Species?" About.com Animals / Wildlife. N.p., n.d. Web. 20 May 2013.

• Wikipedia. N.p., n.d. Web. 20 May 2013.

The End