page_title: Keystone species
hierarchical_section_title: Keystone species
caption_attribution_description: Enhydra lutris English: Sea Otter (Enhydra lutris) preening itself in Morro Bay Feb. 21, 2007. taken from a kayak on a calm day... this critter got very comfortable with us... so we did not molest it by drifting fairly close. In fact, I discarded many shots because the focus range was set for ≥6.5 meters, and I was closer than that. Français&#160;: Une Loutre de mer (Enhydra lutris) se nettoie elle même. Photo prise depuis un kayak de mer par temps calme au large de Morro Bay en Californie, aux États-Unis. Cliché pris avec un appareil Canon 20D et un objectif 100-400 mm f/4.5-5.6 IS. Exposition 1/250 s, f/11, sensibilité ISO 400. Русский: Калан (или морская выдра) (Enhydra lutris) прихорашивается в Morro Bay. Снято с байдарки в тихий день... этому товарищу наше общество было вполне сносно... поэтому он не возражал, чтобы мы подплыли ближе и сфотографировали его.
context_page_description: A keystone species is a species which has a big effect on its environment relative to its numbers. The ecosystem depends on them, and would be much changed if they were not there. This is because they affect many other organisms in the ecosystem. They affect the types and numbers of other species in the community.
  Some sea stars prey on sea urchins, mussels, and other shellfish that have no other natural predators. If the sea star is removed from the ecosystem, the mussel population explodes uncontrollably. This drives out most other species. The urchin population grows likewise, and destroys coral reefs. Living coral reefs are the habitat for many hundreds of other species.
  Some other examples of keystone species are the sea otter, horseshoe crab, and wolves. Sea otters and kelp depend on each other. Without the sea otter, sea urchins would destroy the kelp, and much else in the ecosystem.
context_section_description: A keystone species is a species which has a big effect on its environment relative to its numbers. The ecosystem depends on them, and would be much changed if they were not there. This is because they affect many other organisms in the ecosystem. They affect the types and numbers of other species in the community.
  Some sea stars (e.g. Pisaster ochraceus) prey on sea urchins, mussels, and other shellfish that have no other natural predators. If the sea star is removed from the ecosystem, the mussel population explodes uncontrollably. This drives out most other species. The urchin population grows likewise, and destroys coral reefs. Living coral reefs are the habitat for many hundreds of other species.
  Some other examples of keystone species are the sea otter, horseshoe crab, and wolves. Sea otters and kelp depend on each other. Without the sea otter, sea urchins would destroy the kelp, and much else in the ecosystem.
caption: As a keystone species, the otter is crucial to a kelp forest's survival.
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