Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Sea otters are a keystone species in kelp forest ecosystems, eating sea urchins that would otherwise consume the kelp, according to the aquarium.

From Los Angeles Times • Apr. 29, 2026

They "play a central role in the food web, consuming fish and invertebrates and recycling nutrients" and are one of the "keystone species" of their ecosystem.

From Barron's • Oct. 10, 2025

Considered "keystone species" by many, crayfish play an outsized role as food sources for other animals and as ecosystem engineers, creating burrows that act as habitat for many species in semi-terrestrial environments.

From Science Daily • Nov. 25, 2024

Beavers are a keystone species on which many other species rely.

From BBC • May 28, 2024

Until Columbus, Indians were a keystone species in most of the hemisphere.

From "1491" by Charles C. Mann