Mechanism

Keystone Species

TL;DR

Keystone companies create disproportionate impact relative to their size.

Ecosystem Structure

Remove one brick from a wall, and the wall stands. Remove the keystone from an arch, and the entire structure collapses.

A keystone species is an organism whose impact on the ecosystem is disproportionately large relative to its abundance. Salmon aren't the most common species in the Pacific Northwest ecosystem - trees outnumber them enormously. But salmon are the mechanism connecting ocean nutrients to forest growth. In Alaska's Tongass National Forest, trees growing along salmon streams have 20-25% more growth than trees further inland. Up to 80% of the nitrogen in streamside trees came from the ocean, transported by salmon and distributed by bears and eagles who drag carcasses into the forest.

In Yellowstone National Park, wolves were extirpated in 1926. For 70 years, elk populations exploded, overgrazing willows and aspens. Rivers widened. Beavers disappeared. Songbird diversity collapsed. When wolves were reintroduced in 1995, the entire ecosystem transformed within a decade. One species reintroduced. Entire ecosystem transformed.

Business Application of Keystone Species

Keystone companies create disproportionate impact relative to their size. Remove Visa, and global commerce freezes. Remove ASML, and Moore's Law stops. Remove TSMC, and iPhones, AI, and automotive electrification stall. Keystone status brings both leverage and systemic risk.

Discovery

Robert Paine (1963)

Paine removed a single species of starfish (Pisaster ochraceus) from a stretch of rocky coastline in Washington State. Within three years, the diverse intertidal zone collapsed from 15 species to a monoculture of mussels. This experiment established that some species have influence vastly disproportionate to their abundance.