Organism
Pisaster ochraceus
TL;DR
The ochre sea star is the original keystone species, studied by Robert Paine in his foundational 1963 experiment.
The ochre sea star is the original keystone species, studied by Robert Paine in his foundational 1963 experiment. This starfish represented less than 1% of the ecosystem's biomass in rocky intertidal zones of Washington State, yet its removal triggered ecosystem collapse. The starfish preys on mussels, preventing them from monopolizing rock surfaces. Within three years of removal, the diverse intertidal zone collapsed from 15 species to a monoculture of mussels.
Notable Traits of Pisaster ochraceus
- Keystone predator
- Selective predation on competitive dominants
- Maintains species diversity through predation