noun (plural same)
A species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically.
More example sentences
- Well, you remove a keystone species and the entire ecosystem can collapse.
- A keystone species in several ecosystems, the grizzly was listed in 1975 as threatened in the lower 48 states.
- Meanwhile the keystone species of the entire ecosystem - the humble capelin - has again become the target of a sizeable fishery.