Study
A note on trophic complexity and community stability
Paine, Robert T.
The American Naturalist, 1969
A brief note proposing that certain predators exert an influence on community composition out of proportion to their abundance, and naming such species keystones by analogy with the stone that holds an arch.
- Studied in
- Pisaster ochraceus
- Sample size
- a short note generalising from shore removal work
Some species have effects on community structure disproportionate to their numbers or biomass, so that their removal changes the community more than their abundance would suggest.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
A small number of species may be structurally critical to a community in a way that abundance does not reveal.
How NatureHQ reads it
The origin of a term that escaped its evidence almost immediately. The note is short and careful, and the definition has a specific, testable core — the effect is large *relative to abundance*. Within two decades "keystone" was being applied to any species anybody considered important, including the most abundant ones, which is the opposite of what the word was coined to mean.
- A short note rather than a study; it generalises from one shore system.
- It does not specify how large an effect must be, or relative to what, which is part of why the term drifted.
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Published by: University press journalsPublished in a university press journal.
Checked against Crossref on 2026-09-28, and they agree on the title, the authors and the year.
NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-09-04.