Question

Answer the following questions about Paine’s research study.

What changes occurred within the first few months?


What changes had occurred after a year?


What changes had occurred after 10 years?

Answer 1

I assume you mean Robert Paine’s classic intertidal keystone‑predator experiments (removal of the starfish Pisaster). Key changes he reported:

- Within the first few months
- Rapid increase in mussel (Mytilus) recruitment and growth into the freed space.
- Beginning losses of many of the smaller sessile species as mussels started to overgrow and occupy space.

- After about a year
- Mussels dominated most of the experimental plots, occupying much of the available substrate.
- Overall species richness and diversity in the plots had dropped sharply (roughly halved in Paine’s original results) because competitively dominant mussels excluded many other species.

- After ~10 years
- The mussel‑dominated community persisted as a long‑term, simplified state with much lower diversity than plots where the starfish were present.
- In other words, removal of the keystone predator produced a durable shift in community composition and structure until the predator was returned or other large disturbances intervened.

If you meant a different Paine study, tell me which one and I’ll tailor the summary.