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Kelp Beds and Sea Otters: An Experimental Approach
- Duggins, David O.
- Ecology 1980 v.61 no.3 pp. 447-453
- Echinoidea, Saccharina groenlandica, biomass, field experimentation, macroalgae, prediction, species diversity, Alaska
- In Torch Bay, Alaska, USA, sea urchins structure shallow subtidal communities by consuming most macroscopic algae. Experimental removal of urchins leads to the development, within 1 yr, of a kelp association of high biomass and diversity. In the 2nd yr, however, these attributes decrease as a single kelp species, Laminaria groenlandica, becomes dominant. Additional field experiments confirm the competitive superiority of this kelp. These manipulations lead to predictions regarding the ecological role of sea otters, a once common (but now absent) sea urchin predator. The predictions are tested and verified by examining areas into which sea otters have recently been transplanted. As expected, a rapid and extensive modification of algal species composition and a dramatic increase in kelp biomass follow the return of sea otters.