Residual Effects of Grazing: Inhibition of Competitor Recruitment by Encrusting Coralline Algae
1984
Breitburg, Denise L.
Adult—adult and adult—recruit competitive interactions between members of the same pair of species can have differing outcomes; thus, chronology and history may be important determinants of existing community structure. Examples of different outcomes of adult—adult and adult—recruit interactions can be found among species that are potential competitors for space on rocky subtidal substrate. As found in the present study, crustose coralline algae significantly decrease recruitment by sessile epibenthic invertebrate species from several taxa. Nonetheless, sessile invertebrates appear to be superior competitors for space as adults, since established individuals or colonies can overgrown coralline algal crusts. It is suggested that (1) by decreasing total invertebrate recruitment, even in the temporary absence of grazing on portions of the substrate, extensive encrusting coralline algal cover may contribute to the persistence of "coralline algae—sea urchin communities" (composed mostly of crustose coralline algae, sea urchins, and sea stars), and (2) by altering the relative abundance of other recruiting species, grazing—resistant organisms such as crustose coralline algae may decrease the probability that, after grazing abates, a community will return to its pregrazed species composition.
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