Experiments on the interaction between predation and the availability of different prey on rocky seashores

Abstract

Experiments on southeastern Australian rocky intertidal communities tested the hypothesis that patterns of predation depend on variations in the availability of different species of prey. Experiments involving the addition of either barnacles, limpets, or tubeworms to sites in which they were normally rare suggested that any individuals arriving in such areas (by recruitment or immigration) would be quickly consumed by local predatory whelks. Removal of prey species to test if predators respond to whether the preferred species (of species pairs) are present or absent showed that interactions between predation and availability of prey were mostly not significant (although trends were similar to earlier, significant results). The relative strength of preferences among different types of prey may be important in determining the intensities of predation on them. Thus, some prey that are rarely eaten because they are not preferred, are scarcely affected by the availability of preferred prey. These results are relevant to the rôle of predation in communities where the availabilities of different prey vary in time and space.