Check out our new paper in Functional Ecology: 'Cascading effects of a top predator on intraspecific competition at intermediate and basal trophic levels'
On rocky shores, crowded, fast-growing barnacles (Semibalanus balanoides) compete for space and form clusters of elongated individuals called "hummocks." By consuming barnacles, carnivorous snails (Nucella lapillus) limit competition hummock development. However, by consuming snails or causing them to change their feeding behavior, predatory green crabs (Carcinus maenas) enhance barnacle competition and hummock development. Interestingly, crabs cause more hummocking even when they heave little or no indirect effects on barnacle density.