The laboratory experiments undertaken here also supported this conclusion. The preference for the artificial root structures by both epifaunal species was not affected by predator presence (Fig. 2). Furthermore, the structures did not reduce crab predation rates (Fig. 3), the vertical nature of the former resulting in large interstructural spaces which would barely impede predator movements. Consequently, habitat shifting by crabs, being predator avoidance behavior, would not occur due to similar predation risks in both bare and structured areas. This suggests that relatively small highly mobile carnivores could also be significant predators, in addition to ambush or stalk-and-attack type predators.