Temperate rocky reefs may occur in two alternative states (coralline barrens and erect algal forests), whoseformation and maintenance are often determined by sea urchin grazing. The two sea urchin speciesParacentrotus lividus and Arbacia lixula are considered to play a similar ecological role despite their differingmorphological traits and diets. The patchy mosaic areas of Ustica Island, Italy, offer an ideal environment inwhich to study differences in the performance of P. lividus and A. lixula in barren versus forest states. Resultsshow that the two sea urchin species differ in diet, trophic position, grazing adaptation, movement ability andfitness in both barren and forest patches. We confirmed herbivory in P. lividus and omnivory with a strongtendency to carnivory in A. lixula. When the sea urchin escape response to a predator was triggered, P. lividusresponded faster in barren and forest patches. Forest patch restricted movement, especially in A. lixula (velocityin barren ≈10-fold greater than in forest). A large Aristotle's lantern, indicative of durophagy, confirmedadaptation of A. lixula to barren state.
|Number of pages||8|
|Journal||Journal of Sea Research|
|Publication status||Published - 2013|
All Science Journal Classification (ASJC) codes
- Ecology, Evolution, Behavior and Systematics
- Aquatic Science