The Big Dwellers and Their Interactions

Large vertebrates are fundamental in maintaining the structure and dynamics of the trophic webs in the reefs. In addition, these top predators, and large herbivores (e.g. sharks, turtles and marine mammals) are umbrella species. In Brazil, about 44 species of Chondrichthyes, either demersal or pelagic, are reef-associated. Some species of sharks tend to play the same trophic role as large actinopterygian fish, such as serranids and lutjanids, which inhabit caves and recesses in the reefs where they are mesopredators. Other fish assist in the survival of corals, such as schools of greenbeak parrotfish, playing an important ecological function as it is herbivore and bioeroder. Reefs and associated algae beds are considered abundant feeding sites for many organisms, including female sea turtles that spawn on islands or on beaches on the mainland. It is also in these environments where there are several algae and plants identified in the manatee diet, especially species of rhodophytes and marine angiosperms. The prey (e.g. actinopterygians, crustaceans and cephalopods) of the odontocetes cetaceans can be found, especially, in the reefs, demonstrating the importance of this ecosystem for the feeding of these species, mainly in oceanic islands. For large residents, reefs provide food, a nursery area, a refuge from predation, shelter against currents and removal of parasites. Thus, the decline of reefs, caused by various stressors, such as climate change, fishing, pollution, as well as habitat conditions are of concern to the species that depend on them.