It\u27s not easy being a reef: Impacts of competition and corallivory in the Florida Keys

As coral cover in the Florida Keys continues to decline, understanding the factors driving this trend has become a priority for researchers. Previous studies have shown that macroalgae directly competes with corals for nutrients and space, and that parrotfish herbivory can reduce macroalgae density. However, parrotfish also graze on corals so the net impact of parrotfish on corals is unclear. To estimate the net impact of parrotfish abundance on macroalgae and corals, we measured substrate composition and parrotfish density on 14 reefs in the middle Florida Keys. Parrotfish abundance was not significantly related to macroalgal cover nor was macroalgal cover significantly related to coral cover. Parrotfish density, however, was sometimes positively related to coral cover. This suggests that the net impact of parrotfish grazing may have a positive impact on corals in the Florida Keys