Coral reefs are amongst the most diverse ecosystems in the biosphere. However, they also represent oneof the most threatened marine systems. Apart from global change, especially fishing and tourism affect coral reefs either with mechanical damage or with increase of pollution and sedimentation. Recently,the increase of disturbances has induced extensive changes in community structure and composition of coral reefs. Well-balanced and rich communities can better resist disturbances and show a more rapid recovery, compared to less biodiverse systems.