Recovery and Recolonization of Coral Reefs

While considerable attention has focussed on factors respons~ble for damaging coral communities, few studies have been made of the recovery of coral communities followlng natural and man-made d~sturbances This contribut~on reviews s t u d ~e s of recovery following various d~sturbances such as cyclones, volcan~c activity, catastrophic low tides, man-made d~sturbances and Acanthasterplanci infestations In a d d i t ~o n some results are presented of the author S long-term studies of recovery following Acanthaster infestations on the Great Barner Reef From the evidence avallable ~t appears that coral communities require at least several decades to recover from major natural disturbances The situation is not as clear followlng man-made disturbances where the environment may have undergone permanent change Recovery can take place by the regenerat~on of partially damaged colonies and of fragments produced by mechan~cal damage during storms However In most instances recovery occurs through recolonizat~on of denuded areas by settlement of coral larvae Factors are discussed which can Influence coral recolonization and hence recovery They Include the extent of damage and ~t s location the avallabllity of coral larvae, the requirement for a cond~tlonlng period of the substratum before corals can settle the a v a ~l a b i l ~t y and d~versity of m~cro-habitats for settlement and surv~val, the role of grazers and competition with other organisms such as algae and soft corals Future quantitat~ve studies of recovery should include more long-term ~nvestigat~ons coverlng a wide g e o g r a p h ~c range and incorporating varlous reef habitats where adequate base-llne data are avallable A proper understanding of the recovery process will necess~tate examination of not only the factors influencing coral recolonization but also the ways in which they themselves are mod~fied by d~sturbances Before t h ~s can be achieved ~t is essent~al that a b a s ~c knowledge of coral life histones be a c q u ~r e d