CORAL-REEFS - PRESENT PROBLEMS AND FUTURE CONCERNS RESULTING FROM ANTHROPOGENIC DISTURBANCE

Coral reefs, with their vast diversity of invertebrate, vertebrate and algal species, have undoubtedly been subjected to natural disturbance since their appearance millions of years ago. Anthropogenic disturban ce has been a factor affecting reefs for a fraction of that time, yet in terms of overall impact, may be of greater concern. Data on habitat destruction, pesticide and heavy metal accumulation, nutrient loading ,. sedimentation, runoff and related impacts of man's activities indic ate that many coastal reefs are endangered by these processes through alterations in animal-algal symbioses, shifts in competitive interacti ons, direct mortality, reproductive failure, and insufficient recruitm ent. The death of corals critically affects reef communities, as coral s provide an important trophic link as well as the main habitat struct ure. While natural disturbance is an important factor affecting reef i nteractions, species diversity and evolution, chronic anthropogenic di sturbances combined with unsuitable environments for recovery, are of great concern. Physiological stress can be measured in corals in addit ion to outright mortality, allowing the impacts of specific disturbanc es to be assessed. Sufficient data for distinguishing real problems fr om temporal variability are becoming available, allowing scientists to focus on practical solutions to problems in coral reef management and preservation.