Coral population structure:the hidden information of colony size-frequency distributions

Abstract

Analyses of coral colony size-frequency distributions reveal Important characteristics of populations on the reef. Coral colony size-frequencies can be modelled by log normal d l s t r~bu t~ons and coral populations can be described by statistics of frequency distlibutions such as coefficient of vanation, skewness and mode. Coefficient of vanatlon allows comparison of var~ation in coral populations of d~fferent mean colony size. Skewness reflects the proportion of sinall versus larger colonies, representing juvenile Input and longevity. The mode in the size-frequency dlstnbut~ons represents the most frequent colony size The mode appears ind~cative of a change in the relative impact of total and partial n~ortality in coral populat~ons. These size-frequency var~ables dlffer significantly between coral species and, w i t h ~ n specles, between reef localities. Coral colony size-frequency diagrams provide insight into past events and have some predictive power with respect to population development. Our data demonstrate that measurement of the above-ment~oned variables could be a tool to estlniate the response of coral populat~ons to the reef environment