Abstract Summary
The success of restoration efforts is usually measured on the basis of coral survival and growth rates, but that approach may be improved by taking in consideration specific evaluations of the ecological role that transplanted colonies play in the reef. Corals are ecological engineers and offer shelter to numerous species, and also provide food in form of mucus; these functions are in direct relation to the size of the colony, and thus it is relevant to determine the minimum size that a fragment needs to fulfill its role in a reef. The objective of the study was to detect the size that colonies of naturally settled Pocillopora spp. require to host a full set of associated reef fishes, and use that information as a proxy indicator of success for restoration projects. The study was carried out at three locations in the southern Gulf of California, Mexico. We measured the largest diameter, perpendicular diameter and height in cm of 1,144 colonies, and calculated its volume; at the same time, visual censuses of associated fish were conducted observing individuals inside the colonies or in a perimeter of 30 cm around them. From these data, fish richness and abundance were calculated, and these response variables were introduced in non-linear regression models to determine the minimum volume that a colony should have to reach its maximum number of individuals and species richness (considering this as a measure of ecological functionality). The resulting models presented an asymptote, and we estimated that the volume that a Pocillopora colony requires to have its complete fish collection is between 30,000 and 40,000 cm 3, which according to local estimations of growth rate represents an approximate age of 6-7 years. We suggest that managers apply these results to plan more efficient restoration efforts.
