Recolonization of Hermatypic Corals on Submerged Lava Flows in Hawaii

Recovery time for recolonization of coral communities on submerged lava flows in Hawaii may largely depend on exposure to sea and swell. In exposed areas, recovery time (in terms of number of species, per cent cover, and diversity) of areas decimated by lava and perhaps similar disturbances appears to be about 20 yr. At sheltered stations, more than 50 yr may be required for complete recovery. This difference in recovery time is apparently related to differences between undisturbed coral communities at exposed and sheltered stations: in exposed areas succession seems to be constantly interrupted, resulting in pioneer stages, whereas at sheltered stations reefs are more fully developed in terms of percent cover and thickness, and are thus closer to being climax coral communities; they therefore require more time for full recovery. The data, although meager, indicate that diversity increases during succession, but attains a peak value before climax is reached. The apparent decline in diversity as climax is approached may be due to interspecific competition for space, which leads to resource monopolization. Comparison of community structurewith more tropical coral reefs reveals that this pattern may apply only to physically controlled communities.