Low-tech coral reef restoration methods modeled after natural fragmentation processes

Low-cost and environmentally sustainable coral reef restoration methods modeled after natural coral reef recovery processes and appropriate for use in developing countries were investigated. The study focused on post-fragmentation processes important to natural coral reef recovery and to successful transplantation, quantifying size-specific, substrate-specific, site-specific, and species-specific survival, growth, and self-attachment of coral fragments. Acropora cervicornis and A. prolifera, with distinct morphotypes from high and low energy environments were used for all experiments. Coral fragments of similar size from axial and basal regions were also tested to determine if senescence affects survival. Results indicate that the mortality and growth of unattached coral fragments are strongly size and substrate dependent, with insignificant differences between morphotypes, species, and sites. Axial fragments had significantly lower mortality than did inner/older fragments. Back reef and reef front morphotypes of A. cervicornis grown together in the sheltered back reef for 1 yr continued to differ significantly in branch diameter, relative growth, and self-attachment ability, indicating a genetic basis to morphology and adaptation to specific reef environments. Scattering coral fragments onto unstable rubble or attaching fragments to simple frames on sand proved effective for restoring coral cover to substrates where natural larval-based recruitment processes are inhibited.