Restoration is increasingly implemented to reestablish habitat structure and function following natural and anthropogenic physical disturbances, but scientific knowledge of the effectiveness of methods lags behind demand for guidelines. On coral reefs, recovery is largely dependent on coral reestablishment, and substratum stability is critical to the survival of coral fragments and recruits. Concrete is often used to immobilize or replace loose rubble, but its ecological performance, in terms of fostering coral recruitment, has not been rigorously evaluated, and attempts to restore coral reefs have generally fallen short of returning degraded habitat to pre-disturbance conditions. Fragments of erect branching sponges are known to mediate natural reef recovery by facilitating coral rubble consolidation, yet such natural processes have been largely overlooked in reef restoration practice. Effectively harnessing the recovery abilities of sponges to restore and repopulate damaged coral reefs requires basic ecological information (e.g., rates of growth, fragment attachment, and wound healing) that is currently in short supply for the majority of Caribbean reef sponge species. However, observation of injury and recovery following natural disturbances and experimental wounding suggests that sponge growth form, skeletal composition, and investment in chemical defense in large part determine susceptibility to injury, which appears to be inversely related to recovery ability. If these factors operate under less stressful conditions, they could aid in the selection of sponge species that might most effectively be used to rehabilitate damaged reefs. Through the use of observational studies and field experiments this dissertation focused on: 1) the potential of using fragments of Caribbean coral reef sponges to aid the rejuvenation of coral reefs; and 2) the influence of growth form, skeletal composition, and investment in chemical defense on patterns and rates of: a) size change; b) fragment reattachment; and c) wound healing. The results of this research suggest that employing organisms that jump start successional pathways and facilitate recovery can significantly improve restoration outcomes; however, best practices require techniques be tailored to each system. Furthermore, patterns and rates of size change, fragment attachment, and wound healing among growth forms, and within growth forms among species differing in their composition of skeletal elements, support the resistance vs. recovery hypothesis, and suggest that these traits, in addition to influencing the ecology and evolution of reef sponges, can aid selection of sponge species that might most easily be restored following disturbance or that might most effectively be used to rehabilitate degraded coral reefs.
