Climate-driven trophic interactions and their impact on the phenotypic plasticity of coral and the keystone urchin Diadema antillarum in shaping Caribbean reef resilience

Caribbean coral reefs face unprecedented degradation from climate change and anthropogenic stressors, yet critical knowledge gaps remain regarding how organismal plasticity and trophic dynamics interdependently determine ecosystem trajectories. This review synthesizes emerging evidence demonstrating that plasticity in reef-building corals and a keystone herbivore, the long-spined sea urchin Diadema antillarum , operates interdependently, with functional significance contingent upon ecological context. We examined how epigenetic mechanisms, particularly DNA methylation, facilitate coral acclimatization and transgenerational resilience, while behavioral and physiological adjustments in D. antillarum maintain grazing functions under stress. Critically, even thermally acclimated corals cannot persist without functional herbivory to suppress macroalgal competition, revealing that plasticity and trophic structure are inseparable determinants of reef resilience. By integrating molecular, physiological, and ecological perspectives, we identify thresholds beyond which plastic responses prove insufficient to prevent phase shifts toward macroalgal dominance. This synthesis provides mechanistic insights essential for designing evidence-based conservation strategies that simultaneously enhance organismal adaptive capacity and restore functional trophic relationships in degraded reef ecosystems.