Impacts of different recruitment density-dependences on post-disturbance coral reef recovery

Coral reefs, among the most productive and diverse ecosystems on our planet, are rapidly degrading and losing corals through a variety of disturbances. Post-disturbance reef recovery rates depend strongly on local community structure and recovery processes. Larval recruitment, a fundamental process regulating reef recovery, is closely related to adult coral cover (i.e. it is a density-dependent process). However, it remains unclear how the form of this density-dependence relationship influences post-disturbance trajectories of coral populations. Here, we use a coral-macroalgae competition model to examine how different functional forms of recruitment density-dependence (linear, convex and concave) affect coral recovery. Our results reveal that coral species characterized by a concave density dependence are more likely to recover following disturbances. By contrast, species with a convex density dependence can recover only when the disturbance is weak or when maximum local recruitment rates are high. We argue that a comprehensive understanding of coral recovery after disturbances requires detailed examination of recruitment processes, particularly their density dependence. Selecting corals expressing concave density dependences and high maximum recruitment rates could lead to more effective reef restoration practices because these corals are more likely to regain ecological dominance following a disturbance.