Modelled larval supply predicts coral population recovery potential following disturbance

Abstract

It is hypothesized that spatio-temporal variability in larval supply is caused by multiple biophysical drivers which correlate with the occurrence of recruitment pulses, influencing the recovery potential of coral reefs following large-scale disturbances. Here, we used a larval dispersal model to explore coral larvae dispersal patterns under variable oceanographic conditions, densities of parental colonies, and taxon-specific biology of propagules. Model predictions were validated with observed settlement and recruitment data to test the robustness of larval dispersal modelling for forecasting the recovery potential of study reefs. The model was applied to the western Pacific archipelago of Palau for 3 yr before and after major typhoon disturbances, and simulations were run and validated for 2 major broadcast-spawning reef-building taxa: Acropora and Porites. Investigations into the relative role of physical (currents, wind, waves) and biological (taxa, disturbance impact) parameters on overall larval supply show that low wind speeds and the intermittent occurrence of north and southwest oceanic currents contributed significantly to enhancing larval supply at the scale of the archipelago. Reduced parental colony densities on eastern reefs following disturbances did not have a major impact on predicted larval supply patterns. Relatively low larval supply to most of the disturbed eastern reefs is predicted during the most common oceanographic conditions, forecasting low recovery potential through larval recruitment. Mapping the spatio-temporal dynamics of larval supply and identifying barriers to dispersal from intact to disturbed reefs can help predict recovery patterns across reef communities.