Predation, community asynchrony, and metacommunity stability in cyanobacterial mats

Abstract

The dynamism of ecological interactions in rapidly changing ecosystems can be understood only by linking community context to population dynamics. Holistic characterization of such mechanisms requires integrating patterns of variability across scales. Here, we integrated observational, experimental, and theoretical approaches to unify local and regional ecological processes driving the dynamics of benthic cyanobacterial mats on coral reefs off the island of Bonaire, Caribbean Netherlands. Community and metacommunity dynamics of mats were tracked for 49 days alongside quantification of macropredation pressure from fishes. We tested the hypothesis that enhanced predation would result in decreased mat persistence in situ. Finally, we constructed a cellular automaton model to predict patterns in mat metacommunity dynamics across different scenarios of top-down and bottom-up control and dispersal. Cyanobacterial mat metacommunities were temporally stable across the study, stabilized by asynchrony in the dynamics of communities. Diverse reef fishes foraged on mats in situ and experimental increases in predation pressure decreased the instantaneous mortality rate of mat communities over mat communities experiencing natural levels of predation pressure. Theoretical simulations suggested that dispersal conveys a rescuing effect on mat metacommunity abundance under scenarios of strong trophic control.