An individual-based metapopulation model of coral community dynamics

Coral reefs are threatened by multiple natural and anthropogenic disturbances. Resilience is important in the persistence of coral reefs despite these multiple perturbations. Connectivity is one of the primary drivers of resilience at the scale of metapopulations. It is often estimated using larval dispersal models. This approach is however limited to potential connectivity. The state of the source and sink habitats greatly influence the strength of the connectivity and therefore the resilience of coral reef communities. This study is an extension of an existing biophysical larval dispersal model. The state of the benthic communities are added as grid cells with different relative abundances of corals (branching and massive), algae (turf and macroalgae), suitable space for settlement (rock, CCA covered stable substrate) as well as unsuitable substrates (sand and rubble). Processes represented in the model include: acquisition/increase of space of corals and algae representative of coral growth and algal spread, mortality and competition. Fish abundance is implicitly represented as the increase or decrease of algal mortality. The model was used to estimate connectivity between different coral reef communities, identify the relative importance of different processes to connectivity and coral persistence, as well as assess the impact of increase and decrease in fishing effort in different sites. The application of the model is initially limited to El Nido, Palawan.