Emergent connectivity patterns on the Great Barrier Reef

The analysis of connectivity networks of marine organisms can help us assess the relative importance of local populations as sources of larvae for the wider system. However, these connectivity patterns will be inherently dynamic and transient due to factors such as seasonal variability in ocean currents and local disturbance regimes. While there are many examples that use connectivity networks to represent the structure of metapopulations and plan reserves in marine systems, capturing the spatio-temporal dynamics of the emergent connectivity patterns has proven challenging. Here, we explore the connectivity dynamics of populations inhabiting individual reefs that together comprise Australia’s iconic Great Barrier Reef. We first discuss how network analysis methods can be used to explicitly capture the dynamics of larval connectivity patterns at different spatial and temporal scales and consequently assess the importance of individual reefs as sources of coral larvae. We then consider how network analysis can also be used to understand the disturbance risks that periodic population explosions of coral-eating crown-of-thorns starfish pose to coral metapopulations. These predatory starfish not only devastate local coral populations, but also form emergent connectivity patterns by spreading among the reefs in a manner similar to rapidly expanding exotic species. Finally, we introduce a model framework that jointly considers the dynamic connectivity networks of both coral and starfish. This framework will help managers to adaptively deploy limited resources at strategic locations with maximum efficiency and under changing circumstances.