Determine the effect of variability in habitat quality on dispersal

The dispersal of individuals between populations is a foundational process to understand at the interface of ecology and evolution. The natal habitat is theorized to strongly influence the degree of dispersal expected. However, understanding the interaction between habitat and dispersal is difficult to study empirically, particularly in a single location where other environmental factors are held constant. Understanding how habitats influence dispersal is important not only for the foundational understanding of ecological and evolutionary processes but also as they relate to the design of marine protected area networks. Here I seek to understand how heterogeneity in habitat quality influences the dispersal dynamics of the common Caribbean reef goby Coryphopterus hyalinus as a model for other species with similar life histories in different systems. To determine how variation in habitat quality influences dispersal first I had to establish what topographical features of the reef equate to greater habitat quality from the perspective of the previously presumed habitat generalist C. hyalinus. I found that as adults C. hyalinus live in mixed species shoals with their congener C. personatus and are distributed across shallow coral reef ecosystems tending to be found in greater densities in more complex, deeper reef areas at the margin of large sand patches. In Turneffe Atoll, C. hyalinus has an average dispersal distance of 3.1 ± 0.3 km with 95% of individuals dispersing less than 7.7 ± 0.65 km. However, spatially heterogeneous habitats are characterized by shorter mean dispersal distances, smaller dispersal spreads, and higher propensity for long-distance dispersal events. This observation likely has strong conservation implications for the design and futureproofing of network-based conservation designs which depend upon dispersal between individual nodes of the network for proper functioning. As anthropogenic climate change alters habitats and in the short-term leads to increasingly fragmented and heterogeneous landscapes these networks may no longer be sustainable given the shrinking of the dispersal spread of the species these networks are designed to protect.