Determining the effect of variability on habitat quality on dispersal in a marine fish

The dispersal of individuals between populations is a foundational process to understand at the interface of ecology and evolution. 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, partic- ularly 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 we 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. To understand the influence of habitat heterogeneity on dispersal first it is important to establish what features of the reef equate to greater habitat quality from the perspective of the previously presumed habitat generalist C. hyalinus. Adult C. hyalinus live in large shoals distributed across shallow coral reef ecosystems in greater densities in more complex, deeper reef areas at the margin of large sand patches. In Turneffe Atoll, C. hyalinus have an aver- age 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 rare dispersal events. This observation has 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.