My research interests revolve around the concept of connected metapopulations. Metapopulations are networks of connected sub-populations. But what connects them? For many marine organisms, these sub-populations are connected by larvae dispersing on ocean currents. In others, adult individuals may move between populations. Regardless, it is this connectivity that is the prevailing feature of metapopulations.
How connected a metapopulation is – or will be in the future – can determine whether or not it will persist in time and space. Extinctions occur when sub-populations can no longer be rescued by upstream neighbors.
I’m fascinated by how these complex structures function. How does the spatial arrangement of sub-populations, or the larval traits of a species, promote persistence? Are there tell-tale signs of metapopulations at risk of extinction? How will metapopulations react to a changing climate?
Marine larvae are tiny, and notoriously difficult to keep track of. How do we know where larvae from one reef will end up? How do we know where adults on another reef came from? What proportion of adults were born and live in the same place? One way to tackle this complicated set of questions is through larval dispersal modeling. I integrate organismal and larval biology with models of hydrography, and use Lagrangian particle tracking to develop probabilities of dispersal and connectivity between habitats.
Refuges, or refugia, are habitats that are consistently removed from some sort of stress or perturbation. In the case of coral reefs, deeper mesophotic reefs may be one example. Their depth and distance from shore allows corals and associated plants and animals to live in slightly cooler, darker, and less polluted water. But in order for refuges to support metapopulation persistence, connectivity, or the exchange of larvae, must occur. Otherwise, they’re a dead-end!
I am interested in finding and testing potential refuges for coral reefs and other marine ecosystems. What areas are protected, and how protected are they? Can larvae disperse from protected refuges to other habitats? Are refuges connected to each other? What role to refuges play in resisting extinction?
Of course, all of these ideas have important implications for the design of effective protected areas. What spatial arrangement of protected areas simultaneously maximizes connectivity, and preserves the habitat heterogeneity necessary to incorporate refuge habitats? How do we design protected areas that serve animals and plants with very different dispersal potentials, or larval traits?