The unifying theme of my research is the ecological causes and consequences of biodiversity. I have found seaweeds and marine invertebrates to be particularly tractable experimental subjects and have conducted research involving a diverse suite of invertebrate taxa including corals, hydroids, crabs, echinoderms, polychaetes, ascidians, bryozoans, and gastropods. The main issues my research has focused on are the effects of species diversity on communities and ecosystems, the ecological consequences of genetic diversity, positive interactions and mutualisms, the ecology and evolution of decorator crabs, and biological invasions.