UC Santa Cruz

The interactions among organisms shape the earth's biodiversity in striking ways, and these interactions are known to vary substantially over both time and space. Identifying the scale of variation in species interactions allows for a better understanding of the origins and organization of biodiversity, and informs expectations of the dynamics of these systems. In order to study the scale of variation in species interactions, I focused on the anemonefishes, a group of coral reef damselfishes engaged in a mutualism with sea anemones. I used three complementary approaches. First, I used population genetic methods to show that populations of anemonefishes are genetically isolated over relatively small spatial scales in the Mozambique Channel. Second, I employed data from social media to reveal spatial variation in the interactions between anemonefishes and their host sea anemones. Third, I reconstructed the phylogenetic history of the anemonefishes to examine their pattern of diversification in the context of both ecological and geographic processes. The relatively low dispersal potential of anemonefishes likely contributes to both the spatial structure among populations within species, and the strong geographic pattern of diversification among species. In turn, the spatial variation in diversity within the anemonefishes has led to variation in their interactions with sea anemones.