Identification and conservation of evolutionary processes in the Coral Triangle biodiversity hotspot

Abstract

The reefs of the Coral Triangle are the most diverse in the world. While the patterns of origin have long attracted the attention of evolutionary biologists, answering this question has largely been considered of purely academic interest. However, given the increasing threats facing the reefs of the Coral Triangle, it is becoming increasingly clear that understanding the processes generating high biodiversity in this region is critical for preserving this diversity, including the processes that create it. This study compares the phylogeography and genetic connectivity of over 30 fish and invertebrate taxa which are codistributed across the Coral Triangle, representing multiple reef functional groups ranging from corals to pelagic fish. Results indicate a broad array of evolutionary patterns in this shared physical environment. Some taxa exhibit the classic pattern of differentiation between Pacific and Indian Ocean populations, suggesting Pleistocene vicariance. Others show fine-scale genetic differentiation, suggesting a common history of regional geographic isolation. Still others show no genetic structure at all. Although patterns fell into these three basic classes, there were few commonalities among taxa with similar patterns of genetic structure. The unique responses of multiple taxa to a shared environment suggest a multiplicity of physical and ecological processes contributing to the evolution of high biodiversity in the Coral Triangle. While the commonalities seen among some taxa suggest some support for regional seascape conservation initiatives, the idiosyncrasies among taxa demonstrate the challenges facing marine managers in designing reserve systems that will effectively protect a broad array of biodiversity.