Predicting Biodiversity "Hotspots" in Coral Reefs: Combining Amphipod Phylogenies and Geotectonics as a Proxy to Identify Areas of Composite Evolutionary Diversity

Event Name/Location

International Society for Reef Studies, Cambridge, England, September 3-7, 2002

Document Type

Conference Proceeding

Publication Date



While reports and evidence of large-scale change and decline in coral reefs and associated reef communities increase, scientists and marine resource managers often view and assess reef biodiversity through a narrow lens of “spatially obvious” species such as corals, fish, and mollusks while paying little attention to the multitude of small cryptic invertebrates found on reefs. Often these larger candidate organisms have long- lived dispersive larvae capable of long distance transport prior to settlement. In contrast, many of the smaller, more cryptic reef organisms such as amphipod crustaceans lack dispersive larvae and have restricted distribution patterns that help define subtle and important differences in biodiversity among reefs. This is best seen in island archipelagos where each island may have an endemic cryptofaunal form or species while larger, more widely distributed taxa show little or no variation at the same spatial scale. While numerous surveys and taxonomic lists are being compiled they are rarely followed with detailed systematic studies capable of explaining fine scale evolutionary relationships. Such information is crucial in identifying important areas of lineage-driven hyper diversity that could serve as potential long-term sources of propagules for nearby impacted reefs. Merely compiling lists and species numbers provide little or no detail in this regard but are often used in decision- making such as locating marine protected areas. Inventories and lists provide information on species presence, but not the processes that could have resulted in observed patterns that could be informative in analyzing evolutionary diverse reef systems. Research that incorporates evolutionary scenarios and geological process information at a variety of spatial and temporal scales has been used to identify composite distribution patterns found in reef systems along plate boundary margins. Therefore, knowledge of geotectonic processes is pertinent to the interpretation of diversity in reef assemblages. This is evident where once distant and remote reef systems are docked and amalgamated by multiple collision and subduction events along plate boundaries. Using amphipod crustaceans from reefs in the South Pacific and Indian Ocean reef systems proved highly informative in suggesting where similar patterns of what were likely to be found. Predictive and testable hypotheses blending biological and geological components can provide plausible explanations of evolutionary diversity and result in levels of detail and discrimination that most current biodiversity and assessment activities cannot achieve. This combined approach can help explain examples of widespread paleoendemic fauna, high levels of regional endemism, areas of composite biodiversity, and ex-situ vs. in-situ evolutionary patterns and processes. Data resulting from this blending of geological processes and biodiversity patterns can suggest avenues of further research such as molecular genetics that can further test assumptions about biodiversity pattern in coral reefs.