The MEGAFAUNA project

Relative importance of ecological and evolutionary determinants of coral reef fish biodiversity

The diversity of organisms that results from the continuous divergence of lineages shaping the tree of life is currently threatened worldwide by anthropogenic global changes (e.g. climate change) and the increasing overexploitation of natural resources. In particular, coral reefs are at threat nearly worldwide with profound economical, sociological and ecological consequences. Increasing efforts are invested in protecting coral reef biodiversity, but conservation is currently limited by our partial understanding of the mechanisms that shaped the diversity of lineages in the past. To ensure the maintenance of coral reef services for the future, management should not solely focus in conserving current biodiversity but also permit that the processes that generate new diversity can be kept functioning. As a corollary, enlightened conservation measures require unravelling the mechanisms that generate biodiversity in this ecosystem, especially to distinguish those related to contemporary ecological or micro-evolutionary processes and those related to macroevolution and the sequence of change in past environments.

By bridging the gap between different disciplines of natural sciences (evolutionary biology, biogeography, community ecology, paleoecology, phylogenetic and geology), our project aims to test five key hypotheses to unravel the main processes having shaped fish biodiversity on coral reefs: (H1) Quaternary climate change, (H2) Historical continental drift, (H3) Ecological speciation, (H4) Niche filtering and (H5) Neutral vs. Trait-based assembly rules. Our ambitious project at global scale is possible because it follows a recently completed data-gathering project which provided a unique database including the distribution of all tropical reef fish species (more than 6,000) together with their functional traits. Our goal is to couple this unique database with the most accurate phylogenies for several speciose reef fish families in order to evaluate the relative roles of historical vs. contemporary ecological processes in generating and maintaining coral reef fish biodiversity. The project will gather a large dataset on phylogenetic relationships of coral reef fishes which, combined with spatio-temporal (millennial past, centurial past, present) reconstruction of coral reef habitat, will allow unravelling the nature of processes in action and their relative importance. The integrated nature of this project requires the active collaboration of three Franco-Swiss partners and their international collaborators, which display complementary expertise in reef ecology, phylogenetic and paleo-distribution modelling. This interdisciplinary project will provide new insights to our understanding of the mechanisms generating fish biodiversity and how to maintain it in coral reef ecosystem with increasing anthropic pressure. To guarantee the excellence of the work undertaken in each task, to reach equilibrium among partners and the two countries, and to promote international collaborations, we chose a pair of highly-qualified coordinators from two different countries for each sub-task according to their skills. The project will provide the general public, scientists and stakeholders with a fully documented online open database containing an Atlas of geographic distribution for all tropical marine fishes, their phylogenies, biological traits as well as environmental information. Beyond scientific advances the project will also feed students from different countries through the transfer of knowledge insured by the academic partners.

MEGAFAUNA Martinic mission