David completed a Masters degree and a PhD in Theoretical Ecology from the University of Corsica (France). Then he got a lecturer position in Ecology and Statistics at the University of Montpellier. He went for a sabbatical at the University of Sheffield working in Macroecology with KJ Gaston and thereafter he got a professorship position in Montpellier. From last July he is working, as a Marie Curie European fellow, on the functional and phylogenetic biogeography of coral reef fishes with David Bellwood at the Centre, combining large databases on species occurrences, traits and phylogenies.
MacArthur & Wilson’s Theory of Island Biogeography (TIB) is among the most well known process-based explanations for the distribution of species richness among local communities. It helps understand the species-area relationship, a fundamental pattern in ecology and an essential tool for conservation. However, the classic TIB does not account for the complex structure of ecological systems such as species interactions within food webs, which is known to underpin species occurrences at large spatial scales. Here, we extend the TIB to explicitly take into account trophic interactions. We assume that a consumer species needs at least one prey to colonize and maintain its presence on an island and derive a species-specific model for species occurrence probability. We find that the properties of the regional food web influence the slope of the species-area relationship, and that, in return, immigration and extinction dynamics affect local food web properties. We compare the accuracy of the classic TIB to our trophic TIB (TTIB) to predict community composition of real food webs from Adirondack lakes and Florida keys and find strong support for our trophic extension of the TIB.
We investigated the species-area relationships for reef fish assemblages in Caledonia, Fiji, Tonga and French Polynesia and we found that slopes are significantly different between trophic levels. As predicted by the TTIB, piscivorous fishes show the steepest slope while herbivorous fishes have the lowest slop value consistently across the regions. This finding may have implications for coral reefs such as uneven rates of biodiversity loss among fish trophic groups following habitat degradation which may impact ecosystem functioning. More generally, our approach provides a parsimonious explanation to species distributions and open new perspectives to integrate the complexity of ecological interactions into simple species distribution models.