Résumé
We develop a spatially explicit model of diversification based on
paleohabitat to explore the predictions of four major hypotheses
potentially explaining the latitudinal diversity gradient (LDG), namely,
the ‘time-area’, ‘tropical niche conservatism’, ‘ecological limits’ and
‘evolutionary speed’ hypotheses. We compare simulation outputs to observed
diversity gradients in the global reef fish fauna. Our simulations show
that these hypotheses are non-mutually exclusive and that their relative
influence depends on the time scale considered. Indeed, simulations
suggest that reef habitat dynamics produced the LDG during deep geological
time, while ecological constraints shaped the modern LDG, with a strong
influence of the reduction in the latitudinal extent of tropical reefs
during the Neogene. Overall, this study illustrates how mechanistic models
in ecology and evolution can provide a temporal and spatial understanding
of the role of speciation, extinction and dispersal in generating
contemporary biodiversity patterns.