Abstracts (first author)
Adaptive radiations in alpha and beta niche dimensions
Adaptive radiations are interesting and important, and probably more than just a sequence of speciations. Recently, there has been an increased interest in the more exact sequence of events, how a clade develops from its first ancestral population to a group of closely related species, adapted to different niches in the landscape in which they occur. Some traits seem to be conserved through evolutionary history, whereas some are more labile, with little phylogenetic signal. The concepts of alpha and beta niches, corresponding to within- and between-habitat selection, has made it possible it hypothesize that one set of traits diverge sooner than others. However, data points in different directions. Moreover, theory is essentially lacking. I here present a first attempt to disentangle the mechanisms underlying the sequence of trait divergence. A first, tentative, prediction is that traits with the strongest trade-off will diverge first. Model simulations show that this pattern is surprisingly robust to the level of dispersal between habitat types. They also show that there is more to learn about the ecological mechanisms driving adaptive radiations.