Island biogeography aims at inferring the processes that govern the assembly of communities in space and time. Molecular phylogenies can tell us about the timings of island colonisations and diversification, but have rarely been used for the estimation of colonisation, speciation and extinction rates on islands. In this study we illustrate the effects of including phylogenetic information with the Galápagos avifauna. We find that by including colonisation times we obtain much more precise and accurate parameter estimates than if we rely solely on species richness and endemicity status. Inclusion of branching times improves estimates even further. As molecular phylogenies become increasingly available, we urge biogeographers to start using more of the information they contain.
We consider three derived datasets of the Galápagos avifauna in order of increasing phylogenetic information: G1 – includes only a + b; G2 – includes a + b + c; and G3 – includes a + b + c + d (Fig. 1). We fitted DAISIE to each of the datasets to estimate the four parameters of the model (colonisation, extinction, cladogenesis and anagenesis) using maximum likelihood (ML).
- Island biogeography