Colonization and diversification: towards a phylogeographic synthesis for the Canary Islands.

Recently, the Canary Islands have become a focus for studies of the colonization and the diversification of different organisms. Some authors have considered Canarian endemisms as relicts of Tertiary origin, but new molecular data suggest a general pattern of continental dispersion followed by in situ speciation. Recent phylogeographic studies are revealing variants of the simple stepping-stone colonization model that seems to hold for many Hawaiian groups. Many factors can generate deviations from such a pattern: the stochastic nature of colonization, competitive exclusion, phylogenetic constraints on adaptive evolution and extinction. An understanding of island colonization and diversification can best be developed from an ecosystem level synthesis as more data for the Canarian archipelago come to hand.