Is a new paradigm emerging for oceanic island biogeography?

Abstract

Following several decades during which two dissimilar and incompatible models (equilibrium and vicariance) dominated island biogeography, recent publications have documented patterns that point the way towards a new paradigm that includes elements of both models, as well as some novel aspects. Many of these seminal contributions have been made possible by the recent development of robust, temporally calibrated phylogenies used in concert with increasingly precise and reliable geological reconstructions of oceanic regions. Although a new general model of oceanic island biogeography has not yet been proposed, in this brief overview I present six hypotheses that summarize aspects of the emerging paradigm. These hypotheses deal with: the frequency of dispersal over oceanic water barriers by terrestrial organisms; the existence of substantial variation in the amount of dispersal (and gene flow) within a given set of related species within a given archipelago; the frequency, extent and impact on species richness of diversification within archipelagos; the frequent correlation of island age and the age of the species that live on the island; the long-term persistence of species on oceanic islands; and the occasional recolonization of continents by species from clades that diversified on islands. Identifying, testing, and seeking means of synthesizing these and other emerging hypotheses may allow a new conceptual paradigm to emerge. © 2007 The Author Journal compilation 2007 Blackwell Publishing Ltd.