What Is Evolutionary Biogeography?

Abstract

Most of the authors involved in the theoretical development of evolutionary biogeography assume that dispersalism, panbiogeography, cladistic biogeography, and phylogeography represent alternative approaches. Instead, I consider that different biogeographic methods may be used to answer different questions, which are different steps of an integrative biogeographic analysis. This stepwise approach comprises five steps, each corresponding to particular questions and methods. Track analysis and methods for identifying areas of endemism are used initially to identify biotas (graphically represented on maps as generalized tracks or areas of endemism), which represent hypotheses of primary biogeographic homology and are the basic units of evolutionary biogeography. Then, cladistic biogeography uses available phylogenetic data to test the historical relationships between these biotas (secondary biogeographic homology). Based on the results of these analyses, a biogeographic regionalization is achieved. Intraspecific phylogeography, molecular dating, and fossils are incorporated to help identify the different cenocrons (set of taxa that share the same biogeographic history, which constitute identifiable subsets within a biota by their common biotic origin and evolutionary history) that became assembled in a biota. Finally, the geological and biological knowledge available is integrated to construct a geobiotic scenario that helps explain the way different dispersal and vicariance events contributed to biotic assembly and how the cenocrons dispersed to the biota analyzed. I present the concepts implied in these steps and some of the methods that may be applied to answer particular biogeographic questions and discuss how they can be integrated to explain biotic assembly within an integrative framework.