Diversification of the Amazonian flora and its relation to key geological and environmental events: a molecular perspective.

Abstract

This chapter provides a molecular perspective on Neogene plant diversification in the Amazon drainage basin. The history of Amazon plant diversification must be understood in a broader context of migration of lineages from other continents during the Neogene and earlier periods. The history of major migration events, as revealed by recent molecular systematics research, is reviewed here. These studies demonstrate the role of land bridge migration and oceanic dispersal in forming contemporary Amazon plant diversity. Many of the diversification histories coincide geographically and in timing with the uplift period of the Andean orogeny and, in some cases, with Pleistocene climatic changes. Although the Pleistocene history of Amazon vegetation is poorly understood, population genetics approaches may help to elucidate the occurrence of population contractions and expansions and their relation to putative moist forest refuges during glacial periods. The overlay of ecological traits, such as soil or habitat preference, onto phylogenies highlights the role of habitat specialization in plant diversification across the Amazon drainage basin. This review suggests that collaboration between molecular systematists, ecologists, geologists and palaeobotanists will advance future research on the driving factors of Amazon plant diversification.