In this study, researchers used almost 25 million GBIF-mediated records alongside 9,000 fossil records and a single dated phylogenetic tree to provide insights into patterns of plant diversification and biogeography. The results shed light on differences in plant diversity between tropical and non-tropical regions, as well as between the tropical regions of Africa, Asia, and the Americas. Examining more than 27,500 species of flowering (angiosperm) plants in the last 60 million years, the authors found no difference in speciation and extinction rates between tropics and non-tropics, implying that another model might be needed to explain the so-called latitudinal diversity gradient. Their findings also noted significant differences between the world’s three tropical regions, as a massive spike in emigration shifts out of America around 57 million years ago suggests that this region became a “species pump” for the rest of the world.
Antonelli, A., Zizka, A., Silvestro, D., Scharn, R., Cascales-Miñana, B., & Bacon, C. D. (2015). An engine for global plant diversity: highest evolutionary turnover and emigration in the American tropics. Frontiers in Genetics, 6, 130. doi:10.3389/fgene.2015.00130