Global Diversification of Tropical Rain Forests: from Herbaria to Spectra

Tropical rain forests are the most diverse ecosystems on Earth. How this extraordinary diversity arose remains one of evolutionary biology’s enduring questions. I will present results from a global study of Annonaceae, a pantropical plant family of about 2,500 species, as a window into rain forest evolution.

At the heart of our approach is the herbarium specimen, from which we extracted DNA, morphology, distribution data and spectra. Our near-complete phylogenomic tree, covering 82% of species, 65% from herbarium specimens, and interpreted with fossil evidence, reveals a more dynamic history than expected, with waxing and waning of diversity over the past 90 million years.

To explain present-day diversity, we analyzed more than 100 environmental and evolutionary variables, identifying large regions, even across continents, where similar processes shape diversity. We also show that future extinctions would have a decoupled impact on phylogenetic and functional diversity across the family. Near-infrared spectroscopy now extends what a specimen can tell us, offering a rapid, non-destructive way, to identify specimens and to prioritize them for genomic work.

Finally, I will briefly show how these global patterns can guide local action, through a community-based forest conservation partnership in Ecuador. Herbaria are not only archives of the past, but living infrastructures for understanding, and helping to conserve biodiversity.

Speaker:Institut de Recherche pour le Developpement

Jamie Lloyd-Smith, UC Los Angeles, was originally scheduled to speak today.