Format: ORAL

Medina, N.G.1,2, Coca de la Iglesia, M.1, Gallego, A.1, Wen, J.3, Valcrcel, V.1,2

1Departamento de Biología, Universidad Autónoma de Madrid, Madrid 28049, Spain. 2Centro de Investigación en Biodiversidad y Cambio Global (CIBC-UAM), Universidad Autónoma de Madrid, Madrid 28049, Spain. 3Department of Botany/MRC 166, Smithsonian Institution, Washington, DC, USA.

The so-called latitudinal diversity pattern has often been explained invoking the clear-cut climatic differences between tropical-temperate latitudes. However, this hypothesis assumes that moving from the tropics to the temperate latitudes implies drastic changes in the climatic preferences of the species. Yet the climatic transitions between regions are often gradual and overlooking their importance can deeply affect how we perceive the impact of climate on evolutionary patterns. We examined the nature and distribution of the transitions between climatic regions worldwide and evaluated their impact for inferring the past and present climatic preferences in the Asian Palmates, a highly diverse and climatically complex lineage of Araliaceae. We find consistent geographic patterns in the climatic transitions worldwide. Particularly, we detect a consistent higher extent and spatial complexity of the transitions between tropical-temperate climates in the Old World. By considering climatic transitions we identified that the early ancestors of the Asian Palmates had strong affinities for the subtropical-temperate transitions suggesting an initial diversification under such climate. This leads us to propose that the Asian Palmates diversified under these transitional climates and its evolution was interspersed with occasional shifts towards more pronounced tropical or temperate climates. Such results emphasized the significance of transitional climates in understanding niche diversity and evolutionary patterns and calls for a (re)evaluation of the role of transitional areas in promoting biodiversity across the Tree of Life.