Tropical-temperate dichotomy falls apart in the Asian Palmate Group of Araliaceae

PREMISEThe use of climatic data on phylogenetic studies has greatly increased in the last decades. High-quality spatial data and accurate climatic information are essential to minimize errors in the climatic reconstructions to the past. However, despite the huge amount of already available biodiversity digital information, the process of compiling, cleaning, and comparing spatial data from different open data sources is a time-consuming task that sometimes ends up with low-quality geographical information. For this reason, researchers often resort qualitative approximations among which World bioclimatic classification systems or the experts criteria are the most used. Our aim is to evaluate the climatic characterization of the genera of the Asian Palmate Group (AsPG) of the ginseng family (Araliaceae), one of the classical examples of tropical-temperate plant families. METHODSWe compiled a curated worldwide spatial database of the AsPG genera. We then created five raster layers representing bioclimatic regionalizations of the World. Finally, we crossed the database with the layers to characterize the AsPG genera. RESULTSWe found large disagreement in the climatic characterization of genera among regionalizations and little support for the tropical-temperate dichotomy. Both results are attributed to the complexity of delimiting tropical, subtropical and temperate climates in the World and to the distribution of the study group in regions with transitional climatic conditions. CONCLUSIONSThe complexity in the climatic classification of this classical example tropical-temperate dichotomy, calls for a general revision in other families. In fact, we claim that to properly evaluate tropical-temperate transitions we cannot ignore the complexity of distribution ranges.