Made in Brazil: Human Dispersal of the Brazil Nut (Bertholletia excelsa, Lecythidaceae) in Ancient Amazonia

Made in Brazil: Human Dispersal of the Brazil Nut ( Bertholletia excelsa , Lecythidaceae) in Ancient Amazonia. The Brazil nut, Bertholletia excelsa, is a colossal tree of terra firme forest whose seeds represent the most important non-timber forest product in Amazonia. Its peculiarly inefficient dispersal strategy and discontinuous distribution have led some to hypothesize anthropogenic origins, but evidence to date has been inconclusive. Here we present results of a multidisciplinary study addressing this question. A review of the geographic distribution of B. excelsa and comparison with that of similar Lecythis species suggest a number of anomalies that are consistent with a recent and wide colonization of Bertholletia. Published studies and field observations indicate that anthropogenic disturbance facilitates Brazil nut regeneration. Recent genetic studies showing no sequence diversity and no geographical structuring of within-population variability support a rapid and recent irradiation from an ancestral population. Historical linguistic analysis of indigenous terms for Brazil nut suggests a northern/eastern Amazonian origin for Bertholletia, with a concomitant spread of Brazil nut distribution or cultivation to the south and west. Such an expansion would have been particularly facilitated by the emergence of intensive bitter manioc cultivation and networks of interethnic trade beginning in the first millennium C.E. Together, ecological, phytogeographic, genetic, linguistic, and archeological data reinforce the hypothesis that ancient Amazonian peoples played a role in establishing this emblematic and economically important rainforest landscape.