Article

Demographic Threats to the Sustainability of Brazil Nut Exploitation

Utrecht University, Utrecht, Utrecht, Netherlands
Science (Impact Factor: 31.48). 12/2003; 302(5653):2112-2114. DOI: 10.1126/science.1091698
Source: PubMed

ABSTRACT A comparative analysis of 23 populations of the Brazil nut tree (Bertholletia excelsa) across the Brazilian, Peruvian, and Bolivian Amazon shows that the history and intensity of Brazil nut exploitation are
major determinants of population size structure. Populations subjected to persistent levels of harvest lack juvenile trees
less than 60 centimeters in diameter at breast height; only populations with a history of either light or recent exploitation
contain large numbers of juvenile trees. A harvesting model confirms that intensive exploitation levels over the past century
are such that juvenile recruitment is insufficient to maintain populations over the long term. Without management, intensively
harvested populations will succumb to a process of senescence and demographic collapse, threatening this cornerstone of the
Amazonian extractive economy.

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    • "For example, scatter-hoarding rodents play a pivotal role in the dispersal of largeseeded species in neotropical rain forests, especially in those once dispersed by the extinct Pleistocene megafauna (Guimar~ aes, Galetti & Jordano 2008; Jansen et al. 2012). In Amazonian forests, the overharvesting of the Brazilian nut (Bertholetia excelsa) may have important consequences not only for the recruitment of B. excelsa and agouti populations, but also for the entire scatter-hoarding dispersal service of other largeseeded tree species (Peres et al. 2003; Galetti et al. 2006). Similar examples have been reported for flying foxes, gorillas and elephants for which overhunting and habitat loss has resulted in a recruitment reduction of a significant number of large-seeded species (McConkey & Drake 2006; Beaune et al. 2013; Haurez, Petre & Doucet 2013). "
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    • "Due to its uncontestable economic importance, there has been concern over the sustainability of Brazil nut harvesting [17]–[20]. While some studies have shown that medium and even high levels of harvesting may be sustainable over the long term, a meta-analysis conducted by Peres et al. [18], which was later criticized by Scoles & Gribel [20], concluded that long-term intensive Brazil nut harvesting has reduced B. excelsa recruitment throughout the Amazon. Despite the possible demographic impacts of high-intensity Brazil nut harvesting, the historical evidence [6], [8], [14] suggest that past human activities favored B. excelsa and, therefore, that low levels of harvesting may play a positive role in the recruitment of this species. "
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