Brazil nuts in the Peruvian Amazon: Linking genetic diversity and sustainable forest management of a socio-ecological system

Abstract

• Non-timber forest products offer a critical opportunity for supporting sustainable development of rural communities and conservation of natural ecosystems. The Brazil nut (Bertholletia excelsa) is arguably the most prominent NFTP from the Neo-tropics, as a globallytraded product from a hyperdominant carbon-rich tree and cornerstone species for rainforest conservation with potential for restoration. Hence, this species has the capacity to contribute to resilient stewardship of forest landscapes, while generating income and improving the livelihood of a vast number of people and local communities throughout the Amazon basin, as well as playing a role in climate change mitigation. • Although it is a protected species, the habitat where Brazil nuts occur is being degraded due to logging of other tree species and land conversion from forest to unsustainable agricultural systems. In this thesis I adopt an interdisciplinary approach across ecosystem management and applied molecular ecology and genomics to 1) Explore the reproductive vulnerability of natural Brazil nut populations in a categorized forest-degradation gradient in the highly biodiverse region of Madre de Dios; 2) Increase our understanding of the role of forest genetic resources as a foundation for resilient oroduction and a vital source of material for forest enrichment and Brazil-nut based restoration; and 3) Provide evidence-based recommendations for management practices that have demonstrated positive effects on the sustainability of Brazil nut populations and its value for restoration. • For genetic analyses, I used a combination of traditional microsatellite SSR loci and developed ddRAD-generated SNPs novel to the species. I place the overall results in the context of patterns of fine-scale genetic structure (FSFS), comparisons genetic-diversity and pollen geneflow patterns, signs of inbreeding through genetic erosion, heterozygosity-fitness correlations related to survival, growth and fruit productivity, monitoring of the success of planting initiatives, and exploration of cost-efficient management practices from collaborative research components. • These findings are detailed and discussed in three main chapters, followed by an additional genome-size technical note and information from co-authored studies related to similar topics within sustainable forest management. Together, they aim to contribute to our holistic understanding of approaches required for resilient management of this vulnerable and socioecologically valuable Amazon rainforest species.