SNP dataset for Buchenavia oxycarpa

Wallace’s (1854) Riverine Barrier hypothesis is one of the earliest
explanations for Amazon biotic diversification. Despite the importance of
this hypothesis for explaining speciation in some animal groups, it has
not been studied extensively for plant species. In this study we use a
prominent Amazon tree, Buchenavia oxycarpa (Mart.) Eichler (Combretaceae),
to evaluate Wallace’s hypothesis along the Rio Negro, a major Amazon
tributary that has driven allopatric speciation for several animal taxa.
We sampled six individuals from sixteen localities along both river banks,
and used a modified ddRADseq protocol to identify SNP markers. Our
population genomic data revealed strong genetic structure for B. oxycarpa
sampled across banks of the Rio Negro (ϕCT = 0.576, P < 0.001),
supporting the hypothesis that the Rio Negro acted as a significant
genetic barrier for B. oxycarpa. Our study shows that gene flow
for this large and well-dispersed Amazon tree is impeded by riverine
barriers though this has not yet resulted in speciation. Future studies
focused on species with different life histories, including species
restricted to non-flooded forests, are need to further advance our
understanding of Amazon rivers as drivers of biotic diversification.