The Amazon is the primary source of Neotropical diversity and a nexus for discussions on processes that drive biotic diversification. Biogeographers have focused on the roles of rivers and Pleistocene climate change in explaining high rates of speciation. We combine phylogeographic and niche-based paleodistributional projections for 23 upland terra firme forest bird lineages from across the Amazon to derive a new model of regional biological diversification. We found that climate-driven refugial dynamics interact with dynamic riverine barriers to produce a dominant pattern: Older lineages in the wetter western and northern parts of the Amazon gave rise to lineages in the drier southern and eastern parts. This climate/drainage basin evolution interaction links landscape dynamics with biotic diversification and explains the east-west diversity gradients across the Amazon.

Oil palm plantations have expanded around the world, increasing concern about its pressure on deforestation rates and the homogenization of the landscape. In this context, the present study aimed to evaluate the impact of oil palm plantations on the physical characteristics of streams in Amazonia and their effects on Heteroptera, Odonata and Fish assemblages. A total of 23 streams were sampled, eight within fragments of primary forest, while 15 were in oil palm plantations. Data were collected on characteristics of the channel morphology, substrate, hydraulics, instream cover for aquatic organisms, riparian vegetation, human impacts and woody debris. Instream cover and proximity of human impacts were the variables that had the greatest effects on the physical structure of the streams, showing variation between streams of forest in pristine areas and oil palm plantations. Of the analyzed parameters, substrate, instream cover and woody debris influence the richness of Heteroptera, Odonata and Fish. The impact of oil palm plantations on local streams depended on the size of the plantations, and they cannot be considered an adequate substitute for lost habitats in efforts to preserve the physical habitat of Amazonian streams. Any type of conversion of the natural forest can have direct or indirect impacts on the dynamics and structure of these environments, with potentially negative consequences for their biodiversity. The maintenance of an adequate buffer zone of native riparian vegetation adjacent to the streams that flow through the plantations recommended, because this appears to be the principal factor determining the physical conditions of these streams.

Aim To uncover geographical and temporal patterns of diversification in the puffbird genus Malacoptila, focusing on the influence of landscape and palaeoclimate evolution as drivers of diversification.Location Neotropical, with an emphasis on the Amazon basin.Methods We sequenced eight mtDNA and nuclear gene regions of 176 individuals belonging to seven of the eight recognized Malacoptila species. Concatenated and time calibrated coalescent multi-locus phylogenies, along with a Bayesian species delimitation analysis, were performed for the genus. Phylogeographical and historical demography patterns were reconstructed for the Amazonian species. Ancestral ranges estimation was performed in BioGeoBEARS.Results Our analysis recovered 23 reciprocally monophyletic lineages within Malacoptila. All currently recognized species were recovered as monophyletic. With the exception of M. semicincta, all species presented some level of intraspecific phylogeographical structure, varying up to 10 reciprocally monophyletic phylogroups (M. rufa). The distributions of these lineages are generally coincident with known Neotropical areas of endemism (AE). Main ConclusionOur results corroborate the influence of Andean uplift and the Plio-Pleistocene establishment of the current drainage system in Amazonia as likely drivers of diversification. The spatially structured genetic diversity that exists within Malacoptila is underestimated by current taxonomy and provides another example of widespread cryptic avian endemism in the Neotropics.