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Borges S.H.,Fundacao Vitoria Amazonica FVA | Cornelius C.,Federal University of Amazonas | Moreira M.,Fundacao Vitoria Amazonica FVA | Ribas C.C.,National Institute of Amazonian Research | And 5 more authors.
Biotropica | Year: 2016

Vegetation growing on white-sand soils is patchily distributed across the Amazon and is characterized by scrublands or open vegetation types (white-sand campinas) and by forests (white-sand forests) surrounded by contrasting habitat types. We studied birds in patches of white-sand campinas in contrasting landscapes in four regions located in distinct biogeographic units delimited by major rivers. Our aim was to investigate the contribution of landscape configuration and biogeographic context to patterns of species diversity and distribution. Aracá and Viruá landscapes (on opposite sides of Rio Branco) are composed by large and continuous patches of white-sand campinas, while Jaú, Novo Airão and Uatumã landscapes (on opposite sides of Rio Negro) are composed by small patches of white-sand campinas isolated by continuous terra firme forests. Birds were sampled using mist-nets and qualitative censuses, and were classified as white-sand vegetation specialists or non-specialists. Bird species diversity was significantly different among studied regions, and composition was significantly different for both, specialists and non-specialists birds. Local variability in species diversity and composition was best explained by white-sand campina area, patch proximity, and distance to major rivers. We conclude that landscape configuration and biogeographical context influence patterns of bird diversity, abundance, and composition in Amazonian white-sand campinas. © 2016 The Association for Tropical Biology and Conservation.

BORGES S.H.,Fundacao Vitoria Amazonica FVA | CORNELIUS C.,Federal University of Amazonas | RIBAS C.,National Institute of Amazonian Research | ALMEIDA R.,Fundacao Vitoria Amazonica FVA | And 5 more authors.
Bird Conservation International | Year: 2015

White-sand vegetation (WSV) is a rare vegetation type in the Amazon basin that grows in nutrient impoverished sandy soils that occur as patches of variable size. Associated with this vegetation is bird assemblage that has not yet been fully characterized. Based on published species inventories and our own field data we compile a checklist of bird species recorded in WSV. In addition, we compared the avifauna of WSV with that found in savanna patches, another type of Amazonian open vegetation. WSV hosted a distinctive avifauna including endemic and threatened species. The number of bird species was lower in WSV compared to nearby terra firme forests, seasonally flooded forests and Amazonian savannas. Despite its low diversity, the avifauna of WSV has a distinctive species composition and makes a significant contribution to Amazonian beta diversity. At least 35 bird species can be considered as indicator species for this environment. Previously identified areas of endemism within the Amazon basin house at least one WSV indicator bird including cases of congeneric species with allopatric distributions. Seven of the WSV indicator species (20% of this avifauna) are in an IUCN threatened category, with one species Polioptila clementsi considered Critically Endangered. Their isolated distribution, small area occupied, and fragility to human-driven disturbances makes WSV one of the most threatened vegetation types in the Amazon basin. The study of WSV avifauna contributes to a better understanding of mechanisms that generate and maintain species diversity as well as of the environmental history of the most biologically diverse biome of the planet. Copyright © BirdLife International 2015

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