Phylogeographic and demographic patterns reveal congruent histories in seven Amazonian White-Sand ecosystems birds

Aim: The drivers of genetic diversity in Amazonia, the most species-rich set of ecosystems on Earth, are still incompletely understood. Species from distinct Amazonian ecosystems have unique biogeographic histories that will reflect regional landscape and climatic drivers of genetic diversity. We studied bird species from patchy Amazonian white-sand ecosystems (WSE) to evaluate the occurrence of shared biogeographic patterns to better understand the complex environmental and landscape history of Amazonia and its biodiversity. Location: Northern South America; Amazonia. Taxon: Passeriformes. Methods: We sequenced Ultra-conserved Elements (UCEs) from 177 samples of seven bird species associated with WSE that have overlapping ranges. We used the SNP matrices and sequence data to estimate genetic structure and migration surfaces using 'conStruct' and eems, performed model-selection to obtain the most probable demographic histories on 'PipeMaster' and implemented analyses of shared demography with ecoevolity. Results: Shallow genetic structure patterns varied among species. The Amazon river was the only barrier shared among them. Population structure dates to no more than 450,000 years ago. Nine geographically structured populations showed signals of population size changes and eight of these occur in Northern Amazonia. Population expansion was inferred at two distinct times: similar to 100,000 and similar to 50,000 years ago. The timing of co-expanding populations is consistent with differences in habitat preference, as species that prefer dense scrubby to forested vegetation expanded more recently compared to species that prefer open vegetation. Main conclusions: WSE species responded in concert to environmental and landscape changes that occurred in the relatively recent past. Population expansions were likely driven by the genesis of new WSE patches and a return to wetter conditions after glacial periods. Pleistocene climatic cycles affected the distribution and dynamics of open vegetation habitats in Amazonia, especially in the Northern region, driving genetic diversity and demographic patterns of its associated biota.