Fine scale patterns of genetic structure in three species of forest birds reveal no population structure and dynamic history within an Amazonian area of endemism

Abstract Phylogeographic studies of Amazonian birds have revealed large intraspecific diversity, even within recognized areas of endemism. To understand the origin and organization of Amazonian diversity, including the influence of recent history and current landscape, we need to evaluate fine scale patterns of genetic diversity in relation to detailed environmental information. We investigated the phylogeography and demographic history of three understory bird species, Oneillornis salvini, Willisornis poecilonotus, and Lepidothrix coronata, from the Purus-Madeira interfluvium, within the Inambari area of endemism using one mtDNA and two nuclear markers with dense sampling. All species showed signs of recent population expansion and had no genetic structure within the interfluvium, which includes distinct ecoregions and geological formations. This result is likely due to a dynamic geological history and recent occupation of the landscape by current populations and suggests that biogeographic history is a better predictor of bird genetic diversity within the Purus-Madeira interfluvium than the current environmental heterogeneity. The pavement of the BR-319 road is of great concern in this scenario, since this anthropogenic barrier will isolate connected populations, well beyond its potential drive of habitat loss and fragmentation.