Subspecies-level distribution maps for birds of the Amazon basin and adjacent areas

Aim: Distribution maps for Amazonian birds are often limited to species-level taxonomy even though many subspecies represent biological species. We provide digital maps depicting subspecies-level distributions of Neotropical birds in the Amazonas River basin and adjoining areas.Location: Amazon region, which includes the entire Amazon basin, the east slope of the tropical Andes, French Guiana, Suriname, Guyana, south Venezuela (Bolivar and Amazonas departments), parts of the Brazilian Cerrado and the Araguaia-Tocantins basin.Taxon: Birds (Class Aves).Methods: To build the distribution maps, we compiled a point-locality database of 620,000 records, 90% of which represent specimens vouchered in research collections. After manually cleaning and optimising the quality of the point localities, we generated extent-of-occurrence polygons at the subspecies level using a concave hull function. We corrected each polygon based on the literature and expert knowledge. We used this data set to define zoogeographical regions based on multidimensional scaling and clustering analyses, and then compared subspecies-defined regions to zoogeographic regions inferred from species-level data.Results: We inferred range polygons for 3990 subspecies, representing 2043 species from 65 families. The average distribution size was 955,739 km(2), with half of the taxa having range sizes smaller than 230,484 km(2) (median value) and nearly one-quarter of all subspecies having ranges smaller than 50,000 km(2). We identified 10 zoogeographical regions from the subspecies data set in comparison with four areas based on a species-level analysis of the same data. The 10 zoogeographical regions are largely congruent with previously identified areas of endemism.Main Conclusions: The new maps of Amazonian bird subspecies distributions allow biodiversity studies (e.g. macroecology, evolution, and conservation) to be conducted at the subspecies level, and facilitate biogeographic, ecological, evolutionary and conservation research on birds in the most biologically diverse region in the world.

Automated summary

The maps of Amazonian bird subspecies distributions provide a valuable tool for studying subspecies-level biodiversity and conducting research on bird biogeography, ecology, evolution, and conservation in the most biologically diverse region in the world.