Dissecting bird diversity in the Pantepui area of endemism, northern South America

Abstract

The Pantepui region harbors one of the most distinctive endemic montane bird faunas in the Neotropics, and is located across the tepuis of northern South America. We made an extensive literature review to understand large-scale distribution patterns of birds in the Pantepui. The core avifauna of the tepuis is composed of 138 bird species, most forest-dwelling insectivores, of which 43 are endemic. In addition, 167 subspecies of birds are endemic to these mountains. The number of endemic species peaks between 1251 and 2000 m, whereas the diversity of non-endemic species is highest between 751 and 1000 m. A high proportion (28%) of endemic taxa (species plus subspecies) is restricted to a single mountain. Tepuis are distributed along a longitudinal gradient, and bird species compositions of mountains located in the eastern and western portion of this gradient are clearly differentiated. Maximum altitude of the mountains and their distance from the Andes are the best predictors of species richness and composition across the Pantepui. Also, bird species composition at site level exhibits significant nested patterns which are affected by maximum altitude, isolation and geographic position of the mountains. The unique bird assemblage of the Pantepui area of endemism is structured through a combination of the spatial distribution of the mountains, habitat diversity, and complex historical events. © Dt. Ornithologen-Gesellschaft e.V. 2018.