Is the largest river valley west of the Andes a driver of diversification in Neotropical lowland birds?

Abstract

ABSTRACT Physical and environmental barriers drive evolutionary diversification by limiting gene flow among populations. Rivers are barriers to gene flow in birds and other vertebrates, but differences in ecological conditions among sites also can affect the genetic structure of populations. The Magdalena River Valley (MRV) of Colombia, the largest South American river valley west of the Andes, is an appropriate location in which to test for the joint role of physical and ecological barriers because the river separates populations to the east and west, and a marked precipitation gradient leads to the occurrence of dry forests in the south and wet forests in the north. We conducted phylogeographic and population genetic analyses using mitochondrial DNA sequences of 4 avian species (Xiphorhynchus susurrans, Mionectes oleagineus, Leptopogon amaurocephalus, and Eucometis penicillata) sampled across 15 localities along the MRV. We found no spatial genetic structure in any of the species in the MRV region, and ...