Comparative phylogeography of the avifauna of the Pernambuco Center of endemism using mitochondrial DNA

The Pernambuco Center of Endemism (PCE) is the most deforested and fragmented Brazilian region, with many endangered and extinct bird taxa. Nevertheless, biogeographical relationships among the PCE, the southern Atlantic Forest and Amazonia have hardly been addressed in recent studies. Derived from the classic Refuge Hypothesis (RH), the stability-extinction model assumes that during the Last Glacial Maximum the PCE was environmentally more stable, generating diversity due to its isolation. The Riverine Barrier Hypothesis (RBH) suggests that the Rio São Francisco would be responsible for the PCE biodiversity. Many taxa endemic to the PCE have their sister taxon in Amazonia and not in the Atlantic Forest indicating that there has probably been connections between these regions. Moreover, there is a likely relationship between lineages’ current elevational range and their origin. We sequenced the mitochondrial gene ND2 from 237 samples from seven PCE endemic taxa to 1) test whether patterns of populational divergence and demographic history are concordant with either the RH or the RBH, and to 2) assess whether there is a relationship between a lineages’ origin and current elevation. We inferred phylogeographic trees, haplotype networks, and calculated various demographic parameters. The results showed that PCE populations are well structured, monophyletic, do not share haplotypes with other populations, and are closer to the Atlantic Forest than to Amazonia, with no obvious association with elevation. The nucleotide diversity index of the PCE populations indicated possible demographic stability and isolation in the putative Pernambuco refuge.