Recent divergence and lack of shared phylogeographic history characterize the diversification of neotropical savanna birds

Abstract

Aim: Neotropical savanna birds occur north and south of, but mostly not in the Amazon Basin, except for a few isolated savanna patches. Here, we investigate the phylogeography of 23 taxa of Neotropical savanna birds co-distributed across multiple isolated savanna patches to assess to what extent these species have a shared history of spatial diversification. We explore the role of the forested Amazon Basin as a vicariant barrier separating northern and southern populations, particularly focusing on the role of the coastal savannas of Amapá as a potential corridor of gene flow between northern and southern populations. Location: Neotropical savannas. Taxon: Aves. Method: We employ 775 mtDNA samples of 24 co-distributed savanna bird taxa from all major savanna patches in South America to infer phylogeographic patterns. For this | 1125 van ELS Et aL. B I OS K E TCH Paul van Els focuses mainly on the ecology and evolution of Neotropical birds, particularly birds of grass-dominated ecosystems. He is especially interested in the timing and spatiality of diversification of this group in relation to the vicariant events that shaped the South American savannas and to the life history characteristics inherent to a life in open habitats with a high degree of seasonal climatic variation. Author Contributions: PVE conceived the research idea and performed most sequencing, analysis, and writing. EZ aligned UCE data, LRM performed UCE-based analyses, VGB provided samples of Tyrannus savana, AS, AA, CCR, PSDR, and MPDS provided samples of Formicivora grisea, Neopelma pallescens, and Schistochlamys melanops, KZ, ROP, and JB provided samples of Emberizoides herbicola, Tyrannus albogularis, Sporophila plumbea, and Chordeiles pusillus. All reviewed the manuscript.

A comparative phylogenomic analysis of birds reveals heterogeneous differentiation processes among Neotropical savannas

“…A lack of consensus in intraspecific tree topologies of organisms shared between the Cerrado and the Amazonian savannas is in accordance with a previous study (van Els et al, 2021), which supported multiple origins of the isolated Amazonian savannas as well as of the Cerrado populations. For some plant species, genomic and chloroplast DNA data suggest colonization of Amazonian savannas from the Cerrado about 149,000 years ago (Buzatti et al, 2018), whereas in other organisms divergence between the savannas to the north and south of the Amazon River pre‐dates the LIG (Buzatti et al, 2018; Resende‐Moreira et al, 2019).…”

“…angustirostris is one exception (Kopuchian et al, 2020; Rocha et al, 2020). These studies rejecting isolation by distance in Cerrado birds differ from our study with respect to the different geographic scale of the study area (e.g., Luna et al, 2017), and in the use of different genetic markers (e.g., van Els et al, 2021; Lima‐Rezende et al, 2019; Luna et al, 2017; Savit & Bates, 2015). It is becoming commonly accepted that multilocus studies are more suitable than single‐locus studies to evaluate population genetic structure and evolutionary phenomena such as isolation by distance (Teske et al, 2018).…”

“…The relatively high importance of isolation by distance found here is not frequently reported for Cerrado bird species (van Els et al, 2021; Lima‐Rezende et al, 2019; Luna et al, 2017; Savit & Bates, 2015), although L . angustirostris is one exception (Kopuchian et al, 2020; Rocha et al, 2020).…”

Amazonian birds in more dynamic habitats have less population genetic structure and higher gene flow

“…Similarly, across many Central American bird species, diet—but not habitat—was a better predictor of dispersal ability (Miller et al, 2021), with species that track ephemeral food resources having greater dispersal ability and lower population structure. In contrast, habitat preference was associated with the amount of population genetic structure (Bates et al, 2003; van Els et al, 2021). In Amazonian birds, Harvey et al (2017) found greater genetic structure in upland forest species than in floodplain forest species, and Barbosa et al (2022) found differences in structure between species in distinct habitats within Amazonian floodplains.…”

Noteworthy records of birds from Pando including two new species for Bolivia

“…Several Leistes specimens from Pando at the Louisiana State University Museum of Natural Science, Baton Rouge (LSUMZ) were identified as L. superciliaris based on phenotype. However, some have the mitochondrial DNA of militaris (van Els et al . 2021, in prep.…”