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

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 Amapa 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 purpose, we use 24 genomic samples (UCEs) of a subset of 12 taxa in addition to the mtDNA samples to estimate timing of divergence across the Amazon Basin. We use phylogeographic concordance factors (PCF) to assess the level of phylogeographic congruence across co-distributed taxa. Finally, we assess to which level physical distance drives genetic structuring by estimating isolation-by-distance (IBD) effects. Results We find that although the study taxa generally do not share similar diversification patterns geographically, many have at least two distinct genetic groups, one north and one south of the Amazon Basin, that have only recently diverged. The timing of divergence between both areas is generally centered in the late Pleistocene, but somewhat variable, indicating there is no single vicariant event responsible for driving diversification. Main conclusions Variability in divergence times indicates that landscape processes have not led to shared phylogeographic responses, which indicates a relatively minor role for vicariance. Shallow divergences suggest that Neotropical grassland habitats may have recently been more connected or that gene flow has played an important role. We did not find evidence of a single dominant corridor of dispersal between savannas north and south of the forested Amazon Basin.Peer reviewe

AVONET: morphological, ecological and geographical data for all birds

Functional traits offer a rich quantitative framework for developing and testing theories in evolutionary biology, ecology and ecosystem science. However, the potential of functional traits to drive theoretical advances and refine models of global change can only be fully realised when species‐level information is complete. Here we present the AVONET dataset containing comprehensive functional trait data for all birds, including six ecological variables, 11 continuous morphological traits, and information on range size and location. Raw morphological measurements are presented from 90,020 individuals of 11,009 extant bird species sampled from 181 countries. These data are also summarised as species averages in three taxonomic formats, allowing integration with a global phylogeny, geographical range maps, IUCN Red List data and the eBird citizen science database. The AVONET dataset provides the most detailed picture of continuous trait variation for any major radiation of organisms, offering a global template for testing hypotheses and exploring the evolutionary origins, structure and functioning of biodiversity

Avifaunas of two dry forest sites in northern Oaxaca, Mexico

Avifaunas de dos bosques secos del norte de Oaxaca, México Se realizaron inventarios avifaunísticos en el norte de Oaxaca, en dos sitios de la región de la Cañada del Valle de Tehuacán. Se observaron 142 especies de aves, encontrándose cerca de 100 especies en cada sitio. Se encontró un número sorprendente de especies (37) que representan poblaciones aisladas del interior restringidas por una u otra vertiente costera. Además, proporciones similares de especies fueron exclusivamente de una vertiente costera o la otra, creando una extraña mezcla en la avifauna de estos sitios que incluye aves del interior, de la vertiente costera del Pacífico y de la vertiente costera del Atlántico

Deep genome-wide phylogeographic structure indicates cryptic diversity in the Middle Spotted Woodpecker (Dendrocoptes medius)

Deep phylogeographic structure in mitochondrial DNA not reflected in morphological variation has been uncovered in a number of species over the past few decades. However, inferred phylogeographic structure based solely on mitochondrial DNA can be misleading and might not reflect the true history of evolutionary lineages. Consequently, such cases should be further investigated based on genome-wide data. One of these examples is provided by the Middle Spotted Woodpecker Dendrocoptes medius, a non-migratory habitat specialist associated with old deciduous forests of the Western Palaearctic. It displays strong genetic divergence in mitochondrial DNA between Asian and European populations despite there being only slight variation in morphology between them. Here, we found a clear genomic divergence between Asian and European populations that is consistent with mitochondrial divergence patterns. As revealed by isolation by distance analyses, this differentiation in two lineages was not merely an effect of geography. Genomic population structure indicates that both the Asian and European lineages might each have been separated in more than one refugium during the last glacial maximum. The Middle Spotted Woodpecker might represent a case of cryptic diversity throughout its distribution range, as has been previously found for other taxa across the tree of life. However, we also found footprints of gene flow from the Asian into the European populations, suggesting at least limited introgression upon secondary contact. The processes and mechanisms that might prevent lineage fusion between the morphologically cryptic but genetically divergent lineages of the Middle Spotted Woodpecker need to be further investigated especially in the area of potential secondary contact

An inverse latitudinal gradient in infection probability and phylogenetic diversity for Leucocytozoon blood parasites in New World birds

Geographic variation in environmental conditions as well as host traits that promote parasite transmission may impact infection rates and community assembly of vector-transmitted parasites. Identifying the ecological, environmental and historical determinants of parasite distributions and diversity is therefore necessary to understand disease outbreaks under changing environments. Here, we identified the predictors and contributions of infection probability and phylogenetic diversity of Leucocytozoon (an avian blood parasite) at site and species levels across the New World. To explore spatial patterns in infection probability and lineage diversity for Leucocytozoon parasites, we surveyed 69 bird communities from Alaska to Patagonia. Using phylogenetic Bayesian hierarchical models and high-resolution satellite remote-sensing data, we determined the relative influence of climate, landscape, geography and host phylogeny on regional parasite community assembly. Infection rates and parasite diversity exhibited considerable variation across regions in the Americas. In opposition to the latitudinal gradient hypothesis, both the diversity and prevalence of Leucocytozoon parasites decreased towards the equator. Host relatedness and traits known to promote vector exposure neither predicted infection probability nor parasite diversity. Instead, the probability of a bird being infected with Leucocytozoon increased with increasing vegetation cover (NDVI) and moisture levels (NDWI), whereas the diversity of parasite lineages decreased with increasing NDVI. Infection rates and parasite diversity also tended to be higher in cooler regions and higher latitudes. Whereas temperature partially constrains Leucocytozoon diversity and infection rates, landscape features, such as vegetation cover and water body availability, play a significant role in modulating the probability of a bird being infected. This suggests that, for Leucocytozoon, the barriers to host shifting and parasite host range expansion are jointly determined by environmental filtering and landscape, but not by host phylogeny. Our results show that integrating host traits, host ancestry, bioclimatic data and microhabitat characteristics that are important for vector reproduction are imperative to understand and predict infection prevalence and diversity of vector-transmitted parasites. Unlike other vector-transmitted diseases, our results show that Leucocytozoon diversity and prevalence will likely decrease with warming temperatures. © 2019 The Authors. Journal of Animal Ecology © 2019 British Ecological Societ