Publications by authors named "Alexandre Aleixo"

This study aims to enhance our understanding of the temporal and spatial processes scales governing the evolutionary diversification of Neotropical birds with Trans- and Cis-Andean populations of the species from South and Central America. Through a multilocus analysis of the mitochondrial (CytB and ND2) and nuclear genes (I7BF, I5BF, and G3PDH) of 41 samples representing six subspecies, we describe the existing molecular lineages of , and estimate their demographic dynamics. We used Ecological Niche Modeling (ENM) with six different algorithms to predict the potential distribution of in both present-day and past scenarios, examining the overlap climatic niche between Cis- and Trans-Andean lineages.

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We combined mitochondrial DNA sequence data and paleoclimatic distribution models to document phylogeographic patterns and investigate the historical demography of two manakins, and , as well as to explore connections between Amazonia and the Atlantic Forest. ND2 sequences of (75 individuals, 24 sites) and (196, 77) were used in Bayesian inference and maximum likelihood analyses. We estimated mitochondrial nucleotide diversity, employed statistical tests to detect deviations from neutral evolution and constant population sizes, and used species distribution modeling to infer the location of suitable climate for both species under present-day conditions, the Last Glacial Maximum (LGM), and the Last Interglacial Maximum (LIG).

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Interactions between birds and plastics cause several damages like death due to entanglement and blockage of the digestive tract. However, the impacts of plastics on both marine and terrestrial bird nests require further investigation. Recently, Lopes et al.

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Article Synopsis
  • Current genetic diversity and population connectivity are crucial for endangered species like the Hyacinth Macaw, especially due to threats like illegal harvesting.
  • Genetic monitoring can guide conservation efforts and inform strategies for managing viable populations and reintroducing animals from captive breeding.
  • The study revealed four genetically distinct clusters of Hyacinth Macaws in Brazil, with significant diversity and declining effective population sizes, underlining the importance of preserving all wild populations to protect their evolutionary potential.
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The biodiversity crisis is a global phenomenon, and measures to monitor, stop, and revert the impacts on species' extinction risk are urgently needed. Megadiverse countries, especially in the Global South, are responsible for managing and protecting Earth's biodiversity. Various initiatives have started to sequence reference-level genomes or perform large-scale species detection and monitoring through environmental DNA.

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Article Synopsis
  • The Harpy Eagle, a vulnerable species facing habitat loss, is the focus of a new chromosome-scale genome assembly study that provides valuable insights into its genetics.
  • The assembled genome spans 1.35 Gb, showcasing high completeness and identifying over 7,200 intact transposable elements, including significant bursts of TEs at key evolutionary points.
  • The research highlights major chromosome rearrangements in the Harpy Eagle's lineage compared to related bird families and reveals a concerning decline in its population over the past 20,000 years, emphasizing the importance of the genome for future conservation initiatives.
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The natural world is under unprecedented and accelerating pressure. Much work on understanding resilience to local and global environmental change has, so far, focussed on ecosystems. However, understanding a system's behaviour requires knowledge of its component parts and their interactions.

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Ever since Alfred Russel Wallace's nineteenth-century observation that related terrestrial species are often separated on opposing riverbanks, major Amazonian rivers have been recognized as key drivers of speciation. However, rivers are dynamic entities whose widths and courses may vary through time. It thus remains unknown how effective rivers are at reducing gene flow and promoting speciation over long timescales.

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The Least Nighthawk Chordeiles pusillus is widespread wherever there are savannas in the South American tropics, often in isolated patches, such as white-sands savannas in the Amazon rainforest realm. Here, we investigate genetic relationships between populations of the Least Nighthawk to understand historical processes leading to its diversification and to determine dispersal routes between northern and southern savannas by way of three hypothesized dispersal corridors by comparing samples from white-sand savannas to samples from other savannas outside of the Amazon rainforest region. We use 32 mtDNA samples from the range of C.

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The "Amazon tipping point" is a global change scenario resulting in replacement of upland forests by large-scale "savannization" of mostly southern and eastern Amazon. Reduced rainfall accompanying the Last Glacial Maximum (LGM) has been proposed to have acted as such a tipping point in the past, with the prediction that inhabiting species should have experienced reductions in population size as drier habitats expanded. Here, we use whole-genomes of an Amazonian endemic organism (Scale-backed antbirds - spp.

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Geographic barriers are frequently invoked to explain genetic structuring across the landscape. However, inferences on the spatial and temporal origins of population variation have been largely limited to evolutionary neutral models, ignoring the potential role of natural selection and intrinsic genomic processes known as genomic architecture in producing heterogeneity in differentiation across the genome. To test how variation in genomic characteristics (e.

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Rivers frequently delimit the geographic ranges of species in the Amazon Basin. These rivers also define the boundaries between genetic clusters within many species, yet river boundaries have been documented to break down in headwater regions where rivers are narrower. To explore the evolutionary implications of headwater contact zones in Amazonia, we examined genetic variation in the Blue-capped Manakin (Lepidothrix coronata), a species previously shown to contain several genetically and phenotypically distinct populations across the western Amazon Basin.

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Understanding the factors that govern variation in genetic structure across species is key to the study of speciation and population genetics. Genetic structure has been linked to several aspects of life history, such as foraging strategy, habitat association, migration distance, and dispersal ability, all of which might influence dispersal and gene flow. Comparative studies of population genetic data from species with differing life histories provide opportunities to tease apart the role of dispersal in shaping gene flow and population genetic structure.

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Although vicariant processes are expected to leave similar genomic signatures among codistributed taxa, ecological traits such as habitat and stratum can influence genetic divergence within species. Here, we combined landscape history and habitat specialization to understand the historical and ecological factors responsible for current levels of genetic divergence in three species of birds specialized in seasonally flooded habitats in muddy rivers and which are widespread in the Amazon basin but have isolated populations in the Rio Branco. Populations of the white-bellied spinetail (Mazaria propinqua), lesser wagtail-tyrant (Stigmatura napensis) and bicolored conebill (Conirostrum bicolor) are currently isolated in the Rio Branco by the black-waters of the lower Rio Negro, offering a unique opportunity to test the effect of river colour as a barrier to gene flow.

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Phylogeographical studies of the most species-rich region of the planet-the Amazon basin-have repeatedly uncovered genetically distinctive, allopatric lineages within currently named species, but understanding whether such lineages are reproductively isolated species is challenging. Here we harness the power of genome-wide data sets together with detailed phylogeographical sampling to both characterize the number of unique lineages and infer levels of reproductive isolation for three parapatric manakin species that make up the genus Pipra. The mitochondrial and nuclear genomes both support six distinctive lineages.

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Large Amazonian rivers impede dispersal for many species, but lowland river networks frequently rearrange, thereby altering the location and effectiveness of river barriers through time. These rearrangements may promote biotic diversification by facilitating episodic allopatry and secondary contact among populations. We sequenced genome-wide markers to evaluate the histories of divergence and introgression in six Amazonian avian species complexes.

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Article Synopsis
  • - AVONET is a comprehensive dataset providing functional traits for all bird species, featuring data on ecological variables, morphological traits, and species' range sizes from over 90,000 individuals across 181 countries.
  • - The dataset includes both raw measurements and summarized species averages in multiple taxonomic formats, enabling integration with phylogenies, geographical maps, and conservation status information.
  • - AVONET aims to enhance research in evolutionary biology and ecology by offering detailed insights into biodiversity, facilitating the testing of theories and models related to global change.
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We assessed population structure and the spatio-temporal pattern of diversification in the Glossy Antshrike (Aves, Thamnophilidae) to understand the processes shaping the evolutionary history of Amazonian floodplains and address unresolved taxonomic controversies surrounding its species limits. By targeting ultraconserved elements (UCEs) from 32 specimens of . , we identified independent lineages and estimated their differentiation, divergence times, and migration rates.

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Several bird taxa have been recently described or elevated to full species and almost twice as many bird species than are currently recognized may exist. Defining species is one of the most basic and important issues in biological science because unknown or poorly defined species hamper subsequent studies. Here, we evaluate the species limits and evolutionary history of Tunchiornis ochraceiceps-a widespread forest songbird that occurs in the lowlands of Central America, Chocó and Amazonia-using an integrative approach that includes plumage coloration, morphometrics, vocalization and genomic data.

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Megascops is the most species-rich owl genus in the New World, with 21 species currently recognized. Phylogenetic relationships within this genus are notoriously difficult to establish due to the considerable plumage similarity among species and polymorphism within species. Previous studies have suggested that the widespread lowland Amazonian M.

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Background: Thamnophilidae birds are the result of a monophyletic radiation of insectivorous Passeriformes. They are a diverse group of 225 species and 45 genera and occur in lowlands and lower montane forests of Neotropics. Despite the large degree of diversity seen in this family, just four species of Thamnophilidae have been karyotyped with a diploid number ranging from 76 to 82 chromosomes.

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The tropics are the source of most biodiversity yet inadequate sampling obscures answers to fundamental questions about how this diversity evolves. We leveraged samples assembled over decades of fieldwork to study diversification of the largest tropical bird radiation, the suboscine passerines. Our phylogeny, estimated using data from 2389 genomic regions in 1940 individuals of 1283 species, reveals that peak suboscine species diversity in the Neotropics is not associated with high recent speciation rates but rather with the gradual accumulation of species over time.

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Target capture sequencing effectively generates molecular marker arrays useful for molecular systematics. These extensive data sets are advantageous where previous studies using a few loci have failed to resolve relationships confidently. Moreover, target capture is well-suited to fragmented source DNA, allowing data collection from species that lack fresh tissues.

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Article Synopsis
  • Scientists are studying bird genomes to learn more about their diversity and evolution, analyzing 363 bird genomes from nearly all bird families for a big project called Bird 10,000 Genomes (B10K).
  • By using advanced methods, they can compare DNA more effectively, finding new patterns and understanding how different bird species are related.
  • This research helps improve our understanding of how birds evolve and can also aid in protecting them in the future.
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