Geomorphology of fluvial deposits in the middle Tocantins River, eastern Amazon

Jesus, Jandessa Silva de; Pupim, Fabiano do Nascimento; Sawakuchi, André Oliveira; Felipe, Leonardo Brasil

doi:10.1080/17445647.2020.1822938

Cited by 6 publications

(11 citation statements)

References 52 publications

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“…Other widespread floodplain-associated Amazonian lineages exhibiting significant genetic differentiation in the Tocantins drainage are the river dolphins of the genus Inia (Hrbek et al, 2014) and the Arapaima fishes (Nogueira et al, 2020). Details on the dynamics of past connections between the Tocantins and the Amazon´s floodplains have yet to be clarified, but the Tocantins floodplain is known to have had a very recent dynamic history and high loads of Quaternary sediments (Jesus et al, 2020), which have impacted the extent and distribution riverine-created habitats.…”

Section: Historical Demographic Inferencementioning

confidence: 99%

Genomic differentiation with gene flow in a widespread Amazonian floodplain‐specialist bird species

Luna

Ribas

Aleixo

2021

Journal of Biogeography

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Aim: Ecological, climatic and palaeogeographical processes drive biological diversification. However, the evolutionary outcomes of those mechanisms are complex and difficult to discriminate. Here, we test how alternative drivers affected connectivity along the Amazonian floodplains generating current patterns of population structure and diversity within the Striped Woodcreeper, a widespread bird species tied to forests seasonally flooded by Amazonian rivers.Location: Amazonian floodplains.Taxon: Xiphorhynchus obsoletus (Aves, Furnariidae). Methods:We sequenced 2213 loci of ultraconserved elements (UCEs) and 20 exons to investigate patterns of genetic structure and connectivity across the Striped Woodcreeper distribution, using a set of spatially explicit methods. Population genetics statistics were calculated for each sampled drainage and within each identified cluster. We tested alternative evolutionary scenarios and estimated past and current demographic parameters implementing a simulation-based framework.Results: Three genetic clusters with high admixture proportions were identified.These clusters are distributed in the western, central and eastern parts of the Amazon Basin and are not correlated with different river water types representing ecological gradients along the floodplains. Instead, migration rates indicate two putative historical barriers along the main channel of the Amazonas-Solimões River. Demographic model tests suggest a process of sequential differentiation, partitioned across the Amazon Basin, with stable population sizes and continuous gene flow. Main conclusion:Our results support the hypothesis that late Quaternary changes in connectivity between the eastern and western Amazonian drainages were responsible for driving genetic differentiation in the Striped Woodcreeper. Genomic differentiation occurred in the presence of long-term gene flow throughout the X. obsoletus distribution, suggesting some degree of continuous historical connectivity across Amazonian floodplains. Compared to previous studies, our results suggest that although connectivity among populations of Amazonian bird species specialized in floodplain habitats varies in response to the same abiotic mechanisms, speciesspecific differences in habitat use may be a strong predictor of population divergence.

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Section: Historical Demographic Inferencementioning

confidence: 99%

Genomic differentiation with gene flow in a widespread Amazonian floodplain‐specialist bird species

Luna

Ribas

Aleixo

2021

Journal of Biogeography

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“…Future work explicitly testing pulse migration versus continuous migration models of gene flow may help clarify the relative contributions of these two nonmutually exclusive mechanisms. Nevertheless, the explicit assumption of the framework presented here is that the underlying lowland riverine landscape is not stable, which has also been confirmed, for instance, on the easternmost Amazonian part of the Brazilian Shield (66,67). Within this conceptual framework, drainage network evolution is a simple solution to the question of how secondary contact occurs between differentiated taxa that are otherwise isolated by rivers.…”

Section: Limitations and Future Directionsmentioning

confidence: 63%

River network rearrangements promote speciation in lowland Amazonian birds

et al. 2022

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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. We first tested the assumption that rivers are barriers for these taxa and found that even relatively small rivers facilitate divergence. We then tested whether species diverged with gene flow and recovered reticulate histories for all species, including one potential case of hybrid speciation. Our results support the hypothesis that river rearrangements promote speciation and reveal that many rainforest taxa are micro-endemic, unrecognized, and thus threatened with imminent extinction. We propose that Amazonian hyper-diversity originates partly from fine-scale barrier displacement processes—including river dynamics—which allow small populations to differentiate and disperse into secondary contact.

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“…Moreover, because we do not explicitly test pulse-migration versus continuous-migration models of gene flow, the process of happenstance dispersal across stable barriers may be difficult to distinguish from a barrier displacement model in practice. However, the explicit assumption of the framework presented herein is that the underlying lowland riverine landscape is not stable, which has also been confirmed, for instance, on the easternmost Amazonian part of the Brazilian Shield (71,72).…”

Section: Limitations and Future Directionsmentioning

confidence: 52%

River network rearrangements promote speciation in lowland Amazonian birds

Musher

Giakoumis

Albert

et al. 2021

Preprint

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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 histories of divergence and introgression in six Amazonian avian species-complexes. We first tested the assumption that rivers are barriers for these taxa and found that even relatively small rivers facilitate divergence. We then tested whether species diverged with gene flow and recovered reticulate histories for all species, including one potential case of hybrid speciation. Our results support the hypothesis that river dynamics promote speciation and reveal that many rainforest taxa are micro-endemic, unrecognized and thus threatened with imminent extinction. We propose that Amazonian hyper-diversity originates in part from fine-scale barrier displacement processes –including river dynamics– which allow small populations to differentiate and disperse into secondary contact.

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Geomorphology of fluvial deposits in the middle Tocantins River, eastern Amazon

Cited by 6 publications

References 52 publications

Genomic differentiation with gene flow in a widespread Amazonian floodplain‐specialist bird species

Genomic differentiation with gene flow in a widespread Amazonian floodplain‐specialist bird species

River network rearrangements promote speciation in lowland Amazonian birds

River network rearrangements promote speciation in lowland Amazonian birds

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