The Development of the Amazonian Mega‐Wetland (Miocene; Brazil, Colombia, Peru, Bolivia)

Aim To evaluate the role of historical processes in the evolution of Sclerurus leaftossers by integrating phylogenetic and phylogeographical approaches. Location Humid forests of the Neotropical region. Methods We reconstructed the evolutionary history of Sclerurus based on DNA sequences representing all species and 20 of the 26 recognized subspecies using one autosomal nuclear locus and three protein‐coding mitochondrial gene sequences. Phylogenetic relationships were inferred using Bayesian and maximum‐likelihood methods. We used Bayesian coalescent‐based approaches to evaluate demographic changes through time, and to estimate the timing of diversification events. Based on these results, we examined the temporal accumulation of divergence events using lineage‐through‐time plots. Results The monophyly of all Sclerurus species was strongly supported except for Sclerurus mexicanus, which was paraphyletic in relation to Sclerurus rufigularis, and for the sister pair Sclerurus scansor–Sclerurus albigularis, which were not reciprocally monophyletic in the nuclear tree. We found remarkably deep phylogeographical structure within all Sclerurus species, and overall this structure was congruent with currently recognized subspecies and Neotropical areas of endemism. Diversification within Sclerurus has occurred at a relatively constant rate since the Middle Miocene. Main conclusions Our results strongly support the relevance of physiographical (e.g. Nicaragua Depression, Isthmus of Panama, Andean Cordillera, great rivers of Amazonia) and ecological barriers (open vegetation corridor) and ecological gradients (elevational zonation) to the diversification of Neotropical forest‐dwelling organisms. Despite the high congruence among the spatial patterns identified, the variance in divergence times suggests multiple speciation events occurring independently across the same barrier, and a role for dispersal. The phylogenetic patterns and cryptic diversity uncovered in this study demonstrate that the current taxonomy of Sclerurus underestimates the number of species.

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“…Recent studies have shed new light on the processes of landscape change in Amazonia since the Miocene (Hoorn et al. , 1995, 2010; Rossetti et al.…”

Section: Discussionmentioning

confidence: 99%

“…Marine incursions during the Miocene (Räsänen et al. , 1995), as well as the development of a mega‐wetland system in western Amazonia during the Early to Middle Miocene, caused by the Andean uplift (Hoorn et al. , 2010), would have isolated three regions of Amazonia (Bates, 2001; Aleixo & Rossetti, 2007): GUY, BS and BAN (Fig.…”

Section: Discussionmentioning

confidence: 99%

Phylogeny and comparative phylogeography of Sclerurus (Aves: Furnariidae) reveal constant and cryptic diversification in an old radiation of rain forest understorey specialists

d’Horta

Cuervo

Ribas

et al. 2012

Journal of Biogeography

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“…We would expect this distinct environment to lead to both parapatric and allopatric speciation, as has been shown for white-sand forests in both plant and bird communities (Fine et al 2004, Fine and Kembel 2011, Fine and Baraloto 2016. Wetland swamp habitats have occurred at least intermittently in western Amazonia since the early Miocene, although their permanence on the landscape remains unclear (Hoorn 1994, Hoorn et al 2010a. white-sand forests in western Amazonia, 114 endemic trees species (Fine et al 2010); Amazonian white water seasonally-flooded forests, 68 endemic tree species (Wittmann et al 2013); SE Asian peatland forests, 172 endemic tree species (Posa et al 2011)).…”

Section: Endemism In Peatlandsmentioning

confidence: 91%

Peatland forests are the least diverse tree communities documented in Amazonia, but contribute to high regional beta‐diversity

et al. 2018

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Western Amazonia is known to harbour some of Earth's most diverse forests, but previous floristic analyses have excluded peatland forests which are extensive in northern Peru and are among the most environmentally extreme ecosystems in the lowland tropics. Understanding patterns of tree species diversity in these ecosystems is important both for quantifying beta-diversity in this region, and for understanding determinants of diversity more generally in tropical forests. Here we explore patterns of tree diversity and composition in two peatland forest types -palm swamps and peatland pole forests -using 26 forest plots distributed over a large area of northern Peru. We place our results in a regional context by making comparisons with three other major forest types: terra firme forests (29 plots), white-sand forests (23 plots) and seasonally-flooded forests (11 plots).Peatland forests had extremely low (within-plot) alpha-diversity compared with the other forest types that were sampled. In particular, peatland pole forests had the lowest levels of tree diversity yet recorded in Amazonia (20 species per 500 stems, Fisher's alpha 4.57). However, peatland pole forests and palm swamps were compositionally different from each other as well as from other forest types in the region. Few species appeared to be peatland endemics. Instead, peatland forests were largely characterised by a distinctive combination of generalist species and species previously thought to be specialists of other habitats, especially white-sand forests.We suggest that the transient nature and extreme environmental conditions of Amazonian peatland ecosystems have shaped their current patterns of tree composition and diversity. Despite their low alpha-diversity, the unique combination of species found in tree communities in Amazonian peatlands augment regional beta-diversity. This contribution, alongside their extremely high carbon storage capacity and lack of protection at national level, strengthens their status as a conservation priority.

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“…Third, the only known highland populations of Manicaria are found in the Guiana Shield, reaching up to 1,225 m. Fourth, dichotomously branched stems in palms (like those of trans‐Andean populations of Manicaria ) are considered derived from unbranched stems like those in Amazonian and other cis‐Andean populations (Fisher & Maidman, ). Our results from the dated Manicaria phylogeny suggest that the species originated along the Atlantic coast, dispersed into Amazonia and likely became isolated from the coastal populations after the embayment retreated and transformed into the Amazon fluvial system (‘Acre System’ in the sedimentary record; Figure ; Hoorn, Wesselingh, Hovikoski, et al., ).…”

Section: Molecular Phylogeneticsmentioning

confidence: 74%

Could coastal plants in western Amazonia be relicts of past marine incursions?

Bernal

Bacon

Balslev

et al. 2019

Journal of Biogeography

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The rainforests of Amazonia comprise some of the most biologically diverse ecosystems on Earth. Despite this high biodiversity, little is known about how landscape changes that took place in deep history have affected the assembly of its species, and whether the impact of such changes on biodiversity can still be observed. Here, we present a hypothesis to explain our observation that plants typical of Neotropical coastal habitats also occur in western Amazonia, in some cases thousands of kilometres away from the coast. Evidence on their current distribution, dispersal biology and divergence times estimated from molecular phylogenies suggest that these plants may be the legacy of the large marine‐influenced embayment that dominated the area for millions of years in the Neogene. We hypothesize that coastal plants dispersed along the shores of this embayment and persisted as inland relicts after the marine incursion(s) retreated, probably with the aid of changes in soil conditions caused by the deposition of marine sediments. This dispersal corridor may also have facilitated the colonization of coastal environments by Amazonian lineages. These scenarios could imply an unexpected coastal source that has contributed to Amazonia's high floristic diversity and led to disjunct distributions across the Neotropics. We highlight the need for future studies and additional evidence to validate and shed further light on this potentially important pattern.

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The Development of the Amazonian Mega‐Wetland (Miocene; Brazil, Colombia, Peru, Bolivia)

Cited by 67 publications

References 67 publications

Phylogeny and comparative phylogeography of Sclerurus (Aves: Furnariidae) reveal constant and cryptic diversification in an old radiation of rain forest understorey specialists

Phylogeny and comparative phylogeography of Sclerurus (Aves: Furnariidae) reveal constant and cryptic diversification in an old radiation of rain forest understorey specialists

Peatland forests are the least diverse tree communities documented in Amazonia, but contribute to high regional beta‐diversity

Could coastal plants in western Amazonia be relicts of past marine incursions?

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