The historical connections between the Amazon and the Atlantic Forest revisited

Abstract

Aim: To assess ancient biotic connections between the Amazon Forest (AmF) and the Atlantic Forest (AtF) based on environmental niche modelling (ENM), palaeobiological, and molecular evidence; to test Por (1992)'s hypothesis of the south-eastern -north-western (SE-NW) route as the most important route in terms of frequency and duration; to evaluate past climatic conditions associated with the routes.Location: South America. Methods:We generated random points in climate space of AmF and AtF and identified two major climatic groups in the shared environmental space (colder and warmer) with a K-means cluster analysis. We modelled each climatic group using eleven algorithms of ENM and selected the best model, projecting the results back to 120 ka. We used published data on South American palaeopalynology, speleothem and travertine chronology for model validation. We also accessed vertebrate molecular studies and extracted the split timing of lineages distributed both in the AmF and the AtF to test Por (1992)'s hypothesis in more ancient times.Results: Palynological and speleothem studies supported the results of our ENM models, indicating expansion of cold-adapted species along the SE-NW and NE routes in the LGM. The SE-NW route was also supported in the LIG, however, involving warm-adapted species. Our results support Por (1992)'s hypothesis and suggest that the SE-NW was established more than once in the past, involving different plant communities each time, adapted to different temperature conditions. Vertebrate molecular studies also support Por (1992)'s hypothesis and suggest that the SE-NW route was established since the Andean uplift. Main Conclusions: The SE-NW route is the most ancient connection route between the AmF and the AtF and probably was established since the Andean uplift and the formation of the South American monsoon system. This route was established many times in the past, alternating by the distribution expansion of coldadapted and warm-adapted plant communities. Educac ßão, Ciência e Tecnologia de Bras ılia. He is interested in biogeography, ecology, phylogeography and conservation, with emphasis in reptiles. This work is the result of his doctoral dissertation and is part of the efforts of the research group led by Guarino R. Colli to uncover patterns and processes associated with the diversification of the herpetofauna of South American open biomes, especially the Cerrado. SUPPORTING INFORMATIONAdditional Supporting Information may be found online in the supporting information tab for this article.How to cite this article: Ledo RMD, Colli GR. The historical connections between the Amazon and the Atlantic Forest revisited.

Contrasting evolutionary histories in Neotropical birds: Divergence across an environmental barrier in South America

“…We found signs of population expansion of P. m. melanonota within the Atlantic Forest, which is congruent with previous reports for other forest specialists that inhabit this region (e.g. Cabanne, D'Horta, Sari, Santos, & Miyaki, ; Harvey & Brumfield, ; Lavinia et al, ; Trujillo‐Arias et al, ), and is probably the consequence of Pleistocene climatic oscillations that altered the spatial coverage of the Atlantic Forest (Ledo & Colli, ; Ribas, Maldonado et al, ; Sobral‐Souza, Lima‐Ribeiro, & Solferini, ). By contrast, our results suggest population stability within the Andes region, in agreement with what has been reported for other Andean and western Amazonian taxa and indicating that forests from the west side of the continent might have been more stable than their eastern counterparts (Cheng et al, ; Ribas, Aleixo et al, ; Sobral‐Souza et al, ; Trujillo‐Arias et al, ), with the exception of the high Andes, where Pleistocene climatic cycles had a more direct and profound effect (Weir, ).…”

Avian host composition, local speciation and dispersal drive the regional assembly of avian malaria parasites in South American birds

“…Amazonia was recovered as the main source of parasite lineage dispersal into the Caatinga (the driest region) and Andean‐Patagonian Forest as well, despite a lack of current connection between Amazonia and these two regions. A high level of Plasmodium dispersal from Amazonia into the Atlantic Rain Forest was observed, which concurs with several studies on vertebrates that suggest periodic contact between these biomes since the Miocene (Costa, ; Batalha‐Filho, Fjeldså, Fabre, & Miyaki, ; Ledo & Colli, ). The high level of Plasmodium lineage dispersal from the Atlantic Rain Forest to the Peruvian Andes is remarkable considering the geographical distance and isolation between these two regions.…”

Isolation by instability: Historical climate change shapes population structure and genomic divergence of treefrogs in the Neotropical Cerrado savanna

“…Hypsiboas lundii mostly occurs in gallery forests, the most mesic habitat of the Cerrado savanna, and its response might be only representative of organisms in this environment. Ledo and Colli (), for example, showed that LGM favoured the expansion of forest habitats allowing a connection between the Atlantic Forest and the Amazon through a southeast‐northwest route. The gallery forests in the Cerrado might have followed this pattern, given that our LGM model was also more widespread towards the western Cerrado.…”