Palaeodistribution of epiphytic bromeliads points to past connections between the Atlantic and Amazon forests

Abstract

The disjunct geographical distributions of species between the Amazon and Atlantic forests have been used as evidence of past connections through the interior of north-eastern Brazilian as a result of climate fluctuations. Here we test this hypothesis for the first time using plant species with disjunct geographical distributions and ecological niche modelling. We generated ecological niche models for two Aechmea spp. using two different modelling methods. These models were projected onto mid-Holocene and Last Interglacial climate scenarios and the results were calculated for each species separately. Our results show that the connection between the Amazon and Atlantic forests was along the coastal region of north-eastern Brazil. This result contradicts the currently most widely accepted paradigm explaining the biogeographic connections between the Amazon and Atlantic forests through non-coastal forest formations. Our results are supported by molecular records of several other biological groups and with recently re-evaluated floristic studies. However, the variations found in our analyses highlight the fact that different species can show distinct biogeographic histories, reinforcing the importance of species-specific analyses in palaeodistribution modelling.