Insights into the origin and distribution of biodiversity in the Brazilian Atlantic
forest hot spot: a statistical phylogeographic study using a low-dispersal organism |
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Authors: | M álvarez-Presas A Sánchez-Gracia F Carbayo J Rozas M Riutort |
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Institution: | 1.Departament de Genètica and Institut
de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Spain;2.Laboratório de Ecologia e
Evolução, Escola de Artes, Ciências e Humanidades, Universidade de
São Paulo, São Paulo, Brazil |
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Abstract: | The relative importance of the processes that generate and maintain biodiversity is a
major and controversial topic in evolutionary biology with large implications for
conservation management. The Atlantic Forest of Brazil, one of the world''s richest
biodiversity hot spots, is severely damaged by human activities. To formulate an efficient
conservation policy, a good understanding of spatial and temporal biodiversity patterns
and their underlying evolutionary mechanisms is required. With this aim, we performed a
comprehensive phylogeographic study using a low-dispersal organism, the land planarian
species Cephaloflexa bergi (Platyhelminthes, Tricladida). Analysing multi-locus
DNA sequence variation under the Approximate Bayesian Computation framework, we evaluated
two scenarios proposed to explain the diversity of Southern Atlantic Forest (SAF) region.
We found that most sampled localities harbour high levels of genetic diversity, with
lineages sharing common ancestors that predate the Pleistocene. Remarkably, we detected
the molecular hallmark of the isolation-by-distance effect and little evidence of a recent
colonization of SAF localities; nevertheless, some populations might result from very
recent secondary contacts. We conclude that extant SAF biodiversity originated and has
been shaped by complex interactions between ancient geological events and more recent
evolutionary processes, whereas Pleistocene climate changes had a minor influence in
generating present-day diversity. We also demonstrate that land planarians are an
advantageous biological model for making phylogeographic and, particularly, fine-scale
evolutionary inferences, and propose appropriate conservation policies. |
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Keywords: | Approximate Bayesian Computation biodiversity hot spots coalescent simulation conservation policies land planarian Tricladida |
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