Biogeografia e conservação das Phyllomedusa (Anura, Hylidae) endêmicas de ilhas de altitude do Escudo Brasileiro

Abstract

The Brazilian Shield sky islands complex is distributed from the north of Rio Grande do Sul to the central region of Bahia, and is composed by several mountain chains mountains isolated from each other. The northern region of the system is constituting the boundary between the Cerrado, Atlantic Forest and Caatinga domains. These islands are dominated by campos rupestres, a rich ecosystem with a high endemism rate, and associated with quartzite, sandstone or ironstone outcrops, and poor soils. In this work, we evaluated the influence of geographic isolation on speciation and genetic structuration of populations. Therefore, we used an endemic frog species complex as model, including the formally described species Phyllomedusa ayeaye, P. centralis, and P. oreades. We found evidence of recent speciation with gene flow among these species, in addition to a cryptic lineage under the name P. oreades. This suggests that, although geological evidence points to campos rupestres as an ancient environment, climatic fluctuations of the Pleistocene may have influenced the diversification of part of its endemic biota. In addition, we also found genetic structuring in P. ayeaye, with three evolutionarily significant units associated with distinct mountain chains. This species is classified as "critically endangered" by the International Union for Conservation of Nature and our results point to the inefficacy of the national protected areas network in preserving it. These results suggest that geographic isolation is an important factor in the history of the diversification of campos rupestres, so it should be considered in scientific investigations and conservation planning.