Modelagem de distribuição e bioacústica de aves co-distribuídas em florestas úmidas da América do Sul

Abstract

The tropical rainforests of South America have a somewhat intriguing evolutionary history. Moments of expansion and retraction of these forests at different periods of time are suggested to be crucial for species dispersal, extinction, and speciation events. Studies with numerous taxa co-distributed between the Amazon and Atlantic Forest, and the existence of forest refugia, such as the Brejos de Altitude, in the middle of the Caatinga demonstrate the existing similarity between these forests and evidence a past and recurrent forest connectivity between the biomes. Routes through which such connections between forests have occurred have been proposed for a better understanding of their historical dynamics. In the present research, we predicted, through distribution modeling and analysis of vocal characters of different bird species co-distributed in the Amazon, Atlantic Forest and in fragments of these forests along the Cerrado and Caatinga (Brejos de Altitude), biogeographic connections between the biomes during the Last Glacial Maximum (UMG - 21 thousand years - Ka). In addition to identifying past connections, this study sought to understand how climate changes that occurred from the UMG into the future may influence the distribution of species. To do so, potential distribution models were built in different scenarios, being past (UMG-21Ka, Holocene-6Ka), Present (1970-2000) and Future (2070); and vocal parameters of suboscine and oscine species were analyzed. Modeling results for the UMG identified connections between Amazon and Atlantic Forest through the southernmost regions of the country, supporting the SE-NW route, and through Caatinga, via the NE route. Both connection routes may have played an important role in the dispersal of taxa between the biomes. Vocal analysis found no difference between the vocalizations of the species and the different environments, thus suggesting recent connections between forests and contact between populations so that the time of separation between Amazon and Atlantic Forest was not enough to distinguish them vocally. For the future, the models indicate shrinking areas suitable for the occurrence of the species. This result serves as a warning for actions aimed at the conservation of biomes and birds that occur in forest environments.