Modelagem de distribuição e variação vocal do bacurauzinho, Nannochordeiles pusillus (Aves: Caprimulgidae), em diferentes biomas neotropicais

Abstract

The Bacurauzinho, Nannochordeiles pusillus, has a wide distribution in areas with open vegetation and occurs in different phytophysiognomies such as Cerrado, Caatinga and Pantanal. However, the evolutionary history, genetic and phenotypic differentiation of the group is still not well understood, and thus there is no consensus regarding the number of subspecies existing for the taxon. Our recent, unpublished studies based on mitochondrial and genomic DNA sequencing data suggest that there are two morphologically distinct lineages in N. pusillus separated about 2 million years ago. One of these lineages has a distribution in open vegetation areas in the Amazon, known as Campinas, and has the plumage of the subcaudal region with black bars, while the other lineage has a circum-Amazonian distribution and has white subcaudal plumage. Thus, the present work aimed to analyze whether there are differences in potential distribution in different periods (past, present and future) and whether there are differences in song between the two lineages of the nighthawk. For this, we used the distribution modeling, in which occurrence points and maps of environmental variables are combined to create distribution models. To investigate the variation of vocalizations in the species, initially a survey of singing data was carried out on online platforms and after a screening different parameters were used, with frequency being the main parameter analyzed. The results obtained corroborate the existence of two lineages, and reinforce that the two lineages should be recognized as full species, since they present morphological differences, high genetic and vocal divergence, in addition to having a parapatric distribution in different phytophysiognomies. The bioacoustics data determine that the Amazon lineage has a slower song with a greater number of phrases, in addition to the frequency being lower when compared to the circum-Amazonian lineage, and the N. pusillus lineage circum-Amazonian has a faster song and with higher frequency. Regarding distribution modeling, the circumAmazonian lineage is more generalist, occurs in different open vegetation biomes and may not be affected by climate change, but benefited, while the Amazon lineage is a specialist in the Amazonian grasslands and may suffer population reduction. due to loss of habitat by climate change. In addition to resolving taxonomic uncertainties, the present work contributes to the adoption of conservation policies, since in addition to the Amazon lineage, other species are endemic to the campinas and these areas are not within the Conservation Units (UC's) of integral protection, thus, the present work contributes for these to be defined as priorities to avoid the loss of biological diversity endemic to the campinas as a result of climate change.