Abstract:
Historical climate and landscape features are important mechanisms that can drive genetic differentiation of lineages. Habitat shifts between forested and open environments during the Quaternary Period contributed substantially to regional diversity in Amazonia and other South American environments. Herein, we used a widely distributed frog species in the Guiana Shield to assess whether the species’ spatiotemporal dynamics are related to historical climate changes and other regional landscape features. For that, we used ecological niche models (ENMs) and phylogeographical analyses with a single-locus approach (mitochondrial DNA). We found two genetic clusters spatially structured along the Guiana Shield, with some degree of overlap and low genetic diversity. Part of the genetic differentiation was attributed to spatial distances. Population structure did not match to any strong vicariant barrier that could completely preclude gene flow. However, ENMs detected large unsuitable climatic areas for current and historical periods that likely restricted the dispersion of populations. The divergence time of clusters was relatively recent, dating from the middle-to-late Pleistocene, a period of intense climate oscillations. Although such historical changes seem to have influenced the spatial distribution of the species genealogies, demographic analyses suggested that populations were stable from the Late Pleistocene. Climate shifts may have shaped the patterns of gene flow by reducing or increasing connectivity of populations, depending on the period.