The effects of climate change on the distribution of South American antbirds (Thamnophilus punctatus complex) as affected by niche divergences and contact zone interactions between species

Several studies have shown that climatic changehas been accelerating due to human activities, leading to dramatic effects on biodiversity. Modeling studies describe how species have reacted in the past to climatic change, and this information can help us to understand the degree of biotic susceptibility to current and future climatic change. This work aims to determine the effects of past, current and future climatic changeson the geographic distribution of the species complex Thamnophilus punctatus, a bird clade widely distributed across Neotropical dry forests. We also investigate if species that are phylogenetically similar have comparable climatic nichesand, consequently, can be expected to respond similarly to climatic change. For this purpose, we calculated similarity, nicheoverlap, equivalence and genetic distance between all species, modeling their geographic distributions during the Last Glacial Maximum(LGM) as well as under current conditions and future (2050–2080) scenarios. Our results indicate that there are differences in responses to climatic changesfrom the LGM to the present among the five species of the T. punctatus complex and that the nichesin the measured dimensions are not conserved among the studied species. We therefore suggest that the adequate environmental space of taxa of a widely distributed lineage can be shaped in distinct way, regardless of how closely related their species are or how much their nichesoverlap. Competitive exclusion in zones of contact is an important factor determining the geographical range of the species of the Thamnophilus punctatuscomplex, particularly for the very closely related species T. sticturus, T. pelzelni and T. ambiguus.