Critical areas for retaining multiple dimensions of bird diversity in the Cerrado

Abstract

The taxonomic, phylogenetic, and functional components of diversity in communities show different spatial patterns that respond to climate and land-use change and are geographically convergent, i.e., areas with high species richness usually hold very different evolutionary lineages. The opposite – known as biotic homogenization – can also occur, which means that some sites end up concentrating closely related lineages or species that perform very similar roles in the system. Here, we assessed current relationships among the taxonomic, phylogenetic, and functional diversity components. We also analyzed how expected climate and land-use changes may alter such patterns in bird communities inhabiting the Cerrado. For this, we assessed the species range exposure to climatic variables and land use between the current period and 2050. We considered that the species would no longer occur in sites in their range where the climatic conditions in 2050 would exceed the limits currently tolerated and simultaneously lose native vegetation. In general, we found a high spatial incongruency among the three diversity components. We found that the higher the number of species in a site, the higher the number of different lineages it shelters. However, sites containing many species do not necessarily have more functional traits. We also found that due to climate changes and land use, only a small set of areas is expected to lose several bird species, while most Cerrado will lose few. Because of such expected species loss, bird communities might become more clustered in the future – both phylogenetically and functionally – and only a few areas will simultaneously safeguard this group's phylogenetic and functional diversity components.