Biogeography and evolution of the Cerrado endemic avifauna

Aim

Endemicity is one of the main indicators to describe and compare regional biotas. Endemic species can originate from inter- or intra-regional speciation, but few studies have measured the relative contribution of these two mechanisms in the assembly of regional biotas. We investigated the relative contributions of inter- and intra-regional speciation in assembling the endemic avifauna of the Cerrado, the largest South American savanna region. We also tested hypotheses about the relationships between habitat preferences with range size and evolutionary age, as well as whether the biogeographical relationships between the Cerrado and neighbouring regions are randomly distributed around the region.

Location

Cerrado, central South America.

Taxon

Birds.

Methods

We used distributional and phylogenetic data of Cerrado endemic birds.

Results

The proportion of endemic species in the Cerrado region is relatively low, when compared to other organisms living in the same region. Furthermore, we found that inter-regional speciation is the primary factor promoting bird endemism in the Cerrado and that sister species of Cerrado endemics are concentrated in northwestern (forest species) and southwestern (nonforest species) South America. We also found that nonforest endemic bird species do not necessarily have larger geographical ranges than forest endemic species; however, nonforest endemic species are evolutionarily older than forest species.

Main conclusions

The assembly of the Cerrado endemic avifauna is complex and idiosyncratic. The intricate history of the Cerrado endemic avifauna suggests that it is constantly exchanging species with its neighbouring regions. Due to its high ecological heterogeneity, the Cerrado ecosystems are capable of harbouring populations of both endemic and non-endemic species acquired during periods of significant biotic exchange.