Post-Eocene climate change, niche conservatism, and the latitudinal diversity gradient of New World birds

The latitudinal diversity gradient is one of the most important problems in ecology and biogeography, but there is little consensus on its causes. Broad-scale species richness gradients are usually correlated with contemporary climate, with the highest number of species in warm, wet areas (Wright et al., 1993; Hawkins et al., 2003a). Even so, such associations do not Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, USA, Departamento de Biologia Geral, ICB, Universidade Federal de Goiás, CP, Goiânia, and Departamento de Biologia, MCAS/ PROPE, Universidade Católica de Goiás, Goiânia, GO, Brazil, Center for Tropical Paleoecology and Archeology, Smithsonian Tropical Research Institute, Balboa, Panama and Network & Academic Computing Services, University of California, Irvine, CA, USA