Gradient in avian species richness in the Himalayas

• Applicant: Dr. Dieter Thomas Tietze
• Subject Area: Evolution, Anthropology
• Term: from 2008 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 84845609

Causes for the considerable variation in species diversity around the globe are subject of much debate. Recently, so-called historical hypotheses have been given renewed prominence because they can be tested using dated molecular phylogenies. In such hypotheses adaptation to the warmer, moister climatic conditions of the globe over long time spans have resulted in relatively few species which have been able to adapt to colder, drier regions. This hypothesis can be tested using molecular phylogenies by asking how often species from warmer, moister regions have split off new species into colder, drier regions. I propose to use this approach to ask why the number of passerine bird species in the southeastern Himalayas is more than twice the number than that in the northwestern part. All passerine species (about 300) that breed above 2000 m (i. e. in the largely undisturbed upper part of the mountains) will be studied. I will estimate phylogenetic relationships among the study species and the ages of species and clades. I will also use ecological data to assess historical causes for the fading out of species numbers. Under the historical hypothesis, dispersal into the colder, drier northwestern habitats is difficult due to less finely subdivided niches, so extension to the northwest of the Himalayas should have occurred relatively rarely. Further I will ask, whether species occupying colder, drier habitats in the southeast (or close relatives of these species) do preferentially occur in the northwest.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Trevor Price