Temperature differentially mediates species richness of birds of different biogeographic types

Climate is one of the most important factors determining the distribution of avian species richness (e.g. Rahbek & Graves 2001) by its effect on primary production (van Rensburg et al. 2002, Chown et al. 2003, Hurlbert & Haskell 2003), and by its interaction with physiological requirements and tolerances of species (Turner et al. 1988, Woodward & Kelly 2003). Factors determining species richness are not universal, but vary among taxa (e.g. Miller et al. 2003). This is because the distribution of species is mediated by their ecological niche (Pulliam 2000, Wiens & Donoghue 2004), and groups of species differentiated by their taxonomy, behaviour, or physiology can have a shared or convergent evolution, responding differentially to certain factors which interact with the necessities imposed by their niche. Knowledge on the way how climate affects the distribution of avian species richness is of prime importance as the Earth is under a climatic warming (IPCC 2001). This climatic change is already affecting bird distribution (Thomas & Lennon 1999), and dramatic changes in the distribution of birds are predicted (Huntley et al. 2006). Short notes