My main interests are on patterns of species diversity in the Himalaya, and evolution of coloration.
Species diversity: working with collaborators Dr. Dhananjai Mohan of the Wildlife Institute of India and Dr. Pratap Singh, recently retired from the Indian Forest Service, we study distributions of birds across the Himalaya. Why are there more species in the east Himalaya than the west Himalaya, and why, in the east, are there more at mid-elevations? We have compiled evidence for both resources and competition, and historical effects, such as past ice ages in affecting species distributions. Working with former graduate student, Drs. Alex White, and Suresh Rana (G.B. Pant National Institute of Himalayan Environment) we are now extending these studies to plants, using new methods we have developed to assess how species are co-distributed.
Picture from N. I. Bloch, T. D. Price and B. S. W. Chang. (2015) Evolutionary dynamics of Rh2 opsins in birds demonstrate an episode of accelerated evolution in the New World warblers (Setophaga). Molecular Ecology 24: 2449–2462
Color vision in birds. Birds have four cone classes that enable excellent color vision, and can see UV light. Different cones classes contain different visual pigments, which consist of an opsin protein bound to a light-sensitive chromophore. The sequence of the opsin protein determines the wavelength of maximum absorbance. Natasha Bloch and I discovered that, across species, one particular opsin (the one tuned to “blue” light) correlates with the light environment. Species that live in the open, where there is more blue light have this opsin tuned to shorter wavelengths than those that live in the forest, where blue light is filtered out. We are pursuing this result by asking if these differences affect color perception, and eventually, the evolution of bird coloration. To do this we are focusing on bird species that vary greatly in habitat occupied and their color.
As a whole, the lab investigates the following broad research themes, generally focusing on but not limited to birds: speciation and biodiversity; phylogenetics and genomics; species range shifts, dispersal, and migration; conservation and climate change; behavioral ecology and phenotypic plasticity; & color vision evolution. Please see personal websites (linked from the People page) and check out our publications for more details.